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Energy payback time (EPBT) and energy return on energy invested (EROI) of solar photovoltaic systems: A systematic review and meta-analysis
... Starting from high-purity solar-grade silicon, the production process varies according to the technology (monocrystalline and polycrystalline). An estimate of the energy spent in the silicon manufacturing process is given in [16,17]. From this study, we took the average of the reported data, obtaining 5476.1 MJ/m 2 for monocrystalline (mono-Si) production and 4676.1 MJ/m 2 for polycrystalline (poly-Si) manufacturing. ...
... For example, the energy needed to produce a solar panel depends both on its surface and on the employed technology (mono-Si or poly-Si). Due to the heterogeneity of the components involved and the different production processes, we employ the following average values extracted from [16,17,20]: The energy U d i spent for the utilization of the devices during their operation life is estimated with Equation (6): ...
... As we have seen in the previous section, solar panel and battery are the essential components for an energy harvesting system. Other elements can be introduced and their energy consumption can be considered in the design by adding their efficiency in the denominator of Equation (16). ...
The Internet of Things (IoT) is demonstrating its huge innovation potential, but at the same time, its spread can induce one of highest environmental impacts caused by the IoT industry. This concern has motivated the rise of a new research area aimed at devising green IoT deployments. Our work falls in this research area by contributing to addressing the problem of assessing the environmental impact of IoT deployments. Specifically, we propose a methodology based on an analytical model to assess the environmental impact of an outdoor IoT deployment powered by solar energy harvesting. The model inputs the specification of the IoT devices that constitute the deployment in terms of the battery, solar panel and electronic components, and it outputs the energy required for the entire life-cycle of the deployment and the waste generated by its disposal. Given an existing IoT deployment, the models also determine a functionally equivalent baseline green solution, which is an ideal configuration with a lower environmental impact than the original solution. We validated the proposed methodology by means of the analysis of a case study conducted over an existing IoT deployment developed within the European project RESCATAME. In particular, by means of the model, we evaluate the impact of the RESCATAME system and assess its impact with respect to its baseline. In a scenario with a 30-year lifespan, the model estimates for the system more than 3 times the energy required by its baseline green solution and a waste for a volume 15 times greater. We also show how the impact of the baseline increases when assuming deployments in locations at increasing latitudes. Finally, the article presents an implementation of the proposed methodology as a web service that is publicly available.
... LCOE explains PV technologies' cost-performance evaluations (cost per kWh, against lifetime) beyond energy payback potential. 111 The PCE of PSMs with assembling and installation costs and a module's lifetime decide the LCOE. PSM's expansion to the GW scale requires consideration of any fundamental constraints that might be characteristic for a given technology, such as raw-materials availability or large-scale coating of thin film, which may provide operational stability for general devised applications. ...
... Several studies regarding the cost-performance analysis for PSMs presented cost models based on different hypothesized device stacks and production line flows. 111,254,255 These studies posed the cost advantages of PSMs over other PV technologies. 256 Besides operational stability and efficiency, manufacturing PSM costs are also considered a crucial factor. ...
... PCE versus PSM area statistics against the large-area coating techniques International Summit on Organic and Hybrid Photovoltaic Stability [ISOS])109,110 and making them efficient enough for large-area modules are two major hindrances to commercialization. The instability of PSCs against moisture, oxygen, light, and temperature limits the lifetime of PSCs to a fraction of the warranty lifetime (often >25 years).3,111,112 Recently, reputable progress has been made to enhance the stability of PSCs over 1,000 h (for lab-scale cells) through tailored interface113 and meticulous Pb leakage 114 and over 2,000 h (for modules of areas of 22.4 cm 2 ) through interface stabilization, 75 but significant advances are needed to lift this technology to a level where it is ready to compete with other PV technologies. ...
Perovskite solar cells (PSCs) have a comparable performance to silicon and other thin-film photovoltaic (PV) technologies, which are near commercialization. PSCs have several advantages over other established PV technologies such as higher power output, enhanced performance at low light intensities, and mechanical flexibility, which allow their integration into several applications. Industrial opportunities include specific applications in building-integrated photovoltaics, agrivoltaics, and the internet of things. Although it is likely that PSCs will enter a commercialization phase, there are remaining challenges related to various economic and technical issues, including scalable fabrication and operational stability. Here, we review advanced techniques for scalable fabrication and operational stability of PSCs and perovskite solar modules. The required characteristics, such as operational stability and fabrication costs, that remain a challenge to be resolved before entering the PV market are discussed. Moreover, a proposed framework is presented for PSC technology based on material evolution with the perspective of massive scale deployment and marketplace values.
... EROI is defined as the ratio between the total energy produced or returned by an energy source and the energy invested or consumed to obtain it (Hall et al. 2014;Arvesen and Hertwich 2015;Walmsley et al. 2018;Fabre 2019;Capellán-Pérez et al. 2019;Diesendorf and Wiedmann 2020;Wang et al. 2021;Jackson and Jackson 2021). Together with the energy payback time (EBPT), EROI is the most widely used metric to evaluate the energy benefit of different energy technologies (Bhandari et al. 2015;Jackson and Jackson 2021). ...
... Despite several studies having focused on performing meta-analyses to identify the EROI values of RES (Bhandari et al. 2015;Walmsley et al. 2018;Capellán-Pérez et al. 2019), as far as we know, there is no paper that performed EROI estimates for GH 2 . ...
... This tool has been widely used and disseminated in health sciences and clinical research, progressively extending to other areas such as life cycle assessment (LCA) and EROI. (Bhandari et al. 2015;Walmsley et al. 2018). As shown in Fig. 1 (in red), the search was performed under the queries (metaanalysis and EROI); in the case of geothermal energy searched by (EROI and geothermal) and for hydropower (EROI and hydro) because when combined with "meta-analysis" no results appear. ...
In order to address Climate Change and energy dependency challenges, hydrogen (H 2 ) is emerging as a promising energy carrier. Studies related to its production have conceptualized it as green (GH 2 ), clean, renewable (RH 2 ), ecological, and sustainable (SH 2 ). The aim of this research is to deepen the understanding of the GH 2 concept and to state boundaries between different terms. To reach this objective, a bibliometric analysis of publications indexed in SCOPUS is launched. Also, in order to assess the potential of renewable energy sources (RES) for GH 2 production, a review of the meta-analysis literature on the Energy Return on Energy Invested (EROI) ratio as regards these RES is performed. Additionally, an analysis of main national strategies on GH 2 is launched. Results indicate that the GH 2 concept is gaining remarkable relevance, while the keyword maps show no significant differences between SH 2 , RH 2 and GH 2 . EROI reveals low average values for the different biomass energy production processes. For their part, GH 2 national strategies focus mainly on solar and wind technologies, albeit leaving the door open to biomass, where EROI could become an adequate metric to guide these strategies towards a low carbon energy path. Although the role of biomass may become fundamental in this energy transition process, given its low EROI values and considering that it is not a totally clean RES, it should be indexed as RH 2 , but not always as GH 2 . Finally, a proposal that guides a more appropriate use of the term GH 2 is made .
Graphical abstract
... LCOE explains PV technologies' cost-performance evaluations (cost per kWh, against lifetime) beyond energy payback potential. 111 The PCE of PSMs with assembling and installation costs and a module's lifetime decide the LCOE. PSM's expansion to the GW scale requires consideration of any fundamental constraints that might be characteristic for a given technology, such as raw-materials availability or large-scale coating of thin film, which may provide operational stability for general devised applications. ...
... Several studies regarding the cost-performance analysis for PSMs presented cost models based on different hypothesized device stacks and production line flows. 111,254,255 These studies posed the cost advantages of PSMs over other PV technologies. 256 Besides operational stability and efficiency, manufacturing PSM costs are also considered a crucial factor. ...
... PCE versus PSM area statistics against the large-area coating techniques International Summit on Organic and Hybrid Photovoltaic Stability [ISOS])109,110 and making them efficient enough for large-area modules are two major hindrances to commercialization. The instability of PSCs against moisture, oxygen, light, and temperature limits the lifetime of PSCs to a fraction of the warranty lifetime (often >25 years).3,111,112 Recently, reputable progress has been made to enhance the stability of PSCs over 1,000 h (for lab-scale cells) through tailored interface113 and meticulous Pb leakage 114 and over 2,000 h (for modules of areas of 22.4 cm 2 ) through interface stabilization, 75 but significant advances are needed to lift this technology to a level where it is ready to compete with other PV technologies. ...
Perovskite solar cells (PSCs) have a comparable performance to silicon and other thin-film photovoltaic (PV) technologies, which are near commercialization. PSCs have several advantages over other established PV technologies such as higher power output, enhanced performance at low light intensities, and mechanical flexibility, which allow their integration into several applications. Industrial opportunities include specific applications in building-integrated photovoltaics, agrivoltaics, and the internet of things. Although it is likely that PSCs will enter a commercialization phase, there are remaining challenges related to various economic and technical issues, including scalable fabrication and operational stability. Here, we review advanced techniques for scalable fabrication and operational stability of PSCs and perovskite solar modules. The required characteristics, such as operational stability and fabrication costs, that remain a challenge to be resolved before entering the PV market are discussed. Moreover, a proposed framework is presented for PSC technology based on material evolution with the perspective of massive scale deployment and marketplace values.
... They reported that average harmonized EPBT changes from 1.0 to 4.1 years for PV modules ranked in order as thin-film (CdTe, CIGS and a: Si), crystalline silicon (p-Si and m-Si). The average harmonized EROI varied from 8.7 to 34.2 for various kinds of PV technology (Bhandari et al. 2015). Wong et al. (2016) have reviewed lots of work done on the EPBT for single and p-Si PV technologies, considering the mean conversion efficiency of 15.84% and 14.11%, respectively, and found the EPBT 3.52 and 2.33 years, respectively. ...
... The scope of this significance has an impact on the amount of time needed to pay this energy back. The energy metric analysis is computed from three basic parameters energy payback time (EPBT), energy returned on invested (EROI), and life cycle conversion efficiency (LCCE) (Agrawal and Tiwari 2010;Bhandari et al. 2015). ...
This paper analyzes the economics of a grid-interactive rooftop solar photovoltaic (PV) system and the impact of the temperature on it. The analysis related to energy metrics, lifecycle costing, and environmental economics was performed considering the PV system’s life as 30 years. The system economics is also compared at different conditions like theoretical, temperature-corrected, and real electricity generation data. The parameters like energy payback time (EPBT), energy return on energy invested (EROI), and lifecycle conversion efficiency are determined as 5.95 years, 5.04, and 0.078, respectively, based on actual generation. The unit electricity cost of the rooftop PV system was estimated as INR 5.37 at the 5% interest rate. The electricity cost varies with the interest rate variation and operation system life. The results show a reduction in overall economic performance on the increase in module temperature. The effect of temperature on the economics of the system is presented in terms of the per degree rise of module temperature. One degree increase of module temperature 8.5 days in EPBT of the PV system increases, and INR 0.021 increases in the unit cost of electricity considering a reference temperature 25 °C. A PV system has environmental benefits by reducing greenhouse gas emissions, which are also affected by the rise of module temperature. The system lost INR 355.93 in carbon credits at an increase of one-degree module temperature.
... Of course, the logical corollary to the argument made above, about the need to calculate Net Energy in terms of primary energy equivalents, is that whenever any EROI value for electricity is discussed in relation to the concept of net energy, and more specifically when such value is positioned on the "net energy cliff", such EROI value should always be calculated according to Equation (6) [22,33,34]. ...
... Process chain for thermal fuels from extraction (1) to point-of-use(6). ...
Net energy, that is, the energy remaining after accounting for the energy “cost” of extraction and processing, is the “profit” energy used to support modern society. Energy Return on Investment (EROI) is a popular metric to assess the profitability of energy extraction processes, with EROI > 1 indicating that more energy is delivered to society than is used in the extraction process. Over the past decade, EROI analysis in particular has grown in popularity, resulting in an increase in publications in recent years. The lack of methodological consistency, however, among these papers has led to a situation where inappropriate comparisons are being made across technologies. In this paper we provide both a literature review and harmonization of EROI values to provide accurate comparisons of EROIs across both thermal fuels and electricity producing technologies. Most importantly, the authors advocate for the use of point-of-use EROIs rather than point-of-extraction EROIs as the energy “cost” of the processes to get most thermal fuels from extraction to point of use drastically lowers their EROI. The main results indicate that PV, wind and hydropower have EROIs at or above ten while the EROIs for thermal fuels vary significantly, with that for petroleum oil notably below ten.
... To organize such a broad range of information, we divided our literature review into several sections dedicated to specific problems of interest to the glass science community, and these topics are organized in terms of the "energy return on investment" (EROI) concept [16,17,18,19,20]. The EROI for a solar panel is the sum of energy invested in all materials and processes needed to build the devices, divided by all the energy produced during the panel's lifespan. ...
... We see that through technological advancements, module efficiency is also anticipated to go up as a result of panel design improvements 6 , and we see an up to 17% increase in EROI and up to 15% decrease in carbon emission factor and EPBT as a result of improved module efficiency. We also take into consideration the degradation rates of c-Si PV panels which are reflected in their decreasing module efficiencies 48 . The results show that panel degradation leads to a 12% reduction in EROI for sc-Si and a 17% decrease for mc-Si, as well as a 14% increase in carbon emission factor and EPBT for sc-Si and a 20% increase for mc-Si. ...
The globalized supply chain for crystalline silicon (c-Si) photovoltaic (PV) panels is increasingly fragile, as the now-mundane freight crisis and other geopolitical risks threaten to postpone major PV projects. Here, we study and report the results of climate change implications of reshoring solar panel manufacturing as a robust and resilient strategy to reduce reliance on foreign PV panel supplies. We project that if the U.S. could fully bring c-Si PV panel manufacturing back home by 2035, the estimated greenhouse gas emissions and energy consumption would be 30% and 13% lower, respectively, than having relied on global imports in 2020, as solar power emerges as a major renewable energy source. If the reshored manufacturing target is achieved by 2050, the climate change and energy impacts would be further reduced by 33% and 17%, compared to the 2020 level. The reshored manufacturing demonstrates significant progress in domestic competitiveness and toward decarbonization goals, and the positive reductions in climate change impacts align with the climate target.
... This PV growth is great news for the environment because PV are substantial net energy producers [21] and as PV efficiencies have steadily climbed [22], PV can pay their energy back in a year [23]. This large PV growth, however, comes with challenges. ...
There is an intense need to optimize agrivoltaic systems. This article describes the invention of a new testing system: the parametric open source cold-frame agrivoltaic system (POSCAS). POSCAS is an adapted gardening cold-frame used in cold climates as it acts as a small greenhouse for agricultural production. POSCAS is designed to test partially transparent solar photovoltaic (PV) modules targeting the agrivoltaic market. It can both function as a traditional cold frame, but it can also be automated to function as a full-service greenhouse. The integrated PV module roof can be used to power the controls or it can be attached to a microinverter to produce power. POSCAS can be placed in an experimental array for testing agricultural and power production. It can be easily adapted for any type of partially transparent PV module. An array of POSCAS systems allows for the testing of agrivoltaic impacts from the percent transparency of the modules by varying the thickness of a thin film PV material or the density of silicon-based cells, and various forms of optical enhancement, anti-reflection coatings and solar light spectral shifting materials in the back sheet. All agrivoltaic variables can be customized to identify ideal PV designs for a given agricultural crop.
... A PV system's PR over time is calculated as energy measured (kW h)/(irradiance (kW h m −2 ) on the panel × active area of PV module (m 2 ) × PV module efficiency). Another method to analyze the efficacy of solar cells is to calculate the energy return on investment (EROI), 176 which is a function of EPBT and lifespan, as indicated: ...
Even though power conversion efficiency has already reached 25.8%, poor stability is one of the major challenges hindering the commercialization of perovskite solar cells (PSCs). Several initiatives, such as structural modification and fabrication techniques by numerous ways, have been employed by researchers around the world to achieve the desired level of stability. The goal of this review is to address the recent improvements in PSCs in terms of structural modification and fabrication procedures. Perovskite films are used to provide a broad range of stability and to lose up to 20% of their initial performance. A thorough comprehension of the effect of the fabrication process on the device's stability is considered to be crucial in order to provide the foundation for future attempts. We summarize several commonly used fabrication techniques-spin coating, doctor blade, sequential deposition, hybrid chemical vapor, and alternating layer-by-layer. The evolution of device structure from regular to inverted, HTL free, and ETL including the changes in material utilization from organic to inorganic, as well as the perovskite material are presented in a systematic manner. We also aimed to gain insight into the functioning stability of PSCs, as well as practical information on how to increase their operational longevity through sensible device fabrication and materials processing, to promote PSC commercialization at the end.
... Furthermore, the cumulative energy demand (CED) was also estimated for each system using the corresponding life cycle impact assessment (LCIA) method, as discussed below. CED was then used to estimate the energy payback time (EBPT), i.e., how much time is required for compensating CED, and the energy return on energy invested (EROI), i.e., the total produced energy divided by the CED, which are both common indicators for solar PV systems [39]. ...
The energy and environmental performance of photovoltaic (PV) panel cooling, when using phase change materials (PCMs), was examined. Actual, long-term field data were collected from a PV and a PV-PCM system, both operating under Mediterranean conditions (Greece). The energy analysis revealed that even though cooling increases (9.4%) the panel's energy output, PCM cooling is associated with a high initial energy investment, leading to low energy-return-on-investment values (1.79) compared to PV (4.94). High energy payback times were observed for the PV-PCM (⁓14 years) compared to the PV system (⁓5 years). Furthermore, the life cycle assessment methodology revealed that PCM cooling increases PV's total environmental footprint by 21.9%. However, in the Greek context, the additional electricity attributed to PV cooling leads to significant environmental gains through fossil-fuel-dependent electricity substitution. Cooling can also decrease the rate of cell degradation and prolong PV useful life, leading to additional environmental gains. Due to PCM's initial high energy investment, other cooling technologies should also be examined since, apart from improving electricity output and stability, cooling can also reduce PV's impact on land use, increase the power sector's decarbonization, and address global warming's impact on PV performance by reducing temperature fluctuations and extremes on the panel's surface.
... Moreover, solar energy tallies with the decentralized, democratic model of governance and control befitting a future global solar community [51]. Moreover, the current mean harmonized EROI (energy return on energy invested) values for solar photovoltaic systems range from 8.7 to 34.2, depending on the technology used, which is very promising, and these values could be even higher in the future [55]. ...
This paper describes the present and the future of the energy sector in relation to the dominant and constantly evolving form of the global economic system. These considerations have their starting point in transformations of the energy sector in prosumer capitalism, which has dramatically changed the picture of the global economy in recent years. Subsequently, a futuristic approach is applied to determine the role and importance of energy from renewable sources for further human development. The main objective of the paper is to explain the current situation of the energy sector in prosumer capitalism and to extrapolate these relationships for the future, considering the need to enter the path of sustainable development to eliminate the global warming processes and climate changes. A review of the existing scientific literature was applied as the research method. The historical wave concept, proposed by Toffler, was found to be highly useful because of its high potential in futurology, where it enables one to study megatrends. The Fourth Wave was linked to prosumer capitalism, and it provided the base for defining the next ones: the Fifth Wave of Computing (ecosocialism) and the Sixth Wave in the form of technological and energy communism (solar communism). It also turned out that the key to solving mankind’s energy problems lies in the global mean entropy budget. The literature review shows that founding the global energy system on solar radiation is the only known method for eliminating the anthropogenic greenhouse effect, which is the source of global warming and, consequently, of climate change. Therefore, the second law of thermodynamics provides a physical, economic, and logical justification for introducing a new and ultimate management form—solar communism—by 2050.
... EPBT means the time when the energy consumed in producing, installing, maintaining, and recycling a system is compensated by the energy produced from the system [22,44,48]. For example, if the EPBT of a PV system that has an expected lifetime of 30 years is found to be 2 years, this implies that the needed energy for this system will be compensated in 2 years and the energy generated from the system is free energy for the remaining 28 years [49]. If the value of EPBT exceeds the lifetime of the PV panels, then the recovery of the energy consumed is impossible [50]. ...
The shift toward renewable energy resources, and photovoltaic systems specifically, has gained a huge focus in the past two decades. This study aimed to assess several environmental and economic impacts of a photovoltaic system that installed on the rooftop of an industrial facility in Dubai, United Arab Emirates (UAE). The life cycle assessment method was employed to study all the flows and evaluate the environmental impacts, while several economic indicators were calculated to assess the feasibility and profitability of this photovoltaic system. The results showed that the production processes contributed the most to the environmental impacts, where the total primary energy demand was 1152 MWh for the whole photovoltaic system, the total global warming potential was 6.83 × 10–2 kg CO2-eq, the energy payback time was 2.15 years, the carbon dioxide payback time was 1.87 years, the acidification potential was 2.87 × 10–4 kg SO2-eq, eutrophication potential was 2.45 × 10–5 kg PO43-eq, the ozone layer depletion potential was 4.685 × 10–9 kgCFC-11-eq, the photochemical ozone creation potential was 3.81 × 10–5 kg C2H4-eq, and the human toxicity potential was 2.38 × 10–2 kg1,4-DB-eq for the defined function unit of the photovoltaic system, while the economic impact indicators for the whole system resulted in a 3.5 year payback period, the benefit to cost ratio of 11.8, and 0.142 AED/kWh levelized cost of electricity. This was the first study to comprehensively consider all of these impact indicators together. These findings are beneficial inputs for policy- and decision-makers, photovoltaic panel manufacturers, and photovoltaic contractors to enhance the sustainability of their processes and improve the environment.
... La energía solar es un recurso que por sus características es limpio e inagotable. Además, es una muy buena alternativa, debido a la continua disminución en los precios de los módulos solares y otros componentes del sistema fotovoltaico; su instalación es fácil; los costos de operación y mantenimiento son muy bajos; su funcionamiento es silencioso, ya que no generan ruido y su operación es libre de emisiones de contaminantes (Ayop et al., 2018;Bhandari et al., 2015;Liu et al., 2017;Mewes et al., 2017). Por otro lado, al ser los sistemas fotovoltaicos una tecnología descentralizada de generación de energía, estos permiten una mayor autonomía e independencia de la infraestructura eléctrica tradicional (Al-najideen y Alrwashdeh, 2017). ...
CLASIFICACIÓN JEL:
I23, O13, Q42, Q56
CONTENIDO:
Introducción; 1. ¿Por qué energía solar fotovoltaica (FV)?; 2. Consideraciones sobre el diseño de un sistema fotovoltaico sin almacenamiento, para la generación de energía eléctrica; 3. Condiciones para el diseño de un sistema fotovoltaico para la generación de energía eléctrica en el ITM; 4. Consumo de electricidad en el ITM campus Robledo; 5. Diseño conceptual y análisis de prefactibilidad técnico, económico y ambiental; Conclusiones; y Referencias
... These values only get better as the energy conversion efficiency of all the major commercial and precommercial PV types are increasing [11]. Today PV energy payback times have dropped below a year [12]. As PV costs have declined, more have been installed and large surface areas are needed to power high-population-density cities, which are normally supplied in large PV tracts located in rural agricultural areas [13]. ...
As Alberta increases solar power generation, land use conflicts with agriculture increase. A solution that enables low-carbon electricity generation and continued (in some cases increased) agricultural output is the co-locating of solar photovoltaics and agriculture: agrivoltaics. This study reviews policies that impact the growth of agri-voltaics in Alberta. Solar PV-based electricity generation is governed by three regula-tions based on system capacity. In addition, agrivoltaics falls under various legisla-tions, frameworks, and guidelines for land utilization. These include Land Use Frame-work, Alberta Land Stewardship Act, Municipal Government Act, Special Areas Dis-position, Bill 22 and other laws/policies all of which are reviewed in the context of agrivoltaics. Several policies are recommended to support rapid diffusion of agrivolta-ics. First, open access research into agrivoltaics, which not only will help optimize agrivoltaic systems for the region, but also coupled with public education is expected to galvanize social acceptability of large-scale PV deployment. Clearly defining and categorizing agrivoltaic technology, developing agrivoltaic standards, making agri-voltaic technology-friendly regulations/frameworks and developing programs and pol-icies to incentivize agrivoltaic deployment over conventional PV will all accelerate dif-fusion. Through these measures, Alberta can achieve conservation and sustainability in food and energy sector while simultaneously addressing the renewable energy and climate-related goals.
... One key indicator in this regard is the Energy Payback Time (EPBT) which describes how many years a system must operate in order to recover the lifetime energy. EPBT-values are dependent on different factors, e.g., module technology, nominal module power and local solar irradiation but commonly range between 1 and 4 years [1][2][3], thus easily falling below the usual lifetime and providing a significant net energy gain. From an economic standpoint a similar trend can be observed, although to a lesser degree, meaning the payback time is longer but still below the expected lifetime [4,5]. ...
Cracked backsheets have become an increasing problem for the reliability of photovoltaic modules. These defects can cause insulation faults and accelerate degradation, therefore leading to a significant shortening of the module lifetime. Repair solutions based on coatings have been developed to counteract this problem and ensure that modules reach their expected lifetime. Besides the technical suitability of these repair solutions, questions of environmental and economic feasibility should also be considered in regard to the implementation potential of these measures. In this work, models assessing the repair process from an environmental and economic standpoint have been developed and applied to several case studies representing a broad spectrum of potential use cases. Results show that the repair process, when comparing it to disposal with and without module replacement, is highly advantageous regarding the environmental performance in almost every case while also providing good results from an economic standpoint. 1 INTRODUCTION Photovoltaics (PV) is widely regarded as one of the critical technologies in enabling a sustainable energy transition. Although the lifecycle of a PV system is associated with environmental impacts (mostly from module production incl. upstream processes), the long lifetime of the system (25 years and more) along with the fact that basically no impacts are caused during the use phase, make this form of power generation environmentally-friendly. One key indicator in this regard is the Energy Payback Time (EPBT) which describes how many years a system must operate in order to recover the lifetime energy. EPBT-values are dependent on different factors, e.g., module technology, nominal module power and local solar irradiation but commonly range between 1 and 4 years [1-3], thus easily falling below the usual lifetime and providing a significant net energy gain. From an economic standpoint a similar trend can be observed, although to a lesser degree, meaning the payback time is longer but still below the expected lifetime [4,5]. Several failure modes for PV modules are known from literature [6], with backsheet failures (especially cracking but also delamination and discolouration) being identified as one of the most relevant issues over the last years [7]. Cracked backsheets (see Figure 4) lead to insulation failures and can also cause accelerated degradation in modules. These defects result in performance loss over time and, in the worst case, can make the module unusable because of safety risks [8]. When dealing with this problem the disposal of the faulty modules (with or without replacement) can be seen as the current standard. In view of a more sustainable approach, the topic of backsheet repair has garnered increasing interest in the PV industry over the last years. Some companies already provide solutions, based mostly on repair tapes, with evaluations of solutions based on coatings also ongoing. Besides the technical suitability and long-term stability of such repair solutions, questions about environmental and economic aspects are also important in order to assess whether an implementation on a large scale can be achieved successfully. Therefore, the goal of this work is to assess and compare repair solutions with other options (disposal with and without replacement) of dealing with defective modules with cracked backsheets from an environmental and economic standpoint.
... LCA studies have been widely performed to evaluate the environmental impact generated from monocrystalline silicon (mono-Si) PV systems in Europe (Sumper et al., 2011;Muneer et al., 2006;Sherwani et al., 2010;De Wild-Scholten, 2013), the United States (Fthenakis and Kim, 2011;Pacca et al., 2007), and Asia (Kannan et al., 2006). Reviews (Bhandari et al., 2015;Peng et al., 2013) of PV systems on energy payback time (PBT E ) and GHG emission also have been widely performed. However, previous works only considered GHG emission and PBT E or primary energy demand. ...
Life cycle assessment on monocrystalline silicon (mono-Si) solar photovoltaic (PV) cell production in China is performed in the present study, aiming to evaluate the environmental burden, identify key factors, and explore approaches for potential environmental improvement. Results show that the impact generated from the categories of human toxicity, marine ecotoxicity, and metal depletion contribute dominantly to the overall environmental burden because of silver (Ag) paste, electricity, and glass consumption. The energy payback time and greenhouse gas emission range from 0.42 to 0.91 years and 5.60e12.07 g CO 2 eq/kWh respectively, both of which are lower than the previously reported results in studies in Europe, the United States, and Asia. However, compared with coal-based electricity generation that uses ultra-supercritical technology, the environmental payback time in human toxicity, marine ecotoxicity, and metal depletion categories is quite high because of the direct air emissions of lead, arsenic, mercury, copper, and nickel, as well as the use of Ag. Additionally, utilization of PV systems in regions with high solar radiation values has a high potential environmental benefit from PV systems.
... Oil and gas production reportedly exhibit ERoEIs above 10, with coal being above 45 (Murphy and Hall, 2010). Renewable energy is more variable (e.g., higher than 100 for hydropower and up to 40 for solar power (Raugei, Fullana-i-Palmer, and Fthenakis, 2012;Bhandari et al., 2015)) but must be above 1, and usually more, to be of value (Murphy and Hall, 2010). ERoEI for renewable fuels are usually lower than renewable electricity production (King and Van Den Bergh, 2018;Hall et al., 2014;Rana et al., 2020). ...
Microalgae-based renewable fuels offer low carbon alternatives to fossil fuels, and can theoretically support energy and climate security, regional employment and sustainable development. However, to achieve price parity with fossil fuels and fast track scale up, a benchmark production price of US$0.67 L-1 ($2.54 gal−1) must be achieved. The financial performance of microalgae systems can be enhanced through the cascaded conversion of biomass into multiple co-products, such as proteins and high-density liquid fuels. Here we evaluate the use of hydrothermal pre-treatment (HTP: 180 °C, 1 MPa, 10 min) green chemical-based protein extraction processes (acetone and urea treatment) followed by hydrothermal liquefaction (HTL) crude oil production and high-density liquid fuel refining. This experimental data was incorporated into an integrated Techno-Economic and Life-Cycle Analysis (TELCA 2.1) simulation of a 500 ha microalgae production and biorefinery facility to simulate protein and fuel co-production at scale. At a minimum diesel selling price of US$0.67 L-1 the protein co-product (32% purity) required a minimum selling price of US$7.2 kg−1. The low protein purity can be improved to at least 40% using low carbohydrate biomass and further process optimisation to deliver a more sustainable alternative to cheap protein sources, such as soybean meal or fishmeal. Competitive and green co-production of fuel and food/feed will help achieve a circular bioeconomy and support UN Sustainable Development Goals.
... The intention of an SLR is to find the most relevant publications in an area, and be as comprehensive as possible [47]. This tool was first used in medical scientific publications to assess previous works; however, it has been also adopted in engineering and particularly in the energy field to present reliable conclusions [48][49][50]. According to Dresch et al. [51], the SLR must evidence all decisions and steps throughout the work, and be as clear as possible regarding the adopted methodology. ...
Air-source heat pumps (ASHPs) can support a decarbonized economy by replacing combustion appliances in homes and electrifying heating systems in buildings. However, ASHPs have not seen significant adoption primarily due to deteriorated performance under cold conditions—at very low temperatures they require auxiliary resistance heating to meet the heating demand and defrost the evaporator. The additional heat lowers the system efficiency. Thermal energy storage (TES) is a candidate technology to help overcome some of these issues. This paper presents a systematic literature review to map the existing research on integration of TES into ASHPs. Our review of 59 publications indicates that thermal storage increases the ASHP coefficient of performance by 27% on average, albeit with higher initial cost compared to conventional fossil-fueled heating systems. Phase change materials may be ideal to be integrated with ASHPs due to their high energy density and compact design, but only a few publications address TES sizing and design. First and Second Laws of Thermodynamics are widely used to create metrics to assess ASHP-TES integration, and only recently have cost and environmental impact been explored. This literature review suggests that more comprehensive metrics are needed to evaluate the potential benefits of ASHP-TES systems.
... On the other hand, enhancing the life-cycle of c-Si panels should reduce environmental impacts and carbon emissions, contributing further to our carbon budget and the related climate goals [10][11][12][13]. The industry has pursued to reduce materials waste and replace expensive minerals with cheaper alternatives [3], which often contributes to reducing the environmental impacts. ...
The cover glass in a silicon solar panel accounts for about 2/3 of the device’s weight. Recycling these devices at their end-of-life is fundamental to reducing the industry’s environmental impact. Here we investigate the recovery of these glass sheets by a heat-assisted mechanical process. A panel was delaminated, and we have utilized Fourier-transform infrared, Raman, and energy-dispersive spectroscopies to confirm the composition of the remaining components and identify aging signals. The results demonstrate that the panel’s design was similar to most Silicon solar panels in the market, and we concluded that it would be feasible to recover the glass in most of these devices. Due to its chemical and mechanical strength, this glass would be ready to be reused without the need to melt it again, bringing substantial savings in its energy content and carbon emission related to its production. The glass sheet would be ready to be used as cover glass in another solar panel or architecture material. Our estimates showed that this could be a pathway to reducing the photovoltaic industry’s carbon emissions by more than 2 million tonnes per year.
... The capacity of wind energy is more (400-600 W) compared to solar energy (100-200 W) per square meter of land use [3]. Energy payback time for solar technology is 1-4.1 years [4], whereas the same for wind technology is only 0.69 years [5,6]. Thus, wind energy is seen as a better alternative among the renewable resources for electricity generation. ...
Wind energy is an alternative energy generation from non-renewable energy resources. The turbine is used to exploit wind energy. Different components of a wind turbine necessitate different materials and metals. There is a dependency of the materials on foreign countries. To avoid future problems regarding the availability of these materials in India, it is necessary to forecast the quantity and the price of the materials and metals. Thus, this study mainly focuses on the estimation of the raw materials, rare earth, and critical metals used in manufacturing the wind turbine. Two wind turbines of 1.65 MW and 3.45 MW capacity, 78 m and 94 m hub height are considered for the study. The major raw materials are steel, aluminum, copper, cast iron, fiber glass with epoxy resin, and ceramic/glass. The requirement of rare earth elements (Nd) depends on the type of wind turbine direct drive or geared, and the type of generator used in the direct-drive wind turbine. The results estimated the requirement of materials and rare earth elements and the expected price in the future for 100% wind energy production in India.
... Comparisons of materials choices and the resulting environmental burdens can use various approaches, such as embodied carbon [433], whole-life carbon emissions [434] and/or payback time [435][436][437][438][439]. The use of a timber façade on a building can make a substantial contribution to the reduction in the environmental footprint of the construction phase [440,441]. ...
Timber cladding has been used since historical times as a locally available, affordable weather protection option. Nowadays, interest in timber cladding is again increasing because of ecological reasons as well as naturalistic viewpoints. This review presents a comprehensive report on timber cladding in a European context, beginning with a brief overview of the history before considering contemporary use of timber cladding for building envelopes. The basic principles of good design are considered, paying attention to timber orientation, fixings and environmental risk factors. The relationship of timber with moisture is discussed with respect to sorption behaviour, dimensional instability and design methods to minimise the negative consequences associated with wetting. The behaviour of timber cladding in fires, the effects of environmental stresses and weathering, as well as the cladding properties and the variation thereof with different types of wood and anatomical factors (including exposure of different timber faces), are examined. The review then moves on to considering different methods for protecting timber, such as the use of coatings, preservatives, fire retardants and wood modification. A brief discussion of various environmental considerations is also included, including life cycle assessment, embodied carbon and sequestered atmospheric carbon. The review finishes by making concluding remarks, providing a basis for the selection of appropriate cladding types for different environments.
... For this paper, the equivalent for carbon dioxide emissions that are obtained from the creation of PV modules is calculated by multiplying a coefficient of emission for both manufacturing and the recycling of the module at the end of its life, and the inverters used in the installation, these factors are listed in Table 2. According to [24], the carbon dioxide payback time (CPBT) can clearly express the time it takes for a project to avoid the same amount of CO 2 e that emits during its life cycle (Equation (1) ...
Solar energy is in high demand due to its environmental benefits and economic potential; however, concerns remain about the total impact it holds. In 2020, for Spain, Castilla-La Mancha was the second autonomous community with the highest photovoltaic energy production. Thus, a systematic review on 15 large-scale PV solar energy projects was carried out to assess the industry impacts, through environmental impact assessment (EIA), within the Autonomous Community of Castilla—La Mancha. An estimation of these impacts from a pre-operational approach is presented, based on primary energy needs and emissions discarded during its life cycle due to the manufacture, operation, and recycling of the photovoltaic modules. Based on both the life cycle assessment (LCA) and EIA, the approaches were compared with the results obtained. The obtained results suggest that determining the actual impacts of power plants in this region could provide justified information for the public administration and technicians in the measures for the installation and operation of PV plants and the future benefits of renewable solar technologies. Furthermore, the results indicate the possibility to recognize the relationship between the size of the plant and a high generation capacity, with a shorter time to pay for emissions from the manufacture and recycling of panels, suggesting that it is around 1.66–2.08 years for the Castilla-La Mancha region.
... Canadian PV growth is good for the environment as PV is a well-established, sustainable energy source [7], having been shown to be a net energy producer for the last 20 years [8]. Energy conversion efficiencies for PV have increased [9] to the point that the energy payback time is less than a year [10]. These benefits also come with challenges, such as the need for large land surface areas to power high-population-density cities, which are normally supplied by rural areas used for agricultural production [11]. ...
Well-intentioned regulations to protect Canada’s most productive farmland restrict large-scale solar photovoltaic (PV) development. The recent innovation of agrivoltaics, which is the co-development of land for both PV and agriculture, makes these regulations obsolete. Burgeoning agrivoltaics research has shown agricultural benefits, including increased yield for a wide range of crops, plant protection from excess solar energy and hail, and improved water conservation, while maintaining agricultural employment and local food supplies. In addition, the renewable electricity generation decreases greenhouse gas emissions while increasing farm revenue. As Canada, and Ontario in particular, is at a strategic disadvantage in agriculture without agrivoltaics, this study investigates the policy changes necessary to capitalize on the benefits of using agrivoltaics in Ontario. Land-use policies in Ontario are reviewed. Then, three case studies (peppers, sweet corn, and winter wheat) are analysed for agrivoltaic potential in Ontario. These results are analysed in conjunction with potential policies that would continue to protect the green-belt of the Golden Horseshoe, while enabling agrivoltaics in Ontario. Four agrivoltaic policy areas are discussed: increased research and development, enhanced education/public awareness, mechanisms to support Canada’s farmers converting to agrivoltaics, and using agrivoltaics as a potential source of trade surplus with the U.S.
... Based on the knowledge of energy payback period (EPBP) and life of the concerned energy system (L), the percent saving of fossil fuel/kWh (compared to a fossil power plant whose fossil fuel loss is 100%) may be estimated as derived in Eq. (7) (Bhandari et al., 2015). For Bio fuels, the EPBP values may be said to be around 2.5 years, considered for a plant with 25 years life time (Carreras-Sospedra et al., 2016b). ...
A single criterion assessment tool for gradation of the competing energy devices, was considered important for advancing R&D for improving upon their performance efficiency, particularly for the renewable energy systems. It was therefore outlined a theoretical design for ascertaining their individual sustainability percent achievable, from identification of the indices to be considered and a sustainability scale development for quantitative assessment. Case studies were thereafter made illustrating the modus operandi of using the developed model, for comparing the sustainability percentage achievable for different renewable energy systems, against a coal-based power plant as the referral energy unit. The competing renewable energy schemes studied were- solar PV, wind energy (both on-shore and off-shore), bio-fuel, and wave schemes like wave dragon, closed cycle ocean thermal energy conversion system (CC-OTEC) and a proposed barrage scheme (Severn barrage, UK). The study revealed that coal-based fossil fuel plant could hardly meet 40% sustainability against all other renewable energy schemes, achieving much more than 60% sustainability. In addition to the scope of use of the model for comparing the relative merits of the individual energy devices, it can may find use for indexing a product with its environmental signature, on necessary modification and extension of the model.
... EPBT is the length of time that a solar module needs to pay back its primary energy demand throughout the whole life-cycle by means of electricity generation. It is one of the most common metrics adopted to present the energy performance of PV technologies [137,139]. Here, primary energy demand covers all stages of the life cycle that starts from the acquisition of raw materials, production to end-of-life, including all transportation effects. If the EPBT is less than a solar module's lifetime, a multiple of the invested energy can be generated for achieving an energy return on invest. ...
Agrivoltaic greenhouse is a win–win concept which is a creative integration between agriculture and Photovoltaic infrastructures to address the land use competition between solar PV and agriculture especially for anti-seasonal plants. PV shading on the greenhouse roof has attracted more attention in recent years especially in high insolation regions. Heat stress is an inevitable issue that almost exclusively contributed by near-infrared radiation (NIR) and thus affects the microclimate and plant growth of greenhouse. As the emerging PV technology, the absorption spectrum in the active layer of semi-transparent organic PV (OPV) is tunable and extends to NIR range through material selection thus, reduce excess solar heat stress on the plant. Herein, this paper reviews the major studies about different PV materials used in greenhouse roofing at various countries around the world for the last ten years (2010–2020). The development trend of different PV materials on the application of greenhouse could be observed. Active layer materials of OPV with strong NIR absorption and strong visible light transmittance are preferred owing to boosting times of usage and various benefits e.g., non-toxic, flexibility, lowest both on carbon footprint and energy payback time, thus becoming an ideal candidate as greenhouse shading material.
This study examines Shenzhen's potential for utilizing photovoltaics (PV) on buildings in terms of residential electricity consumption. Based on its geographic information system (GIS) data, typical local meteorological data, and electricity demand, the solar potential of Shenzhen has been thoroughly studied, critically analyzed, and compared with different urban morphology characteristics. Urban morphology influences the solar radiation received by individual buildings. First, four representative residential areas have been chosen. Using the 3D architectural modeling software Rhinoceros with its Grasshopper and Ladybug plug-ins, the solar potential of the areas was then evaluated. Following this, an economic analysis was carried out. Due to the high solar radiation of the rooftop areas, the results demonstrated that a combination of rooftops and high-performance facades (over 700 kWh/m2/year) produces a promising payback period. Therefore, this paper calls for action to start a large-scale program to promote and then mandate the use of renewable energy resources (RES), specifically solar, for the residential sector in the cities located in the southern region of China.
Pakistan being a developing country is observing a rapid rise in electricity demand and currently the big cities such as Karachi, Quetta, Rawalpindi and Lahore are most severely affected by the recent power crises. Therefore, at this time it is important to explore and investigates the alternate and renewable power sources in the country. This study investigates the significance in terms of economic feasibility of off-grid solar photovoltaic systems in the residential sector of Pakistan. Study area comprises the rural and urban residential sector of all four provinces of Pakistan. The return on investment and project payback periods are calculated using the NEPRA defined electricity tariff inclusive of tax so that a concrete conclusion of investing in off-grid solar could be drawn. Results of this study show that most selected areas in Pakistan have sufficient solar radiation potential for electricity generation. Study finds that solar electricity in Pakistan is one of the cost effective and environmental and social friendly forms of electricity. Payback periods of photovoltaic system in Sindh, Baluchistan, Punjab and KPK have been calculated 3.98, 2.33, 3.99 & 6.78 years, respectively. Results of this study may be useful for collective as well as individual consumers while calculating the economic viability of an off grid solar system. Keywords: Photovoltaic System, Solar potential, Electricity, Off-Grid Solar System, Return on investment, economic feasibility, Pakistan.
Vertical bifacial solar photovoltaic (PV) racking systems offer the opportunity for large-scale agrivoltaics to be employed at farms producing field crops with conventional farming equipment. Unfortunately, commercial proprietary vertical racks cost more than all types of conventional PV farm racking solutions. To overcome these cost barriers, this study reports on the development of a new wood-based PV racking design. The open-source design consists of a hinge mechanism, which reduces mechanical loading and enables wood to be used as the main structural material, and is the first of its kind. This open-source vertical wood-based PV rack is (i) constructed from locally accessible (domestic) renewable and sustainable materials, (ii) able to be made with hand tools by the average farmer on site, (iii) possesses a 25-year lifetime to match PV warranties, and (iv) is structurally sound, following Canadian building codes to weather high wind speeds and heavy snow loads. The results showed that the capital cost of the racking system is less expensive than the commercial equivalent and all of the previous wood-based rack designs, at a single unit retail cost of CAD 0.21. The racking LCOE is 77% of the cost of an equivalent commercial racking system using retail small-scale component costs, and is 22%, 34%, and 38% less expensive than commercial metal vertical racking, wood fixed tilt racking, and wood seasonal tilt racking costs, respectively. Overall, wooden vertical swinging PV racking provides users with a low-cost, highly available alternative to conventional metal vertical racking, along with a potential increase in energy yield in high wind areas thanks to its unique swinging mechanism.
Australia is facing the twin problems of energy depletion and environmental pollution. This crisis can be alleviated by effective promotion of solar photovoltaic (PV) system installation. The question is: how does solar PV system diffusion occur in various regions in Australia? This study introduces an innovative five-parameter logistic (5PL) curve to analyse the diffusion of solar PV technology in all postcode areas of Australia. Furthermore, it combines principal component analysis (PCA) and cluster analysis to identify the major area types that have similar diffusion characteristics. The study identifies three main diffusion pathways and their corresponding distribution areas in Australia. The results provide a visual representation of the historical diffusion of residential PV systems in Australia. From a technology diffusion perspective, the results also show how residential solar panel diffusion occurs differently in areas at the postcode level. These findings provide insights on how to reduce regional disparities in solar panel adoption, thus facilitating renewable energy equity and justice.
Canada has committed to reducing greenhouse gas (GHG) emissions by increasing the non-emitting share of electricity generation to 90% by 2030. As solar energy costs have plummeted, agrivoltaics (the co-development of solar photovoltaic (PV) systems and agriculture) provide an economic path to these goals. This study quantifies agrivoltaic potential in Canada by province using geographical information system analysis of agricultural areas and numerical simulations. The systems modeled would enable the conventional farming of field crops to continue (and potentially increase yield) by using bifacial PV for single-axis tracking and vertical system configurations. Between a quarter (vertical) and more than one third (single-axis tracking) of Canada’s electrical energy needs can be provided solely by agrivoltaics using only 1% of current agricultural lands. These results show that agrivoltaics could be a major contributor to sustainable electricity generation and provide Canada with the ability to render the power generation sector net zero/GHG emission free. It is clear that the potential of agrivoltaic-based solar energy production in Canada far outstrips current electric demand and can, thus, be used to electrify and decarbonize transportation and heating, expand economic opportunities by powering the burgeoning computing sector, and export green electricity to the U.S. to help eliminate their dependence on fossil fuels.
Door de toenemende vraag naar flexibele microsystemen, worden technologieen om die te integreren steeds belangrijker. In de laatste jaren ging veel aandacht naar de integratie in 2- en 3-dimensionele plastic onderdelen voor mogelijke toepassingen in het moderne dagelijkse leven van de mens. Bij spuitgegoten geinterconnecteerde elektronische systeem technologie worden koperbanen rechtstreeks gedeponeerd op het plastic. Dit proces heeft nood aan hoog gespecialiseerde toestellen en het proces heeft zijn beperkingen. Desalniettemin is er vraag naar kleinere en lichtere producten die gebruikmaken van verschillende materiaalcombinaties. Hiervoor werd een speciaal spuitgietproces om folies te overspuiten aangepast om elektronica te integreren in plastic onderdelen. Hierdoor werd de realisatie van zogenaamde ‘in-mould-electronics’ (IME) een feit.Dit process laat toe om elektronische componenten, apparaten en functionaliteiten te integreren in dunne spuitgegoten onderdelen, door hen in de matrijs te plaatsen en te overspuiten met een polymeer.IME is een relatief nieuwe technologie. Daarom hebben we in dit proefschrift IME geexploreerd en de toepasbaarheid van deze technologie onder verschillende spuitgiet omstandigheden onderzocht door bvb. verschillende materiaalcombinaties en verschillende types elektronische componenten te overspuiten. Daarbij moet de elektronische functionaliteit behouden blijven en een goede adhesie bekomen worden.
Canada has committed to reducing greenhouse gas (GHG) emissions by increasing the non-emitting share of electricity generation to 90% by 2030. As solar energy costs have plummeted, agrivoltaics (co-development of solar photovoltaic (PV) systems and agriculture) provide an economic path to these goals. This study quantifies agrivoltaic potential in Canada by province using geographical information system analysis of agricultural areas and numerical simulations. Systems modeled would enable conventional farming of field crops to continue (and potentially increase yield) by using bifacial PV for single-axis tracking and vertical system configurations. Between a quarter (vertical) to more than one third (single axis tracking) of Canada’s electrical energy needs can be provided solely by agrivoltaics using only 1% of current agricultural lands. These results show that agrivoltaics could be a major contributor to sustainable electricity generation and provide the ability for Canada to render the power generation sector net zero/GHG emission free. It is clear that the potential of agrivoltaic-based solar energy production in Canada far outstrips current electric demand and can thus be used to electrify and decarbonize transportation, heating, expand economic opportunities by powering the burgeoning computing sector, and export green electricity to the U.S. to help eliminate their dependence on fossil fuels.
Policymakers are increasingly moving towards greater investments in research in the renewable energy sector in order to reduce costs, making private investment affordable, so as to accelerate the achievement of grid parity. This evidence boosts for investigating how the convenience of investing in a solar photovoltaic (PV) system, in Italy, is unrelated to any form of public incentive. This paper designs a residential 3 kW PV system and provides a full set of indicators to assess the comprehensive performance of the PV system. Particularly, the energy and environmental indicators, likewise the Energy Payback Time (EPBT), Energy Return on Investment (EROI) and Environmental Impact Mitigation potential (EIMP), which are 1.35 years, 7.05 and 23,215 kg CO2 eq, respectively, allowed the authors to investigate the sustainability of a residential PV system in Italy, while using the Levelized Cost of Energy (LCOE), that is 0.15064 €/kWh, Net Present Value (NPV) equal to € 2881 and Payback Period (PBP) of 8.26 years to evaluate the economic and financial feasibility of the PV system modelized. The variations of EPBT and EROIEL with respect to solar radiation and the efficiency of the PV system and LCOE to discount rate and initial investment cost have been investigated through a sensitivity analysis.
As Alberta increases conventional solar power generation, land-use conflicts with agriculture increase. A solution that enables low-carbon electricity generation and continued (in some cases, increased) agricultural output is the co-locating of solar photovoltaics (PV) and agriculture: agrivoltaics. This review analyzes policies that impact the growth of agrivoltaics in Alberta. Solar PV-based electricity generation is governed by three regulations based on system capacity. In addition, agrivoltaics falls under various legislations, frameworks, and guidelines for land utilization. These include the Land Use Framework, Alberta Land Stewardship Act, Municipal Government Act, Special Areas Disposition, Bill 22, and other policies, which are reviewed in the agrivoltaics context. Several policies are recommended to support the rapid deployment of agrivoltaics. Openly accessible agrivoltaics research will help optimize agrivoltaic systems for the region, and can be coupled with public education to galvanize social acceptability of large-scale PV deployment. Clearly defining and categorizing agrivoltaics technology, developing agrivoltaics standards, making agrivoltaics technology-friendly regulations and frameworks, and developing programs and policies to incentivize agrivoltaics deployment over conventional PV will all accelerate the technology’s deployment. Through these measures, Alberta can achieve conservation and sustainability in the food and energy sectors while simultaneously addressing their renewable energy and climate-related goals.
Building on insights from ecological economics and philosophy of technology, this book offers a novel, interdisciplinary approach to understand the contradictory nature of Solar photovoltaic (PV) technology.
Solar photovoltaic (PV) technology is rapidly emerging as a cost-effective option in the world economy. However, reports about miserable working conditions, environmentally deleterious mineral extraction and toxic waste dumps corrode the image of a problem-free future based on solar power. Against this backdrop, Andreas Roos explores whether ‘ecologically unequal exchange’ – an asymmetric transfer of labour time and natural resources – is a necessary condition for solar PV development. He demonstrates how the massive increase in solar PV installation over recent years would not have been possible without significant wage/price differences in the world economy - notably between Europe/North America and Asia- and concludes that solar PV development is currently contingent on environmental injustices in the world economy. As a solution, Roos argues that solar technology is best coupled with strategies for degrowth, which allow for a transition away from fossil fuels and towards a socially just and ecologically sustainable future.
This book will be of great interest to students and scholars of solar power, philosophy of technology, and environmental justice.
Climate change necessitates a global effort to reduce greenhouse gas emissions while adapting to increased climate risks. This broader climate transition will involve large-scale global interventions including renewable energy deployment, coastal protection and retreat, and enhanced space cooling, all of which will result in CO2 emissions from energy and materials use. Yet, the magnitude of the emissions embedded in these interventions remains unconstrained, opening the potential for underaccounting of emissions and conflicts or synergies between mitigation and adaptation goals. Here, we use a suite of models to estimate the CO2 emissions embedded in the broader climate transition. For a gradual decarbonization pathway limiting warming to 2 °C, selected adaptation-related interventions will emit ∼1.3 GtCO2 through 2100, while emissions from energy used to deploy renewable capacity are much larger at ∼95 GtCO2. Together, these emissions are equivalent to over 2 y of current global emissions and 8.3% of the remaining carbon budget for 2 °C. Total embedded transition emissions are reduced by ∼80% to 21.2 GtCO2 under a rapid pathway limiting warming to 1.5 °C. However, they roughly double to 185 GtCO2 under a delayed pathway consistent with current policies (2.7 °C warming by 2100), mainly because a slower transition relies more on fossil fuel energy. Our results provide a holistic assessment of carbon emissions from the transition itself and suggest that these emissions can be minimized through more ambitious energy decarbonization. We argue that the emissions from mitigation, but likely much less so from adaptation, are of sufficient magnitude to merit greater consideration in climate science and policy.
Photovoltaic installed cumulative capacity reached 849.5 GW worldwide at the end of 2021, and it is expected to rise to 5 TW by 2030. The sustainability of this massive deployment of photovoltaic modules is analysed in this article. A literature review, completed with our own research for emerging technologies has been carried out following life cycle assessment (LCA) methodology complying with ISO 14040 and ISO 14044 standards. Different impact categories have been analysed for five commercial photovoltaic technologies comprising more than 99% of current market (crystalline silicon ~94% and thin film ~6%) and a representative of an emerging technology (hybrid perovskite). By using data from LCA inventories, a quantitative result for 15 impact categories has been calculated at midpoint and then aggregated in four endpoint categories of damage following ReCiPe pathways (global warming potential, human health damage, ecosystems damage and resources depletion) in order to enable a comparison to other renewable, fossil fuel and nuclear electricity production. In all categories, solar electricity has much lower impacts than fossil fuel electricity. This information is complemented with an analysis of the production of minerals with data from the British Geological Survey; the ratio of world production to photovoltaic demand is calculated for 2019 and projected to 2030, thus quantifying the potential risks arising from silver scarcity for c‐Si technology, from tellurium for CdTe technology and from indium for CIGS and organic or hybrid emerging technologies. Mineral scarcity may pose some risk for CdTe and CIGS technologies, while c‐Si based technology is only affected by silver dependence that can be avoided with other metals replacement for electrodes. When the risks grow higher, investment in recycling should boost the recovery ratio of minerals and other components from PV module waste. Life cycle assessment of 15 midpoint impact categories and their aggregation in four endpoint categories of damage (global warming potential, human health damage, ecosystems damage and resources depletion) demonstrate that solar electricity has much lower impacts than fossil fuel electricity. For future IEA scenarios (NZE2050) mineral scarcity may pose some risk for CdTe and CIGS photovoltaic technologies, while c‐Si‐based technology is only affected by silver dependence. Better recycling strategies will contribute to reduce these risks in the future.
The thin‐film photovoltaic technology based on Cu(In,Ga)Se2 (CIGS) has reached high conversion efficiencies exceeding 23%. The gallium gradient in the bulk and the amount of alkali metals in and between CIGS grains strongly affect the cell performance and therefore need to be accurately measured and quantified. ToF‐SIMS is well suited for this task, but the spatial resolution is strongly influenced by the measurement parameters, especially at the required micrometer and nanometer scales. Such highly resolved measurements on CIGS surfaces are challenging. For instance, small copper aggregations occur in SEM images recorded after a focused ion beam (FIB) cut and change the energy‐dispersive spectroscopy (EDS) results. SIMS systems that use an argon ion source generate Cu lamellas, which also influence the measurement. Both effects result from preferential sputtering. Cooling with liquid nitrogen can minimize this negative effect for both techniques. Recent developments in SIMS systems provide more options to avoid these effects. New sources, like the Bi liquid metal gun and cluster guns, are available. However, a systematic investigation on the effect of the ion sources on the sputter craters and the resulting measurement of CIGS absorber is necessary to choose an adequate setup. Thus, we performed a comparison of four different ion sources (argon ion gun, oxygen gun, cesium metal gun, and oxygen cluster gun) and measured CIGS depth profiles at three temperatures [−120°C, −50°C, and room temperature (RT)]. We investigate the influence of these conditions not only on the resulting SIMS depth profile and quantification but also on the morphology of the sputter crater.
Energy, economic and environment performances of 1 MWp photovoltaic power plant has been numerically investigated under climatic condition of Zakho city/Iraq using the reality metrological measurements. Results of PV system have been compared with other available power plants that used fossil fuel under identical power value. The findings displayed that the investment of PV technology is very feasible in Zakho city as compared to other power plants. The economic results displayed that the payback time nearly equal 7 years to recover the primary expense of the plant and the payback energy time is 2 years to recover the embedded energy of PV panels. The cost of PV plant is nearly 10 times less than the other fossil fuel power plants. The employment of PV plant leads to reduce CO2 emission between 600–2000 tCO2. Finally, the results illustrated that the using of PV system in Zakho city is feasible technically, economically and environmentally
Eine der vielversprechensten aufstrebenden neuen Halbleiterklassen ist die Klasse der Metall Halogen Perowskite. Solarzellen mit solchen Perowskiten als aktive Schicht stehen kurz vor der Kommerzialisierung. Aber auch in anderen optoelektronischen Bauteilen, wie lichtemmitierenden Dioden (LEDs) oder Röntgendetektoren zeigen Perowskite vielversprechende Eigenschaften, beispielsweise eine hohe Detektionssensitivität für Röntgenstrahlen. Ein Grund für die schnelle Entwicklung und Verbesserung solcher perowskitbasierter Bauteile war die Erkenntnis, dass die Struktur des Perowskiten und der Perowskitschicht großen Einfluss auf dessen optoelektronische Eigenschaften und damit auf die Funktionalität der entsprechenden Bauteile hat. Durch Optimierung der Perowskit-Kristallisation, welche wiederum Auswirkungen auf die finalen Perowskit-Filmeigenschaften hat, konnten so Bauteileffizienzen für bestimmte Herstellungsmethoden und Materialsysteme kontinuierlich verbessert werden. Meistens fanden diese Optimierungsansätze durch praktisches Herumprobieren statt, und nur die finalen Filmeigenschaften wurden untersucht. Da die Perowskitkristallisation aber sehr sensitiv von den genauen Umgebungsbedingungen sowie dem verwendeten Materialsystem abhängt, sind die gefundenen Optimierungsstrategien nur begrenzt auf andere Herstellungsmethoden und Materialsysteme, und sogar auf andere Labore mit anderen Umgebungsbedingungen, übertragbar. Um einen derartigen Transfer zu ermöglichen, muss zunächst die Perowskitkristallisation während der Filmbildung besser verstanden werden. Eine Methode, mit der die Filmbildung untersucht werden kann und die zunehmend populärer wird, ist optische in situ Spektroskopie. Bei dieser Methode kann die Perowskitbildung indirekt über die Änderung der optischen Eigenschaften des Perowskiten verfolgt werden, da die optischen Eigenschaften des Perowskiten stark von dessen Struktur beeinflusst werden. Um aus den während der Filmbildung aufgenommenen Spektren die relevanten Informationen über die Filmbildung extrahieren zu können, ist daher ein präzises Verständnis des Zusammenhangs der optischen Eigenschaften des Perowskiten und dessen Struktur notwendig. Hierbei sind einige Aspekte der optischen Eigenschaften von Perowskiten, wie beispielsweise der Ursprung mancher Lumineszenz-Banden oder der Einfluss struktureller Inhomogenitäten, noch nicht gänzlich geklärt. Aus diesem Grund wird in dieser Arbeit zunächst ein besseres Verständnis über den Zusammenhang struktureller Änderungen im Perowskiten mit dessen optischen Eigenschaften erarbeiten. Dieses Verständnis wird anschließend verwendet, um mittels optischer in situ Spektroskopie die Filmbildung des Perowskiten zu untersuchen und besser zu verstehen. Kapitel 8-10 befassen sich mit den optischen Eigenschaften und deren Zusammenhang mit der Struktur des Perowskiten. In Kapitel 8 und 9 habe ich dafür Perowskit-Einkristalle mittels Photolumineszenz-(PL-)Spektroskopie untersucht. Dabei war in Kapitel 8 das primäre Ziel, den Ursprung einer zusätzlichen PL-Bande zu klären. Mittels verschiedener PL-Messungen konnte ich verschiedene in der Fachwelt vorgeschlagene Ursachen für diese PL-Bande ausschließen. Gestützt durch optische Modellierung konnte ich schließlich zeigen, dass jene PL-Bande durch interne Reflexion und Selbstabsorption der PL zustande kommt. Mit der Kenntnis des Effekts von Selbstabsorption auf die PL-Spektren war es mir nun möglich, in Kapitel 9 den strukturellen Phasenübergang von MAPbI3-Einkristallen mittels temperaturabhängigen PL-Messungen detailliert zu untersuchen. Hier konnte ich mittels des optischen Modells aus Kapitel 8 die optische Signatur von strukturell verzerrten Einschlüssen der Raumtemperatur-Phase innerhalb der Tieftemperatur-Phase bis weit unterhalb der Temperatur des Phasenübergangs identifizieren. In Kapitel 10 habe ich die optischen Eigenschaften von Perowskit-Pulvern mittels PL- und Reflexionsmessungen untersucht. Hintergrund war hier die Frage, ob sich die optischen Eigenschaften von Perowskit-Pulvern von jenen ihrer Dünnfilm- und Einkristall-Gegenstücken unterscheiden. Im Zuge dessen konnte ich zeigen, dass sich mittels Änderung der Stöchiometrie des Perowskiten die Energie der Bandlücke gezielt verändern lässt, wie es auch für Dünnfilme bekannt ist. Weiter konnte ich das erste Mal zeigen, dass eine für Dünnfilme etablierte Passivierungsmethode ebenfalls auf Perowskit-Pulver anwendbar ist. Kapitel 11 ist ein Überblicksartikel, in dem ich zunächst die wichtigsten optischen Eigenschaften von Metall Halogen Perowskiten und deren Beeinflussung durch strukturelle Änderung zusammengefasst habe. Hierbei sind einige meiner Erkenntnisse aus Kapiteln 8-10 eingeflossen. Anschließend behandelt das Kapitel, wie dieser Zusammenhang zwischen optischen Eigenschaften und Struktur bisher genutzt wurde, um mittels optischer in situ Spektroskopie die Filmbildung von Perowskit-Dünnschichten zu untersuchen. In den Kapiteln 12-14 wird nun das in den vorangehenden Kapiteln generierte Wissen über den Zusammenhang zwischen strukturellen Änderungen im Perowskiten und dessen optischen Eigenschaften genutzt, um mittels optischer in situ Spektroskopie die Perowskit-Schichtbildung bei verschiedenen Prozessierungsmethoden besser zu verstehen. Kapitel 12 untersucht dazu die Bildung von MAPbI3 Dünnfilmen mittels der sogenannten Two-Step-Methode. Hier konnte ich mittels des Modells aus Kapitel 8 den Einfluss von Selbstabsorption auf die PL-Spektren klar identifizieren. Dies erlaubte die Identifikation eines Auflösungs-Rekristallisations-Prozesses, welcher eine wichtige Rolle für die Filmbildung spielt. In Kapitel 13 wird nun die Filmbildung von MAPbI3 mittels der sogenannten One-Step-Methode unter Verwendung der im Labor meistverwendeten Rotationsbeschichtung und der industrierelevanten Spritzdüsenbeschichtung untersucht. Mittels optischer in situ Spektroskopie konnten wir zeigen, dass prozessbedingte Unterschiede in der Struktur der Lösungsmittelkomplex-Phase dazu führen, dass sich das Perowskit-Wachstum bei der Rotationsbeschichtung sowohl quantitativ als auch qualitativ von der bei der Spritzdüsenbeschichtung auftretenden Perowskit-Kristallisation unterscheidet. In Kapitel 14 wird schließlich die Bildung eines Perowskiten mit unterschiedlichen Haliden mittels der Solvent-Engineering-Methode betrachtet, wobei der Einfluss der Temperatur des Anti-Lösungsmittels auf die Perowskit-Bildung und auf fertige Perowskit-Solarzellen untersucht wird. Hier konnte ich zeigen, dass für kälteres Anti-Lösungsmittel die Perowskit-Bildung langsamer und die resultierende Perowskit-Schicht dünner ist. Weiter ergaben meine Analysen, dass sich während der Filmbildung das Halid-Verhältnis im Perowskiten kontinuierlich ändert. Darüber hinaus konnte gezeigt werden, dass die mit kälterem Anti-Lösungsmittel prozessierten Filme eine reduzierte Dichte von Defektzuständen aufweisen, was auf eine bessere Relaxation von mechanischen Spannungen in den entsprechenden Perovskitschichten zurückgeführt wurde.
Massive expansions in the global population and the global digitalization throughout the industrial revolution are causing energy security issues that are no longer environmentally affordable through conventional power generation systems. As an alternative solution, the global power capacities and production of the renewable energy systems in general and the photovoltaic technologies in particular, are significantly increasing every year. With a lifetime range of 25–40 years, the PV power plants will eventually and over their lifetime or cumulatively turn into large masses of waste. This work briefly reviews the market state of the three generations of PV and summarizes their most recent technical challenges. It is highlighted that the c-Si (Crystalline Silicon) and CdTe (Cadmium Telluride) technologies have a relatively high level of market maturity, least number of technical challenges, and most interesting space for sustainable development. Furthermore, a one-of-a-kind sustainable and circular PV industry's business model was developed, to directly and indirectly address the practical business and engineering gaps concerning environmental, economic, social, and technical factors affecting the circular transition of the PV industry. The model assisted in reviewing and discussing articles concerning material compositions, manufacturing processes, and dismantling processes. Previous reviews and surveys reported the lack of dedicated PV dismantling facilities and miscommunications between the supply chain stages and logistics. Therefore, a critical review was done on the most recent and comprehensive articles related to the optimizations and improvements of the PV industry's sustainability towards the anticipated circular economy. Additionally, this work highlights the objectives, key constraints, and major strategies of the sustainability's environmental, economic, and social pillars within the photovoltaic industry and business stages, which introduced the possible contributions of the industry 4.0 technologies. Therefore, a brief section was dedicated to the possible utilizations of Industry 4.0 throughout the critical stages of the photovoltaics' economy. Finally, a research road map was developed to assist all levels of future researches in optimizing the PV's circular economy and the overall sustainability of the industry.
Solar dryers are equipped with photovoltaic panels to increase energy efficiency, profitability and independency on nonrenewable energy. Also, these dryers need to be assessed from economic, environmental, and energy-exergy perspectives to determine whether the devices are cost-effective and feasible on a large scale. This study has performed energy, exergy, economic, and environmental evaluations on the newest solar dryers equipped with photovoltaic panels and photovoltaic thermal collectors. In this regard, solar dryers with hot air collectors, concentrating solar dryers, photovoltaic thermal dryers, infrared, greenhouse, and heat pump solar dryers equipped with photovoltaic panels and photovoltaic thermal collectors were investigated. Then, studied dryers were categorized. Initially, this classification was carried out regarding the dried products and subsequently, their economic-environmental and energy-exergy were compared. Despite the short drying time of infrared and heat pump solar dryers, these dryers’ construction and energy costs are relatively high. Comparatively to other solar dryers, concentrating solar dryers have high energy efficiency and short drying times.
Building integration with photovoltaics has received more and more attention in the development of green buildings. But traditional photovoltaic windows cannot make monthly adjustments to changes in solar altitude and weather. This paper proposes a new type of photovoltaic shutter system, the inclination angle and spacing of which can be adjusted according to the solar altitude angle and weather in different months. In order to better study the natural lighting quality and photoelectric conversion characteristics, this paper builds an experimental test platform for louvered photovoltaic windows. The final results of Illuminance of experiment and simulation are consistent. Furthermore, a new daylighting index is innovatively proposed, which compared to the general annual statistical indicators that are not precise enough. Combined with the typical weather in the area with hot summer and cold winter, the monthly angle and spacing regulation strategy is optimized. The research results show that compared with the change of the inclination angle, the change of the spacing makes the change of indoor lighting and electricity revenue more obvious. The months before and after June are the months with the lowest electric energy and the best indoor lighting quality of louvered photovoltaic windows. Its electricity revenue is between 9.18-22.46 kWh, and the proportion of indoor space that meets the 450-2000 lux illuminance range and the daylighting time exceeds 50% is about 85%. The months with higher electricity revenues are around March and October, with revenues ranging from 14.11 to 53.04 kWh.
This paper presents modeling and experimental studies on water spray coolers for commercial photovoltaic modules. This paper has compared the energy yield of four photovoltaic commercial modules that were installed with a fixed tilt angle being equal to the local latitude in central Vietnam, including one photovoltaic module using a water spray cooler and three photovoltaic modules without cooling. Experimental results on sunny days have been shown that the energy yield difference between four PV modules under the same working condition is lower than 1%. In addition, on sunny days when the set working temperature of the water spray cooler is 45 °C, the average improvement efficiency of a photovoltaic module using a water spray cooler compared to three reference photovoltaic modules is 2.64%, 3.83%, and 6.18%, for an average of 4.22%. A simple thermal–electrical model of a photovoltaic module with a water spray cooler has been developed and tested. The normalized root mean square error between simulated and measured results of photovoltaic module power output on a sunny day without cooling and with water spray cooler reached 6.5% and 8.5%, respectively. The obtained results are also demonstrated that the reasonableness of the simple thermal–electrical model of the photovoltaic module with water spray cooler and the feasibility of a cooling system is improved to increase the efficiency of the photovoltaic module. In addition, they can be considered as a basis for new experimental models in the future.
Mitigation of climate change requires a decrease in greenhouse gas emissions. It motivates an increase in renewable electricity generation. Farmers can develop renewable energy and increase their profitability by allocating agricultural land to PV power plants. This transition from crop production to electricity generation needs ecological and economic assessment from alternative land utilization. The novelty of this study is an integrated assessment that links economic and environmental (carbon dioxide emissions) indicators. They were calculated for crop production and solar power generation in a semi-arid zone. The results showed that gross income (crop production) ranges from USD 508/ha to USD 1389/ha. PV plants can generate up to 794 MWh/ha. Their market cost is EUR 82,000, and their production costs are less than wholesale prices in Ukrainian. The profitability index of a PV project ranges from 1.26 (a discount range is 10%) to 3.24 (a discount rate is 0). The sensitivity analysis was carried out for six variables. For each chosen variable, we found its switching value. It was revealed that the most sensitive variable is a feed-in tariff. Operational expenses and investment costs are the most sensitive variables. Carbon dioxide footprints range from 500 to 3200 kgCO2/ha (depending on the crop). A 618 kW PV plant causes a release of carbon dioxide in the range of 5.2–11.4 gCO2/kWh. The calculated carbon dioxide payback period varies from 5 to 10 months.
Grid-connected utility-scale solar PV has emerged as a potential pathway to ensure deep decarbonization of electricity in regions with fossil fuel-dominated energy mixes. Research on utility-scale solar PV projects mainly focuses on assessing technical or economic feasibility. Environmental performance assessments of large-scale solar applications are scarce. There is limited information on the greenhouse gas (GHG) emissions and energy footprints of utility-scale solar energy systems. Earlier studies conducted on small-scale solar systems have limited application in the grid system. We developed a comprehensive bottom-up life cycle assessment model to evaluate the life cycle GHG emissions and energy profiles of utility-scale solar photovoltaic (PV) system with lithium-ion battery storage to provide a consistent electricity supply to the grid with peak load options. We conducted a case study for a fossil fuel-based energy jurisdiction, Alberta (a western province in Canada). The results of the energy assessment show that raw material extraction, production, and assembly of solar panels are the key drivers, accounting for 53% of the total consumption. Energy consumed during battery manufacturing is responsible for 28%. The system shows a net energy production with a mean net energy ratio as high as 6.6 for two-axis sun tracking orientation. The life cycle GHG emissions range from 98.3 to 149.3 g CO2 eq /kWh with a mean value of 123.8 g CO2 eq /kWh. The largest emissions contribution is due to the manufacturing of batteries, 54% of the total emissions. The solar PV system offers a mean energy payback time of 3.8 years (with a range of 3.3 to 4.2 years). The results are highly sensitive to the expected lifetime of the system, the panel’s peak wattage, and process energy consumption at various life cycle stages.
Calcium looping is a promising thermochemical energy storage process to be integrated into concentrating solar power plants. This work develops for the first time a comprehensive life cycle assessment of the calcium looping integration in solar plants to assess the potential of the technology from an environmental perspective. Two representative integrations are analysed, representing daily (hot) and seasonal (cold) storage designs. Similar performance environmental impacts are observed in both, with slightly better results for the seasonal storage case due to the simplified energy storage integration. The results show the moderate environmental impact of calcium looping thermochemical energy storage technology, resulting in lower equivalent carbon dioxide emissions (24 kg/MWh) than other energy storage options such as molten salt-based solar facilities (40 kg/MWh). Plant construction involves a higher energy demand for the process, whilst the operation and maintenance on the plant represent a moderate impact due to the low environmental impact of limestone, the unique raw material of the process, and the lower water consumption compared to typical concentrating solar power plants. Besides, the energy required for the system is first time analysed, obtaining an energy payback time of 2.2 years and 2.5 years depending on the storage strategy design.
All the components of a photovoltaic system that are not photovoltaic modules are considered “Balance of System” (BoS) components. From a life cycle assessment perspective, BoS is becoming an important contributor to impacts, both environmental and economic, with an increasing share of impacts compared to the contribution of modules. In this chapter, an overview of all required BoS components for an operational photovoltaic system and its life cycle assessment are presented: mounting sytems, cabling, regulators, inverters, transformers; for roof-top or ground systems, for DC or AC electricity supply. Although most new installed capacity is grid connected, electricity storage is becoming a key component, for stand alone systems, but also for grid stabilisation when renewable sources are the main electricity suppliers to the grid. Two sections are devoted to a brief presentation of electricity storage and an introduction to life cycle assessment methodology for batteries (in some cases including a second life) and results of impacts for lithium ion battery technologies, the most broadly used today for photovoltaic systems which include electricity storage.
Fossil fuel reserves have played a crucial role for over a century, by providing high net energy gains to fuel our societies. The Energy Return on Investment (EROI) of conventional oil and gas has been in constant decline since the 1930's, though, and the common belief has been that no viable alternatives exist to offset this trend. In particular, photovoltaic (PV) technologies have long been shunned because of supposedly low EROI. We show that the latter is an artifact of inconsistent calculations, and that switching from burning fossil fuels as feedstock in thermal power plants to using them for building large-scale PV systems would increase the associated EROI by at least one order of magnitude. Deploying large PV capacities worldwide, long before the EROI of fossil fuels eventually approaches unity, may actually be amongst the most effective strategies to reach the ultimate long-term goal of putting an end to our dependence on non-renewable energy.
Energy payback time and carbon footprint of commercial roof-top photovoltaic systems are calculated based on new 2011 manufacturers' data; and on 2013 equipment manufacturers' estimates of "micromorph" silicon photovoltaic modules. The energy payback times and carbon footprints are 1.96, 1.24, 1.39, 0.92, 0.68, and 1.02 years and 38.1, 27.2, 34.8, 22.8, 15.8, and 21.4 g CO2-eq/kWh for monocrystalline silicon, multicrystalline silicon, amorphous silicon, "micromorph" silicon, cadmium telluride and CIGS roof-top photovoltaic systems, respectively, assuming a poly-silicon production with hydropower; ingot-, wafer-, solar cell and module production with UCTE electricity; an irradiation on an optimized-angle of 1700 kWh/(m 2×year); excluding installation, operation and maintenance and end-of-life phase. Shifting production of poly-silicon, ingots, wafers, cells and modules to China results in similar energy payback times but increases the carbon footprint by a factor 1.3-2.1, depending on the electricity intensity of manufacturing.
In this study, we investigate the performance ratio (PR) of about 100 German photovoltaic system installations. Monitored PR is found to be systematically lower by ~2–4% when calculated with irradiation data obtained by pyranometers (henceforth denoted as PRPyr) as compared with irradiation amounts measured by reference cells (denoted as PRSi). Annual PRSi for the ~100 systems is found to be between ~70% and ~90% for the year 2010, with a median PR of ~84%. Next, simulations were performed to determine loss mechanisms of the top 10 performing systems, revealing a number of these loss
mechanisms may still allow for some optimization. Despite the fact that we do not see such values from our monitoring data base up to now, we believe PRSi values above 90% are realistic even today, using today’s commercially available components, and should be expected more frequently in the future. This contribution may help in deepening our knowledge on both energy loss mechanisms and efficiency limits on the system level and standardization processes of system-related aspects.
In this report the environmental aspects of solar cell modules based on multicrystalline silicon are investigated by means of the Environmental Life Cycle Assessment method. Three technology cases are distinguished, namely present-day module production technology, future probable technology and future optimistic technology. For these three cases the production technology is described, the material requirements and environmental emissions are inventarised and the energy requirements and energy pay-back times are discussed. Finally recommendations with respect to Dutch photovoltaic R&D policy are given.
Because of the pressure for timely, informed decisions in public health and clinical practice and the explosion of information in the scientific literature, research results must be synthesized. Meta-analyses are increasingly used to address this problem, and they often evaluate observational studies. A workshop was held in Atlanta, Ga, in April 1997, to examine the reporting of meta-analyses of observational studies and to make recommendations to aid authors, reviewers, editors, and readers.
Twenty-seven participants were selected by a steering committee, based on expertise in clinical practice, trials, statistics, epidemiology, social sciences, and biomedical editing. Deliberations of the workshop were open to other interested scientists. Funding for this activity was provided by the Centers for Disease Control and Prevention.
We conducted a systematic review of the published literature on the conduct and reporting of meta-analyses in observational studies using MEDLINE, Educational Research Information Center (ERIC), PsycLIT, and the Current Index to Statistics. We also examined reference lists of the 32 studies retrieved and contacted experts in the field. Participants were assigned to small-group discussions on the subjects of bias, searching and abstracting, heterogeneity, study categorization, and statistical methods.
From the material presented at the workshop, the authors developed a checklist summarizing recommendations for reporting meta-analyses of observational studies. The checklist and supporting evidence were circulated to all conference attendees and additional experts. All suggestions for revisions were addressed.
The proposed checklist contains specifications for reporting of meta-analyses of observational studies in epidemiology, including background, search strategy, methods, results, discussion, and conclusion. Use of the checklist should improve the usefulness of meta-analyses for authors, reviewers, editors, readers, and decision makers. An evaluation plan is suggested and research areas are explored.
Recently, the data for photovoltaics in the ecoinvent database have been updated on behalf of the European Photovoltaics Industry Association and the Swiss Federal Authority for Energy. Data have been collected in this project directly from manufacturers and were provided by other research projects. LCA studies from different authors are considered for the assessment. The information is used to elaborate a life cycle inventory from cradle to grave for the PV electricity production in 3kWp plants in the year 2005.
The inventories cover mono- and polycrystalline cells, amorphous and ribbon-silicon, CdTe and CIS thin film cells. Environmental impacts due to the infrastructure for all production stages and the effluents from wafer production are also considered. The ecoinvent database is used as background database.
Results from the LCA study are presented, comparing different types of cells and analysing also the electricity production in a range of different countries. It is also discussed how the environmental impacts of photovoltaics have been reduced over the last 15 years, using the CED indicator. The consistent and coherent LCI datasets for basic processes make it easier to perform LCA studies, and increase the credibility and acceptance of the life cycle results. The content of the PV LCI datasets is made publicly available via the website www.ecoinvent.org for ecoinvent members.
Together with 11 European and US photovoltaic companies an extensive effort has been made to collect Life Cycle Inventory (LCI) data that represents the status of production technology for crystalline silicon modules for the year 2004. These data can be used to evaluate the environmental impacts of photovoltaic solar energy systems.
The new data covers all processes from silicon feedstock production via wafer- and cell- to module manufacturing. All commercial wafer technologies are covered, i.e multi- and mono-crystalline wafers as well as ribbon technologies. For monocrystalline silicon wafer production further improvement of the data quality is recommended.
This paper describes the life cycle assessment (LCA) for photovoltaic (PV) power plants in the new ecoinvent database. Twelve different, grid-connected photovoltaic systems were studied for the situation in Switzerland in the year 2000. They are manufactured as panels or laminates, from monocrystalline or polycrystalline silicon, installed on facades, slanted or flat roofs, and have 3 kWp capacity. The process data include quartz reduction, silicon purification, wafer, panel and laminate production, mounting structure, 30 years operation and dismantling. In contrast to existing LCA studies, country-specific electricity mixes have been considered in the life cycle inventory (LCI) in order to reflect the present market situation. The new approach for the allocation procedure in the inventory of silicon purification, as a critical issue of former studies, is discussed in detail. The LCI for photovoltaic electricity shows that each production stage is important for certain elementary flows. A life cycle impact assessment (LCIA) shows that there are important environmental impacts not directly related to the energy use (e.g., process emissions of NOx from wafer etching). The assumption for the used supply energy mixes is important for the overall LCIA results of different production stages. The presented life cycle inventories for photovoltaic power plants are representative for newly constructed plants and for the average photovoltaic mix in Switzerland in the year 2000. A scenario for a future technology (until 2010) helps to assess the relative influence of technology improvements for some processes. The very detailed ecoinvent database forms a good basis for similar studies in other European countries or for other types of solar cells. Copyright © 2005 John Wiley & Sons, Ltd.
This analysis reviews and synthesizes the literature on the net energy return for electric power generation by wind turbines. Energy return on investment (EROI) is the ratio of energy delivered to energy costs. We examine 119 wind turbines from 50 different analyses, ranging in publication date from 1977 to 2007. We extend on previous work by including additional and more recent analyses, distinguishing between important assumptions about system boundaries and methodological approaches, and viewing the EROI as function of power rating. Our survey shows an average EROI for all studies (operational and conceptual) of 25.2 (n = 114; std. dev = 22.3). The average EROI for just the operational studies is 19.8 (n = 60; std. dev = 13.7). This places wind in a favorable position relative to fossil fuels, nuclear, and solar power generation technologies in terms of EROI.
Together with a number of PV companies an extensive effort has been made to collect Life Cycle Inventory data that represents the current status of production technology for crystalline silicon modules. The new data cover all processes from silicon feedstock production to cell and module manufacturing. All commercial wafer technologies are covered, that is multi- and monocrystalline wafers as well as ribbon technology. The presented data should be representative for the technology status in 2004, although for monocrystalline Si crystallisation further improvement of the data quality is recommended. On the basis of the new data a Life Cycle Assessment has been performed, which shows that c-Si PV systems are in a good position to compete with other energy technologies. Energy Pay-Back Times of 1.7-2.7 yr are found for South-European locations, while life-cycle CO 2 emissions are in the 30-45 g/kWh range. Clear perspectives exist for further improvements of roughly 40-50%.
In this paper we investigate the energy requirements of PV modules and systems and calculate the Energy Pay-Back Time for two major PV applications. Based on a review of past energy analysis studies we explain the main sources of differences and establish a "best estimate" for key system components. For present-day c-Si modules the main source of uncertainty is the preparation of silicon feedstock from semiconductor industry scrap. The best estimates of 4200 respectively 6000 MJ (primary energy) per m2 module area are probably representative for near-future, frameless mc-Si and sc-Si modules. For a-Si thin film modules we estimate energy requirements at 1200 MJ/m2 for present technology. Present-day and future energy requirements have also been estimated for the BOS in grid-connected roof-top systems and for Solar Home Systems. The Energy Pay-Back Time of present-day grid-connected systems is estimated at 3-8 years (under 1700 kWh/m2 irradiation) and 1-2 years for future systems. The specific CO2 emission of these systems is 60-150 g/kWh now and 20-30 g/kWh in the future. In Solar Home Systems the battery is the cause for a relatively high EPBT of more than 7 years, with little prospects for future improvements. The CO2 emision is now estimated at 250-400 g/kWh and around 200 g/kWh in the future. This leads to the conclusion that PV systems, especially grid-connected systems, can contribute significantly to the mitigation of CO2 emissions.
Economic production and, more generally, most global societies, are overwhelmingly dependant upon depleting supplies of fossil fuels. There is considerable concern amongst resource scientists, if not most economists, as to whether market signals or cost benefit analysis based on today’s prices are sufficient to guide our decisions about our energy future. These suspicions and concerns were escalated during the oil price increase from 2005 – 2008 and the subsequent but probably related market collapse of 2008. We believe that Energy Return On Investment (EROI) analysis provides a useful approach for examining disadvantages and advantages of different fuels and also offers the possibility to look into the future in ways that markets seem unable to do. The goal of this paper is to review the application of EROI theory to both natural and economic realms, and to assess preliminarily the minimum EROI that a society must attain from its energy exploitation to support continued economic activity and social function. In doing so we calculate herein a basic first attempt at the minimum EROI for current society and some of the consequences when that minimum is approached. The theory of the minimum EROI discussed here, which describes the somewhat obvious but nonetheless important idea that for any being or system to survive or grow it must gain substantially more energy than it uses in obtaining that energy, may be especially important. Thus any particular being or system must abide by a “Law of Minimum EROI”, which we calculate for both oil and corn-based ethanol as about 3:1 at the mine-mouth/farm-gate. Since most biofuels have EROI’s of less than 3:1 they must be subsidized by fossil fuels to be useful.
Providing care for a frail older adult has been described as a stressful experience that may erode psychological well-being and physical health of caregivers. In this meta-analysis, the authors integrated findings from 84 articles on differences between caregivers and noncaregivers in perceived stress, depression, general subjective well-being, physical health, and self-efficacy. The largest differences were found with regard to depression (g = .58), stress (g = .55), self-efficacy (g = .54), and general subjective well-being (g = -.40). Differences in the levels of physical health in favor of noncaregivers were statistically significant, but small (g = .18). However, larger differences were found between dementia caregivers and noncaregivers than between heterogeneous samples of caregivers and noncaregivers. Differences were also influenced by the quality of the study, relationship of caregiver to the care recipient, gender, and mean age of caregivers.
In this study, life cycle assessment (LCA) of Cadmium Telluride (CdTe) photovoltaic (PV) system is carried out to analyze its environmental impact on global warming (GW) and abiotic resource depletion (ARD). The CdTe PV system consists of CdTe PV module, power conditioning system (PCS) and balance of system (BOS). The global warming potential (GWP) of CdTe PV system is 11.1g CO2 eq./kWh under the condition of 1,810.4 kWh/m2/yr, 11.2% of conversion efficiency, 80% of performance ratio. The ARD of system is 1.20E-02/yr/kWh. The CdTe PV module accounts for 62.9% and 59.3% of the GWPs and ARDs of the entire CdTe PV system, respectively. And energy payback time (EPBT) which is the time required to compensate the energy used during the life cycle of PV system with avoided primary energy reduction by using PV system is estimated. The EPBT of CdTe PV system is 0.69 years, meaning that the electricity generated by the PV is regarded as net energy profit.
In this paper a Life Cycle Analysis (LCA) methodology is used to investigate the energetic and environmental impact of a Building Integrated Photovoltaic installation (BIPV) with reference to a roof installation case study. The results reveal that the roof integrated photovoltaic systems can bring both energy and environmental benefits even in areas characterised by medium values of insolation. It is demonstrated that the embodied energy consumed during manufacturing phases is normally recovered after few years of operation; the same can be said for pollutant emissions. On the contrary, the economic payback time is always higher than the energy payback time and sometimes exceeds the expected life of the systems.
The energy requirements for the production of PV modules and BOS components are analyzed in order to evaluate the energy pay-back time and the CO2 emissions of grid-connected PV systems. Both c-Si and thin film module technologies are investigated. Assuming an irradiation of 1700 kWh/m2/yr the energy pay-back time was found to be 2·5–3 years for present-day roof-top installations and 3–4 years for multi-megawatt, ground-mounted systems. The specific CO2 emission of the rooftop systems was calculated as 50–60 g/kWh now and possibly 20–30 g/kWh in the future. This leads to the conclusion that in the longer term grid-connected PV systems can contribute significantly to the mitigation of CO2 emissions. Copyright © 2000 John Wiley & Sons, Ltd.
Performance of a 160 m2photovoltaic installation at the Napier University's Merchiston Campus, situated 3 km from Edinburgh's city centre, is presented. The alternative current and direct current electrical outputs were recorded since the installation of the facility was completed in April 2005. An analysis of the efficiency of the facility, as well as energetic, environmental, and monetary life cycle assessments, using long-term meteorological data is presented in this article.
The energetic and environmental life cycle assessment of a 4.2kWp stand-alone photovoltaic system (SAPV) at the University of Murcia (south-east of Spain) is presented. PV modules and batteries are the energetically and environmentally most expensive elements. The energy pay-back time was found to be 9.08years and the specific CO2 emissions was calculated as 131g/kWh. The SAPV system has been environmentally compared with other supply options (diesel generator and Spanish grid) showing lower impacts in both cases. The results show the CO2-emission reduction potential of SAPV systems in southern European countries and point out the critical environmental issues in these systems.
A high energy return on energy investment (EROI) of an energy production process is crucial to its long-term viability. The EROI of conventional thermal electricity from fossil fuels has been viewed as being much higher than those of renewable energy life-cycles, and specifically of photovoltaics (PVs). We show that this is largely a misconception fostered by the use of outdated data and, often, a lack of consistency among calculation methods. We hereby present a thorough review of the methodology, discuss methodological variations and present updated EROI values for a range of modern PV systems, in comparison to conventional fossil-fuel based electricity life-cycles.
The body of life cycle assessment (LCA) literature is vast and has grown over the last decade at a dauntingly rapid rate. Many LCAs have been published on the same or very similar technologies or products, in some cases leading to hundreds of publications. One result is the impression among decision makers that LCAs are inconclusive, owing to perceived and real variability in published estimates of life cycle impacts. Despite the extensive available literature and policy need formore conclusive assessments, only modest attempts have been made to synthesize previous research. A significant challenge to doing so are differences in characteristics of the considered technologies and inconsistencies in methodological choices (e.g., system boundaries, coproduct allocation, and impact assessment methods) among the studies that hamper easy comparisons and related decision support. An emerging trend is meta-analysis of a set of results from LCAs, which has the potential to clarify the impacts of a particular technology, process, product, or material and produce more robust and policy-relevant results. Meta-analysis in this context is defined here as an analysis of a set of published LCA results to estimate a single or multiple impacts for a single technology or a technology category, either in a statistical sense (e.g., following the practice in the biomedical sciences) or by quantitative adjustment of the underlying studies to make them more methodologically consistent. One example of the latter approach was published in Science by Farrell and colleagues (2006) clarifying the net energy and greenhouse gas (GHG) emissions of ethanol, in which adjustments included the addition of coproduct credit, the addition and subtraction of processes within the system boundary, and a reconciliation of differences in the definition of net energy metrics. Such adjustments therefore provide an even playing field on which all studies can be considered and at the same time specify the conditions of the playing field itself. Understanding the conditions under which a meta-analysis was conducted is important for proper interpretation of both the magnitude and variability in results. This special supplemental issue of the Journal of Industrial Ecology includes 12 high-quality metaanalyses and critical reviews of LCAs that advance understanding of the life cycle environmental impacts of different technologies, processes, products, and materials. Also published are three contributions on methodology and related discussions of the role of meta-analysis in LCA. The goal of this special supplemental issue is to contribute to the state of the science in LCA beyond the core practice of producing independent studies on specific products or technologies by highlighting the ability of meta-analysis of LCAs to advance understanding in areas of extensive existing literature. The inspiration for the issue came from a series of meta-analyses of life cycle GHG emissions from electricity generation technologies based on research from the LCA Harmonization Project of the National Renewable Energy Laboratory (NREL), a laboratory of the U.S. Department of Energy, which also provided financial support for this special supplemental issue. (See the editorial from this special supplemental issue [Lifset 2012], which introduces this supplemental issue and discusses the origins, funding, peer review, and other aspects.) The first article on reporting considerations for meta-analyses/critical reviews for LCA is from Heath and Mann (2012), who describe the methods used and experience gained in NREL's LCA Harmonization Project, which produced six of the studies in this special supplemental issue. Their harmonization approach adapts key features of systematic review to identify and screen published LCAs followed by a meta-analytical procedure to adjust published estimates to ones based on a consistent set of methods and assumptions to allow interstudy comparisons and conclusions to be made. In a second study on methods, Zumsteg and colleagues (2012) propose a checklist for a standardized technique to assist in conducting and reporting systematic reviews of LCAs, including meta-analysis, that is based on a framework used in evidence-based medicine. Widespread use of such a checklist would facilitate planning successful reviews, improve the ability to identify systematic reviews in literature searches, ease the ability to update content in future reviews, and allow more transparency of methods to ease peer review and more appropriately generalize findings. Finally, Zamagni and colleagues (2012) propose an approach, inspired by a meta-analysis, for categorizing main methodological topics, reconciling diverging methodological developments, and identifying future research directions in LCA. Their procedure involves the carrying out of a literature review on articles selected according to predefined criteria.
A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.
We present the process and the results of harmonization of greenhouse gas (GHG) emissions during the life cycle of commercial thin-film photovoltaics (PVs), that is, amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium gallium diselenide (CIGS). We reviewed 109 studies and harmonized the estimates of GHG emissions by aligning the assumptions, parameters, and system boundaries. During the initial screening we eliminated abstracts, short conference papers, presentations without supporting documentation, and unrelated analyses; 91 studies passed this initial screening. In the primary screening we applied rigorous criteria for completeness of reporting, validity of analysis methods, and modern relevance of the PV system studied. Additionally, we examined whether the product is a commercial one, whether the production line still exists, and whether the study's core data are original or secondary. These screenings produced five studies as the best representations of the carbon footprint of modern thin-film PV technologies. These were harmonized through alignment of efficiency, irradiation, performance ratio, balance of system, and lifetime. The resulting estimates for carbon footprints are 20, 14, and 26 grams carbon dioxide equivalent per kilowatt-hour (g CO2-eq/kWh), respectively, for a-Si, CdTe, and CIGS, for ground-mount application under southwestern United States (US-SW) irradiation of 2,400 kilowatt-hours per square meter per year (kWh/m2/yr), a performance ratio of 0.8, and a lifetime of 30 years. Harmonization for the rooftop PV systems with a performance ratio of 0.75 and the same irradiation resulted in carbon footprint estimates of 21, 14, and 27 g CO2-eq/kWh, respectively, for the three technologies. This screening and harmonization rectifies previous incomplete or outdated assessments and clarifies variations in carbon footprints across studies and amongst thin-film technologies.
Published scientific literature contains many studies estimating life cycle greenhouse gas (GHG) emissions of residential and utility-scale solar photovoltaics (PVs). Despite the volume of published work, variability in results hinders generalized conclusions. Most variance between studies can be attributed to differences in methods and assumptions. To clarify the published results for use in decision making and other analyses, we conduct a meta-analysis of existing studies, harmonizing key performance characteristics to produce more comparable and consistently derived results.
Screening 397 life cycle assessments (LCAs) relevant to PVs yielded 13 studies on crystalline silicon (c-Si) that met minimum standards of quality, transparency, and relevance. Prior to harmonization, the median of 42 estimates of life cycle GHG emissions from those 13 LCAs was 57 grams carbon dioxide equivalent per kilowatt-hour (g CO2-eq/kWh), with an interquartile range (IQR) of 44 to 73. After harmonizing key performance characteristics (irradiation of 1,700 kilowatt-hours per square meter per year (kWh/m2/yr); system lifetime of 30 years; module efficiency of 13.2% or 14.0%, depending on module type; and a performance ratio of 0.75 or 0.80, depending on installation, the median estimate decreased to 45 and the IQR tightened to 39 to 49. The median estimate and variability were reduced compared to published estimates mainly because of higher average assumptions for irradiation and system lifetime.
For the sample of studies evaluated, harmonization effectively reduced variability, providing a clearer synopsis of the life cycle GHG emissions from c-Si PVs. The literature used in this harmonization neither covers all possible c-Si installations nor represents the distribution of deployed or manufactured c-Si PVs.
The authors have been studied the life-cycle analysis of the VLS-PV systems installed in desert area using sc-Si, mc-Si, a-Si/sc-Si, a-Si/μc-Si, CdTe, and CIS PV modules. The sc-Si and a-Si/sc-Si, a-Si/μc-Si are new items from the last studies [1]. It is assumed 1 GW system in Gobi desert including transmission lines. We estimated energy requirement, energy pay-back time, CO2 emissions, and CO2 emissions rate. Concerning the energy requirement, the CIS is the smallest, and biggest energy requirement is the sc-Si. The mc-Si, a-Si/sc-Si, thin-film Si and CdTe are average. The energy pay-back time of the CIS’s VLS-PV system is approximately 1.8 years, and sc-Si is 2.5 years. The others are approximately 2.0–2.3 years. Characteristics of the CO2 emissions rate are almost same as energy pay-back time. The CO2 emissions rate is 43–54 g-CO2/kW h. The mc-Si, a-Si/sc-Si, and CIS shows lower CO2 emissions rate.
Crystalline silicon photovoltaic (PV) modules are often stated as being the most reliable element in PV systems. This presumable high reliability is reflected by their long power warranty periods. In agreement with these long warranty times, PV modules have a very low total number of returns, the exceptions usually being the result of catastrophic failures. Up to now, failures resulting from degradation are not typically taken into consideration because of the difficulties in measuring the power of an individual module in a system. However, lasting recent years PV systems are changing from small isolated systems to large grid-connected power stations. In this new scenario, customers will become more sensitive to power losses and the need for a reliability model based on degradation may become of utmost importance. In this paper, a PV module reliability model based on degradation studies is presented. The main analytical functions of reliability engineering are evaluated using this model and applied to a practical case, based on state-of-the-art parameters of crystalline silicon PV technology. Relevant and defensible power warranties and other reliability data are obtained with this model based on measured degradation rates and time-dependent power variability. In the derivation of the model some assumptions are made about the future behaviour of the products—i.e. linear degradation rates—although the approach can be used for other assumed functional profiles as well. The method documented in this paper explicitly shows manufacturers how to make reasonable and sensible warranty projections. Copyright © 2008 John Wiley & Sons, Ltd.
Photovoltaic installations (PV-systems) are heavily promoted in Europe. In this paper, the Life Cycle Analysis (LCA) method is used to find out whether the high subsidy cost can be justified by the environmental benefits. Most existing LCAs of PV only use one-dimensional indicators and are only valid for regions with a high solar irradiation. This paper, however, presents a broad environmental evaluation of residential PV-systems for regions with a rather low solar irradiation of 900-1000Â kWh/m2/year, a value typical for Northern Europe and Canada. Based on the Ecoinvent LCA database, six Life Cycle Impact Assessment (LCIA) methods were considered for six different PV-technologies; the comprehensive Eco-Indicator 99 (EI 99) with its three perspectives (Hierarchist, Egalitarian and Individualistic) next to three one-dimensional indicators, namely Cumulative Energy Demand (CED), Global Warming Potential (GWP) and the Energy Payback Time (EPT). For regions with low solar irradiation, we found that the EPT is less than 5 years. The Global Warming Potential of PV-electricity is about 10 times lower than that of electricity from a coal fired plant, but 4 times higher when compared to a nuclear power plant or a wind farm. Surprisingly, our results from the more comprehensive EI 99 assessment method do not correlate at all with our findings based on EPT and GWP. The results from the Individualist perspective are strongly influenced by the weighting of the different environmental aspects, which can be misleading. Therefore, to obtain a well-balanced environmental assessment of energy technologies, we recommend a carefully evaluated combination of various impact assessment methods.
BP Solar has utilized long term module exposure data and field return data to determine module lifetimes, expected failure rates and to identify failure mechanisms. While outdoor testing is a must for understanding PV reliability, it takes much too long to be of use in determining the effects of changes in materials, processes or equipment. This paper describes how BP Solar utilizes accelerated stress testing to verify the robustness of its new PV products
In order to find an upper theoretical limit for the efficiency of p‐n junction solar energy converters, a limiting efficiency, called the detailed balance limit of efficiency, has been calculated for an ideal case in which the only recombination mechanism of hole‐electron pairs is radiative as required by the principle of detailed balance. The efficiency is also calculated for the case in which radiative recombination is only a fixed fraction f c of the total recombination, the rest being nonradiative. Efficiencies at the matched loads have been calculated with band gap and f c as parameters, the sun and cell being assumed to be blackbodies with temperatures of 6000°K and 300°K, respectively. The maximum efficiency is found to be 30% for an energy gap of 1.1 ev and f c = 1. Actual junctions do not obey the predicted current‐voltage relationship, and reasons for the difference and its relevance to efficiency are discussed.
