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Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants

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... The second way we validate our results is to compare our mean scores with quantitative data where this is available for five of our criteria -cost, deaths, illness, ERoEI and CO2 intensity. R 2 Cost of electricity versus Levelised Cost of Electricity [47] 0.90 Fatalities versus Deaths per TWh [48] 0.71 Fatalities versus Deaths per TWh (49) 0.74 Chronic illness versus serious illness [48] 0.80 ERoEI versus buffered ERoEI [50] 0.92 CO2 intensity versus CO2 intensity for 5 technologies [47] 0.97 ...
... Cost of electricity versus Levelised Cost of Electricity [47] 0.90 Fatalities versus Deaths per TWh [48] 0.64 Fatalities versus Deaths per TWh [49] 0.74 Chronic illness versus serious illness [48] 0.80 ERoEI versus buffered ERoEI [50] 0.92 ...
... The correlation with ERoEI is negative because high ERoEI = good and is consequently given a low score in our scheme and vice versa. We plot our MCDA scores against buffered ERoEI reported by [50], as shown on their Figure 3. [50] report data for 8 technologies, all of which are in our sample set. Only seven are plotted here since nuclear was a major outlier with reported ERoEI of 75 that is well off the scale of our chart (see discussion below). ...
Preprint
Multi criteria decision analysis (MCDA) has been used to provide a holistic evaluation of the quality of 13 electricity generation technologies in use today. A group of 19 energy experts cast scores on a scale of 1 to 10 using 12 quality criteria, based around the pillars of sustainability (society, environment and economy), with the aim of quantifying each criterion for each technology. The total mean score is employed as a holistic measure of system quality. The top three technologies to emerge in rank order are nuclear, combined cycle gas and hydroelectric. The bottom three are solar PV, biomass and tidal lagoon. All seven new renewable technologies fared badly, perceived to be expensive, unreliable, and not as environmentally friendly as is often assumed. We validate our approach by 1) comparing scores for pairs of criteria where we expect a correlation to exist; 2) comparing our qualitative scores with quantitative data; and; 3) comparing our qualitative scores with NEEDS project baseline costs. In many cases, R2>0.8 suggests that the structured hierarchy of our approach has led to scores that may be used in a semi-quantitative way. Adopting the results of this survey would lead to a very different set of energy policy priorities in the OECD and throughout the world.
... This is mainly due to the fact that RES technologies are characterized by high operating instability (depending on weather conditions), relatively short lifetime, very low energy density, and the need to store energy. As a result, the level of the Energy Return on Investment (EROI) coefficient, defined as [2]: EROI = usable energy the plant returns during its lifetime all the invested energy needed to make this energy usable (1) is too low, and practically for all RES technologies (if we take into account energy storage) is below the level required for economic viability [2]. EROI is well correlated with quality-of-life factors such as the human development index (HDI), health expenditure, female literacy, rate of underweight children, and gender inequality [3]. ...
... This is mainly due to the fact that RES technologies are characterized by high operating instability (depending on weather conditions), relatively short lifetime, very low energy density, and the need to store energy. As a result, the level of the Energy Return on Investment (EROI) coefficient, defined as [2]: EROI = usable energy the plant returns during its lifetime all the invested energy needed to make this energy usable (1) is too low, and practically for all RES technologies (if we take into account energy storage) is below the level required for economic viability [2]. EROI is well correlated with quality-of-life factors such as the human development index (HDI), health expenditure, female literacy, rate of underweight children, and gender inequality [3]. ...
... EROI is well correlated with quality-of-life factors such as the human development index (HDI), health expenditure, female literacy, rate of underweight children, and gender inequality [3]. Compilation and comparison of the results of the works [1][2][3] clearly shows that too fast and intensive switching to renewable energy sources may significantly deteriorate quality of life and not significantly reduce greenhouse gas emissions to the atmosphere. ...
Article
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The year 2021 brought a significant increase in CO2 emissions despite the rapid growth of new renewable energy sources (RES) installations being commissioned [...]
... Several researchers have, to date, attempted to define the overall EROI value achieved by nuclear fission technology at the global scale (rather than for any particular technology or location), but the conclusions of these studies have generated debate and controversy [12,[22][23][24]. Nuclear technology and the system it operates within is highly complex, and although the existing body of work has considered the factors that are necessary to build and run nuclear technology (e.g., nuclear fuel enrichment) as well as those that become necessary as a result of nuclear technology (e.g., radioactive waste management), the emphasis and focus of detailed assessment has generally been skewed towards the 'enabling' factors [6,20] and therefore may not capture this complexity adequately. ...
... Weissbach et al. [23] calculated EROI/energy intensity/payback times for different energy sources and concluded that the nuclear EROI value (using pressurised water reactor and centrifuge-based fuel enrichment technology as representative) was in the range 75-105:1 (rising to 115:1 if laser-based enrichment is applied). This paper also analyses the EROI performance of other energy sources (including fossil fuels, renewables, and hydroelectric energy), and the output of the analysis places nuclear energy very favourably in the hierarchy of EROI performance. ...
... It is noted that although this paper [23] is referenced by several sources (e.g., [32]) it has attracted some controversy. Comments challenging the methodology applied were made in a short paper, which the study authors then responded to in 2014, which in turn generated further comments in the form of a rebuttal from the original commentators [24,33]. ...
Article
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Nuclear fission is a primary energy source that may be important to future efforts to reduce greenhouse gas emissions. The energy return on investment (EROI) of any energy source is important because aggregate global EROI must be maintained at a minimum level to support complex global systems. Previous studies considering nuclear EROI have emphasised energy investments linked to ‘enabling’ factors (upstream activities that enable the operation of nuclear technology such as fuel enrichment), have attracted controversy, and challenges also persist regarding system boundary definition. This study advocates that improved consideration of ‘amelioration’ factors (downstream activities that remediate nuclear externalities such as decommissioning), is an important task for calculating a realistic nuclear EROI. Components of the ‘nuclear system’ were analysed and energy investment for five representative ‘amelioration’ factors calculated. These ‘first approximation’ calculations made numerous assumptions, exclusions, and simplifications, but accounted for a greater level of detail than had previously been attempted. The amelioration energy costs were found to be approximately 1.5–2 orders of magnitude lower than representative ‘enabling’ costs. Future refinement of the ‘amelioration’ factors may indicate that they are of greater significance, and may also have characteristics making them systemically significant, notably in terms of timing in relation to future global EROI declines.
... Hall et al. [52] have argued that for functioning of an industrial society, as assumed here, an EROEI value of at least 3 is needed for both corn-based ethanol and oil, measured at the farmgate/mine mouth. Weißbach et al. [53] found an 'economic threshold' for EREOI of 7, while Fizaine and Court [54] have even argued that for the US, an EROEI of 11 was needed for economic growth to continue. Once a minimum value of EREOI is assumed, it is, in principle, possible to read off the total energy available from the EROEI vs. cumulative output curves for each RE type. ...
... Some analyses have concluded that fossil fuels have much higher EROEI values than all renewables except hydropower [53]. Brockway and colleagues [73] found that published EROEI estimates for FF were typically 25 or more, if both FF output and input energy were assessed in thermal units. ...
Article
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Controversy exists as to whether renewable energy (RE) can provide for all the world's energy needs. The purpose of this paper is to help resolve this vital question. Official forecasts see a resumption of a business-as-usual world after the pandemic-induced recession, with further economic growth out to at least 2050. The novel approach taken in this paper is to assume that such a world is fueled entirely with RE at global energy levels at or above those of today, and then to examine whether this scenario is feasible. Because the intermittent primary electricity sources, wind, and solar power, would have to supply nearly all this energy, a simplification made for this analysis is that they do supply 100% of all energy, including non-electrical energy needs. It is found that the energy that could be delivered by these two sources is much less than often assumed, for several reasons: The declining quality of inputs; the need for inclusion of uncounted environmental costs; the need for energy conversion and storage; and the removal of existing fossil fuel energy subsidies. It is concluded that a future world entirely fuelled by RE would necessarily be a lower-energy one.
... El EROI para cultivos templados debería estar en el rango entre 2 y 4 (Murphy et al., 2011). El valor actual fue superior a los 3.5, 1.28 y 0.76 reportados para maíz por Weißbach et al. (2013), Kim y Dale (2005) y Pimentel y Patzek (2008), respectivamente. El EROI de 50 está cerca de los valores reportados por Romanelli y Milán (2010) para Eucalyptus en Brasil. ...
... Ruprecht, G., Huke, A., Czerski, K., Gottlieb, S., Hussein, A. (2013). Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants.Energy, 52, 210-221. ...
... A few researchers convey a long-haul assessment of expertise modification and information about the plants of control coal-fired, by introducing the reliable change in efficiency, with the price of tanks operated in compressed energy regulator plants (Rubin et al. 2007;Weber 2011). Additionally, there are recognized models where costs have expanded at cutting edge paces of position. ...
... As a result, a mediocre information cost-reducing situation is anticipated for correlation. Table 6 shows the power division's improvement, as unsurprising by GCAM (Feldman et al. 1999;Weißbach et al. 2013). In the two circumstances, developmental and radical aptitudes are generally composed. ...
Article
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This study evaluates the sustainable power plant cost in the outlook of global power plant efficiency to reduce fossil fuel dependency and greenhouse gas emissions. For this purpose, the Global Change Assessment Model (GCAM) applied for conducting the cost assessment of power zone technologies for all principal electricity generation. This study considers the characteristics of essential factors (cement, price of resources, possible increases in employees, and metals) that affect costs. This study suggests that the cost of electricity-generating technologies significantly affects growth efficiency, reduction in production cost, and improving environmental conditions. It also suggests that the cost of electricity-generating technologies, combined with technology mixture, is the key factor behind replacing existing technology in the electricity sector. EPRI cost assessments expanded by around 30% and 50% during 2015-2016. Factors like competition amongst power plant owners, the ambiguous marketplace, production procedures, and lack of environment-related strategies have resulted in massive environmental degradation in developing economies like Pakistan. Based on empirical findings, this study recommends designing efficient technologies, which would reduce power plant costs and ensure vertical prospects related to environmental conditions in the future.
... Recent research (e.g. Moriarty & Honnery, 2016, 2019aCapellán-Pérez, de Castro, & González, 2019;Dupont, Koppelaar, & Jeanmart, 2020;King & van den Bergh, 2018;Weißbach et al., 2013) has raised the possibility of low values of energy return on energy invested (EROI) for renewables compared with fossil fuels. Given the dominance of FFs, this implies a present energy subsidy for RE from high-EROI inputs of FF; this subsidy will fall as RE increases its share. ...
... However, various energy researchers have considered higher values of EROI are needed for viability. Weißbach et al. (2013) reported that an EROI of >7 was needed for economic viability. Fizaine and Court (2016) even argued that for the US a value of 11 was needed for economic growth to continue. ...
Article
Increasing discussion is occurring, in both the popular media and scientific research papers, about the risk of catastrophic climate change (CCC). Earth Science researchers have produced evidence that the damage function from ongoing climate change is not linear: damages rise disproportionately with global average temperature increase. This short paper explores the implications of CCC for future energy forecasting and policy. It is argued that the time available is now too short to continue framing the problem solution in terms of a shift to zero carbon fuels or carbon dioxide removal. Also, given the large uncertainties remaining in forecasting future climate—especially regional precipitation—solar radiation management is likely too risky. Instead, major reductions in global fossil fuel energy are needed, largely through energy conservation. The global response to the current pandemic shows the potential for rapid social change in the face of a crisis.
... • EROI (Energy Return on Energy Invested) is a bit controversial measure as it can be seen in the discussions of the [22], [24], [34], and [35]. To overcome these controversies, this paper follows [14]: ...
... Comparative values of EROI for different energy production technologies. (Source:[34] for (a) and ,[23] for (b))• Levelized cost of energy (LCOE) is metric that widely used in studies to compare different energy generation technologies. It calculates the present value of the all costs associated to the system (operation, maintenance, initial, fuel) per unit power generation (discounted to present). ...
Experiment Findings
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Metrics play an important role in decision making processes. Without them the right option can not be chosen and the progress can not be measured. For choosing the best economical option among the various kinds of electricity generating technologies, cost analysis supported by effective financial metrics should be done. Metrics should quantify sustainability as much as possible in order to justify their cost or benefit measures in the long run. This is possible, when metrics include three basic dimensions of the sustainability. Namely environmental, economical, and social dimensions. On the other hand, including these dimensions brings externalities and uncertainties into calculations. In addition to these dimensions, time and space are other important dimensions that an ideal metric should consider. Renewable energy production systems are important for sustainable development. But the intermittent nature of renewables, introduces difficulties in justifying their long run benefits, requiring extensive knowledge on the various kinds of metrics and on their properties. For this purpose, a short survey on the various types of metrics for electricity generation cost will be discussed in this paper. While the main focus will be on the LCOE metric, other types of metrics will be presented and qualitative and quantitative comparisons on them will be given. Different views from literature will be evaluated about the LCOE. Critical analysis will be done for the LCOE metric to list the strong and weak points of it. Kemal Kılıç SEES 502-Fall 2016-A Survey on the LCOE 3
... However, if energy consumption for coal and gas extraction and transportation is added, then their energy return will be 10 and 11 months, respectively. Hydropower plants pay for energy in 3 years, and nuclear power plants pay for itself with energy in just 2 months [11]. ...
Article
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The EU’s “Green Deal” plans a carbonfree energy mix, neglecting nuclear energy, despite high social costs. Photovoltaic and wind power plants lack proper solutions for storing the excessive electricity. Their EROI is still lower compared to that of conventional sources. A complementary pair of combined cycle gas turbines (CCGT) and photovoltaics is a good solution for regular electricity supplies for households at affordable prices. Such a model is based on consumption data in Ruse (Bulgaria), delivered by Nicola Mihaylov et al. It also includes data, delivered by RIS Elektro OOD – a solar park operator. Matching consumption fluctuations with production fluctuations gives the following: A 1 MW CCGT that supplies up to 1,600-1700 households is combined with a 250 kW photovoltaic park. The calculations show that because of the park the CCGT should operate with lower EROI and "green surcharge" in the consumers’ price. The optimal solution for energy deliveries requires a better balance between political, technical and economic factors.
... The EROI for template crops must remain between 2 and 4 [75]. The current value was higher than the 3.5, 1.28, and 0.76 reported for corn by Weißbach et al. [76], Kim and Dale [77], and Pimentel and Patzek [78], respectively. The EROI of 50 is close to the values reported by Romanelli and Milan [51] for Eucalyptus in Brazil. ...
Article
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The current global climate change, the 2030 Agenda, and the planetary boundaries have driven new development strategies, such as the circular economy, bioeconomy, and biorefineries. In this framework, this study analyzes the potential availability and sustainability of the wood supply chain for a small-scale biorefinery aiming at producing 280–300 L of bioethanol per ton of dry biomass, consuming 30,000 t of dry biomass per year harvested in a 50 km radius. This wood production goal was assessed from Eucalyptus grandis stands planted for solid wood in northeastern Uruguay. Moreover, to understand the environmental performance of this biomass supply chain, the energy return on investment (EROI), carbon footprint (CF), and potential soil erosion were also assessed. The results showed that the potential wood production would supply an average of 81,800 t of dry mass per year, maintaining the soil erosion below the upper threshold recommended, an EROI of 2.3, and annual CF of 1.22 kg CO2−eq m−3 (2.6 g CO2−eq MJ−1). Combined with the environmental performance of the bioethanol biorefinery facility, these results would show acceptable values of sustainability according to EU Directive 2009/28/ec because the bioethanol CF becomes 1.7% of this petrol’s CF.
... It can result, for example, in reduced, more compact core dimension, higher efficiency and lower construction and operational costs. Furthermore, the DFR is also characterized by a very high-energy return on invested (EROI) factor compared with other nuclear reactors of the generations II and III as well as compared with conventional and renewable sources of energy [30]. Over the years, many concepts of liquid metal or even liquid eutectic metal fuel reactors were considered though not with the application of the modern methods and codes and not in the context of a novel DFR concept [31,32,33]. ...
Thesis
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The Dual Fluid Reactor (DFR) is a novel concept of innovative, high-temperature and fast nuclear reactor patented by an international group of scientist from the Institut f¨ur Festkorper- Kernphysik (IFK) in Berlin. The distinctive feature of its design is the use of two independent liquid loops for the fuel (molten salts (DFRs) or molten metal (DFRm)) and for the coolant (liquid lead). The DFR combines the advantages of the Molten Salt Fast Reactor (MSFR) and the Lead-cooled Fast Reactor (LFR) and allows for optimization of working parameters in each loop for specific purposes. As a consequence, DFR can be characterized by a very high power density, a high fuel burnup, and a negative temperature coefficient of reactivity. All this leads to a significant cost reduction, an increased reliability, and a larger safety, which are crucial in nuclear power generation. The dissertation presents a new 250 MWth Dual Fluid Reactor metallic design (DFRm) with liquid eutectic uranium-chromium fuel (composed of enriched uranium 235U) and circulating at a nominal temperature of 1000_C. It follows the recent patent WO2020088707-A1 by IFK and verifies its basic principles. According to thermal and neutronic analyses performed in the thesis, the reactor is critical and can operate for about 17 years without refueling. The core region is of 0.6 m in radius, 1.2 m high, and consists 1666 fuel tubes made of silicon carbide (SiC) arranged in a hexagonal grid. The reactor dimensions result from parametric and material analysis with respect mainly to the effective neutron multiplication factor. The unique geometry, the applied materials, and very large values of the working medium parameters lead to a small and a compact construction of the reactor. Further analysis of the safety shows that DFRm is characterized by the negative temperature coefficient of reactivity, which equals to about -3.00 pcm/K. All investigated material coefficients (fuel, coolant, reflector) are negative and stay even more negative with progressing burnup of the fuel. The thermal expansion of reactor materials and some minor changes in geometry do not significantly affect reactivity coefficients which always remain negative. The negative temperature coefficient allows the DFRm reactor to be self-regulated without any additional systems (e.g. control rods) and therefore considerably simplifies the reactor design. Finally, two extra fuel compositions made of spent nuclear fuel (SNF) from Light Water Reactors are investigated. The fuels include series of actinides up to 245Cm. The results show a unique DFRm properties: significant reduction of minor actinides (in particular 237Np and americium isotopes) with high breeding capabilities. A minor change of the initial SNF fuel composition with unchanged geometry achieves a notably higher burnup (above 185 MWd/kgHM), a higher yield of average number of neutrons __ (up to 2.94), and a higher conversion ratio (up to 1.26) as compared to the base U-Cr enriched uranium fuel. This can extend the DFRm operation time without refueling up to 29 years acting as a nuclear battery and can efficiently manage long-lived nuclear waste.
... We will choose a value of 40 e M W h for our study for lack of better terms and to account for the low cost of hydroelectric. [18,48,49] GW P E CO 2,eq per unit of energy 20 kgCO 2 eq(M W h el,produced ) −1 [19,20,31] ...
Thesis
France aims to massively develop intermittent renewable energies --- wind and photovoltaic --- while reducing the share of dispatchable sources, in this case, nuclear power. This paradigm shift implies rethinking the management of energy systems. Indeed, renewables' variable nature generates a need for flexibility on different time-scales, from day to year. As dispatchable means' flexibility can no longer be relied on, this thesis questions the potential of other means to meet this need: electricity storage, oversized production and heating networks.Faced with the need for a systemic approach, we developed simple models to enhance the understanding of the interdependencies between production and storage. The optimized indicators are economic (€), but also environmental: embodied energy and greenhouse gas emissions over the entire life cycle. The performances of the systems considered are those of today and their development is limited by resource and space availability. Without going into the precise details of how each technology works, this physical approach points out optimal operation areas for the different technologies and the difficult cases for which solutions are still lacking.First, the need for flexibility generated for different intermittency penetration rates is quantified for several time scales. It enables us to compare the potential of different electricity storage technologies --- at each of these scales --- to bring production and consumption in phase. The results show that long time-scales --- typically seasonal storage --- require the largest investments for low profitability. The competition mechanisms between several storages and oversizing are then analyzed. It shows how the optimum solutions use complementary flexibility means. The study then addresses the potential of coupling between the electrical grid and the heating grid as a means of flexibility, particularly for the management of long-term needs.This thesis work focuses on the French scale, although the methodology is applicable elsewhere.
... The EROI of corn ethanol is 0.8~2.0 (Gupta and Hall 2011), and that of electric power generated from biogas (maize) is 3.5 (Weißbach et al. 2013). The EROI of electric power generated from wood chips is 5.69 (Yoshioka et al. 2005), and the EROI of wood pellet heating energy is 3.9~6.3, ...
Chapter
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As the tropics are exposed to large amounts of solar radiation, solar energy amelioration is highly important in tropical ecosystems. Among mechanisms of high solar energy amelioration, the water cycle is the first function that removes solar radiation energy in the form of latent heat through evaporation at the sea surface and evapotranspiration from forests. The carbon cycle is the second function as it fixes solar radiation energy into carbohydrates in plants (and forests) through photosynthesis. In addition, forests have a function in the water–carbon linkage, and it is assumed that the water–TREE–carbon linkage is a key function in the tropics, where a TREE (a simplified forest function) is a bioapparatus that serves as natural capital. The TREE model includes functions such as solar panels (leaves), batteries (stems), air conditioning (evapotranspiration), carbon sequestration (biochar), fertilizer production (N2 fixation), water dams (water reserves in the soil), and soil conservation (through the application of organic matter).
... Sources: (a)Peng et al. (2013); (b)Kenny et al. (2010); (c)Weißbach et al. (2013); (d)Neumeyer and Goldston (2016); (e)Kessides and Wade (2011b); (f)Voss (2001) ...
Article
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The growing electricity demand impels the expansion of generation capacity. For an effective and detailed planning, it is vital to know the supply capacity and the growth potential of a power plant technology. For the growth of a power generation technology, the electricity generated from it needs reinvestment for the construction of newer power plants, other than just meeting the demand. This paper proposes a framework employing dynamic energy analysis to examine the capacity expansion, growth potential and energy dynamics of six different technologies (solar PV, wind, hydro, nuclear, coal and gas). The power plant characteristics include lifetime, construction time, energy payback time and energy reinvestment factor. Energy payback time, relative to the lifetime of a power plant, is the primary constraint in capacity expansion. We analyze energy reinvestment strategies, affecting the growth rate, and determine its optimal value. The solar PV power plant has the least maximum growth potential of 15%, while gas power plant has the highest maximum growth potential of 124%. Relationships are developed to find the minimum time frame required to follow a self-sustainable path with optimal reinvestment for any technology. A case study is presented to reach the global demand capacity target for the year 2030 following a low-carbon-emission path. Graphical abstract
... The energy return on investment (EROI) is also far higher for nuclear than other power generation technologies (distributed solar: 1.6; biomass: 3.5; wind: 3.9; utility solar: 9; hydro: 35; nuclear: 75) (Weißbach et al., 2013). In terms of lifetime carbon dioxide release, nuclear power returns the best figures: 9 gCO 2 / kWh e compared to wind (11), hydro (16), biomass (17), and solar (30) (McCombie & Jefferson, 2016). ...
Article
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This article reviews the environmental, ecological, and social impacts of current renewable energy technologies. Problems of these technologies are highlighted in terms of manufacturing, installation, lifetime, and end-of-life. What emerges are concerning issues that need to be urgently addressed as they potentially threaten the recovery of the Earth system and therefore also impact society. It is suggested that many of these issues have been overlooked because of our focus on carbon reduction, which, while important, may lead to a failure to deal with other equally concerning threats, and even exacerbate them. These threats are highlighted and then urgent priorities, in terms of policy, regulation, and research, are identified, paving the way to an energy future that does not threaten the functionality of the Earth system. Finally, key underlying themes are identified that may inform our decision-making as we move forward. If we are to aim for a truly sustainable future, in terms of economics, ecology, and society, this article argues that we must seek to aim higher than current practice and plan for a future that not only arrests anthropogenic climate destabilization and its threat to many species, including our own, but that builds the foundations for ecological recovery. Better-than-before is not good enough. We need energy technologies that minimize our impact on our planet.
... At the annual climate summits, it always calls for faster and more decisive action to protect the environment. The Intergovernmental Panel on Climate Change (IPCC) in its latest report, "Climate Change 2021: the Physical Science Basis" [15], emphasizes that the remedy for climate change is determined and ambitious action to reduce emissions of carbon dioxide and other greenhouse gases is needed. The European Union (EU) is not deaf to these calls and is an increasingly active and ambitious participant in this process. ...
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The growing climate crisis forces the adoption of radical steps to neutralize our impact on the environment, despite the constantly growing demand for energy. Poland, which according to forecasts will not reach the EU target of 15% share of renewable energy sources by 2030, is nevertheless a leader in the EU in terms of the growth dynamics of the photovoltaic market. The aim of this article is to answer the question as to what caused such a huge interest in solar energy. In this article, the authors focus solely on residential installations. The dataset for the analysis was constructed on readily available national data on photovoltaics showing the key characteristics of the country and prosumers. According to this research, the prosumer’s profile shows that home photovoltaics are most interesting for the poorest households in rural municipalities, in regions with the highest unemployment rate, and among citizens of pre-retirement age. The decision to invest in photovoltaics is also influenced by the availability of subsidies and the price level of energy bills. On the other hand, no impact was found on insolation and environmental pollution. The results of the study will allow for a more conscious shaping of energy policy at the EU, national and regional levels.
... And some of the goals and means of the "green policies" are in clear contradiction with technical and economic expediency. A study of D. Weißbach, G. Ruprechta, A. Huke, K. Czerski, S. Gottlieb, A. Hussein (2013) gives an idea of the biggest problem with alternative ("green") energy sources -their low energy efficiency [17]. The common indicator EROI (EROI = Energy Delivered / Energy Required to Deliver that Energy) is not in favour of these energy sources. ...
Article
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Successful European integration requires its own ideology. This is "Europeanism". In this article "Europeanism" is examined as an internally contradictory combination of irrational and rational considerations, officially presented as part of the paradigm of the European Enlightenment. After the expulsion of rival ideologies, neoliberalism builds the basis of today's Europeanism, which claims to be scientific, together with the several integration theories. Practice refutes most of these rational constructions after the 2008 crisis, both economically and politically. Integration theories cannot explain why the free market is failing. The crisis in the Eurozone 2011 revitalized economic nationalism and contributed to the erosion of the dominant paradigm. In the political field Europeanism has failed in its attempt to transform the EU's immediate environment in a positive way. The enforcement of multiculturalism, despite acknowledgments that it "has failed", has split the Union internally. The reaction is a collapse of the belief in neoliberalism and hence the rise of Euroscepticism. In an attempt to organize some kind of "Counter-Reformation" in search of the lost loyalty, the European elite is trying to renew and supplement the ideological basis of the integration with one of the directions of (delete 'the') left-wing neoliberalism, namely "ecologism". It tries to impose-both domestically and internationally, the fight against "global warming" as an irrational cause that will give a new impetus to social development and integration in particular, as well as (delete 'to') solve specific problems of the energy poor European Union. The ecological ingredient in Europeanism is very suitable psychologically-"alarmism" is very well received by some rich and "anxious" societies. Economically it could help the energy poor Union to restrain its competitors on the world market. But the success of this attempt does not seem certain.
... everything but the fuel procurement) are comparable to that of a fission plant of similar power output. For fission pressurised water reactors (PWRs), the fuel cycle requires about half the total energy input of the whole technology life cycle [87], so even if the fuel were available for zero energy cost, the overall EROI would only approximately double to ∼ 170. This represents an upper bound since we also know that the fusion reactor "island" has a minimum size [88], and that the power-generating plasma of a fusion plant has a lower volumetric power density than the core of a fission plant (∼ 1.2MW/m 3 for EU-DEMO1 vs ∼ 300MW/m 3 for a SCFR). ...
Preprint
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Fusion energy is often regarded as a long-term solution to the world's energy needs. However, even after solving the critical research challenges, engineering and materials science will still impose significant constraints on the characteristics of a fusion power plant. Meanwhile, the global energy grid must transition to low-carbon sources by 2050 to prevent the worst effects of climate change. We review three factors affecting fusion's future trajectory: (1) the significant drop in the price of renewable energy, (2) the intermittency of renewable sources and implications for future energy grids, and (3) the recent proposition of intermediate-level nuclear waste as a product of fusion. Within the scenario assumed by our premises, we find that while there remains a clear motivation to develop fusion power plants, this motivation is likely weakened by the time they become available. We also conclude that most current fusion reactor designs do not take these factors into account and, to increase market penetration, fusion research should consider relaxed nuclear waste design criteria, raw material availability constraints and load-following designs with pulsed operation.
... To begin to understand this, we can look at the results of different EROI calculations of solar PV technology under different technological boundaries. (Raugei et al. 2012;Bhandari et al., 2015; de Castro and Capellán-Peréz, 2020) b (de Castro and Capellán-Peréz, 2020) c (Weißbach et al., 2013;Ferroni and Hopkirk, 2016;de Castro and Capellán-Peréz, 2020) Table 6 shows how the expansion of a technological boundary implies a decrease in calculated EROI ratios. This is an expected result. ...
Thesis
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Solar photovoltaic (PV) technology is one of the most favored means of mitigating climate change. At the same time, there is a growing concern over how this technology is both environmentally harmful and unevenly distributed in the world economy. Researchers and environmentalists differ on whether a global relation of power is inherent in solar technology. This thesis investigates to what extent the global, social and material conditions of solar PV technology contrast with conventional conceptions of it. Building on insights from ecological economics and the philosophy of technology, it offers an interdisciplinary approach to solar PV technology. Its central question is whether ‘ecologically unequal exchange’ is a necessary condition for large-scale solar PV development. The theory of ecologically unequal exchange explains how wealthier nations rely on net imports of resources to sustain their levels of consumption and technological development, while displacing much of their work and environmental loads to poorer nations. This theory is tested in an LCA-based account of ecologically unequal exchange between Germany and China during the emergence of the global solar PV market (2002-2018). It is also tested through an application of the concept of ‘power density’ to four leading solar nation’s PV ambitions (China, Germany, India, Italy). The findings demonstrate how large-scale development of solar PV technology may require global asymmetries as much as polysilicon, electrical components, engineers, or direct sunshine. To the extent that decisionmakers disregard this, it may be a symptom of ‘machine fetishism,’ which masks the global asymmetries of the emerging energy regime while also preventing us from grasping what modern technology ultimately is.
... Capellán-Pérez et al. (2019) underlined that many studies have been carried out to estimate the EROEI of individual RES technologies (as the authors have already shown in Figures 2 and 3) and important differences exist depending on the technology, system design and location, and the field is plagued with methodological differences related to the functional units (e.g., an MJ of heat energy versus an MJ of grid electricity) or the boundaries of the analysis (i.e., mine mouth vs. end use or energy technology vs. energy system) (Price and Kendall 2012;Weißbach et al. 2013;De Castro et al. 2014;Raugei et al. 2015;Ferroni and Hopkirik 2016;Murphy et al. 2016, Hall 2017De Castro and Capellán-Pérez 2018). ...
Article
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The scarcity of fossil fuels and their environmental impact as greenhouse gas (GHG) emissions, have prompted governments around the world to both develop research and foster the use of renewable energy sources (RES), such as biomass, wind, and solar. Therefore, although these efforts represent potential solutions for fossil fuel shortages and GHG emission reduction, some doubts have emerged recently regarding their energy efficiency. Indeed, it is very useful to assess their energy gain, which means quantifying and comparing the amount of energy consumed to produce alternative fuels. In this context, the aim of this paper is to analyze the trend of the academic literature of studies concerning the indices of the energy return ratio (ERR), such as energy return on energy invested (EROEI), considering biomass, wind and solar energy. This could be useful for institutions and to public organizations in order to redefine their political vision for realizing sustainable socio-economic systems in line with the transition from fossil fuels to renewable energies. Results showed that biomass seems to be more expensive and less efficient than the equivalent fossil-based energy, whereas solar photovoltaic (PV) and wind energy have reached mature and advanced levels of technology.
... The common indicator EROI (EROI = Energy Delivered / Energy Required to Deliver that Energy) solves the problem of combining the two groups of factors. The study of D. Weißbach et al. (2013) gives an idea of the biggest problem with alternative energy sources -their low energy efficiency, especially in photovoltaics. ...
Article
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Energy integration is considered to play a key role in the successful development of the European Union. It is assumed that purely market-based mechanisms in this sector, according to the neo-liberal model, can secure a constant supply at low prices. This is the basis of the Union’s energy policy, launched by the European Commission (EC). The main goal of this paper is to examine the adequacy of this model and the extent to which the energy policy succeeds in achieving its objectives. There is a difficult combination of technological, economic and political factors expressed in the Union’s energy mix. In particular, the document examines the gap between neo-liberal free-market postulates and the practices of modern protectionism, assessing the sustainability of the EU’s energy strategy and policy, which often avoid taking efficiency into account. Significant attention is paid to the link between energy and national security, as well as the politically justified intervention of the European Commission in energy projects related to energy supplies for the whole Union. Our research is based on statistics for a long period of time, allowing a comparison between stated intentions and achieved results. Our results stress on the direct link between energy, foreign policy and national security. This link, the cause of the unsatisfactory results, casts doubt on the full integration of the industry and contradicts the views of the Commission
... Much of the world is highly dependent on oil, and there are no ready substitutes. All other sources of energy (renewable, nuclear, etc.) have major issues with the concentration of energy available, with the transportability of the energy, and/or with the EROI (Fridley 2010;Weissbach et al. 2013). Greer (2013:21) sums it up thus, "none of the alternatives to fossil fuels is capable of providing the same cheap, concentrated, abundant supply of energy that industrial civilization currently gets from fossil fuels, especially petroleum." ...
Conference Paper
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... The Dual Fluid Reactor (DFR) is a novel concept of the liquid fuel high temperature reactor (1000 • C -1300 • C) patented by the group from Institut für Festkörper Kernphysik (IFK) Berlin (Huke et al., 2011(Huke et al., , 2017(Huke et al., , 2015. Its first version was with molten salt fuel (DFRs) while the recent patent obeys also the liquid metallic eutectic fuel (Huke et al., 0000;Sierchuła et al., 2019) which has much better efficiency presented in terms of EROI (Energy Returned on Invested) (Weissbach et al., 2013). The metallic version (DFRm) consists of a cylindrical fission zone with Uranium-Chromium (U-Cr) eutectic surrounded by a thick lead coolant reflector. ...
Article
We discuss the temperature coefficients of reactivity for the Dual Fluid Reactor in its metallic fuel version (DFRm) of 250 MWth design. Three material coefficients (fuel, coolant, reflector) are investigated. We find that all of them are negative, so that the total temperature coefficient of reactivity for the DFRm reactor is also negative. We demonstrate that the total temperature coefficient stays negative during burnup of fuel. Besides, we show that some small changes of geometry of our DFRm design leave all temperature coefficients of reactivity negative, too. We then conclude that DFRm reactor possesses the basic characteristics of safety and can be implemented in nuclear technology.
... EROI is shown to increase with increasing NG use with the lowest EROI being 9.5 for 0% NG use. For all cases, the EROI is above the value of 7.0 which is suggested by Weißbach et al. (2013) as being the limit for economic viability. At 0% NG use the lifetime capacity factor of the plant analysed in Corona et al. (2014) is calculated based on Table 2 to be 32%. ...
Article
Limiting the impact of human use of energy on the environment is necessary to maintain the Earth's ecosystems such that they can continue to provide the ecosystem services on which humans and all other living organisms depend. Because the methods available to limit the impact on the environment of energy production and use require energy, energy used for this purpose—termed ecosystem maintenance energy (ESME)—reduces the net energy available. A capacity to estimate the energy that can be produced while sustaining ecosystem services, termed green energy, is critical to future energy use. This paper sets out a method to determine ESME by assigning energy consumption to the processes needed to remove the source of the impact on the ecosystem that results from the energy system lifecycle. We illustrate the method by the use of a case study based on a concentrated solar power plant (CSP) with natural gas back up. Green energy production is assessed in terms of the green energy return on energy invested, EROIg. CSP ecosystem impact is determined via a lifecycle assessment of the plant's operations for varying degrees of natural gas back-up. ESME is then determined by calculating the energy consumption of the impact source removal (ISR) process needed to remove the ecosystem impact. We show that, although the CSP plant produces increasing amounts of net energy with increasing natural gas back-up, the capacity to produce net green energy reduces with increasing natural gas back-up once ESME is included. For the CSP plant examined, EROI increases, while EROIg decreases for increasing use of natural gas. This indicates the large impact of ESME on the plant's energy return and the necessity of its inclusion in energy assessments.
... Note that the carbon intensity varies with energy source and grid efficiency. Compared with "brown" energy from coal or gas, "green" energy from solar, wind, nuclear, or hydropower produces up to 30× fewer GHG emissions [30]- [32]. Scope 2 emissions for a data center therefore depend on the geographic location and energy grid. ...
Preprint
Given recent algorithm, software, and hardware innovation, computing has enabled a plethora of new applications. As computing becomes increasingly ubiquitous, however, so does its environmental impact. This paper brings the issue to the attention of computer-systems researchers. Our analysis, built on industry-reported characterization, quantifies the environmental effects of computing in terms of carbon emissions. Broadly, carbon emissions have two sources: operational energy consumption, and hardware manufacturing and infrastructure. Although carbon emissions from the former are decreasing thanks to algorithmic, software, and hardware innovations that boost performance and power efficiency, the overall carbon footprint of computer systems continues to grow. This work quantifies the carbon output of computer systems to show that most emissions related to modern mobile and data-center equipment come from hardware manufacturing and infrastructure. We therefore outline future directions for minimizing the environmental impact of computing systems.
... This factor can measure the economic efficiency of an energy source. It determines the amount of net energy produced by the source (power plant), taking into account the energy flows involved in all stages of the production process during its lifetime for construction, fuel supply costs, maintenance, and decommissioning [26,27]. To fulfill all the requirements for a bioeconomy, bioenergy production should also be analyzed in terms of energy efficiency. ...
Article
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Increasing interest in bioenergy production in the context of the transition towards a circular economy and the promotion of renewable energy has produced demands for optimization of the value chain of energy production to improve the environmental viability of the system. Hotspot analysis based on life cycle assessment (LCA) contributes to the mitigation of environmental burdens and is a very important step towards the implementation of a bioeconomy strategy. In this study, hotspots identified using two parallel pathways: a literature review and empirical research on four different biogas plants located in Poland. LCA and energy return on investment (EROI) analysis of the whole bioenergy production chain were considered to identify unit processes or activities that are highly damaging to the environment. The biogas plants differ mainly in the type of raw materials used as an input and in the method of delivery. The results show that the most impactful processes are those in the delivery of biomass, especially road transport by tractor. The second contributor was crop cultivation, where fossil fuels are also used. Although the EROI analysis indicates a negligible impact of transport on the energy efficiency of bioenergy plants, the environmental burden of biomass transportation should be taken into consideration when planning further measures to support the development of the bioeconomy.
... Because ESME costs such as those for avoiding CO 2 emissions (for example, by using NETs) are presently ignored in most EROI calculations, average conventional (or standard) EROI values for energy systems powered by FFs are much higher than for RE sources. Weißbach et al. [73], using a consistent basis for calculation, found average values for EROI for FF power generation to be an order of magnitude greater than for wind and solar electricity. Hence, an energy subsidy is presently involved. ...
Chapter
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The ability of RE to fully supply all global energy needs, both now and in the future, is subject to considerable controversy. This chapter first examines the concept of Energy Return on Investment (EROI) as a crucial test for FF project feasibility, and so the technical potential of RE sources. It is found that inclusion of the full input costs of RE, including the energy costs of maintaining ecosystem functions, leads to large reductions in evaluated EROI, even though exact values are not available. In principle, a graph of EROI versus energy production can be drawn for an energy source, enabling technical potential to be determined. The chapter then reviews in turn the prospects for solar, wind, biomass, hydro, geothermal, and ocean energy, pointing out their benefits as well as their environmental disadvantages. Although bioenergy and hydro are the most important sources today, wind and solar energy have by far the greatest potential—and are the most rapidly growing. It is concluded that renewable energy may not be as green or abundant as often portrayed.
... Because ESME costs such as those for avoiding CO 2 emissions (for example, by using NETs) are presently ignored in most EROI calculations, average conventional (or standard) EROI values for energy systems powered by FFs are much higher than for RE sources. Weißbach et al. [73], using a consistent basis for calculation, found average values for EROI for FF power generation to be an order of magnitude greater than for wind and solar electricity. Hence, an energy subsidy is presently involved. ...
... (1984) 2 Según(Elliott, n.d.) 3 Las TRE referidas se refieren, naturalmente, a las tecnologías vigentes en la época para la que se calcularon; obviamente, mejores tecnologías implican mayores rendimientos y, por lo tanto, una mayor TRE. La TRE de la fisión del 235 U es de 75 para Weiβbach, para USA(Weißbach et al., 2013). ...
Chapter
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The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts. (Bertrand Russell) PREÁMBULO Desde hace décadas se percibe como una seria amenaza para el clima el aumento del efecto invernadero que sobre el planeta ocasiona la progresiva acumulación en la atmósfera de determinados gases, como el metano (C 4 H 4) y el dióxido de carbono (CO 2), los así llamados "gases de efecto invernadero" (GEI); no son los únicos, pero sí los más conocidos por la sociedad gracias a la difusión que de sus nombres hacen los medios de información. En particular, la reducción de la cantidad de CO 2 en la atmósfera parece ser la preocupación fundamental y, son menoscabo de otras fuentes del mencionado efecto, a ella nos referiremos en el presente estudio. La reducción de la cantidad de CO 2 en la atmósfera se puede acometer por dos vías: reducción de emisiones y reducción de la cantidad existente en la atmósfera (Cusack et al., 2014). Dejaremos para otra ocasión los posibles mecanismos artificiales para la reducción de la cantidad actualmente existente (así como también su pertinencia y los posibles efectos negativos sobre el clima que podría acarrear, en caso de una disminución brusca) para centrarnos en la reducción de la emisiones, en este caso, por la vía de estudiar las fuentes de obtención de energía y sus repercusiones sobre los niveles de GEI atmosféricos, concretamente de CO 2 , objetivo de este trabajo, en una época de florecimiento explosivo de las mal llamadas "tecnologías verdes", denominación más comercial que objetiva. ALCANCE DEL ESTUDIO En el presente documento nos proponemos describir de manera sucinta las bases de las tecnologías de obtención de energía limpias, así como también sus posibles efectos sobre el medio ambiente, derivados del análisis de su ciclo de vida. Considerando como energías limpias aquellas que no producen CO 2 ni otros gases de efecto invernadero durante su fase de funcionamiento, incluimos entre ellas la nuclear, aun a pesar de la normativa legal y fiscal existente en su contra en España. No siendo objeto de este estudio la descripción exhaustiva de ninguna de las tecnologías que abordaremos, nos remitiremos a hacer de ellas una descripción sucinta, p ero lo suficientemente explicativa como para ilustrar, al menos, sus bases de funcionamiento.
... Although comparing renewable and non-renewable sources has raised methodological issues [18,19] (which must be overcome by a clear definition of the scope and the boundaries of EROI studies [20,21]), these outcomes question whether a fully renewablebased electric system could be capable of sustaining modern energy intensive societies [15,[22][23][24][25]. Future scenarios seem to either imply energy shortages or an undesired increase in emissions, placing the economy in the so called "energy-emissions trap" [26]. ...
Article
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Energy return on investment (EROI) is a ratio of the energy obtained in relation to the energy used to extract/produce it. The EROI of fossil fuels is globally decreasing. What do the declining EROIs of energy sources imply for society as a whole? We answer this question by proposing a novel EROI measure that describes, through one parameter, the efficiency of a society in managing energy resources over time. Our comprehensive societal EROI measure was developed by (1) expanding the boundaries of the analysis up to the useful stage; (2) estimating the amount of energy embodied in the energy-converting capital; (3) considering non-conventional sources such as the muscle work of humans and draught animals; and (4) considering the influence of imported and exported energy. We computed the new EROI for Portugal as a case study. We find a considerably lower EROI value, at around 3, compared to those currently available, which is stable over a long-time range (1960–2014). This suggests an independence of EROI from economic growth. When estimated at the final stage, using conventional methods (i.e., without applying the four novelties here introduced), we find a declining societal EROI. Therefore, our results imply that the production of new and more efficient final-to-useful energy converting capital has historically kept societal EROI around a stable value by offsetting the effects of the changing returns of energy sources at the primary and final stages. This will be crucial in the successful transition to renewables.
Article
Fusion energy is often regarded as a long-term solution to the world's energy needs. However, even after solving the critical research challenges, engineering and materials science will still impose significant constraints on the characteristics of a fusion power plant. Meanwhile, the global energy grid must transition to low-carbon sources by 2050 to prevent the worst effects of climate change. We review three factors affecting fusion's future trajectory: (1) the significant drop in the price of renewable energy, (2) the intermittency of renewable sources and implications for future energy grids, and (3) the recent proposition of intermediate-level nuclear waste as a product of fusion. Within the scenario assumed by our premises, we find that while there remains a clear motivation to develop fusion power plants, this motivation is likely weakened by the time they become available. We also conclude that most current fusion reactor designs do not take these factors into account and, to increase market penetration, fusion research should consider relaxed nuclear waste design criteria, raw material availability constraints and load-following designs with pulsed operation.
Article
Solar energy has been used for decades for the direct production of electricity in various industries and devices; however, harnessing and storing this energy in the form of chemical bonds has emerged as a promising alternative to fossil fuel combustion. The common feedstocks for producing such solar fuels are carbon dioxide and water, yet only the photoconversion of carbon dioxide presents the opportunity to generate liquid fuels capable of integrating into our existing infrastructure, while simultaneously removing atmospheric greenhouse gas pollution. This review presents recent advances in photochemical solar fuel production technology. Although efforts in this field have created an incredible number of methods to convert carbon dioxide into gaseous and liquid fuels, these can generally be classified under one of four categories based on how incident sunlight is utilised: solar concentration for thermoconversion (Category 1), transformation toward electroconversion (Category 2), natural photosynthesis for bioconversion (Category 3), and artificial photosynthesis for direct photoconversion (Category 4). Select examples of developments within each of these categories is presented, showing the state-of-the-art in the use of carbon dioxide as a suitable feedstock for solar fuel production.
Article
Bioenergy systems have a great potential worldwide to substitute fossil fuels mainly because they may contribute to greenhouse gas emissions reduction. In Portugal, several biomass combustion-based power plants have been built in the last decade. Biomass gasification is a potential alternative to combustion but its environmental impacts should be evaluated. The goal of this study is to assess and compare the environmental and energy performance of direct gasification and combustion (both in fluidized bed) using residual forest biomass (RFB) from eucalypt in Portugal. In order to achieve the goal, life cycle assessment was applied, complemented with the Energy-Returned-On-Energy-Invested (EROI) indicator. The boundaries of the systems comprise three stages: (1) forest management, (2) collection, processing and transportation, and (3) electricity generation. The results indicate that gasification performs environmentally better than combustion in 5 out of 8 impact categories addressed. Conversely, combustion has greater EROI than gasification. After running a sensitivity analysis where the efficiency of the gasifier was changed from 53% in the base scenario to 57%, it is shown that the environmental performance of gasification improved in the range of 2 to 8%. The study concludes that gasification may be a good alternative to current combustion systems in Portugal.
Thesis
Partout, les populations ont besoin d’énergie pour subvenir à leur besoin et supporter leur développement. Ces travaux se concentrent sur l’accès à l’énergie électrique des zones isolées trop éloignées du réseau électrique principal pour y être connectées. Parmi elles, nous sélectionnons les zones à proximité d’une mer ou d’une rivière dont l’énergie hydrocinétique peut être récupérée et transformée en électricité par une hydrolienne. Les solutions technologiques disponibles sur le marché ne répondent que partiellement aux besoins spécifiques des communautés de ces zones isolées. L’objectif de la thèse est double : proposer une démarche de conception multicritère afin d’imaginer une solution de production énergétique compatible avec les enjeux de développement durable puis appliquer ladite démarche pour concevoir une solution hydrolienne pour micro-réseau isolé qui soit durable et résiliente. La démarche de conception repose sur la prise en compte dès les phases amont du projet de critères qualitatifs et quantitatifs liés aux durabilités technique, économique, environnementale et sociale. L’outil proposé aide le concepteur à dialoguer avec les différentes parties prenantes afin de cibler une solution de production électrique permettant un développement humain, économique, technique, de la communauté, à la fois ancré sur le territoire et respectueux de l’environnement. L’application de la démarche et de l’outil sur l’hydrolienne pour micro-réseau isolé amène au portrait-robot du système et de ses composants. Nous nous inspirons de la philosophie low-tech qui prône des technologies simples, durables, résilientes et accessibles. Nous avons esquissé les caractéristiques de la génératrice électrique de l’hydrolienne puis proposé un modèle analytique multi-physique et des coûts économiques, environnementaux pour un pré-dimensionnement optimisé. La machine est asynchrone à cage avec un bobinage étanche pour un refroidissement ouvert à eau, un banc de condensateur pour un fonctionnement autonome et une plage de vitesse élargie. Nous avons également étudié les effets du bobinage dentaire sur la génératrice asynchrone à cage. Finalement, nous sélectionnons les villages amazoniens de Guyane comme cas d’étude et en particulier la station de recherche CNRS des Nouragues. Nous appliquons la démarche de conception et pré-dimensionnons la génératrice avec les données disponibles avec les objectifs de maximisation du rendement énergétique ou de minimisation de la masse de la machine et des coûts économiques et environnementaux.
Book
This book presents both the importance of energy transition and its associated difficulties and dangers. It discusses the current state of energy consumption and the links between the economy and energy. Reviewing future energy resources, it evaluates several transition scenarios. Providing an explanation of the concepts of energy and power, the book reviews global energy consumption and our dependence on energy. Examining the available energy resources, it proposes some solutions and encourages the reader to develop better processes, from energy sources to production to consumption. The book will interest engineers and undergraduate/graduate students studying and working in various fields of energy, as well as producers of fossil, gas, oil, coal, electric, renewable, and nuclear energy.
Article
Energy storage have attracted attention to compensate for the mismatches of electricity supply and demand caused by renewable energies. A regenerative hydrogen fuel cell (RHFC) system composed of an electrolyzer, hydrogen storage, and fuel cell is a promising large capacity energy storage technology. A liquid organic hydrogen carrier (LOHC) is considered for hydrogen storage technology because of its advantages of good safety, easy handling, and high storage density. In this original research, a comparative energetic study on LOHC and other hydrogen storage technologies was conducted using net energy analysis to quantitatively compare various hydrogen storage technologies. First, the basic RHFC system was modeled by a 0-dimensional simulation, and the system efficiency was analyzed. Then, a net energy analysis was conducted by evaluating energy stored on investment (ESOIe) values. The RHFC system with LOHC showed a higher ESOIe of 53 for weekly (<100 h) and 18 for monthly (<1000 h) energy storage than other energy storage technologies due to the low embodied energy cost of LOHC materials. Based on the analysis, the RHFC system with LOHC was concluded to be an attractive option for weekly and monthly energy storage of the both wind and solar power.
Article
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Nuclear energy currently accounts for a declining share of global electricity, but it is possible that rising concerns about global climate change and China's ambitious nuclear program could reverse this trend. This review attempts to assess the global future of nuclear power, showing how the optimistic forecasts in the early days of nuclear power have been replaced by far more modest forecasts. The review first discusses the controversies surrounding nuclear power. It then briefly examines the prospects for three proposed reactors of the future: Small Modular Reactors; Generation IV breeder reactors; fusion reactors. It finally discusses the social and political context for nuclear power, both today and in the future.
Chapter
The telecoms industry in general, and designers of new generations of cellular networks in particular, are strongly committed to achieving the United Nations Intergovernmental Panel on Climate Change (UN IPCC) objectives to limit climate change and contribute to the well‐being of future generations. In order to do so, innovation to bolster sustainability has so far mainly been oriented toward resource efficiency. Unfortunately, this has not proven to be sufficient, in part due to the so‐called rebound effect (where increasing energy efficiency ends up driving up energy consumption). If energy efficiency is not sufficient to curb CO 2 emissions, the solution may lie in reducing traffic, which means limiting consumption and uses of Information and Communication Technology (ICT) services on the end user side. This chapter questions the role of the cellular communication industry and its ability to create value with 6G while keeping consumption and uses under control, e.g. by empowering consumers to communicate responsibly. By addressing practical problems, we hope it can stimulate innovation and help to identify new courses of action for a sustainable 6G.
Chapter
The energy efficiency describes the ratio of the given benefit to the necessary energy input to achieve it. Efficiency is primarily related to generation plants or to plants or devices for the end use of energy. From the point of view of the overall system, it is appropriate to also include the infrastructures of the transmission and distribution networks and the energy storage in the consideration of efficiency.
Article
This review covers the recent advancements in selected emerging energy sectors, emphasising carbon emission neutrality and energy sustainability in the post-COVID-19 era. It benefited from the latest development reported in the Virtual Special Issue of ENERGY dedicated to the 6th International Conference on Low Carbon Asia and Beyond (ICLCA′20) and the 4th Sustainable Process Integration Laboratory Scientific Conference (SPIL′20). As nations bind together to tackle global climate change, one of the urgent needs is the energy sector's transition from fossil-fuel reliant to a more sustainable carbon-free solution. Recent progress shows that advancement in energy efficiency modelling of components and energy systems has greatly facilitated the development of more complex and efficient energy systems. The scope of energy system modelling can be based on temporal, spatial and technical resolutions. The emergence of novel materials such as MXene, metal-organic framework and flexible phase change materials have shown promising energy conversion efficiency. The integration of the internet of things (IoT) with an energy storage system and renewable energy supplies has led to the development of a smart energy system that effectively connects the power producer and end-users, thereby allowing more efficient management of energy flow and consumption. The future smart energy system has been redefined to include all energy sectors via a cross-sectoral integration approach, paving the way for the greater utilization of renewable energy. This review highlights that energy system efficiency and sustainability can be improved via innovations in smart energy systems, novel energy materials and low carbon technologies. Their impacts on the environment, resource availability and social well-being need to be holistically considered and supported by diverse solutions, in alignment with the sustainable development goal of Affordable and Clean Energy (SDG 7) and other related SDGs (1, 8, 9, 11,13,15 and 17), as put forth by the United Nations.
Article
In view of the attention Green New Deal proposals have received there has been very little concern to assess its technical feasibility. It involves two major technical claims, firstly that renewable energy can sustain present societies at a relatively low cost, and secondly that economy can be decoupled from resource consumption and environmental impact. The validity of these assumptions is often taken for granted. Robert Pollin is unusual in providing arguments for them. This article puts reasons for rejecting both claims and then considers the implications for the design of sustainable and just systems. It is concluded that GND goals cannot be achieved unless there is large scale degrowth to radically different economic, social and political systems. A novel perspective on the transition, contradicting GND thinking, is indicated.
Article
Calcium looping is a promising thermochemical energy storage process to be integrated into concentrating solar power plants. This work develops for the first time a comprehensive life cycle assessment of the calcium looping integration in solar plants to assess the potential of the technology from an environmental perspective. Two representative integrations are analysed, representing daily (hot) and seasonal (cold) storage designs. Similar performance environmental impacts are observed in both, with slightly better results for the seasonal storage case due to the simplified energy storage integration. The results show the moderate environmental impact of calcium looping thermochemical energy storage technology, resulting in lower equivalent carbon dioxide emissions (24 kg/MWh) than other energy storage options such as molten salt-based solar facilities (40 kg/MWh). Plant construction involves a higher energy demand for the process, whilst the operation and maintenance on the plant represent a moderate impact due to the low environmental impact of limestone, the unique raw material of the process, and the lower water consumption compared to typical concentrating solar power plants. Besides, the energy required for the system is first time analysed, obtaining an energy payback time of 2.2 years and 2.5 years depending on the storage strategy design.
Article
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Solar energy is in high demand due to its environmental benefits and economic potential; however, concerns remain about the total impact it holds. In 2020, for Spain, Castilla-La Mancha was the second autonomous community with the highest photovoltaic energy production. Thus, a systematic review on 15 large-scale PV solar energy projects was carried out to assess the industry impacts, through environmental impact assessment (EIA), within the Autonomous Community of Castilla—La Mancha. An estimation of these impacts from a pre-operational approach is presented, based on primary energy needs and emissions discarded during its life cycle due to the manufacture, operation, and recycling of the photovoltaic modules. Based on both the life cycle assessment (LCA) and EIA, the approaches were compared with the results obtained. The obtained results suggest that determining the actual impacts of power plants in this region could provide justified information for the public administration and technicians in the measures for the installation and operation of PV plants and the future benefits of renewable solar technologies. Furthermore, the results indicate the possibility to recognize the relationship between the size of the plant and a high generation capacity, with a shorter time to pay for emissions from the manufacture and recycling of panels, suggesting that it is around 1.66–2.08 years for the Castilla-La Mancha region.
Article
Grid-connected utility-scale solar PV has emerged as a potential pathway to ensure deep decarbonization of electricity in regions with fossil fuel-dominated energy mixes. Research on utility-scale solar PV projects mainly focuses on assessing technical or economic feasibility. Environmental performance assessments of large-scale solar applications are scarce. There is limited information on the greenhouse gas (GHG) emissions and energy footprints of utility-scale solar energy systems. Earlier studies conducted on small-scale solar systems have limited application in the grid system. We developed a comprehensive bottom-up life cycle assessment model to evaluate the life cycle GHG emissions and energy profiles of utility-scale solar photovoltaic (PV) system with lithium-ion battery storage to provide a consistent electricity supply to the grid with peak load options. We conducted a case study for a fossil fuel-based energy jurisdiction, Alberta (a western province in Canada). The results of the energy assessment show that raw material extraction, production, and assembly of solar panels are the key drivers, accounting for 53% of the total consumption. Energy consumed during battery manufacturing is responsible for 28%. The system shows a net energy production with a mean net energy ratio as high as 6.6 for two-axis sun tracking orientation. The life cycle GHG emissions range from 98.3 to 149.3 g CO2 eq /kWh with a mean value of 123.8 g CO2 eq /kWh. The largest emissions contribution is due to the manufacturing of batteries, 54% of the total emissions. The solar PV system offers a mean energy payback time of 3.8 years (with a range of 3.3 to 4.2 years). The results are highly sensitive to the expected lifetime of the system, the panel’s peak wattage, and process energy consumption at various life cycle stages.
Chapter
Between 2000 and 2020, scientists and non-scientists alike gradually embraced the idea that humankind had created a new epoch, the »Anthropocene,« or the age of humans. In 2000, the atmospheric chemist Paul Crutzen and biologist Eugene Stoermer proposed that a new epoch be declared given humankind’s many impacts on the natural environment, particularly climate change (Crutzen/Stoermer 2000; Crutzen 2002). By May 2019, 29 of the 34 members of the Anthropocene Working Group (AWG) had voted to declare the invention and testing of nuclear weapons as the marker for the end of the Holocene and the beginning of the Anthropocene (Subramanian 2019).
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This research uses Life-Cycle Assessment (LCA) to better understand the energy and environmental performance for two electricity generation systems, a 620 MW combined-cycle natural gas plant, and an 8kW building-integrated photovoltaic system. The results of the LCA are used to provide an effective and accurate means for evaluating greenhouse gas emission reduction strategies for U.S. electricity generation. The modern combined-cycle plant considered in this thesis is nominally 48% thermally efficient, but it is only 43% energy efficient when evaluated across its entire life-cycle, due primarily to energy losses during the natural gas fuel cycle. The emission rate for the combined-cycle natural gas plant life-cycle (469 tonnes CO2-equivalent per GWeh), was 23% higher than the emission rate from plant operation alone (382 tonnes CO2-equivalent per GWeh). Uncertainty in the rate of fuel-cycle methane releases results in a potential range of emission rates between 457 to 534 tonnes CO 2-equivalent per GWeh for the studied plant. The photovoltaic system modules have a sunlight to DC electricity conversion efficiency of 5.7%. However, the system's sunlight to AC electricity conversion efficiency is 4.3%, when accounting for life-cycle energy inputs, as well as losses due to system wiring, AC inversion, and module degradation. The LCA illustrates that the PV system has a low, but not zero, life-cycle greenhouse gas emission rate of 39 Tonnes CO2-equivalent per GWeh. A ternary method of evaluation is used to evaluate three greenhouse gas mitigation alternatives: (1) fuel-switching from coal to natural gas for Kyoto-based compliance, (2) fuel-switching from coal to nuclear/renewable for Kyoto based compliance, and (3) fuel-switching to meet the White House House's Global Climate Change Initiative. In a moderate growth scenario, fuel-switching from coal to natural gas fails to meet a Kyoto-based emission target, while fuel-switching to nuclear/renewable meets the emission objective by reducing coal generated electricity 32% below 2000 levels. The Global Climate Change Initiative allows annual greenhouse gas emissions to increase to levels that are 54% higher than the proposed U.S. commitment under the Kyoto Protocol.
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Together with 11 European and US photovoltaic companies an extensive effort has been made to collect Life Cycle Inventory (LCI) data that represents the status of production technology for crystalline silicon modules for the year 2004. These data can be used to evaluate the environmental impacts of photovoltaic solar energy systems. The new data covers all processes from silicon feedstock production via wafer- and cell- to module manufacturing. All commercial wafer technologies are covered, i.e multi- and mono-crystalline wafers as well as ribbon technologies. For monocrystalline silicon wafer production further improvement of the data quality is recommended.
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This document reports, in the first part, on the possibility to use solar irradiation calculated from satellite images for performance predictions. In the second part, different system performance evaluation models are described. The use of calculated irradiations as an input to a simple parametric model is compared with measurements from systems existing in the Task 2 Performance Database. Conclusions are drawn on the related achievable accuracy.
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In situ transmission electron microscopy was used to investigate the ageing behaviour of Si-based solar cells. The structural and compositional changes of the NiSi layer of such cells were determined.
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One can measure “energy quantities” – e.g. joules, BTU, quads – but only at a given scale and within a specific narrative about energy conversions at the time. Therefore, at the moment of generating aggregate indicators, the arithmetic summing of assessments of energy quantities referring to different scales and narratives is meaningless. This paper addresses epistemological problems typical of energy accounting, which are at the moment tackled by acknowledging the existence of unspecified “qualitative differences” among different energy forms – e.g. a joule of electricity has more “value” than a joule of coal. Three energy forms referring to different scales and narratives about energy conversions are relevant for national accounting: Primary Energy Sources (PES), Energy Carriers (EC), and End Uses (EU). We critically examine the usefulness of current energy statistics in relation to this distinction. The conventional linear representation – flow chart – based on a single scale and a single quantitative accounting confuses the three semantic categories and entails an important loss of information. Finally, we illustrate an innovative scheme for energy accounting across hierarchical levels that: (i) addresses the autocatalytic nature of energy transformations; (ii) provides a multi-scale quantitative representation; and (iii) preserves the semantic distinction between relevant energy forms (PES, EC, and EU).
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Most prior net-energy studies of nuclear-power systems accounted only for the direct consumption of fuels and the indirect consumption of energy embodied in physical materials when making such estimates. Most ignored the energy embodied in labor, government, and financial services. In this study, total economic cost is used as a surrogate to estimate the total input-energy cost of constructing, operating, financing, and disposal of nuclear-power systems. Although the cost and performance data used in this study are from light-water reactor systems experience, it is assumed that fast-neutron reactors may be substituted for light-water reactors when economic conditions dictate. We make the conservative assumption that the cost and performance characteristics of fast-neutron reactors will be similar to those of light-water reactors. We conclude that the operation of a large nuclear-power system, involving a continuing construction program of starting one new lOOO-MW system each month for 100 yrs, would yield a relatively small amount of net energy, under optimistic assumptions. Under less-optimistic assumptions the net-energy yield is negligible to negative. The average net-energy yield increases, somewhat, when optimistic assumptions are added to account for the possibility of improved efficiency in an all-electric economy.
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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.
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A high energy return on energy investment (EROI) of an energy production process is crucial to its long-term viability. The EROI of conventional thermal electricity from fossil fuels has been viewed as being much higher than those of renewable energy life-cycles, and specifically of photovoltaics (PVs). We show that this is largely a misconception fostered by the use of outdated data and, often, a lack of consistency among calculation methods. We hereby present a thorough review of the methodology, discuss methodological variations and present updated EROI values for a range of modern PV systems, in comparison to conventional fossil-fuel based electricity life-cycles.
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Short-rotation woody crops (SRWC) along with other woody biomass feedstocks will play a significant role in a more secure and sustainable energy future for the United States and around the world. In temperate regions, shrub willows are being developed as a SRWC because of their potential for high biomass production in short time periods, ease of vegetative propagation, broad genetic base, and ability to resprout after multiple harvests. Understanding and working with willow's biology is important for the agricultural and economic success of the system.
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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.
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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.
Article
Calculation of Cumulative Energy Demand (CED) of various energy systems and the computation of their Energy Yield Ratio (EYR) suggests that one single renewable energy technology cannot be said to be the best. Due to the difference in availability of renewable energy sources, their suitability varies from place to place. Wind energy converters, solar water heating systems and photovoltaic systems have been analysed for different types of locations. Comparing the general bandwidth of performance of these technologies, however, the wind energy converters tend to be better, followed by solar water heating systems and photovoltaic systems. Since a major part of the methodology of findingCED is very close to that of life cycle assessment and also because of the dominance of environmental impacts caused by the energy demand in the entire life cycle of any product or system, it is suggested that theCED can be used as an indicator of environmental impacts, especially in the case of power producing systems. Keywords: Cumulative energy demand; life cycle assessment; energy yield ratio; photovoltaics; solar water heating; wind energy Abbreviations: CED — Cumulative Energy Demand; EYR — Energy Yield Ratio; LCA — Life Cycle Assessment; Photovoltaics — PV; WEC — Wind Energy Converters
Conference Paper
Installed polycrystalline photovoltaic panels underwent infield degradation; they lost an average of more than 60% of their output peak power in 12 years. We present in this paper the result of our investigation to determine the causes of this degradation. We try to identify these causes and the mechanism of the lost of the cell characteristics by using "hot spot", dark current and transmittance measurements on dismantled parts of a PV panel. A theoretical model is also under development to simulate the degraded I-V characteristic.
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The authors argue that thermodynamics offers a means of accounting for both resource inputs and waste outputs in a systematic and uniform way. The new feature of the present work is to extend the applications of exergy analysis to resource and waste accounting and to present the results in an integrated analytical framework, namely, life-cycle analysis (LCA). We conclude that exergy is appropriate for general statistical use, both as a measure of resource stocks and flows and as a measure of waste emissions and potential for causing environmental harm.
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Despite the fact that the structure and technology of most modern wind turbines differs little over a wide range of power ratings, results from existing life-cycle assessments of their energy and CO2 intensity show considerable variations. While the range of energy intensities reflects economies of scale, their scatter is due to discrepancies in the energy contents of materials and the analyses' methodology and scope. Furthermore, energy intensities depend crucially on the country of manufacture, turbine recycling or overhaul after the service life, and the choice of tower material. In addition, CO2 intensities vary with national fuel mixes. Measures of life-cycle energy or CO2 emissions can be employed in policy and planning, especially for comparative risk and sustainability assessments, and source switching and capacity growth scenarios. If these measures are to assist decision-making, uncertainties in life-cycle assessments should be minimised by compliance to a standardised methodology, and by use of input–output-based hybrid techniques.
Article
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).
Article
Nach der Einführung des EEG im Jahr 2000 hat Deutschland einen regelrechten Boom der Biogasbranche erlebt. Bisher sind die meisten Biogasanlagen in landwirtschaftliche Betriebe integriert. Das produzierte Biogas wird dabei vor Ort verstromt, jedoch kann die anfallende Wärme aufgrund der peripheren Lagen der Betriebe oftmals nicht ausreichend genutzt werden. Wird das Biogas jedoch aufbereitet, in ein Erdgasnetz eingespeist und zu einem Ort mit Wärmesenke transportiert, kann die Wärme optimal ausgenutzt werden. In der vorliegenden Arbeit wurde deshalb am Beispiel der Biogasanlage in Darmstadt-Wixhausen untersucht, wie Energie- und Klima-effizient solche Anlagen sind, welche Faktoren die Energie- und Treibhausgasbilanz am stärksten beeinflussen und wie unsicher die Ergebnisse solcher ökobilanziellen Bewertungen sind. Methodisch wurde zunächst eine ökobilanzielle Bewertung vorgenommen und im Anschluss wurden Sensitivitäts- und Unsicherheitsanalysen durchgeführt. Aus Sicht der Energiebilanz schneidet die Anlage dank des umfangreichen Wärmekonzepte gut ab, denn sie erreicht einen Erntefaktor von 4,5, der spezifische kumulierte Energieaufwand beträgt 2,14 MJ/MJEndenergie und die energetische Amortisationszeit liegt bei 4,46 Jahren. Aus Sicht der Treibhausgasbilanz schneidet die Anlage eher schlecht ab, denn die prozentuale Treibhausgaseinsparung beträgt lediglich 46,8 % und die spezifischen Treibhausgasemissionen liegen mit 72,51 g CO2eq/MJEndenergiein einer ähnlichen Größenordnung wie diejenigen erdgasbetriebener Blockheizkraftwerke. Zu den sensitivsten Parametern in Bezug auf die Energiebilanz zählen der Eigenstromverbrauch der Anlage, insbesondere der Stromverbrauch der Druckwasserwäsche, die Silageverluste und der Methanertrag des Substrates. Die Treibhausgasbilanz wird zusätzlich noch wesentlich von den Parametern „Methanschlupf“, „Lachgasemissionen“ und „Grünlandumbruch“ beeinflusst. Wird der Methanschlupf durch die Abdeckung des Gärrestlagers auf ein Minimum reduziert, kann die Anlage bereits eine Treibhausgaseinsparung von 71,5 % erreichen. Die mittels Latin-Hypercube-Sampling durchgeführte Unsicherheitsanalyse hat gezeigt, dass die Spannweite der Ergebnisse erheblich sein kann. Je nach verwendeter Parameterkombination schwankt der Erntefaktor zwischen 1,07 und 5,81, wobei im Mittel ein Erntefaktor von 2,06 erreicht wird. Die prozentuale Treibhausgaseinsparung erreicht mit Werten zwischen -151 und 83 % eine sehr große Spannweite ebenso wie die spezifischen Treibhausgasemissionen, die zwischen 20 und 331 g CO2eq/MJ schwanken. Die mittlere Treibhausgaseinsparung liegt lediglich bei ca. 6 % und die mittleren spezifischen Treibhausgasemissionen liegen bei ca. 130 g CO2eq/MJ. Die Treibhausgasbilanz solcher Biogasanlagen kann jedoch deutlich verbessert werden, wenn die Gärrestlager gasdicht abgedeckt und Grünlandumbruch vermieden wird. Unter diesen Voraussetzungen beträgt die mittlere Treibhausgaseinsparung bereits 45,5 % und die spezifischen Treibhausgasemissionen liegen bei ca. 70 g CO2eq/MJ. In der Region Südhessen könnten bei entsprechend hohen Preisen für Maissubstrat ca. 443.000 t Mais pro Jahr erzeugt werden. Diese Menge reicht aus, um insgesamt Biogasanlagen (mit Gasaufbereitung) mit einer installierten Leistung von 20 MW zu betreiben. Diese könnten jährlich etwa 0,4 TWh (Brutto) bzw. 0,3 TWh (Netto) an Strom und Wärme erzeugen und dadurch 141.000 t CO2eq einsparen. Dies entspricht 30 % der Einsparungen, die in der Region erreicht werden müssen. After the introduction of the German Renewable Energies Act (EEG), a real boom in the biogas sector in Germany took place. As most biogas plants have, until now, been an integrated part of a farm, the biogas produced is converted directly on site. This often leads to an insufficient use of the heat produced due to the isolated location of farms. However, if the biogas is upgraded, fed into a nearby natural gas grid and transported to a location with an existing heat sink, the heat produced can be used in an optimal way. Using the example of the biogas plant in Darmstadt-Wixhausen, the present study analyses how energy and climate efficient biogas plants are, which factors have the greatest influence on the results of energy and greenhouse-gas balances and finally how uncertain the results of life cycle assessments can be. As a first step I carried out a life cycle assessment of the biogas plant mentioned above, in which the focus was on the calculation of the energy and greenhouse gas balance. Subsequently, I accomplished sensitivity- and uncertainty-analyses. As a result of its sophisticated heat utilization concept, the Darmstadt-Wixhausen biogas plant comes off very well from the point of view of the energy balance. The net energy gain is 4.5, the specific cumulative energy demand amounts to 2.14 MJ/MJend energie and the energetic amortization time is 4.46 years. Regarding the greenhouse gas balance, this plant comes off rather badly due to greenhouse gas savings of only 46.8 % and due to specific greenhouse gas emissions of 72.51 g CO2eq/MJend energie, which range in scales similar to those of natural gas fired block heat and power plants. Amongst the most sensitive parameters related to the energy balance is the electricity consumed by the plant itself, especially the electricity demand of the upgrading technology, the silage losses and the methane yield of the used substrate. The greenhouse gas balance is additionally strongly influenced by the parameters “methane losses”, “nitrous oxide-emissions” and “grassland ploughing”. If the methane losses are reduced to a minimum by closing the digistate storage, the plant already reaches greenhouse gas savings of approx. 71.5 %. The uncertainty analysis was carried out by using the Latin-Hypercube-Sampling method. It showed that the span of LCA results can be substantial. Depending on the parameter combinations used in the calculations, the net energy gain varies between 1.07 and 5.81 with a mean value of 2.06. The relative greenhouse gas savings, achieving values between – 151 and 83 %, are characterized by a huge span, while the variation of the specific greenhouse gas emissions range between 20 and 331 g CO2eq/MJ. The mean relative greenhouse gas saving is only 6 % and the mean specific greenhouse gas emissions are approx. 130 g CO2/MJ. However, the greenhouse gas balance of such biogas plants can be improved enormously if the digistate storage is closed and if no grassland ploughing takes place. If these two aspects are taken into account, the mean relative greenhouse gas savings increase from 6 to approx. 45.5 % and the specific greenhouse gas emissions decrease from 130 to 70 g CO2eq/MJ. In the region of South Hessen, 443.000 t of maize could be produced yearly, if the prices for maize substrate were at a relatively high level of approx. 32.5 €/t. These maize amounts would be sufficient to supply biogas plants (incl. upgrading technology) with an entire installed capacity of 20 MW. Those plants could produce a total amount of electricity and heat of approx. 0.4 TWh (gross), 0.3 TWh (net) respectively and they could therefore save approx. 141.000 t CO2eq per year. This corresponds to approx. 30 % of the greenhouse gas savings, which have to be achieved in that region.
Article
In this paper we investigate the energy requirements of PV modules and systems and calculate the Energy Pay-Back Time for three major PV applications. Based on a review of past energy analysis studies we explain the main sources of differences and establish a "best estimate" for key system components. For present-day c-Si modules the main source of uncertainty is the preparation of silicon feedstock from semiconductor industry scrap. Therefore a low and a high estimate are presented for energy requirement of c-Si. The low estimates of 4200 respectively 6000 MJ (primary energy) per m2 module area are probably most representative for near-future, frameless mc-Si and sc-Si modules. For a-Si thin film modules we estimate energy requirements at 1200 MJ/m2 for present technology. Present-day and future energy requirements have also been estimated for the BOS in array field systems, rooftop systems and Solar Home Systems. The Energy Pay-Back Time of present-day array field and rooftop systems is estimated at 4-8 years (under 1700 kWh/m2 irradiation) and 1.2-2.4 for future systems. In Solar Home Systems the battery is the cause for a relatively high EPBT of more than 7 years, with little prospects for future improvements.
Article
This article presents the environmental impacts of electricity generation systems, based on life-cycle assessments (LCAs). These assessments normally include impacts from extraction, processing and transportation of fuels, building of power plants and generation of electricity.The LCAs show that the following options have an excellent performance: hydropower (run-of-river and with reservoir), nuclear energy and windpower.Hydropower with reservoir does have high land requirements, but in spite of this, it is possible to conclude that it has the highest performance, if we consider 2 factors not always included in LCAs: firstly, reservoirs can provide secondary benefits such as irrigation or flood control; and secondly, hydropower has a high operating flexibility that can improve the reliability of electricity supply.
Life cycle exergy analysis of wind energy systems. Examen work Uppsala University
  • S Davidsson
Davidsson S. Life cycle exergy analysis of wind energy systems. Examen work Uppsala University; 2011.
Solar power realities supply-demand characteristics e storage and capital costs
  • P Lang
Lang P. Solar power realities supply-demand characteristics e storage and capital costs. On bravenewclimate.com by Barry Brook; 2009. Visited 2013/01/04.
Accelerated aging tests in photovoltaics e summary report
  • D Ton
  • J Tillerson
  • T Mcmahon
  • M Quintana
  • K Zweibel
Ton D, Tillerson J, McMahon T, Quintana M, Zweibel K. Accelerated aging tests in photovoltaics e summary report. U.S. Department of Energy; 2007. http:// www1.eere.energy.gov/solar/pdfs/pv_accelerated_aging_summary.pdf.
Performance prediction of gridconnected photovoltaic systems using Remote sensing http://www.iea-pvps.org/index.php?id=95&eID=dam_ frontend_push&docID=193 Visited
  • D Mayer
  • L Wald
  • Y Poissant
  • Pelland
Mayer D, Wald L, Poissant Y, Pelland S. Performance prediction of gridconnected photovoltaic systems using Remote sensing. Report IEA-PVPS T2e 07:2008. IEA; 2008. http://www.iea-pvps.org/index.php?id=95&eID=dam_ frontend_push&docID=193 Visited 2013/01/04.
University of Düsseldorf
  • A Otto
  • Faktensammlung
Otto A. Faktensammlung zur Windenergie 2007. University of Düsseldorf; 2007. Visited 2013/01/04.
Life-cycle analysis of the total Danish energy system Tekst Nr 334 Roskilde (Denmark): IMFUFA, Roskilde Universitetscenter Cumulative energy demand for selected renewable energy technologies
  • B Kuemmel
  • Srensen
  • D Gürzenich
  • J Mathur
  • Bansal
  • Wagner
Kuemmel B, Srensen B. Life-cycle analysis of the total Danish energy system. Tekst Nr 334. Roskilde (Denmark): IMFUFA, Roskilde Universitetscenter; 1997. [37] Gürzenich D, Mathur J, Bansal NK, Wagner H-J. Cumulative energy demand for selected renewable energy technologies. The International Journal of Life Cycle Assessment 1999;4:143e9.
Life cycle assessment of coal-fired power production Report of the National Renewable Energy Laboratory://www.nrel.gov/docs/fy99osti/25119
  • Pl Spath
  • Mann
  • Kerr
Spath PL, Mann MK, Kerr DR. Life cycle assessment of coal-fired power production. Report of the National Renewable Energy Laboratory. U.S. Department of Energy; 1999. http://www.nrel.gov/docs/fy99osti/25119.pdf Visited 2013/01/04.
ecoinvent report No. 6-VI: Kohle Sachbilanzen von Energiesystemen: Grundlagen für den ökologischen Vergleich von Energiesystemen und den Einbezug von Energiesystemen, Ökobilanzen für die://db.ecoinvent.org/ ecoquery/files/06_VI_Kohle.pdf?area=463ee7e58cbf8
  • R Dones
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