Article

Energy Learning Curves of PV Systems

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Abstract

The energy demand of photovoltaic (PV) systems is an important part of energy sustainability of PV systems. PV systems are considered sustainable energy systems when the produced energy is higher than the energy needed for the PV system on a life-cycle basis. This paper employs financial learning curve concepts to determine the energy demand of major PV module technologies and systems. General PV module and PV system energy learning curves are calculated by weighting energy demand of different PV systems according to their share in PV market. Additionally, the contribution of module efficiency for reducing specific energy demand is considered. We find an energy learning rate of 17% for PV modules and 14% for PV systems on the basis of a market weighted mix of technologies and volumes. Energy payback time (EPBT) and energy return on energy investment (EROI) in 2010 and for the year 2020 are calculated via the energy learning rate and indicates a further significant progress in energetic productivity of PV systems. To the knowledge of the authors this publication shows for the first time that the energy consumption in PV manufacturing follows the log-linear learning curve law similar to the evolution of production cost. This allows calculating EPBT or EROI for future prognoses. Furthermore, it shows significant evidence of how sustainable PV systems are and justifies their growing share in the energy market.

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... This value refers to distributed PV systems with monocrystalline silicon PV module technology. This value is also in accordance with the values calculated and presented in Leccisi et al. (2016) (comprised between 25,000 and 30,000 MJ th /kW p (efficiency of the electricity grid of the (Jülch, 2016) country assumed equal to 30%)) and in Görig and Breyer (2016) (21,300 MJ th /kW p ). ...
... The EPBT varies between a minimum and maximum values of 1.8 and 3.2 years respectively, with an average of 2.5 years across the entire country. Similar results have been presented in Görig and Breyer (2016) but with a much lower spatial resolution (1°) and between 65°N and 65°S, thus not considering part of the Swedish territory. Even in the most northern parts of the country, the implementation of PV systems can achieve favourable environmental targets with EPBT lower than 3.5 years. ...
Article
This study aims to develop a gridded optimization model for studying photovoltaic applications in Nordic countries. The model uses the spatial and temporal data generated by the mesoscale models STRÅNG and MESAN developed by the Swedish Meteorological and Hydrological Institute. The model is developed based on the comparison between five irradiance databases, three decomposition models, two transposition models, and two photovoltaic models. Several techno-economic and environmental aspects of photovoltaic systems and photovoltaic systems integrated with batteries are investigated from a spatial perspective. CM SAF SARAH-2, Engerer2, and Perez1990 have shown the best performances among the irradiance databases, and decomposition and transposition models, respectively. STRÅNG resulted in the second-best irradiance database to be used in Sweden for photovoltaic applications when comparing hourly global horizontal irradiance with weather station data. The developed model can be employed for carrying out further detailed gridded techno-economic assessments of photovoltaic applications and energy systems in general in Nordic countries. The model structure is generic and can be applied to every gridded climatological database worldwide.
... Such reductions are confirmed in the literature. In a peer-reviewed study published this year (Görig and Breyer, 2016) the CED for the current market-based mix of PV systems was found to be 3.8 GJ/m 2 (for ground-mounted systems) and 2.7 GJ/m 2 (for rooftop systems). It should also be noted that Ferroni and Hopkirk's assumption that one third of the Swiss PV systems are ground-mounted is incorrect; the vast majority of Swiss PV installations actually consists of rooftop systems (Hüsser, 2016). ...
... Based on the latest and most up-to-date peer-reviewed literature (Görig and Breyer, 2016;Leccisi et al., 2016;Hou et al., 2016.) Based on invalid assumption that 25% of the produced electricity must be stored. ...
Article
A recent paper by Ferroni and Hopkirk (2016) asserts that the ERoEI (also referred to as EROI) of photovoltaic (PV) systems is so low that they actually act as net energy sinks, rather than delivering energy to society. Such claim, if accurate, would call into question many energy investment decisions. In the same paper, a comparison is also drawn between PV and nuclear electricity. We have carefully analysed this paper, and found methodological inconsistencies and calculation errors that, in combination, render its conclusions not scientifically sound. Ferroni and Hopkirk adopt ‘extended’ boundaries for their analysis of PV without acknowledging that such choice of boundaries makes their results incompatible with those for all other technologies that have been analysed using more conventional boundaries, including nuclear energy with which the authors engage in multiple inconsistent comparisons. In addition, they use out-dated information, make invalid assumptions on PV specifications and other key parameters, and conduct calculation errors, including double counting. We herein provide revised EROI calculations for PV electricity in Switzerland, adopting both conventional and ‘extended’ system boundaries, to contrast with their results, which points to an order-of-magnitude underestimate of the EROI of PV in Switzerland by Ferroni and Hopkirk.
... In the few studies that have applied harmonization to NEA, EPBT, and EROI analyses, a reduction in CED across the industry was found. Gorig and Breyer [40] calculated and compared the CED of different modules and systems over time using LCAs. They employed financial learning curve concepts to determine the energy demand for major PV systems. ...
... As calculated by Gorig and Breyer [40], the learning rate for PV modules is 17% and for PV systems it is 14%. They expect strong development until 2020 and forecast an EROI of 20-60:1 approaching the year 2030. ...
Chapter
As the world moves through an energy transition of immense scale, the concept of Energy Return on Investment (EROI or ERoEI) is increasing being studied. In this chapter the focus is on the EROI of PV modules and systems. EROI refers to the ratio of the usable energy returned during a system’s lifetime to all the invested energy needed to make this energy usable. It is a relatively new area of study and is related to Net Energy Analysis and Life Cycle Assessment. The higher the EROI of a fuel technology, the more valuable it is in terms of producing economically useful energy output. A higher EROI allows more net energy to be available to the economy; and to some degree, all economic activity relies on energy. In this chapter the EROI of PV systems are evaluated and illustrated, based on a variety of studies and in terms of technologies and the impact on economies. EROI can be used to rank the quality of fuels in terms of economics and here PV is evaluated in comparison to other fuels used for electricity generation.
... Limited to solar PV, the above results are likely to derive from the already significant EROI of all its technological variants even in mid-latitude areas [2], and to the steep energy learning curve of PV technology, making its deployment increasingly competitive with conventional sources at latitudes as high as 65° [39]. ...
... On the contrary, the EROI of solar PV energy is experiencing a strong increase, due to more than double in 2020 in comparison to 2010 [39]. Hence, previous assessments of energy and capital investments needed to achieve replacement of the oil fraction in the energy mix could be affected by overestimation [40,46]. ...
Preprint
Full-text available
Oil prices above $100/barrel values have proven unaffordable for the world economy, while lower prices have proven unaffordable for unconventional oil sources, resulting in a frantic price swing since 2007-2008. We identify and combine for the first time the competing dynamics of oil price, economic growth and extraction costs in a single model aiming to evaluate the near-term consequences of these dynamics onto forthcoming oil supply. Policies able to cope with the consequences of the resulting energy scenario are suggested in the conclusions.
... such as high-temperature solar thermal (ST), onshore wind, solar photovoltaic (PV) and small hydropower, are entirely comparable with that of oil, natural gas and coal. Limited to solar PV, the above results are likely to derive from the already significant EROI of all its technological variants even in mid-latitude areas [2], and to the steep energy learning curve of PV technology, making its deployment increasingly competitive with conventional sources at latitudes as high as 65° [39]. Overall availability is not an issue for the solar and wind sources [40]; but while deployment of high-temperature ST is profitable only at relatively low latitude, high insolation areas, solar PV can be deployed over a much wider portion of the global world [40,41]. ...
... On the contrary, the EROI of solar PV energy is experiencing a strong increase, due to more than double in 2020 in comparison to 2010 [39]. Hence, previous assessments of energy and capital investments needed to achieve replacement of the oil fraction in the energy mix could be affected by overestimation [40,46]. ...
Article
Full-text available
Oil prices above $100/barrel values have proven unaffordable for the world economy, while lower prices have proven unaffordable for unconventional oil sources, resulting in a frantic price swing since 2007-2008. We identify and combine for the first time the competing dynamics of oil price, economic growth and extraction costs in a single model aiming to evaluate the near-term consequences of these dynamics onto forthcoming oil supply. Policies able to cope with the consequences of the resulting energy scenario are suggested in the conclusions.
... 11 To determine the applicability of using any solar system in any place, solar radiation components-direct, global, and diffuse-must be assessed as a first step, which in turn has a positive effect in increasing the reliability and economic feasibilities of different solar energy applications. [12][13][14] Numerous techno-economic studies, as well as optimization studies of solar energy systems, have been presented in the literature where their analysis highly depends on the accuracy of the solar resources. [15][16][17][18][19] The estimation of the radiation intensity on the horizontal or inclined surfaces is vital and requires deep knowledge about the estimation of various geometrical variables that vary with the sun position as well as the measuring techniques and their accuracies. ...
... Table 1 shows the constant monthly values based on ASHRAE and Iqbal models. 37 In this study, the optimal monthly values of A, B, and C were found for Budapest city using the generalized reduced gradient (GRG) nonlinear algorithm in Microsoft Excel by minimizing the root mean square error (RMSE) of the correlation between the estimated and measured diffuse insolation which can be found using Equation (14). Figure 1 shows the procedure followed for the development of the diffuse insolation model. ...
Article
Solar radiation intensity changes due to the daily and seasonal changes in the sun’s position in addition to the variation in the sky clearness from one location to another which is considered as an important factor that affects the deployment of solar energy systems. This study aims to develop statistical models‐ mainly regression models and parametric model based on ASHRAE model‐ to estimate the hourly diffuse radiation in Budapest as a case study using the measured hourly global and diffuse radiation between 2011 and 2018. The prediction models relate the clearness index (which is obtained from the extraterrestrial and global radiation) and the global radiation through a generalized equation. The parametric model was developed by finding the optimal site‐specific constants of ASHRAE model for Budapest using the measured data that minimize the root mean square error. In addition, this study presents a comparison between the results from the developed models and the models reported in the literature. The results indicate that the developed regression models had almost the same correlation coefficients (R2) where the linear, power and exponential models had the largest R2 (0.69). Finally, the linear model was evaluated on a dataset outside the test data range where the linear model was capable of predicting the diffuse radiation with much better R2 (0.93). This article is protected by copyright. All rights reserved.
... Moreover, placing them on rooftops converts wasted space into the site of energy production. Photovoltaic systems' energy return on energy investment (EROI) is about 10 to 25 for modern technology, and is expected to reach up to 60 in 2020 (Görig and Breyer, 2016). This, of course, depends on geography and seasonality. ...
Article
Our review of some modern trends in the development of energy technologies suggests that the scenario of a significant reduction of the global oil demand can be regarded as quite probable. Such a scenario implies a rather significant decline of oil prices. The aim of this article is to estimate the sociopolitical destabilization risks that such a decline could produce with respect to oil exporting economies. Our analysis of the relationship between changes in oil prices and political crises in these economies shows a large destabilizing effect for price declines in the respective countries. The effect is highly non-linear, showing a power-law type relationship: oil price changes in the range higher than $60 per barrel only exert very slight influence on sociopolitical instability, but if prices fall below this level, each further decrease by $10 leads to a greater increase in the risks of crises. These risks grow particularly sharply at a prolonged oil price collapse below $40 per barrel, and become especially high at a prolonged oil price collapse below $35 per barrel. The analysis also reveals a fairly short-term lag structure: a strong steady drop in oil prices immediately leads to a marked increase in the risks of sociopolitical destabilization in oil-exporting countries, and this risk reaches critical highs within three years. Thus, the possible substantial decline of the global oil demand as a result of the development of the energy technologies reviewed in the first section of the present article could lead to a very substantial increase in the sociopolitical destabilization risks within the oil exporting economies. This suggests that the governments, civil societies, and business communities of the respective countries should amplify their effort aimed at the diversification of their economies and the reduction of their dependence on the oil exports.
... Using the historical learning curve, EROEI el for PV is expected to range between 20 and 40 in areas of moderately good insolation once cumulative PV capacity reaches 1.3 TW (ref. 35 ), which should happen by 2022 at current growth rates. For wind energy, similar meta-analyses found normalized EROEI el in the 20-60 range for large turbines, with several studies reporting values over 100 (refs. ...
Article
Full-text available
Carbon capture and storage (CCS) for fossil-fuel power plants is perceived as a critical technology for climate mitigation. Nevertheless, limited installed capacity to date raises concerns about the ability of CCS to scale sufficiently. Conversely, scalable renewable electricity installations—solar and wind—are already deployed at scale and have demonstrated a rapid expansion potential. Here we show that power-sector CO2 emission reductions accomplished by investing in renewable technologies generally provide a better energetic return than CCS. We estimate the electrical energy return on energy invested ratio of CCS projects, accounting for their operational and infrastructural energy penalties, to range between 6.6:1 and 21.3:1 for 90% capture ratio and 85% capacity factor. These values compare unfavourably with dispatchable scalable renewable electricity with storage, which ranges from 9:1 to 30+:1 under realistic configurations. Therefore, renewables plus storage provide a more energetically effective approach to climate mitigation than constructing CCS fossil-fuel power stations.
... In the context of energy system modeling, the cost variable usually refers to a relative cost (e.g., €/kW or €/unit) or levelized cost (LCOE), while the experience variable refers to installed capacity (GW), installed number (units), or total production (TWh of energy production). Learning curves are also used to describe other developments, such as operating efficiency [21] and consumption of individual input factors in production [22]; however, this study is limited to the cost-related use of learning curves due to its prevalence in energy system models. ...
Preprint
Conventional energy production based on fossil fuels causes emissions which contribute to global warming. Accurate energy system models are required for a cost-optimal transition to a zero-emission energy system, an endeavor that requires an accurate modeling of cost reductions due to technological learning effects. In this review, we summarize common methodologies for modeling technological learning and associated cost reductions. The focus is on learning effects in hydrogen production technologies due to their importance in a low-carbon energy system, as well as the application of endogenous learning in energy system models. Finally, we present an overview of the learning rates of relevant low-carbon technologies required to model future energy systems.
... As well, only a relatively small amount of land is needed, thereof a considerable amount in zero impact areas, such as rooftops. Energetic sustainability is given since the energy payback time for newly installed systems is about 1 year in global average resource conditions 46 and expected to further decline, in particular due to the energetic learning curve for solar PV systems 47 . Fundamental material limitations are not known, since the major input materials are SiO 2 for glass and silicon, and aluminum and hydrocarbons for foils. ...
Article
Full-text available
A transition towards long-term sustainability in global energy systems based on renewable energy resources can mitigate several growing threats to human society simultaneously: greenhouse gas emissions, human-induced climate deviations, and the exceeding of critical planetary boundaries. However, the optimal structure of future systems and potential transition pathways are still open questions. This research describes a global, 100% renewable electricity system, which can be achieved by 2050, and the steps required to enable a realistic transition that prevents societal disruption. Modelling results show that a carbon neutral electricity system can be built in all regions of the world in an economically feasible manner. This radical transformation will require steady but evolutionary changes for the next 35 years, and will lead to sustainable and affordable power supply globally.
... The-annual effective-solar-irradiance varies from 60 to 250 W m −2 worldwide (Luqman et al., 2015). Solar-energy is both; sustainable, and renewable, hence, it will not be depleted (Görig & Breyer, 2016). Besides, solar-energy is considered to-be a-non-polluting, reliable, and clean-source of energy. ...
Article
Full-text available
This-work, being the-first, in-a-series of 10, was intended to-provide a-sufficient-introductory to SWM; yet, it can also-be-treated-as an-independent and a-complete-piece. This-article starts-with a-concentrated-digest (synthesized from over 400 published-reference-documents), providing a-starting point, for readers, interested in-advanced-investigation on the-topic. As-such, the-following-issues were presented and analyzed: SWM history; Global and regional-generation-rates; WM-'value-chain'; SWM-technologies; Impacts of uncontrolled-SW; International-Conventions, Protocols, Agreements, and commitments, addressing SWM, and their-analysis; as-well-as Global-SWM-practices (including municipal-waste management) and current-challenges, incorporating POPs. It was concluded, that waste is completely-unavoidable in-any, and every-human-activity; however, the-way the-waste is handled, stored, collected, and disposed-off, will-determine the-quality of our-surrounding-environment, to-be-either; clean, pleasant, healthy, and sustainable, or filthy, disgusting, harmful, and wasteful. The-way each-individual, company/organization, government, and society, at-large, deal with their-waste, will-eventually-determine our-own-future, as-humans. The-study also justified, that the-waste should-be-treated as a-resource, as it still-contains many-valuable-materials. The-study also-offered anew analogy ; the-sustainable SWM-system should-be analogous to-a-digestive-system, extracting all-the-recyclables from the-waste, and only then discarding, the-small-remainder/waste. The-author, also-believes that Recycling (with a-capital R) is the-future of human-civilization; however, it must be done in the-environmentally sound-sustainable-manner, to-protect health of workers, and also to-extract the-optimum-amount of valuable-materials, from the-waste. This-study also-exposed, that despite the-existence of International, regional, and multilateral-agreements, illegal-trafficking of hazardous, toxic, radioactive, and e-waste, is still widely-practiced. Such-practices can-be regarded-as Environmental-racism, conducted by, or with the-help of, an-international-'eco-mafia'. Environmental-racism was analyzed against human-rights; in-the-context of both; the-Universal-Declaration of Human-Rights and the-generation-approach. The-author also-justified, that Environmental-racism is real, alive, and widespread-global-trend, affecting many, if not all-countries. Environmental-racism is a-sin, against humanity; logically, as any-sin, it should-be exposed, condemned, and fought against, with every-fibre, of impartiality, left in-us. The-study also-exposed an-increasing-interest of majority of African-countries in inherently-dangerous nuclear-energy (with its-by-product-radioactive-waste); the-recommendation was offered, to-shift their-interest to clean/green/renewable-energy-sector, particularly solar-energy. There is also a-common-prejudiced stereotyped-misconception, that, in-the-developed-countries almost-everything (including WM) is: superior, brainy, flawless, highly-organized, and tidy; in-contrast, in-developing countries, and particularly in-the-'dark'-continent of Africa, almost-everything (including WM) is substandard, mediocre, unsound, ad-hoc, and filthy. The-selected-examples, provided in-this-paper, will, possibly, demonstrate, that the-current-situation, at-least, with-regard-to WM, is not so 'black and white'. This-paper has also-offered several-recommendations for further-research. Lastly, this-article does not claim to-be fully comprehensive, as it-is physically-impossible 'to-fill an-ocean into a-small-cup', and even the-most-comprehensive-review, have to-stop, at a-certain-point. Nevertheless, the-cohesive-theoretical-background, alongside-with author's analytical-scholarly-input, hopefully provides a-credible-contribution to-the-body of knowledge, on-the-subject-matter, as-well-as a 'food-for-thought'. With anticipation, this-work will not only attract, but also hold, considerable-attention, from SWM stakeholders, and other-interested-parties, both; locally and internationally.
... Relying on the technological advances and on world solar resource (global horizontal irradiation), the global EPBT of PV systems presented in the Fig. 2.23 reveals the countries that could benefit the most from solar energy such as Africa, Latin America, Australia and the Southern Asia [60]. ...
... The-annual effective-solar-irradiance varies from 60 to 250 W m ?2 worldwide (Luqman et al., 2015). Solar-energy is both; sustainable, and renewable, hence, it will not be depleted (G?rig & Breyer, 2016). Besides, solar-energy is considered to-be a-non-polluting, reliable, and clean-source of energy. ...
Article
This-work, being the-first, in-a-series of 10, was intended to-provide a-sufficient-introductory to SWM; yet, it can also-be-treated-as an-independent and a-complete-piece. This-article starts-with a-concentrated-digest (synthesized from over 400 published-reference-documents), providing a-starting point, for readers, interested in-advanced-investigation on the-topic. As-such, the-following-issues were presented and analyzed: SWM history; Global and regional-generation-rates; WM-‘value-chain’; SWM-technologies; Impacts of uncontrolled- SW; International-Conventions, Protocols, Agreements, and commitments, addressing SWM, and their-analysis; as-well-as Global-SWM-practices (including municipal-waste management) and current-challenges, incorporating POPs. It was concluded, that waste is completely-unavoidable in-any, and every-human-activity; however, the-way the-waste is handled, stored, collected, and disposed-off, will-determine the-quality of oursurrounding- environment, to-be-either; clean, pleasant, healthy, and sustainable, or filthy, disgusting, harmful, and wasteful. The-way each-individual, company/organization, government, and society, at-large, deal with their-waste, will-eventually-determine our-own-future, as-humans. The-study also justified, that the-waste should-be-treated as a-resource, as it still-contains many-valuable-materials. The-study also-offered a-newanalogy; the-sustainable SWM-system should-be analogous to-a-digestive-system, extracting all-the-recyclables from the-waste, and only then discarding, the-small-remainder/waste. The-author, also-believes that Recycling (with a-capital R) is the-future of human-civilization; however, it must be done in the-environmentally soundsustainable- manner, to-protect health of workers, and also to-extract the-optimum-amount of valuable-materials, from the-waste. This-study also-exposed, that despite the-existence of International, regional, and multilateralagreements, illegal-trafficking of hazardous, toxic, radioactive, and e-waste, is still widely-practiced. Suchpractices can-be regarded-as Environmental-racism, conducted by, or with the-help of, an-international-‘ecomafia’. Environmental-racism was analyzed against human-rights; in-the-context of both; the-Universal- Declaration of Human-Rights and the-generation-approach. The-author also-justified, that Environmental-racism is real, alive, and widespread-global-trend, affecting many, if not all-countries. Environmental-racism is a-sin, against humanity; logically, as any-sin, it should-be exposed, condemned, and fought against, with every-fibre, of impartiality, left in-us. The-study also-exposed an-increasing-interest of majority of African-countries in inherently-dangerous nuclear-energy (with its-by-product--radioactive-waste); the-recommendation was offered, to-shift their-interest to clean/green/renewable-energy-sector, particularly solar-energy. There is also a-commonprejudiced stereotyped-misconception, that, in-the-developed-countries almost-everything (including WM) is: superior, brainy, flawless, highly-organized, and tidy; in-contrast, in-developing countries, and particularly inthe-‘ dark’-continent of Africa, almost-everything (including WM) is substandard, mediocre, unsound, ad-hoc, and filthy. The-selected-examples, provided in-this-paper, will, possibly, demonstrate, that the-current-situation, at-least, with-regard-to WM, is not so ‘black and white’. This-paper has also-offered several-recommendations for further-research. Lastly, this-article does not claim to-be fully comprehensive, as it-is physically-impossible ‘to-fill an-ocean into a-small-cup’, and even the-most-comprehensive-review, have to-stop, at a-certain-point. Nevertheless, the-cohesive-theoretical-background, alongside-with author’s analytical-scholarly-input, hopefully provides a-credible-contribution to-the-body of knowledge, on-the-subject-matter, as-well-as a ‘food-forthought’. With anticipation, this-work will not only attract, but also hold, considerable-attention, from SWM stakeholders, and other-interested-parties, both; locally and internationally. Keywords: Environmental racism, Convention, human rights, ‘eco’ mafia, POPs, e-waste, toxic, hazardous, radioactive, nuclear plants, solar energy, Africa.
... The P-V and I-V curves of a photovoltaic solar cell are shown in Figure 1. where open indicates the open-circuit voltage of the photovoltaic solar panel and is also its maximum output voltage; short indicates the short-circuit current of the photovoltaic solar panel and is also its maximum output current; max indicates the maximum output power of the photovoltaic solar panel in the present case; is the current at the maximum power point; and is the voltage at the maximum power point [4,5]. ...
Article
Full-text available
To realize the maximum power output of a grid-connected inverter, the MPPT (maximum power point tracking) control method is needed. The perturbation and observation (P&O) method can cause the inverter operating point to oscillate near the maximum power. In this paper, the fuzzy control P&O method is proposed, and the fuzzy control algorithm is applied to the disturbance observation method. The simulation results of the P&O method with fuzzy control and the traditional P&O method prove that not only can the new method reduce the power loss caused by inverter oscillation during maximum power point tracking, but also it has the advantage of speed. Inductive loads in the post-grid-connected stage cause grid-connected current distortion. A fuzzy control algorithm is added to the traditional deadbeat grid-connected control method to improve the quality of the system’s grid-connected operation. The fuzzy deadbeat control method is verified by experiments, and the harmonic current of the grid-connected current is less than 3%.
... Seen in this light, the current values of the EPBT for the most diffuse renewable energy technologies are promising. According to a recent study (Bhandari et al. 2015), the average EPBT for polycrystalline silicon PV plants is in the range of 1.5-4 years, although it can drop below 1 year in good locations and still follows a steep learning curve (Görig and Breyer 2016). The EPBT for wind energy was on average better than for solar (Davidsson et al. 2012), although highquality wind resources are less abundant and more localized than solar resources creating a scale barrier and, being a more mature technology, further wind EPBT reductions would be limited. ...
Article
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Attaining the objectives set by the COP21 Paris agreement on climate involves not only phasing out fossil fuels from the world’s energy mix but also replacing the energy services they provide with renewable energy and better efficiency, approximately by the mid-twenty-first century. A recent controversy on the viability of 100% renewable energy systems (Jacobson et al. in Proc Natl Acad Sci 112:15060–15065; Clack et al. in PNAS 114:6722–6727) brought forward the question of whether we can actually rely on renewable energy to replace conventional fossil resources. Focusing on the physical factors involved may offer us a currently underutilized method to reduce controversy showing that, in practical terms, the two parties are closer than immediately apparent. A physical perspective suggests that accelerated deployment of renewable energy sources makes attaining the Paris objectives feasible, although not without a major effort. A policy directed to increase capital investments in an early and fast expansion of the renewable energy and storage infrastructure is a crucial requirement for this purpose.
... As solar power is theoretically abundant enough, it is more than capable of fulfilling the world's electricity demands. Because solar energy is not only sustainable but also renewable, it is not necessary to consider the notion that solar energy may eventually be depleted [52]. Global warming is characterized by cataclysmic potential, thus portending its harmful impact on the climate, environment (including animals and plants), and human health [53]. ...
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The development of novel solar power technologies is considered to be one of many key solutions toward fulfilling a worldwide increasing demand for energy. Rapid growth within the field of solar technologies is nonetheless facing various technical barriers, such as low solar cell efficiencies, low performing balance-of-systems (BOS), economic hindrances (e.g., high upfront costs and a lack of financing mechanisms), and institutional obstacles (e.g., inadequate infrastructure and a shortage of skilled manpower). The merits and de-merits of solar energy technologies are both discussed in this article. A number of technical problems affecting renewable energy research are also highlighted, along with beneficial interactions between regulation policy frameworks and their future prospects. In order to help open novel routes with regard to solar energy research and practices, a future roadmap for the field of solar research is discussed.
... Looking forward, the reliance on traditional technologies plus CCS which is the consensus from CES-based GE-IAMs in Sect. 3 contrasts with both current deployment trends (Breyer et al. 2017) and the literature that uses bottom-up, physically constrained analysis to model a 100% carbon-free economy and that considers solar and wind RE as the scalable workhorse technologies with some reliance on biomass depending on the location but with no nuclear or CCS, e.g., Lund and Mathiesen (2009) for Denmark, Ben Elliston et al. (2013) for Australia, Jacobson et al. (2015) for USA, and Singer (2010) and Jacobson and Delucchi (2011) for global transitions. These studies recognize the physical and political scale limitations of nuclear, biomass, and CCS, and the strong learning curve in scalable RE technologies, solar (Görig and Breyer 2016), wind, and storage, which allow them to present a complete energy system alternative. The RE deployment deficit in IAMs is recognized by Pietzcker et al. (2017). ...
Article
Full-text available
Applying constant elasticity of substitution (CES) functions in general equilibrium integrated assessment models (GE-IAMs) for the substitution of technical factor inputs (e.g., replacing fossil fuels) fails to match historically observed patterns in energy transition dynamics. This method of substitution is also very sensitive to the structure of CES implementation (nesting) and parameter choice. The resulting methodology-related artifacts are (i) the extension of the status quo technology shares for future energy supply relying on fossil fuels with carbon capture, biomass, and nuclear; (ii) monotonically increasing marginal abatement costs of carbon; and (iii) substitution of energy with non-physical inputs (e.g., knowledge and capital) without conclusive evidence that this is possible to the extent modeled. We demonstrate these issues using simple examples and analyze how they are relevant in the case of four major CES-based GE-IAMs. To address this, we propose alternative formulations either by opting for carefully applied perfect substitution for alternative energy options or by introducing dynamically variable elasticity of substitution as a potential intermediate solution. Nevertheless, complementing the economic analysis with physical modeling accounting for storage and resource availability at a high resolution spatially and temporally would be preferable.
... In addition, there is a common misunderstanding that rare earth metals will limit the ability to produce solar PV modules in the future, and that modules will ultimately consume more energy than they produce. Despite the fact that research dispels such myths [54,55], the misunderstanding persists. ...
Article
There are several barriers to achieving an energy system based entirely on renewable energy (RE) in Finland, not the least of which is doubt that high capacities of solar photovoltaics (PV) can be feasible due to long, cold and dark Finnish winters. Technologically, several energy storage options can facilitate high penetrations of solar PV and other variable forms of RE. These options include electric and thermal storage systems in addition to a robust role of Power-toGas technology. In an EnergyPLAN simulation of the Finnish energy system for 2050, approximately 45% of electricity produced from solar PV was used directly over the course of the year, which shows the relevance of storage. In terms of public policy, several mechanisms are available to promote various forms of RE. However, many of these are contested in Finland by actors with vested interests in maintaining the status quo rather than by those without confidence in RE conversion or storage technologies. These vested interests must be overcome before a zero fossil carbon future can begin. The results of this study provides insights into how higher capacities of solar PV can be effectively promoted and managed at high latitudes, both north and south.
... and 11.9 ± 1.04% for poly and mono-Si systems. An earlier study indicates learning rates specific for rooftop and ground-mounted PV systems, a distinction not made in our analysis, and reports learning rates of 13 and 11% for ground mounted and 18 and 14% for rooftop-mounted poly and monocrystalline silicon based PV systems, respectively 27 . ...
Article
Full-text available
Since the 1970s, installed solar photovoltaic capacity has grown tremendously to 230 giga-watt worldwide in 2015, with a growth rate between 1975 and 2015 of 45%. This rapid growth has led to concerns regarding the energy consumption and greenhouse gas emissions of photovoltaics production. We present a review of 40 years of photovoltaics development, analysing the development of energy demand and greenhouse gas emissions associated with photovoltaics production. Here we show strong downward trends of environmental impact of photovoltaics production, following the experience curve law. For every doubling of installed photovoltaic capacity, energy use decreases by 13 and 12% and greenhouse gas footprints by 17 and 24%, for poly-and monocrystalline based photovoltaic systems, respectively. As a result, we show a break-even between the cumulative disadvantages and benefits of photovoltaics, for both energy use and greenhouse gas emissions, occurs between 1997 and 2018, depending on photovoltaic performance and model uncertainties.
... As reported in Table 9, the MI used for the panels and the bracket was quite high in the order of 10 4 kg, while the other components presented a lower MI in the 10 2 -10 3 kg range. Where the embedded energy of the PV modules is concerned, recent studies provide diverse CED values, with large uncertainties, for the different types (mono-, poly-crystalline, and metals-based thin-film), ranging from 200 kWh el /m 2 up to 1500 kWh el /m 2 [68][69][70][71]. However, the values reported in literature should be carefully considered. ...
Article
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In the sustainability context, the performance of energy-producing technologies, using different energy sources, needs to be scored and compared. The selective criterion of a higher level of useful energy to feed an ever-increasing demand of energy to satisfy a wide range of endo-and exosomatic human needs seems adequate. In fact, surplus energy is able to cover energy services only after compensating for the energy expenses incurred to build and to run the technology itself. This paper proposes an energy sustainability analysis (ESA) methodology based on the internal and external energy use of a given technology, considering the entire energy trajectory from energy sources to useful energy. ESA analysis is conducted at two levels: (i) short-term, by the use of the energy sustainability index (ESI), which is the first step to establish whether the energy produced is able to cover the direct energy expenses needed to run the technology and (ii) long-term, by which all the indirect energy-quotas are considered, i.e., all the additional energy requirements of the technology, including the energy amortization quota necessary for the replacement of the technology at the end of its operative life. The long-term level of analysis is conducted by the evaluation of two indicators: the energy return per unit of energy invested (EROI) over the operative life and the energy payback-time (EPT), as the minimum lapse at which all energy expenditures for the production of materials and their construction can be repaid to society. The ESA methodology has been applied to the case study of H 2 production at small-scale (10-15 kW H2) comparing three different technologies: (i) steam-methane reforming (SMR), (ii) solar-powered water electrolysis (SPWE), and (iii) two-stage anaerobic digestion (TSAD) in order to score the technologies from an energy sustainability perspective.
... The first of these come from the same types of improvements that have resulted in the dramatic reductions in costs already noted, particularly in the energy requirements for wafer and cell fabrication. Some authors have ascribed a similar learning rate to the corresponding reduction in attributed environmental impact as is commonly used when describing cost reductions [35]. The second time dependency comes from steadily improving environmental quality of the energy generation mix, as discussed above, with photovoltaics expected to accelerate these improvements in the future. ...
... Similarly, PV has had an encouraging energy learning curve; reduced energy consumption through production of materials making supply chains more energy efficient. The energy learning curve for PV systems based on mix of different semiconductor technologies and volumes in the global market sums to be 14% (Görig & Breyer, 2016). ...
Thesis
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The global primary energy demand is anticipated to increase exponentially owing to reasons such as increase of wealth amongst nations as the economies for developing countries grow. Technology innovation, progress, and population increase add to global energy demand as well. This foreseeable increase would need to be fulfilled in line with the Sustainable Development Goals, as set by the United Nations Development Program, where energy needs to be provided through sustainable and affordable energy conversion technologies using clean and renewable sources. This approach is in line with the Paris Agreement, made in 2015, that stressed upon transition from energy conversion technologies that relied on sources whose use contributed to global warming eventually leading to climate change. The major energy demand areas can be roughly segregated as electricity consumption, transport, heating and cooling, and cooking. In the global energy transition, to fight climate change, it is anticipated that a fair percentage of heating & cooling, transport and cooking would be electrified to turn towards clean fuels. This leads to a heavy rise in deployment of electricity generation infrastructure in the future. Given today’s economics, it can be safely assumed that Solar and Wind, with Solar taking the lead, would be the most deployed energy conversion technologies in the future. This raises the question of the environmental footprint of Solar PV plants over the planet provided that they are anticipated to be amongst the most deployed energy generation technologies over the coming years. Life Cycle Assessment (LCA) provides a comprehensive and transparent solution for quantifying the environment impacts made throughout the life cycle of PV plants. LCA is a methodology that quantifies material and energy flows at each stage of the PV plant Life cycle and allows an in-depth analysis of the environment depletion and the contributing elements. This provides with identification of hotspots and allows the optimization of the process of reducing the environmental footprint of PV plants by addressing the most relevant areas, enhancing sustainability of the PV power generation infrastructure. The methodology used for implementation of LCA on PV systems comprises of using the Plant Predict online software, by First Solar, that is used in designing and simulating PV plant energy yield and the ENVI-PV tool, by Mines Paris Tech, that allows a geospatial analysis of PV System environmental performance using Life cycle Assessment methodology. As a part of the thesis research, the tools have been combined to produce results addressing both the yield performance of PV plants along with their quantified environmental footprint using an LCA approach. To illustrate the methodology, to incorporate LCA into PV System design and planning, three different climatic regions were chosen to simulate 10 MWp PV plants for each three different semiconductor technologies for PV modules; Multi-Crystalline Silicon, Mono-Crystalline Silicon, and Cadmium xii Telluride. This approach comprehensively displays the different environmental impacts due to different processes at each life cycle stage of the three technologies and depicts how different weather conditions affect the yield and environmental performance of PV systems. In the analysis, Cadmium Telluride technology 10 MWp, in all the three climatic regions, shows the least energy consumption and the least environmental footprint. This leads to the quickest Energy Payback Times and the most mitigation potential for climate change amongst the three technologies. The most relevant life cycle stages, for 10 MWp PV plants of all three technologies considered, are raw material acquisition and pre-processing and production of the main product. Once the environmental impacts have been quantified, through every life cycle stage of the PV plant, they can be monetized depending on the extent of their damage. Monetization allows the translation of the PV life cycle impacts into financial terms and allows a pathway for internalization of externalities related to PV plants. Incorporation of these damage costs into levelized cost of electricity (LCOE) calculation of PV plants internalizes the externalities related to PV systems as the responsible manufacturers, developers, and financers take into account the cost upfront. This increase in cost is great motive for the stakeholders to, by using LCA, identify the hotspots in their supply chains and reduce the environmental footprint of their products and eventually of PV Plants. To implement this concept, it is important to transform the existing market for PV. The European PV market is already in the process to begin the transformation to implement LCA on PV system components by trying to introduce Green Public Procurement and potentially Energy Labeling requirements through sustainable product policy instruments such as the Eco-Design Directive or the Ecolabling Regulation. Internationally, the NSF/ANSI 457: Sustainability Leadership Standard for PV Modules and Inverters sets a benchmark for the standardized assessment of sustainability performance in the PV world. A 5-year market model has been envisioned as a part of this research to propose a pathway for implementation of total cost pricing of PV system that would incorporate environmental costs in PV LCOE for a healthy PV System competition in the market. The market model goes through three phases and implements the vision. The three phases comprise of implementing policy tools that would filter out PV components – having higher environmental footprint than set thresholds. Introduce environmental assessment criteria in PV auctions for manufacturers, designers, and investors to comply with. Provide incentives such as environmental performance based Investment Tax Credits, or Feed-in-Premiums for private entities opting for PV solutions. And eventually establish total cost pricing for PV systems where the monetized environmental damage costs are included in LCOE calculations and different PV systems, of different technologies, are differentiated on the basis of yield production as well as environmental footprint throughout their Life cycle. xiii The thesis research is focused on providing an adequate methodology and approach for implementation of LCA. In present times, there are quite a few limitations and constraints in data availability globally to perform LCA. Also, the methodology taken for indicators for environmental assessment bear uncertainty brackets for their calculation. These constraints are expected to resolve and refine over time as these practices become the ultimate need of the PV industry.
... Mono crystalline silicon, which has consistent lattice orientation and high quality possessed high photoelectric conversion efficiency, attracts significant attention. However, the production cost of the photovoltaic industry is still a recent challenge (Gorig and Breyer, 2016). Interestingly, some studies found that increasing the solar cell conversion efficiency is a way for reducing the production cost (Urrejola et al., 2015). ...
Article
The passivated emitter and rear cell (PERC), with advantages of reducing rear surface recombination and improving rear surface reflectivity, is extensively applied in monocrystalline and multicrystalline silicon solar cells. In this study, we investigated the rear PERC structure with various contact patterns (type I to VI) and line spacings (800–1000 µm) using 156.75 mm × 156.75 mm p-type Czochralski mono crystalline silicon wafers. The void formation on the rear-side contacts of PERC structures played an important role in affecting conversion efficiencies. A smaller laser ablated opening width may easily lead to the formation of voids under screen printing and co-firing backside aluminum. Further evidence from the electroluminescence (EL) measurements confirmed that the higher laser ablation power would result in a slightly dark region for the solar cell with a rear-side contact opening width greater than 45 µm. The type III backside contact pattern (dash 2:1) with a line spacing of 900 µm surpassed all other contact patterns owing to its excellent aluminum back surface field. As a result, by optimizing both the backside contact pattern and line spacing of PERC solar cells, the best conversion efficiency of 22.25% and 20.9% for the average PERC solar cells were achieved.
... While this study was not intended to be a full life cycle assessment of the technologies utilized, some comment is necessary with regards to GHG emissions and energetic requirements related to the production of such large installed capacities of solar PV and wind power. Several studies have examined life cycle sustainability aspects of wind power and solar PV technologies and concluded that energy payback time (EPBT) and GHG emissions were far lower than fossil fuel-based or nuclear technologies [94][95][96][97][98]103]. Further, other emissions were consistently lower for solar PV throughout its life cycle, such heavy metals, sulphur dioxide and nitrogen-based air pollutants (NO x ). ...
... Refs. [28,29]e and prospective energy mixes) and background databases. ...
Article
The implementation of externalities in energy policies is a potential measure for sustainability-oriented energy planning. Furthermore, decisions on energy policies and plans should be based on the analysis of a number of potential energy scenarios, considering the evolution of key techno-economic and life-cycle sustainability indicators. The joint interpretation of these multiple criteria should drive the choice of appropriate decisions for energy planning. Within this context, this work proposes –for the first time– the combined use of Life Cycle Assessment, externalities calculation, Energy Systems Modelling and dynamic Data Envelopment Analysis to prioritise prospective energy scenarios. For demonstration and illustrative purposes, the application of this methodological framework to the case study of electricity production in Spain leads to quantitatively discriminate between 15 prospective energy scenarios by taking into account the life-cycle profile of the transformation path of the power generation system with time horizon 2050. When compared to the application of the framework without implementation of external costs, the internalisation of climate change externalities is found to affect the ranking of energy scenarios but still showing the rejection of those scenarios based on the lifetime extension of coal power plants, as well as the preference for those scenarios leading to a high penetration of renewable technologies.
... Solar power is readily abundant and efficient to supply the world's energy needs. Since solar energy can be sustained and renewed, its availability cannot be exhausted (Görig and Breyer 2016). Global warming is characterised by disastrous effects, consequently threatening its detrimental influence on climate, environment (with plants and animals) and human health (Resch 2008). ...
Article
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Copper doped tin oxide thin film was synthesised by electrodeposition technique. Film growth was maintained at cathodic potential of 1.60 V at a varied deposition time. Surface morphological studies of the deposited films were achieved by field emission scanning electron microscopy (FE-SEM). The scanning electron microscopy image revealed evenly distributed films, across the substrate with rice-like or dome-like particles, depending on the deposition time. Post-annealing enhanced films crystallinity and particles agglomeration. Energy disperse X-ray spectra revealed the elemental constituents present in the film. The results obtained from electrical characterisation of the samples showed the ohmic properties of the deposited sample. X-ray diffraction results indicated that samples are polycrystalline in nature with tetragonal rutile structure. The average interplanar spacing and crystallite size of the samples were estimated as 2.93 Å and 202.5 Å respectively. Optical characterisation of the samples showed that absorption and transmittance across the ultraviolet-visible spectrum range depend on deposition time. The estimated energy band gaps of 3.06 eV suggested the films as good candidates for transparent contact electrodes in optoelectronic applications.
... However, the reliability and representativeness of environmental experience curves has yet to be proven, since little research has been conducted on this specific topic. For instance, applications are typically restricted to cumulative energy demand (e.g., Görig & Breyer, 2016;Louwen, van Sark, Faaij, & Schropp, 2016;Ramírez & Worrell, 2006) and GHG emissions (e.g., Bergesen & Suh, 2016;Caduff et al., 2012;Kätelhön, von der Assen, Suh, Jung, & Bardow, 2015;Louwen et al., 2016) and it is unclear whether other impact categories show similar log-linear correlation with cumulative production. Furthermore, environmental experience curves are available for a limited set of products and materials. ...
Article
Full-text available
Estimating the environmental impact of emerging technologies at different stages of development is uncertain but necessary to guide investment, research, and development. Here, we propose a systematic procedure to assess the future impacts of emerging technologies. In the technology development stage (technology readiness level < 9), the recommended experience mechanisms to take into account are (a) process changes, (b) size scaling effects, and (c) process synergies. These developments can be based on previous experience with similar technologies or quantified through regression or engineering dimension calculations. In the industrial development phase, (d) industrial learning, based on experience curves or roadmaps, and (e) external developments should be included. External developments, such as changes in the electricity mix can be included with information from integrated assessment models. We show the applicability of our approach with the greenhouse gas (GHG) footprint evaluation for the production of copper indium gallium (di)selenide (CIGS) photovoltaic laminate. We found that the GHG footprint per kilowatt peak of produced CIGS laminate is expected to decrease by 83% going from pilot to mature industrial scale production with the largest decrease being due to expected process changes. The feasibility of applying our approach in practice would greatly benefit from the development of a database containing information on size scaling and experience rates for a wide variety of materials, products, and technologies.
... While new development within technology can lead to new products and optimized performance, it can also help to extend the life cycle (Tsang, Sonnemann, and Bassani 2016) of the technology as a whole, by minimizing the number of resources required for energy generation by use of PV, e.g. through greater panel efficiency, more robust and durable design leading to a longer life span, and continuous improvements to production methods. Ongoing developments also have shown accelerated learning curves for PV systems, making PV systems profitable faster, increasing return on investment (ROI) and decreasing energy pay-back time (EPBT) (Görig and Breyer 2016). PV development is also less linked with international trade than other technologies, such as wind power . ...
Article
In a golf club, players have the chance to rent a buggy to cover the distances in the field. These buggies are electric vehicles that need to be charged and the grid is used to supply the electricity required. In Los Naranjos Golf Club they have no time to charge the cars in between rounds so it is interesting to look for renewable energy as the sun could provide an extra charge while the car is on the field. For this matter, a specific study in situ has been implemented. The estimation of the savings using solar panels with 250 W power was reviewed to economically analyze and calculate the extended range provided by such a system. The results with a 50-car fleet show a return on investment within the fifth year and can lead to an increase in the range in 10 holes for the worst-case scenario (December). The techno-economic analysis, proved that a future investment in solar buggies will results in Average Annual Benefits of EUR15,607 with the total Capital Cost at EUR75,000.
... One possibility to integrate innovation into ESM is the integration of dynamic learning curves (e.g., [152]). These are outputs of economic micromodels. ...
Article
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The transformation of the energy system is a highly complex process involving many dimensions. Energy system models help to understand the process and to define either target systems or policy measures. Insights derived from the social sciences are not sufficiently represented in energy system models, but address crucial aspects of the transformation process. It is, therefore, necessary to develop approaches to integrate results from social science studies into energy system models. Hence, as a result of an interdisciplinary discourse among energy system modellers, social scientists, psychologists, economists and political scientists, this article explains which aspects should be considered in the models, how the respective results can be collected and which aspects of integration into energy system models are conceivable to provide an overview for other modellers. As a result of the discourse, five facets are examined: Investment behaviour (market acceptance), user behaviour, local acceptance, technology innovation and socio-political acceptance. Finally, an approach is presented that introduces a compound of energy system models (with a focus on the macro and micro-perspective) as well as submodels on technology genesis and socio-political acceptance, which serves to gain a more fundamental knowledge of the transformation process.
... The NPC and LCOE are sensitive to the PV cost (PC) and the battery cost (LA ASM) and increase with the PC and LA ASM. The PV costs could be reduced by increased technical development in PV modules (e.g., black silicon [96]), continued economics of scale and the learning rate [97][98][99], and reduced BOS costs through innovative racking [100]. Overall, the significant sensitivity variables, which could deem critical design variables, are discount rate, fuel prices, PV and battery costs. ...
Article
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The Integrated Rural Energy Planning (IREP) framework offers a unified road map for locating, planning and operating decentralized renewable hybrid off-grid energy systems for localized (rural) applications in low-income countries. This paper presents the culmination of the IREP framework and aims to illustrate the final step of the IREP framework for two communities in Nigeria. It is focused on two aspects. Firstly, the techno-economic modeling (investment and operation optimization) of a hybrid mini-grid system using HOMER Pro, a techno-economic evaluation tool; and evaluating the benefits of demand side management (DSM) based on energy efficiency on the overall system economics using a scenario-based approach. Secondly, the conceptualization of a sustainable business model using the business model canvas scheme to deliver measurable socio-economic impacts in these communities. The results provide valuable insights into rural electrification via renewable hybrid mini-grids powered primarily with solar photovoltaic technology. Transcending mere electricity access, electricity is provided for productive uses (considering disaggregated end-uses) by harnessing other dispatchable renewable energy resources such as waste biomass. Given high share of rural population in developing countries, these insights are applicable in these regions and further the realization of the United Nations’ goal of sustainable energy (SDG7) and sustainable cities and communities (SDG11).
... In addition, there is a common misunderstanding that rare earth metals will limit the ability to produce solar PV modules in the future, and that modules will ultimately consume more energy than they produce. Despite the fact that research dispels such myths [54,55], the misunderstanding persists. ...
Conference Paper
There are several barriers to achieving an energy system based entirely on renewable energy (RE), not the least of which is doubt that high capacities of solar PV can be feasible due to long, cold and dark Finnish winters. Technologically, several energy storage options can facilitate high penetrations of solar PV (up to 29 TWhe, or 16% of annual electricity production) and other variable forms of RE. These options include electric and thermal storage systems in addition to a robust role of Power-toGas (PtG) technology. Approximately 45% of electricity produced from solar PV was used directly over the course of the year, which shows the relevance of storage. In terms of public policy, several mechanisms are available to promote various forms of RE. However, many of these are contested in Finland by actors with vested interests in maintaining the status quo rather than by those without faith in RE conversion or storage technologies. These vested interests must be overcome before a zero fossil carbon future can begin.
... 43 In addition, energy learning in manufacturing is not considered, but well documented. 44 However, our main intention was to contribute to the discussion about the use of batteries to support terawatt photovoltaics by assessing a limiting scenario. For the battery capacities used in this study, we observe only moderate increases in GWP and EP time compared with PV-only systems. ...
Article
What role have batteries to play in the transition toward terawatt levels of photovoltaics? In this perspective, we attempt to answer this question by looking at technical, economic, and ecological features of PV-battery systems. We argue that the window of opportunity for batteries lies in the capacities of a few kWh/kWP, the exact amount depending on various factors including battery cost, degradation rate, location, load profile, diversification of renewable energy sources, and interconnections. Using a simple PV plus battery model, we illustrate that such storage capacities efficiently reduce fluctuations in electricity generation, enabling higher PV adoption rates at competitive costs, and with a carbon footprint that is at least five times lower than that of the current energy mixes. Using sensible capacities, batteries are a powerful companion for solar energy, yet technical, economic, and policy innovations are needed to expand adoption. We see longer battery lifetimes and low capacity degradation rates are the most impactful technological parameters. Economic efforts should aim to reduce balance of plant costs and create better market opportunities for stationary storage, whereas policies should provide a strong regulatory framework to facilitate multipurpose usage and sector coupling.
Chapter
Glycerol is a key platform chemical of the forthcoming bioeconomy. This Chapter suggests that the solar and bioeconomy is an inevitable near-term consequence of the conflicting energy, population, and wealth dynamics. Following recent modeling combining the competing dynamics of oil price, economic growth, and extraction costs in a single model to evaluate the near-term consequences onto forthcoming oil supply, we show that large-scale production of bioplastics and bioderived chemicals is inevitable. Thanks to its unique chemical versatility, bioglycerol will become the raw material of both renewable and biodegradable plastics but also of highly valued molecules such as squalene or Vitamin D2. Finally crude glycerin will emerge as the enabler of the lignocellulosic biorefinery as it is the key process enhancer to efficiently decompose plant biomass into lignin, cellulose, and hemicellulose at low temperature and pressure (the Glycell process).
Thesis
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Energy scenarios are used as a tool to examine credible future states and pathways. The one who constructs a scenario defines the framework in which the possible outcomes exist. The credibility of a scenario depends on its compatibility with real world experiences, and on how well the general information of the study, methodology, and originality and processing of data are disclosed. In the thesis, selected global energy scenarios’ transparency and desirability from the society’s point of view were evaluated based on literature derived criteria. The global energy transition consists of changes to social conventions and economic development in addition to technological development. Energy solutions are economic and ethical choices due to far-reaching impacts of energy decision-making. Currently the global energy system is mostly based on fossil fuels, which is unsustainable over the long-term due to various reasons: negative climate change impacts, negative health impacts, depletion of fossil fuel reserves, resource-use conflicts with water management and food supply, loss of biodiversity, challenge to preserve ecosystems and resources for future generations, and inability of fossil fuels to provide universal access to modern energy services. Nuclear power and carbon capture and storage cannot be regarded as sustainable energy solutions due to their inherent risks and required long-term storage. The energy transition is driven by a growing energy demand, decreasing costs of renewables, modularity and scalability of renewable technologies, macroeconomic benefits of using renewables, investors’ risk awareness, renewable energy related attractive business opportunities, almost even distribution of solar and wind resources on the planet, growing awareness of the planet’s environmental status, environmental movements and tougher environmental legislation. Many of the investigated scenarios identified solar and wind power as a backbone for future energy systems. The scenarios, in which the solar and wind potentials were deployed in largest scale, met best the set out sustainability criteria. In future research, energy scenarios’ transparency can be improved by better disclosure on who has ordered the study, clarifying the funding, clearly referencing to used sources and indicating processed data, and by exploring how variations in cost assumptions and deployment of technologies influence on the outcomes of the study.
Thesis
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Supplying the increasing energy demand of communities both economically viable and environmentally friendly is among the primary challenges of the present century. In this regard, the current study aims to suggest a proper approach, in terms of economic and environment, to supply the energy demand of Eram Campus, Shiraz University. Pre-studies are carried out to realize the energy demand, primary energy potentials, and geographical constraints of Eram Campus. In the present study, simulations, optimizations and sensitivity analysis are performed to explore the feasibility of utilizing smart hybrid renewable energy system to meet the load demand of the Eram Campus. The results indicate that the suggested energy system consists of micro gas turbine (combined heat and power) power plant, thermal boiler, converter, photovoltaic panel, pumped hydro energy storage and predictive (smart) controller. To make use of the proposed power plant, 15$M is needed for initial capital cost. The levelized cost of energy and net present cost of the system is 0.09 $/kWh and 42.5 $M, respectively. Based on the obtained results, using the proposed energy system reduces the annual carbon dioxide production of the Eram Campus by 8000 megatonnes compared using the existing one. Moreover, the calculations reflect that the impacts of economic indexes variations, escalation of energy demand and energy consumption pattern change on the characteristics of the energy system are considerable. The optimum sizings of the gas turbine, thermal boiler, photovoltaic panel, converter and pumped hydro storage should be 2650 kW, 17 MW, 13754 kW, 4995 kW and 70 strings to meet the increase of 50 per cent in energy demand in the most economical strategy. It is worth mentioning that by reducing the energy consumption in specific time steps (1 per cent of the total energy demand), the net present cost and Levelized cost of energy would significantly decline 6 and 15 per cent, respectively.
Article
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Batteries for stationary applications can prove to be crucial for enabling high penetration of solar energy, but production and use of batteries comes with an energetic cost. This study quantifies how adding a lithium-ion (Li-ion) battery affects the energetic performance of a typical residential photovoltaic (PV) system for a wide range of climatic conditions. If all generated power is either self-consumed or made available via the existing distribution grid, the PV system has an energy return on investment (EROI) of between 14 (Alaska) and 27 (Arizona). While adding a 12 kWh Li-ion battery increases self-consumption considerably, this has the negative effect of decreasing the EROI by more than 20%. In a situation where all excess power generation is curtailed, the EROI can be as low as 7 (Alaska and Washington), although it can also be as high as 15 (Florida). Introducing a battery increases EROI but is still considerably lower than in cases where use excess power generation is added to the grid. Doubling the battery size increases the average self-consumption marginally, but further decreases EROI of the system because the extra energy invested to build the additonal battery is used inefficienctly. The results show that installing PV systems in locations with good solar resources and a grid that can accept excess prodution is desirable for maximizing net energy return from distributed PV. Batteries have a benefit when excess electricity generation can not be fed into the grid. Oversizing batteries has the effect of significantly reducing the EROI of the PV system.
Article
Two conceptually and computationally simple techniques (one optimistic, the other pessimistic) are introduced to estimate the energy payback time of a photovoltaic array. Both yield values of the Energy Returned On energy Invested (EROI) in excess of approximately 5. Therefore solar photovoltaic electricity appears to be a stably sustainable source of renewable energy.
Article
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A paper by Ferroni and Hopkirk (2016) provided evidence that presently available PV systems in regions of moderate insolation like Switzerland and countries north of the Swiss Alps act as net energy sink. These findings were disputed in a paper (Raugei et al., 2017). Additional clarifications in support of our conclusions are explained, including mention of weak points in the argumentation by Raugei et al. Our study is based on the concept of the extended ERoEI (ERoEIEXT) for PV systems, knowing that this is not the mainstream concept in the Life Cycle Assessment (LCA), applying the Process-Based Life Cycle Assessment. The concept of the ERoEIEXT considers many possible energy contributions needed for assessing the envisioned transition from fossil fuel to other types of energy sources and here in particular to photovoltaics in regions of moderate insolation. The conclusions of our original study remain unchanged. Any attempt to adopt an Energy Transition strategy by substitution of intermittent for base load power generation in countries like Switzerland or further north will result in unavoidable net energy loss. This applies both to the technologies considered, to the available data from the original study and to newer data from recent studies.
Article
The experience curve theory assumes that technology costs decline as experience of a technology is gained through production and use. This article reviews the literature on the experience curve theory and its empirical evidence in the field of electricity generation technologies. Differences in the characteristics of experience curves found in the literature are systematically presented and the limitations of the experience curve theory, as well as its use in energy models, are discussed. The article finds that for some electricity generation technologies, especially small-scale modular technologies, there has been a remarkably strong (negative) relationship between experience and cost for several decades. Conversely, for other technologies, especially large-scale and highly complex technologies, the experience curve does not appear to be a useful tool for explaining cost changes over time. The literature review suggests that when analysing past cost developments and projecting future cost developments, researchers should be aware that factors other than experience may have significant influence. It may be worthwhile trying to incorporate some of these additional factors into energy system models, although considerable uncertainties remain in quantifying the relevance of some of these factors.
Article
India achieved a significant milestone by enabling electric access to all villages in April 2018. More importantly, the focus is now on stable and regular electric supply. Government of India led various modifications in the Electricity Acts, revised Tariff Policy, and various State-level policies along with other market friendly incentives together have led to growth of Roof Top Photo Voltaic (RTPV) systems installation rates and capacity in India over last decade. Yet, key regulatory and operational issues are observed in the RTPV market setup during study (2016-2018) delaying adoption of the roof top PV systems in India. These include skills for solar panels installation, maintainence and higher costs of operations. Research required to develop interconnectivity, designing and installation related engineering skills. The solar market analysis has emphasized that awareness amongst users, ease of installation and energy payback time as important parameters considered for technology diffusion. Typical north Indian market conditions have been observed through an experiment using 1.5 kW domestic RTPV system experimental setup and detailed interviews in the area. Analysis shows that Energy Pay Back Time of the RTPV system in India is 8.61 years (without Maximum Power Point Tracking) owing to market barriers and lack of skilled manpower. Roof top PV system brings large Reduction in CO2 emission as compared to coal based plant.
Chapter
A energia solar fotovoltaica surge como uma alternativa promissora para a geração de energia limpa para regiões e países com alto potencial de irradiação solar e pouco aproveitamento desta fonte, o Brasil por exemplo. Sendo assim, o trabalho trata do assunto energia solar, apontando uma tecnologia da nova geração fotovoltaica chamada de Célula Solar Sensibilizada por Corante (CSSC). A CSSC é uma tecnologia de fabricação de baixo custo em comparação com células solares de silício que são maioria no mercado fotovoltaico. O seu funcionamento é comparado com a fotossíntese, em que as plantas retiram energia do sol, só que na célula, esta energia é convertida em eletricidade. Com isso, o objetivo deste trabalho foi construir células solares sensibilizadas por corantes naturais, demonstrando os testes de geração de tensão para cada tipo de corante. Os corantes utilizados foram o açaí em pó, o mirtilo triturado e a clorofila em pó. Realizou-se duas montagens diferentes nas células, a segunda montagem foi feita para corrigir erros da primeira montagem como a falta de contatos elétricos estáveis nas células, possibilitando a avaliação da célula com uma combinação de corantes. Apesar de algumas adversidades encontradas no decorrer da confecção das CSSC, todas as células geraram energia na ordem de mV e a célula de clorofila atingiu o maior pico, gerando 258 mV.
Article
Recent papers argue that the energy return on energy invested (EROI) for renewable electricity technologies and systems may be so low that the transition from fossil fuelled to renewable electricity may displace investment in other important economic sectors. For the case of large-scale electricity supply, we draw upon insights from Net Energy Analysis and renewable energy engineering to examine critically some assumptions, data and arguments in these papers, focussing on regions in which wind and solar can provide the majority of electricity. We show that the above claim is based on outdated data on EROIs, on failing to consider the energy efficiency advantages of transitioning away from fuel combustion and on overestimates of storage requirements. EROIs of wind and solar photovoltaics, which can provide the vast majority of electricity and indeed of all energy in the future, are generally high (≥ 10) and increasing. The impact of storage on EROI depends on the quantities and types of storage adopted and their operational strategies. In the regions considered in this paper, the quantity of storage required to maintain generation reliability is relatively small.
Article
Photovoltaic (PV) power is expected to play an important role in reducing global warming and improving energy security. China promotes PV power development by implementing feed-in tariff policies. However, the economic and environmental impacts of substituting coal-fired electricity with PV power, particularly as the subsidy rate declines, are not well-known. This study estimates the economic and environmental impacts in different cases and scenarios by combining life-cycle assessment with input-output analysis. Results indicate that substituting PV power for coal-fired electricity has negative impacts on employment, household income, and tax revenue. Although this substitution can promote economic growth when PV power generation is subsidised, the impact of the substitution on GDP will gradually decline as the subsidy rate is reduced and finally becomes negative. Assuming that the levelized cost of PV power declines following the learning curve, the same results will hold even if PV power generation becomes profitable in the future. Despite its negative impacts on employment, household income and tax revenue, the substitution has huge external values. Therefore, policies are needed to internalise the external value and address the economic impacts of the substitution.
Article
We examine cumulative net energy use and cumulative net CO2 emissions associated with the development of photovoltaics (PVs) on a global scale. The analysis is focused on the performance of five countries with the largest installed PV capacities —Italy, Japan, Germany, Spain, and the United States—and on the aggregate values for the world (23 countries). The historical record shows that, during the past 19 years of development, the installed base has grown to 64 GW, with an average annual growth rate of almost 40%. During that period the manufacturing and use of photovoltaics has led to a cumulative net consumption of approximately 286 PJ of energy, and cumulative net emissions of 34 Mt of CO2 as a result of a considerable payback time. While energy/CO2 payback time is not unique to PV systems, it plays a larger role in the development of new energy systems than other low-carbon systems. PV energy/CO2 payback time decreases with the following measures: installation of PVs in locations with a large PV potential and high CO2 emissions of the electricity replaced, manufacturing PVs at locations with low CO2 emissions of kWh of electricity used in the production, recycling PVs, and increasing PV conversion efficiency. The analysis is therefore extended into the future for three scenarios with different maximum capacities of photovoltaics (20%, 50%, and 100% of total electricity production). In these scenarios, cumulative net CO2 emissions can be reduced by 4%, 9%, and 18%, respectively, over the long term (by the year 2050). Short-term CO2 increases during growth versus long-term CO2 reduction present a trade-off in developmental growth strategies.
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The objective of this article is to evaluate the energy consumption in solar photovoltaic (SPV) module production in India and examine its implications for large-scale introduction of SPV plants in the country. Data on energy used in SPV production were collected from existing manufacturing facilities in the country. The energy payback period turns out to be approximately 4 years. This is comparable to energy payback periods of similar modules produced internationally. However, if an ambitious program of introducing SPV power production is undertaken to contribute substantially to the power scenario in the country, an annual growth rate beyond 21% will render the program an energy sink rather than an energy source, as borne out by dynamic energy analysis. Policy implications are also discussed in light of this analysis.
Article
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This study is a life-cycle analysis of the balance of system (BOS) components of the 3·5 MWp multi-crystalline PV installation at Tucson Electric Power's (TEP) Springerville, AZ field PV plant. TEP instituted an innovative PV installation program guided by design optimization and cost minimization. The advanced design of the PV structure incorporated the weight of the PV modules as an element of support design, thereby eliminating the need for concrete foundations. The estimate of the life-cycle energy requirements embodied in the BOS is 542 MJ/m2, a 71% reduction from those of an older central plant; the corresponding life-cycle greenhouse gas emissions are 29 kg CO2 eq./m2. From field measurements, the energy payback time (EPT) of the BOS is 0·21 years for the actual location of this plant, and 0·37 years for average US insolation/temperature conditions. This is a great improvement from the EPT of about 1·3 years, estimated for an older central plant. The total cost of the balance of system components was $940 US per kWp of installed PV, another milestone in improvement. These results were verified with data from different databases and further tested with sensitivity- and data-uncertainty analyses. Copyright © 2005 John Wiley & Sons, Ltd.
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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.
Article
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Oil and gas are the main sources of energy in the United States. Part of their appeal is the high Energy Return on Energy Investment (EROI) when procuring them. We assessed data from the United States Bureau of the Census of Mineral Industries, the Energy Information Administration (EIA), the Oil and Gas Journal for the years 1919–2007 and from oil analyst Jean Laherrere to derive EROI for both finding and producing oil and gas. We found two general patterns in the relation of energy gains compared to energy costs: a gradual secular decrease in EROI and an inverse relation to drilling effort. EROI for finding oil and gas decreased exponentially from 1200:1 in 1919 to 5:1 in 2007. The EROI for production of the oil and gas industry was about 20:1 from 1919 to 1972, declined to about 8:1 in 1982 when peak drilling occurred, recovered to about 17:1 from 1986–2002 and declined sharply to about 11:1 in the mid to late 2000s. The slowly declining secular trend has been partly masked by changing effort: the lower the intensity of drilling, the higher the EROI compared to the secular trend. Fuel consumption within the oil and gas industry grew continuously from 1919 through the early 1980s, declined in the mid-1990s, and has increased recently, not surprisingly linked to the increased cost of finding and extracting oil.
Article
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A CO2 comprehensive balance within the life-cycle of a photovoltaic energy system requires careful examination of the CO2 sinks and sources at the locations and under the conditions of production of each component, during transport, installation and operation, as well as at the site of recycling. Calculations of the possible effect on CO2 reduction by PV energy systems may be incorrect if system borders are not set wide enough and remain on a national level, as can be found in the literature. For the examples of Brazil and Germany, the effective CO2 reductions have been derived, also considering possible interchange scenarios for production and operation of the PV systems considering the carbon dioxide intensity of the local electricity grids. In the case of Brazil also off-grid applications and the substitution of diesel generating sets by photovoltaics are examined: CO2 reduction may reach 26,805 kg/kWp in that case. Doing these calculations, the compositions of the local grids and their CO2 intensity at the time of PV grid injection have to be taken into account. Also possible changes of the generation fuel mix in the future have to be considered: During the operation time of a PV system, different kinds of power plants could be installed that might change the CO2 intensity of the grid. In the future also advanced technologies such as thin films have to be considered.
Article
New crystalline silicon technologies are evaluated to determine energy pay-back time for PV-modules. Five solar-grade silicon production methods, four sheet processes, and improved methods for cell and module production are considered. Using an advanced carbothermic reduction process for silicon production and the S-web technique for ribbon growth, a pay-back time of 5 months was determined. This compares favorable with energy-pay-back times calculated for an amorphous silicon module (7 years) and 1 year for alpha -Si cells (1 year). This result shows that photovoltaic energy conversion based on a new crystalline silicon technology leads to short energy pay-back time, a necessary precondition for large-scale application.
Conference Paper
Today's almost fully non-sustainable global energy system needs to be transformed towards a 100% sustainable basis. Solar photovoltaic (PV) is considered by a growing base of organizations and researchers as a backbone technology for global energy supply in the decades to come. Global energy scenarios of the recent years are compared in their level of acknowledging the significant role of solar PV. Using logistic growth functions it is possible to extrapolate the trend in the various studies to the years 2050 and 2100. The studies can be distinguished in a group of progressive and conservative ones. The reports of the IEA set the lower limit of all studies. The three most progressive studies are from the WBGU, the IEA PVPS and the Solar Economy scenario published in this paper. The Solar Economy scenario is based on a stabilized population which may require by the end of this century about 400,000 TWhel for all energetic needs. The PV share of TPED among the studies varies between 3-73% in the year 2100 when the currently available long-term forecasts are being compared. According to the Solar Economy scenario a PV share of up to 40%, would lead to a total installed capacity of up to 93 TWp and annual installations of up to 2.3 TWp for harvesting sustainable energy on a cost level of about 11-12 €/MWh in the global average. The global energy problem might be easier solvable than most people expect today.
Article
The transition from a fossil-based energy economy to one based on renewable energy is driven by the double challenge of climate change and resource depletion. Building a renewable energy infrastructure requires an upfront energy investment that subtracts from the net energy available to society. This investment is determined by the need to transition to renewable energy fast enough to stave off the worst consequences of climate change and, at the same time, maintain a sufficient net energy flow to sustain the world's economy and population. We show that a feasible transition pathway requires that the rate of investment in renewable energy should accelerate approximately by an order of magnitude if we are to stay within the range of IPCC recommendations.
Article
Energy payback time and carbon footprint have been calculated for 2 commercially available and 3 new CPV systems by life cycle assessment. Calculations have been carried out for the location of Catania, Sicily (Italy). The energy payback time varies from between 0.8 and 1.9 years. The carbon footprint varies from between 18 and 45 grams of CO 2 -eq/kWh produced. The CPV systems are at varying stages of development, with different sizes and scale of production. Further development, increased size and scale of production are expected to bring a further decrease in the impacts. The largest contribution to the payback time and carbon footprint is from the tracking and module materials. Achieving high efficiencies and increasing the lifetime of the components is important to increase the kWh produced by the CPV system.
Conference Paper
Tilt angles show decisive impact on fixed tilted PV power plant design. A comprehensive irradiation and cost optimizing model is presented based on Hay-Davis-Klucher-Reindl (HDKR) approach coupled with levelized cost of electricity (LCOE). Results of the analysis are shown for all regions in the world. Trade-off between irradiation and cost optimization is found. Rule of thumb, that tilt angle should be respective latitude can be confirmed for most regions in the world, except those higher than 45°N or lower 45°S or of very special local climatic conditions. Nevertheless, overall impact of tilt angle on maximizing irradiation should not be overestimated.
Conference Paper
The photovoltaic (PV) energy technology has the potential to contribute to the global energy supply on a large scale. This potential can only be realised if sustainable and highly competitive PV economics are achieved. An integrated economic PV market potential assessment is presented consisting of grid-parity and fuel-parity analyses for the on-grid markets and an amortization analysis for rural off-grid PV markets. All analyses are mainly driven by cost projections based on the experience curve approach and growth rates for PV systems and electricity and fossil fuel prices for the currently used power supply. A total economic PV market potential of 2,800 GW to 4,300 GW is derived for the year 2020. 600 GW to 1,600 GW of cumulated installed PV capacity is estimated for the year 2020, depending on scenario assumptions. Even the low edge of the expected total installed PV capacity exceeds the scenario assumptions of leading energy organizations, such as IEA, by a factor of more than three to five. In conclusion, PV is on its way to become a highly competitive energy technology. Being complementary to wind power, PV together with wind power might become the backbone of the global energy supply in the coming decades.
Article
Grid-parity is a very important milestone for further photovoltaic (PV) diffusion. A grid-parity model is presented, which is based on levelized cost of electricity (LCOE) coupled with the experience curve approach. Relevant assumptions for the model are given, and its key driving forces are discussed in detail. Results of the analysis are shown for more than 150 countries and a total of 305 market segments all over the world, representing 98.0% of world population and 99.7% of global gross domestic product. High PV industry growth rates enable a fast reduction of LCOE. Depletion of fossil fuel resources and climate change mitigation forces societies to internalize these effects and pave the way for sustainable energy technologies. First grid-parity events occur right now. The 2010s are characterized by ongoing grid-parity events throughout the most regions in the world, reaching an addressable market of about 75–90% of total global electricity market. In consequence, new political frameworks for maximizing social benefits will be required. In parallel, PV industry tackle its next milestone, fuel-parity. In conclusion, PV is on the pathway to become a highly competitive energy technology.
Article
The energy input requirements for thin-film PV (photovoltaic) modules are discussed, using CuInSe2-based cells as an example. Energy payback times and energy ratios are calculated over a range of insolation levels for various semiconductor deposition techniques. The sensitivity of the energy requirements to single and double process parameter variations for the stacked elemental layer technique is also investigated
Article
The energy invested in photovoltaic modules has been investigated on the basis of currently operating commercial production lines in France. The analysis was made for two types of solar cells, polycrystalline silicon and amorphous silicon. The energy which was calculated in this way was compared with the energy produced by these modules under operating conditions in various European climates. An average energy pay-back time of 1.2 years for amorphous silicon modules and 2.1 years for crystalline silicon modules was found. It can be anticipated that these energy pay-back times will decrease in the future.
Article
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.
Article
Photovoltaic power generation and other renewable generation forms are compared with conventional generation forms in terms of some environmental characteristics.First a comparative analysis of the surface and material reqirements of different power stations is given.The results of a detailed investigation about the accumulated energy consumption (“hidden energy”) in the manufacturing and construction of photovoltaic power plants and corresponding data about the CO2-emissions caused by photovoltaic power generation are presented.The definitions of the characteristic figures, yield factor and energy amortisation time (energy pay-back time), frequently used in evaluations related with hidden energy, are discussed.A short introduction in one project concerning further investigations in the material and quality balances for the production of photovoltaic systems gives an outlook on our present research work in this field.
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.
Article
Developments in the design and manufacture of photovoltaic cells have, over the last few years, been very rapid such that they are now predicted to become a major renewable energy source for buildings. This paper considers the embodied energy in photovoltaic modules applied to U.K. buildings, and determines a payback period in terms of the embodied energy rather than cost. The embodied energy payback is important for renewable technologies as their use makes no sense if the energy used in their manufacture is more than they can save in their life-time. The embodied energy payback period should always be one of the criteria used for comparing the viability of one renewable technology against another. The results show that, for the U.K. buildings studied and for an optimistic scenario with an ideal location with no overshadowing and without the use of storage batteries, the embodied energy payback period for photovoltaic modules is in the region of 8–12 years. At present therefore other renewable technologies would appear to be more suitable for the U.K. Photovoltaics applied to buildings may be a realistic option in climates with higher levels of solar radiation. They may also prove to be successful in the future in the U.K. if photoelectric generation efficiencies improve substantially, or economies are made in the manufacturing process.
Article
We present estimates of the lifetime carbon dioxide emissions from coal-fired, photovoltaic, and solar thermal power plants in the United States. These CO2 estimates are based on a net energy analysis derived from both operational systems and detailed design studies. It appears that energy-conservation measures and shifting from fossil to renewable energy sources have significant long-term potential to reduce CO2 production caused by energy generation. The implications of these results for a national energy policy are discussed.
Article
The methodology used and results obtained for grid-connected photovoltaic (PV) plants in recent Swiss life-cycle assessment (LCA) studies on current and future energy systems are discussed. Mono- and polycrystalline silicon cell technologies utilized in current panels as well as monocrystalline and amorphous cells for future applications were analysed for Swiss conditions. The environmental inventories of slanted-roof solar panels and large plants are presented. Greenhouse gas emissions from present and future electricity systems are compared. The high electricity requirements for manufacturing determine most of the environmental burdens associated with current photovoltaics. However, due to increasing efficiency of production processes and cells, the environmental performance of PV systems is likely to improve substantially in the future. © 1998 John Wiley & Sons, Ltd.
Article
The concerns about environmental impacts of photovoltaic (PV) power systems are growing with the increasing expectation of PV technologies. In this paper, three kinds of silicon-based PV modules, namely single-crystalline silicon (c-Si), polycrystalline silicon (poly-Si) and amorphous silicon (a-Si) PV modules, are evaluated from the viewpoint of their life-cycle. For the c-Si PV module it was assumed that off-grade silicon from semiconductor industries is used with existing production technologies. On the other hand, new technologies and the growth of production scale were presumed with respect to the poly-Si and a-Si PV modules.Our results show that c-Si PV modules have a shorter energy pay-back time than their expected lifetime and lower CO2 emission than the average CO2 emission calculated from the recent energy mix in Japan, even with present technologies. Furthermore the poly-Si and the a-Si PV modules with the near-future technologies give much reduction in energy pay-back times and CO2 emissions compared with the present c-Si PV modules. The reduction of glass use and the frameless design of the PV module may be effective means to decrease them more, although the lifetime of the PV module must be taken into account. © 1998 John Wiley & Sons, Ltd.
Article
The integration of photovoltaic (PV) systems in buildings shows several advantages compared to conventional PV power plants. The main objectives of the present study are the quantitative evaluation of the benefits of building-integrated PV systems over their entire life-cycle and the identification of best solutions to maximize their energy efficiency and CO2 mitigation potential. In order to achieve these objectives, a simplified life-cycle analysis (LCA) has been carried out. Firstly, a number of existing applications have been studied. Secondly, a parametric analysis of possible improvements in the balance-of-system (BOS) has been developed. Finally, the two steps have been combined with the analysis of crystalline silicon technologies. Results are reported in terms of several indicators: energy pay-back time, CO2 yield and specific CO2 emissions. The indicators show that the integration of PV systems in buildings clearly increases the environmental benefits of present PV technology. These benefits will further increase with future PV technologies. Future optimized PV roof-integrated systems are expected to have an energy pay-back time of around 1·5 years (1 year with heat recovery) and to save during their lifetime more than 20 times the amount of CO2 emitted during their manufacturing (34 times with heat recovery). © 1998 John Wiley & Sons, Ltd.
Article
Preliminary Environmental Life Cycle Assessment of solar grade silicon production via gas- and metallurgical route indicates that environmental impacts can be reduced by: • making efficient use of the metallurgical silicon, • installing waste heat recovery systems, • using a clean source of electricity. The metallurgical route has the advantage of a lower energy consumption compared to the traditional routes with purification via the gas phase resulting in lower environmental impacts.
Article
The total energy required to produce silicon solar cells from the raw material SiO2 is estimated. Metallurgical-grade silicon, semiconductor-grade trichlorosilane, polycrystalline semiconductor-grade silicon, and silicon solar cells are considered in terms of the process energy required to produce them and in relation to the total energy expended in their manufacture. The energy payback times using present technology is 24 years for space cells and 12 years for terrestrial cells. Improvements are described which could reduce the energy payback time to as little as four months for terrestrial cells.
Article
This paper is a study of comparisons between five types of 100 MW Very Large-Scale Photovoltaic Power Generation (VLS-PV) Systems, from economic and environmental viewpoints. The authors designed VLS-PV systems using typical PV modules of multi-crystalline silicon (12·8% efficiency), high efficiency multi-crystalline silicon (15·8%), amorphous silicon (6·9%), cadmium tellurium (9·0%), and copper indium selenium (11·0%), and evaluated them by Life-Cycle Analysis (LCA). Cost, energy requirement, and CO2 emissions were calculated. In addition, the authors evaluated generation cost, energy payback time (EPT), and CO2 emission rates. As a result, it was found that the EPT is 1·5–2·5 years and the CO2 emission rate is 9–16 g-C/kWh. The generation cost was 11–12 US Cent/kWh on using 2 USD/W PV modules, and 19–20 US Cent/kWh on using 4 USD/W PV module price. Copyright © 2007 John Wiley & Sons, Ltd.
Article
The ecological benefit and sustainability of a new energy technology and its potential to reduce CO2 emissions depend strongly on the amount of energy embodied in the materials and production processes. The energy payback time is a measure for the amount of time that a renewable energy system has to operate until the energy involved in its complete life-cycle is regenerated. In this paper, the energy payback time of the high-concentration photovoltaic system FLATCON® using III–V semiconductor multi-junction solar cells has been evaluated. Considering the energy demand for the system manufacturing, including transportation, balance of system and system losses, the energy payback time turns out to be as low as 8–10 months for a FLATCON® concentrator built in Germany and operated in Spain. The energy payback time rises slightly to 12 to 16 months for a system installed in Germany. The main energy demand in the production of such a high-concentration photovoltaic system was found to be the zinced steel for the tracking unit. Copyright © 2005 John Wiley & Sons, Ltd.
Article
The purpose of this study was to identify a suitable type of mega-solar system from an environmental viewpoint. The authors evaluated six types of 20 different PV modules by life cycle analysis (LCA) with actual equipment data and output. The types were single crystal silicon (sc-Si), amorphous silicon (a-Si)/sc-Si, multicrystalline silicon (mc-Si), a-Si, microcrystalline silicon (µc-Si)/a-Si and CIS. The boundaries of LCA were from the mining stage to that of waste management. Mining, manufacturing and waste management information was taken from an LCA database, while data on transport, construction and amounts of equipment were obtained from actual systems. Since the irradiation figures and electricity output were also actual data, we could avoid the difficulties of making assumptions for values such as the actual output power of thin films. In addition, installation at a single plant provided suitable conditions for comparing PV systems. The results showed an energy requirement ranging from 19 to 48 GJ/kW and an energy payback time of between 1.4 and 3.8 years. CO2 emissions were from 1.3 to 2.7 t-CO2/kW, and CO2 emission rates ranged from 31 to 67 g-CO2/kWh. The multicrystalline (mc-Si) and CIS types showed good results because mc-Si and CIS PV modules have high efficiency and a lower energy requirement. In particular, the CIS module generated more electricity than expected with catalogue efficiency. The single crystal silicon PV module did not produce good results because, considering their energy requirement, installed sc-Si PV modules do not have high efficiency. However, the operation data used covered only 1 year; data from a longer period should be collected to obtain long-term irradiation figures and clarify degradation. Copyright
Article
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.
Article
CO2 emissions from construction of various power plants were calculated by the LCA (Life Cycle Assessment) methodology. The LCI (Life Cycle Inventory) was calculated by “NIRE-LCA”, LCA software developed at the National Institute for Resources and Environment using a bottom-up approach. CO2 payback times of renewable energy electric power plants (hydroelectric, OTEC and PV) were calculated vs. conventional fossil fuel-fired power plants (coal, oil and LNG). The evaluated payback times were much shorter than the typical operational lifetimes of the respective renewable energy electric power plants.
Article
Organic solar cells, both in the hybrid dye sensitized technology and in the full organic polymeric technology, are a promising alternative that could supply solar electricity at a cost much lower than other more conventional inorganic photovoltaic technologies. This paper presents a life cycle analysis of the laboratory production of a typical bulk heterojunction organic solar cell and compares this result with those obtained for the industrial production of other photovoltaic technologies. Also a detailed material inventory from raw materials to final photovoltaic module is presented, allowing us to identify potential bottlenecks in a future supply chain for a large industrial output. Even at this initial stage of laboratory production, the energy payback time and CO2 emission factor for the organic photovoltaic technology is of the same order of other inorganic photovoltaic technologies, demonstrating that there is plenty of room for improvement if the fabrication procedure is optimized and scaled up to an industrial process. Copyright © 2010 John Wiley & Sons, Ltd.
Article
This paper presents an environmental comparison based on life cycle assessment (LCA) of the production under average European circumstances and use in The Netherlands of modules based on two kinds of III–V solar cells in an early development stage: a thin-film gallium arsenide (GaAs) cell and a thin-film gallium-indium phosphide/gallium arsenide (GaInP/GaAs) tandem cell. A more general comparison of these modules with the common multicrystalline silicon (multi-Si) module is also included. The evaluation of the both III–V systems is made for a limited industrial production scale of 0·1 MWp per year, compared to a scale of about 10 MWp per year for the multi-Si system. The here considered III–V cells allow for reuse of the GaAs wafers that are required for their production. The LCA indicates that the overall environmental impact of the production of the III–V modules is larger than the impact of the common multi-Si module production; per category their scores have the same order of magnitude. For the III–V systems the metal-organic vapour phase epitaxy (MOVPE) process is the main contributor to the primary energy consumption. The energy payback times of the thin-film GaAs and GaInP/GaAs modules are 5·0 and 4·6 years, respectively. For the multi-Si module an energy payback time of 4·2 years is found. The results for the III–V modules have an uncertainty up to approximately 40%. The highly comparable results for the III–V systems and the multi-Si system indicate that from an environmental point of view there is a case for further development of both III–V systems. Copyright
Article
A higher conversion efficiency of photovoltaic modules does not automatically imply a lower environmental impact, when the life-cycle of modules is taken into account. An environmental comparison is carried out between the production and use phase, except maintenance, of an indium–gallium–phosphide (InGaP) on multicrystalline silicon (mc-Si) tandem module, a thin-film InGaP cell module and a mc-Si module. The evaluation of the InGaP systems was made for a very limited industrial production scale. Assuming a fourfold reuse of the GaAs substrates in the production of the thin-film InGaP (half) modules, the environmental impacts of the tandem module and of the thin-film InGaP module are estimated to be respectively 50 and 80% higher than the environmental impact of the mc-Si module. The energy payback times of the tandem module, the thin-film InGaP module and the mc-Si module are estimated to be respectively 5.3, 6.3 and 3.5 years. There are several ways to improve the life-cycle environmental performance of thin-film InGaP cells, including improved materials efficiency in production and reuse of the GaAs wafer and higher energy efficiency of the metalorganic chemical vapour deposition process. Copyright © 2003 John Wiley & Sons, Ltd.
Conference Paper
Life cycle analysis has identified the production and decommissioning/disposal of thin film CdTe modules as the stages which have potentially the most severe environmental impacts. This paper investigates these stages with respect to materials, energy input and possible environmental and health implications
Conference Paper
Previous work has demonstrated that photovoltaic modules are net energy producers. Based on empirical analysis of utility bills and production records at Siemens Solar Industries, energy payback time for crystalline silicon is of the order of three years and for thin film copper indium diselenide ranges from ten years in research mode to under two years in production. About half of the energy content is process energy, half is embodied energy in incoming raw materials. This paper explores the energy balance implications of ongoing and longer-term development efforts. Future prospects for both crystalline silicon and copper indium diselenide are discussed, including production scale and yields, new processes and equipment, waste reduction and reclamation, of existing equipment reconfiguration, and product design
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This paper assesses modeling parameters that affect the environmental performance of two state-of-the-art photovoltaic (PV) electricity generation technologies: the PVL136 thin film laminates and the KC120 multi-crystalline modules. We selected three metrics to assess the modules’ environmental performance, which are part of an actual 33 kW installation in Ann Arbor, MI. The net energy ratio (NER), the energy pay back time (E-PBT), and the CO2 emissions are calculated using process based LCA methods. The results reveal some of the parameters, such as the level of solar radiation, the position of the modules, the modules’ manufacturing energy intensity and its corresponding fuel mix, and the solar radiation conversion efficiency of the modules, which affect the final analytical results. A sensitivity analysis shows the effect of selected parameters on the final results. For the baseline scenario, the E-PBT for the PVL136 and KC120 are 3.2 and 7.5 years, respectively. When expected future conversion efficiencies are tested, the E-PBT is 1.6 and 5.7 years for the PVL136 and the KC120, respectively. Based on the US fuel mix, the CO2 emissions for the PVL136 and the KC120 are 34.3 and 72.4 g of CO2/kW h, respectively. The most effective way to improve the modules’ environmental performance is to reduce the energy input in the manufacturing phase of the modules, provided that other parameters remain constant. Consequently, the use of PV as an electricity source during PV manufacturing is also assessed. The NER of the supplier PV is key for the performance of this scheme. The results show that the NER based on a PV system can be 3.7 times higher than the NER based on electricity supplied by the traditional grid mix, and the CO2 emissions can be reduced by 80%.
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Energy payback time is the energy analog to financial payback, defined as the time necessary for a photovoltaic panel to generate the energy equivalent to that used to produce it. This research contributes to the growing literature on net benefits of renewable energy systems by conducting an empirical investigation of as-manufactured photovoltaic modules, evaluating both established and emerging products. Crystalline silicon modules achieve an energy break-even in 3 to 4 years. At the current R&D pilot production rate (8% of capacity) the energy payback time for thin film copper indium diselenide modules is between 9 and 12 years, and in full production is ∼2 years. Over their lifetime, these solar panels generate 7 to 14 times the energy required to produce them. Energy content findings for the major materials and process steps are presented, and important implications for current research efforts and future prospects are discussed.
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Using life cycle assessment, metrics for calculation of the input energy requirements and greenhouse gas emissions from utility scale energy storage systems have been developed and applied to three storage technologies: pumped hydro storage (PHS), compressed air energy storage (CAES) and advanced battery energy storage (BES) using vanadium and sodium polysulphide electrolytes. In general, the use of energy storage with electricity generation increases the input energy required to produce electricity, as well as the total greenhouse gas emissions. Despite this increase, the life cycle GHG emission rate from storage systems when coupled with nuclear or renewable sources is substantially lower than from fossil fuel derived electricity sources. GHG emissions from PHS when coupled with nuclear and renewable energy systems are lower than those from BES or CAES. When coupled with fossil generation, CAES has significantly lower net GHG emissions than PHS or BES.
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The paper is concerned with the results of a thorough energy and life cycle assessment (LIA) of CdTe and CIS photovoltaic modules. The analysis is based on actual production data, making it one of the very first of its kind to be presented to the scientific community, and therefore especially worthy of attention as a preliminary indication of the future environmental impact that the up-scaling of thin film module production may entail. The analysis is consistent with the recommendations provided by ISO norms 14040 and updates, and makes use of an in-house developed multi-method impact assessment method named SUMMA, which includes resource demand indicators, energy efficiency indicators, and “downstream” environmental impact indicators. A comparative framework is also provided, wherein electricity produced by thin film systems such as the ones under study is set up against electricity from poly-Si systems and the average European electricity mix. Results clearly show an overall very promising picture for thin film technologies, which are found to be characterised by favourable environmental impact indicators (with special reference to CdTe systems), in spite of their still comparatively lower efficiencies.
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Authors have evaluated the life cycle of a thin-film CdS/CdTe PV module to estimate the energy payback time (EPT) and the life-cycle CO2 emissions of a residential rooftop PV system using the CdS/CdTe PV modules. The primary energy requirement for producing 1 m2 of the CdS/CdTe PV module was similar to a-Si PV module at annual production scale of 100 MW. EPT was calculated at 1.7–1.1 yr, which was much shorter than the lifetime of the PV system and similar to that of a-Si PV modules. The life-cycle CO2 emissions were also estimated at 14–9 g-C/kWh, which was less than that of electricity generated by utility companies.
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The complex structure of energy supply systems and the range of environmental issues involved, make decisions regarding the use of new or improved energy resources and energy technologies far from being straightforward. A life-cycle approach is required to reveal the full potential for an option to realize increased energy performance and reduced emissions of greenhouse gases. In addition, the life-cycle assessment reveals possible bottlenecks regarding other environmental issues.
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This paper concentrates on the assessment of energy and emissions related to the production and manufacture of materials for an offshore wind farm as well as a wind farm on land based on a life cycle analysis (LCA) model. In Denmark a model has been developed for life cycle assessments of different materials. The model is able to assess the energy use related to the production, transportation and manufacture of 1 kg of material. The energy use is divided into fuels used in order to estimate the emissions through the life cycle. In the paper the model and the attached assumptions are described, and the model is demonstrated for two wind farms. The externalities for the wind farms are reported, showing the importance of life cycle assessment for renewable energy technologies.
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In this study, single-crystalline silicon (c-Si) photovoltaic (PV) cells and residential PV systems using off-grade silicon supplied from semiconductor industries were evaluated from a life cycle point of view. Energy payback time (EPT) of the residential PV system with the c-Si PV cells made of the off-grade silicon was estimated at 15.5 years and indirect CO2 emission per unit electrical output was calculated at 91 g-C/kWh even in the worst case. These figures were more than those of the polycrystalline-Si and the amorphous-Si PV cells to be used in the near future, but the EPT was shorter than its lifetime and the indirect CO2 emissions were less than the recent average CO2 emissions per kWh from the utilities in Japan. The recycling of the c-Si PV cells should be discussed for the reason of the effective use of energy and silicon material.
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Life-cycle analysis is an invaluable tool for investigating the environmental profile of a product or technology from cradle to grave. Such life-cycle analyses of energy technologies are essential, especially as material and energy flows are often interwoven, and divergent emissions into the environment may occur at different life-cycle-stages. This approach is well exemplified by our description of material and energy flows in four commercial PV technologies, i.e., mono-crystalline silicon, multi-crystalline silicon, ribbon-silicon, and cadmium telluride. The same life-cycle approach is applied to the balance of system that supports flat, fixed PV modules during operation. We also discuss the life-cycle environmental metrics for a concentration PV system with a tracker and lenses to capture more sunlight per cell area than the flat, fixed system but requires large auxiliary components. Select life-cycle risk indicators for PV, i.e., fatalities, injures, and maximum consequences are evaluated in a comparative context with other electricity-generation pathways.
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Since solar energy systems feed on a ‘clean’ energy source, they do not produce polluting emissions during their operation. However, they carry the environmental weight of other phases in their life cycle. In order to analyze the energy and environmental profile of these systems, it is necessary to expand the system boundaries, taking into account also the ‘hidden impacts’ related to production, transportation and system disposal at the end of its technical life. Here, the life cycle assessment methodology is applied to derive a complete and extended energy and environmental profile of photovoltaic systems. As reference case, a conventional multi-crystalline building integrated system is selected, retrofitted on a tilted roof, located in Rome (Italy) and connected to the national electricity grid. Then improved configurations of the reference system are assessed, focusing on building integration issues and the operational phase (considering an experimental hybrid photovoltaic system with heat recovery). Environmental ‘pay back times’ of the assessed systems are then calculated for CO2 equivalent emissions and embodied energy. All the analyzed configurations are characterized by environmental pay back times one order of magnitude lower than their expected life time (3–4 years vs. 15–30 years). Thanks to a wider exploitation of photovoltaic potential during its ‘zero emission operation’, these results are further lowered by photovoltaic hybrid systems (environmental pay back times, depending on heat recovery configuration, go down to 40–50% of the values calculated for the reference case).