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Cradle-to-grave greenhouse gas emissions from dams in the United States of America
Abstract
Hydropower is traditionally considered to be one type of “clean” energy, and has been heavily developed in many regions of the world. Nevertheless, this assumption is increasingly being challenged by recent findings that a large amount of methane and other greenhouse gases (GHGs) are emitted during reservoir creation, turbine operation, and dam decommissioning. Via a critical review of existing hydropower life cycle assessments and reservoir emission studies, we compared the GHG emissions of various types of dams based on their structural type, size, primary function, and geographical location during their construction, operation, and decommissioning phases. Means to improve dam performance and reduce related GHG emissions were identified. It was found that dams with reservoirs usually have much higher GHG emission rates than diversion dams. GHG emissions are mainly generated at the construction and maintenance stages for small-scale run-of-river dams, whereas decomposition of flooded biomass and organic matter in the sediment has the highest GHG emission contribution to large-scale reservoir-based dams. Generally, reservoir-based dams located in boreal and temperate regions have much lower reservoir emissions (3–70 g CO2 eq./kW h) compared with dams located in tropical regions (8–6647 g CO2 eq./kW h). Our analysis shows that although most hydroelectric dams have comparable GHG emissions to other types of renewable energy (e.g., solar, wind energy), electricity produced from tropical reservoir-based dams could potentially have a higher emission rate than fossil-based electricity.
... River dams are divided into runoff dams and reservoir dams (Almeida et al. 2019;Song et al. 2018). Compared with runoff dam, reservoir dam has long storage time, huge storage scale, and powerful water level adjustment ability, which can retain larger water bodies, create a large range of fluctuation zones, and deposit more materials (Almeida et al. 2019;Fearnside et al. 2012;Song et al. 2018;Zhang et al. 2008). ...
... River dams are divided into runoff dams and reservoir dams (Almeida et al. 2019;Song et al. 2018). Compared with runoff dam, reservoir dam has long storage time, huge storage scale, and powerful water level adjustment ability, which can retain larger water bodies, create a large range of fluctuation zones, and deposit more materials (Almeida et al. 2019;Fearnside et al. 2012;Song et al. 2018;Zhang et al. 2008). The most obvious difference between runoff dam and reservoir dam is their size; some findings suggest that more profound impacts are generated by the "large dams" than are expected from "small dams" or "large-dam effects" (Ni et al. 2022). ...
... The emission depends on the CH 4 concentration at the turbine pumping point, and the CH 4 concentration varies at different depths of reservoirs (Fearnside et al. 2012). The concentration of CH 4 increases with turbine depth, which boosts degassing emissions (Song et al. 2018). ...
Dams built on rivers can bring economic benefits to local production and are considered to be environmentally friendly. However, in recent years, many researchers found that the establishment of dams has created excellent conditions for the production of methane (CH4) in rivers, making it change from a “weak source” of rivers to a “strong source” of dams. In particular, reservoir dams have a great impact on CH4 emission in rivers within their regions in terms of time and space. Spatially, the sedimentary layer and water level fluctuation zone of reservoirs are the main direct and indirect causes of CH4 production. Temporally, the synergetic effect between water level adjustment of the reservoir dam and environmental factors leads to large changes in the substances of the water body, impacts on the production and transport of CH4. Finally, the generated CH4 is emitted into the atmosphere through several important emission modes: molecular diffusion, bubbling, and degassing. The contribution of CH4 emitted from reservoir dams to the global greenhouse effect cannot be ignored.
... Compared with conventional non-renewable energy, such as coal or gas, hydropower will emit less greenhouse gas in the same operation cycle [52], [53], [54], which is the embodiment of its environmental benefits under the current carbon-neutral and green industry requirements. The Chinese Government has decided to provide certain benefits and subsidies for exporting hydropower due to its significant contribution to energy conservation and emissions reduction. ...
... Constraints (46) to (54) represent the hydropower generation function using the interpolation technique: ...
... Constraints (51) to (53) select the vertices used in interpolation. Constraint (54) relates to the type of variable. ...
Regional cross-border electricity trading is popular in price and cooperation. It is a reliable path to alleviate the shortage of power supply during rapid economic growth. As an important export commodity, the pricing options for hydropower directly relate to the cooperation intention of business parties. This study demonstrates the price formation methods and internal relationships of cascade hydropower stations in CBET. To simulate the decision-making of a bilateral forward contract, a bi-level optimization model was constructed, and the objectives of each layer represent the interests of both parties. The BOM was linearized with Karush-Kuhn-Tucker conditions and strong duality, and finally solved using mixed-integer linear programming. The prices of CHSs in southwestern China were calculated under different pricing options and the results were absorbed in an actual transaction case. Consequently, the complementarity between different exporting countries was verified. The most suitable pricing option for CBET was determined, that is the unified electricity price based on the marginal cost, to be
$481~\textrm {CNY/MW}\cdot \textrm {h}$
, which is 20% to 60% higher than the thermal and photovoltaic from other countries. Furthermore, national policy support and economic subsidies are key guarantees for the sustainable development of CBET, which can reduce the discount electricity price to below that of thermal generation by 30%.
... Recently, several findings showed that a large amount of methane and other GHG are emitted during reservoir creation (Ion & Ene, 2021). Song et al. (2018) have warned that the reservoir-based hydroelectric dams located in boreal and temperate regions have much lower reservoir emissions (3-70 g CO 2 eq./kW h) compared with dams located in tropical regions (8-6,647 g CO 2 eq./kW h). The author also showed that tropical reservoir-based dams could potentially have a higher emission rate than fossil-based electricity. ...
... Dams and reservoirs have been criticized for altering natural flow regimes, blocking fish passage, affecting sediment transport, and changing watershed characteristics, all of which contribute to water quality degradation, fish population decline, and biodiversity loss, as well as cascading social and economic issues (Song et al., 2018). With a large number of dams and reservoirs formed from the dams, Vietnam faces the risk of GHG emissions from these works. ...
Vertical distribution of free–living nematodes from the tropical region are still poorly documented, especially in Vietnam. Field sampling was conducted at the Ba Lai river, a tributary of the Mekong river, to insight into the regularity of the vertical pattern of nematode assemblages. Furthermore, some sediment environmental characteristics such as greenhouse gases were also detected in order to understand how to influence nematode distribution. The study found that nematode composition differed significantly between the upper and deeper layers of sediment but not among the deeper layers. Nematode density showed spatial variability across layers, with higher values in the upper layer. Nematode diversity decreased with increasing depth. Non–selective deposit feeders (1B) were dominated in the surface layers, while the predator–omnivores feeders (2B) was numerous in the deeper layers. In the dry season, both methane and hydrogen sulfur were found negatively affecting nematode diversity in sediment profile, particularly, methane effects negatively also to species richness, densities, and evenness. However, only methane has a significant correlation to the diversity, species richness, densities, and evenness of the nematode communities.
... Figs. 6 and 7 demonstrated that ENIs and ELMs differed significantly for each portion of the drawdown zone of the TGRA. Many variables, such as topography, land usage, human elements, and models used, may have caused these differences (Cook and Overpeck, 2019;Huang et al., 2019;Song et al., 2018). Ecological network models are often coupled with hydrological models that include scenarios (Guo et al., 2021). ...
... Whether reservoirs are clean production suppliers depends on various variables, including land use type, meteorological circumstances, and aquatic conditions . Recent research used Life Cycle Assessment to measure and compare reservoir ecological network capacities (Briones Hidrovo et al., 2017;Song et al., 2018). So, managers of freshwater resources must concentrate on both variety and ecological functioning (Arif et al., 2022b;Xu et al., 2020). ...
Environmental illiteracy threatens the functioning mechanisms of ecological networks worldwide, yet many people remain dubious about their existence. The knowledge deficit model suggests that giving the public (local people and government personnel) additional information would alleviate distrust. There is limited evidence indicating that environmental literacy metrics (ELMs) influence ecological network indicators (ENIs) such as plant cover, habitat, exotics, regeneration, erosion, and stressors throughout the drawdown zone (upstream, midstream, and downstream) within dams and reservoirs, despite widespread implementation to enhance riparian zone conservation. This study tackles this knowledge gap by using multivariate statistical methods to assess ENIs on the covered area of 58,000 km 2 in 327 transects through a field-based approach inside China's Three Gorges Reservoir area (TGRA) in 2019. The bar graph results showed the largest lack of information about ELMs (e.g., knowledge, attitude, and behavior) from the general populace, and it had the biggest effect on the plant cover in the midstream and the least impact on regeneration in the upstream. The ELMs of local people influenced the ENIs most within the downstream, with coefficients of Pearson correlation in the range of − 0.67 < r < 0.98. However, the ELMs (knowledge and behavior) of government personnel showed the greatest correlations with ENIs (− 0.41 < r < 0.74) in the midstream, while attitude towards downstream. In comparison among ENIs, vegetation cover, grass exotics, gullying, longitudinal continuity, and farming systems were all-important ENIs within the TGRA. ENIs and ELMs varied substantially for each section of the drawdown zone, according to hierarchical approaches. These results educate decision-makers about the spatial variations in ENIs of riparian regions in dams and reservoirs, which need location-based initiatives to raise inclusive impact awareness among the Chinese public.
... RZCs and ELMs varied substantially for each land-use type within the TGDR, as shown in Figure 7. A range of variables, including land use, human factors, and the model employed, may have contributed to these result discrepancies (Cook & Overpeck, 2019;Huang et al., 2019;Song et al., 2018). Scenario-based clean production change models are often used to assess levels of riparian zone changes (Guo et al., 2021). ...
... Researchers have used the life cycle assessment method to quantify and evaluate reservoir-cleaning capability (Briones Hidrovo et al., 2017;Song et al., 2018). In the context of these challenges, those responsible for water source management must be aware of distinctive resource types Xu et al., 2020). ...
Environmental illiteracy threatens ecosystem functions globally, however, many continue to deny its existence. Knowledge deficit theory suggests that suspicions will decrease once officials and the public are presented with new facts. Despite extensive worldwide initiatives to improve riparian buffer zones, there is minimal evidence about the impact of environmental literacy metrics (ELMs) on riparian zone components (RZCs) across different land‐use types (i.e., rural, rural–urban transitional, and urban regions) within the riparian zones of dams and reservoirs. In this study, multiple statistical techniques were used to explore the extent of impacts on a 58,000 km2 area within China's Three Gorges Dam Reservoir (TGDR) in 2019. Network visualization investigated RZC themes, such as plant cover, regeneration, exotics, erosion, habitat, and stresses, based on 5326 articles published over the past 121 years. Our analysis revealed the greatest lack of information regarding ELM (e.g., knowledge, attitude, and behavior) among the general public, which, in turn, had the greatest impact on the components of plant cover in transitional regions and the least impact on regeneration in rural areas. Furthermore, the ELMs of local people had the most significant effect on RZCs, with Pearson correlation values ranging from −0.79 < r < 0.98 throughout the TGDR. In contrast, the ELM of government employees correlated more strongly with RZCs (−0.70 < r < 0.92) in transitional and rural areas. Comparatively, exposed soil, understory cover, and environmentally unfriendly activities, including pollution, were the most significant RZCs within the TGDR. Based on hierarchical methods, RZCs and ELMs differed significantly between land‐use categories. RZCs near dams and reservoirs exhibit many differences; thus, land‐use initiatives are required to raise awareness of their global impacts. This article is protected by copyright. All rights reserved.
... CPEs and ELMs differed significantly by stream type within the TGDRA, as shown in Fig. 7. Several variables, such as land use, human characteristics, and the model used may have led to these differences in findings (Song et al., 2018;Cook and Overpeck, 2019;Huang et al., 2019). Scenario-based clean production change models are ubiquitous (Guo et al., 2021). ...
... Reservoirs exert great and harmful effects on global clean production, studies have revealed, with results from the last 30 years exposing their benefits and downfalls (Xiang et al., 2021b). The life cycle assessment technique has been utilized to measure and evaluate reservoir cleaning capacities (Briones Hidrovo et al., 2017;Song et al., 2018). Thus, those who oversee water supplies must differentiate between various types of resources (Xu et al., 2020;Arif et al., 2021a). ...
Although environmental illiteracy threatens the functioning of landscapes throughout the world, it is frequently ignored. The traditional wisdom assumes that suspicions will evaporate when the public and government authorities are provided with new information. Despite significant efforts to enhance riparian corridor output, limited data are available on the effect of environmental literacy metrics (ELMs) on clean production elements (CPEs) across various streams (e.g., main rivers and tributaries) within impoundments. This study examined such effects within the China Three Gorges Dam Reservoir area (TGDRA) by collecting 336 transects that assessed the breadth of effects on 58,000 km² in 2019. The network visualization revealed 7234 papers published over the last 121 years, each of which focused on themes such as plant cover, regeneration, exotics, erosion, habitat, and stressors. The bar graph showed that the general public lacked understanding of environmental literacy (e.g., knowledge, attitudes, and behavior), which influenced plant cover elements most in tributary zones but had little direct effect on regeneration. Locals' environmental literacy had the greatest impact on CPEs, with Pearson correlation coefficients ranging from −0.69 < r < 0.96 in the main river zones. Moreover, public employees' environmental literacy had a stronger correlation with CPEs (−0.58 < r < 0.83) within the main river regions. Farming systems, exposed soil, dominant grass regeneration, and instream structures, including pollution, were among the most notable CPEs within the TGDRA. According to hierarchical approaches, CPEs and ELMs change substantially across stream types. CPEs and ELMs vary significantly around main rivers and tributaries, requiring efforts to raise the public understanding of the worldwide impacts of stream health on humans.
... De igual forma, Barros et al. (2011) y Delsontro et al. (2010 hallaron que las represas tropicales emiten más GEI que en otras latitudes, como Suiza. Por su parte, Song et al. (2018) estimaron las emisiones para presas ubicadas en regiones boreales y templadas en 3 a 70 g CO 2 eq/kWh, en comparación con las de regiones tropicales que varían de 8 a 6.647 g CO 2 eq/kWh. Estos estudios consideraron evaluaciones de ciclo de vida en sus metodologías. ...
... Las emisiones se generan principalmente en las etapas de construcción y mantenimiento de represas de ríos a pequeña escala, mientras que la descomposición de la biomasa inundada y la materia orgánica en el sedimento tiene la mayor contribución de emisiones de GEI en las represas de gran escala. Song et al. (2018) indican que, aunque la mayoría de las hidroeléctricas tienen emisiones de GEI comparables con otros tipos de energía renovable (energía solar, eólica), la electricidad producida en represas de regiones tropicales podría tener una tasa de emisión más alta que la electricidad basada en fósiles. Bajo este escenario, las emisiones de GEI constituyen un elemento fundamental en el análisis de los proyectos hidroeléctricos. ...
La capacidad instalada para generación de energía hidroeléctrica constituye el 69,2% de la matriz energética de Colombia, lo cual se debe a las características geográficas y a los recursos hídricos de este país. Aunque esta forma de generación es considerada renovable, las hidroeléctricas implican la construcción de presas y depósitos de agua (áreas inundadas) que, además de impactos ambientales en las comunidades, el suelo, el agua y el entorno en general, generan gases de efecto invernadero. Nuevas centrales hidroeléctricas se construirán en el país, por lo que se sugiere evaluarlas bajo una perspectiva de la sustentabilidad, entendida como la articulación de variables sociales, económicas, ambientales y culturales en búsqueda de un equilibrio a lo largo del tiempo. Se propone para esto el Análisis de Ciclo de Vida (ACV) como una herramienta para determinar impactos ambientales de proyectos hidroeléctricos. Este trabajo revisa cómo el enfoque de sustentabilidad puede apoyarse en herramientas ampliamente utilizadas en los proyectos de ingeniería como el ACV y el Análisis de Ciclo de Vida Social (ACVs) para conocer el impacto de proyectos hidroeléctricos en todas sus fases, abordando las dimensiones ambientales y sociales. La dimensión económica no se tuvo en cuenta, abriendo el camino para nuevos aportes. Se concluye que existe la necesidad de iniciar la construcción de una línea base de información para aplicar herramientas como el ACV y el ACVs, orientada a la sustentabilidad para proyectos de hidroeléctricas, tanto para los que se encuentren en planeación, como los que operan actualmente. Se sugieren aspectos para tener en cuenta en la toma de decisiones con el fin de contribuir a la sustentabilidad para futuros proyectos.
... Positive and negative feedbacks refer to reservoirs as carbon sink and carbon source to the climate system, respectively. Hydropower is considered a lowcarbon, clean energy source with significant positive effects in slowing down the global greenhouse effect (Song et al., 2018). In contrast to natural rivers and lakes, carbon buried in reservoir sediments is much larger (Phyoe and Wang, 2019). ...
... It is essential to estimate greenhouse gases emissions from reservoirs over their entire life cycle on a global scale to confirm whether the reservoir carbon cycle is generally a positive or negative feedback loop to the climate system. Current studies have been conducted using Life Cycle Assessment to quantify and compare greenhouse gas fluxes from reservoirs (Briones Hidrovo et al., 2017;Song et al., 2018). Yet, lack of long-term monitoring data and difficulty of quantifying emissions from some process indicators make it difficult to measure reservoir life-cycle emissions accurately. ...
Reservoirs account for about 10% of the freshwater stored in lakes worldwide. These reservoirs are home to ‘reservoir ecosystems’, that is, the aquatic and non-aquatic interactive ecosystems associated with artificial lakes where water is stored, typically behind a dam, for human purposes. While reservoir ecosystems provide various ecosystem services for sustainable development, their significance in research and policy has not been well understood and not well defined in the 2030 United Nation’s (UN) Agenda for Sustainable Development. To advance understanding of reservoir ecosystems and their impact on policy, here we provide an overview of research on reservoir ecosystems and link it to UN SDGs and their Targets. Based on 5,280 articles published in the last three decades, we applied network visualization to construct a framework for research addressing reservoir ecosystems. The framework covers four major themes: (1) ecosystem structure and function, (2) environmental pollution and stress effects, (3) climate impacts and ecological feedbacks, and (4) ecosystem services and management. We have found that sustainable reservoir ecosystems synergistically support 121 Targets of UN SDGs (71% of all). Reservoir ecosystems have both negative and positive implications for 15 targets (9%) and negative trade-offs for only 3 targets (2%). Thirty SDG Targets (18%) are unrelated to sustainable reservoir ecosystems. The synergies and trade-offs exist in three fields, securing basic material needs (SDGs 2, 6, 7, 14 and 15), pursuing common human well-being (SDGs 1, 3, 4, 5, 8 and 10), and coordinating sustainable governance policies (SDGs 9, 11, 12, 13, 16 and 17). Exploring these linkages allows better integration of reservoir ecosystems into the UN SDGs framework and guides sustainable management of reservoir ecosystems for sustainable development.
... The authors proposed a three-leveled tariff structure: time-of-use (TOU) tariff, critical peak pricing (CPP), and real-time pricing (RTP) with their advantages over the conventional tariff schemes. The environmental impact of solar PV and wind energy systems concerning the GHG emissions rate throughout their life cycles is discussed in [13][14][15]. ...
This paper proposes a dynamic time-of-use (d-TOU) tariff scheme for microgrid (MG) systems in islanded mode. The main problem for the islanded MG is the high cost of electricity, and the output from renewable energy is uncontrollable compared to the traditional grid. Therefore, this paper focuses on developing a suitable tariff scheme that provides reliability and financial benefits for both utility and customer. The time zone energy prices based on the Levelized Cost of Energy (LCOE) are introduced for islanded MG. The results show a contradiction between islanded MG with the standard traditional power generation TOU. Even though the LCOE obtained for MG is higher than conventional electricity rates, the greenhouse gas (GHG) emissions rate is reduced by 85%. In conclusion, the proposed d-TOU tariff scheme is suitable for the islanded MG system and it is beneficial for both the utility and the customer by not causing a financial burden to the utility and encouraging the customer to make a demand response in the future.
... The age of the reservoir and the type and amount of vegetation, which have been shown to increase in the period immediately after reservoir creation, have the greatest impact on CH4 emissions [42]. ...
Greenhouse gas emissions are related to non-renewable sources. For this reason, the methodological guide for the estimation of methane and carbon dioxide emissions in flooded lands was published in 2006 by the Intergovernmental Panel on Climate Change. Since 2016, several studies have been carried out in temperate and tropical zones reservoirs. Costa Rica is a Central American country known for its large hydroelectric resources and its highly renewable electricity generation matrix. This work represents the first study for 11 of 24 hydroelectric plants managed by the Costa Rican Electricity Institute. Methane emissions, energy density and emission factors for electricity generation are determined. Furthermore, a static mathematical model is used to determine these factors with little input data. It is estimated that the greatest contribution to methane emissions corresponds to the Arenal reservoir, which has the largest surface area and the lowest energy density.
... Conducting these methodologies on a large and impactful structure such as a dam is crucial as it helps determine the trade-off between the benefits and costs associated with its environmental footprint and resource use. Researchers investigated various aspects of a dam for conducting LCA, such as dredged sediments usage [6], dam decommissioning [7], biomass decay in reservoirs [8][9][10], and hydroelectric plants [11][12][13]. In association with different construction materials, Liu et al. [14] applied a hybrid LCA model to evaluate and compare the environmental impact of rock-filled concrete (RFC) and conventional concrete (CC) over the entire life cycle of a concrete dam. ...
Exploring the life cycle of infrastructures, like dams, is important for decision-makers since it allows for evaluating its overall sustainability, and identifying ways to balance the benefits and costs of dam development. In this study, the life cycle assessment (LCA) of the existing concrete gravity Pine Flat dam in the stages of construction to destruction, disposal, and recycling is investigated through ReCiPe 2016 methodology and the effect of two approaches of seismic retrofitting and non-retrofitting in the life cycle of the dam is studied. For a comprehensive understanding of the sustainability of the dam's life cycle, carbon footprint analysis (CFA) and life cycle costing (LCC) are also conducted to identify the main sources of greenhouse gas (GHG) emissions and evaluate the economic performance. These demands begin by assessing the dam's life cycle across three distinct stages, namely, initial construction, seismic retrofitting, and decommissioning, assuming recycling 20% of demolished concrete for the last stage. The outcomes of the evaluation are then presented for four different life cycle scenarios. The findings have underscored the importance of reducing air pollution and emphasize that human health is the most significant environmental concern as compared to the ecosystem and resource indicators. The concrete recycling considered during the decommissioning stage led to a 32% reduction in pollution caused by the dam disposal process. Additionally, the effect of retrofitting dams in decreasing environmental impact indicators such as carbon footprint and human health has been considered when compared to dam disposal. The economic and environmental costs of retrofitting Pine Flat dam were obtained about half of the equivalent expenses for its disposal and recycling stage.
... However, this was a review of dam life-cycle assessments, so the results reported have no comparators and the authors indicate that there has been relatively little research on the carbon effects of dam decommissioning. This review indicates that dam removal can result in carbon emissions from sediments resulting from decomposition of organic matter (unresolved) (Song et al. 2018), but these results come from a single primary source paper. That paper does report that sediment emissions after dam removal could be significant, greater even than emissions associated with dam construction and operation and maintenance. ...
Natural and working lands (NWLs) provide many benefits to people, including storing greenhouse gases (GHGs), supporting biodiversity, and generating other ecosystem services. Management of NWLs can influence their condition and function and therefore the benefits they provide. This project surveys the synthesis literature to assess how different management actions on various types of NWLs affect biodiversity and GHG outcomes. This information can help to determine how to best manage these lands to contribute to both biodiversity and climate solutions in the United States.
These results are a starting point to assess how different forms of management on various types of NWLs contribute to or detract from biodiversity and GHG outcomes. Though this study’s scope was limited to an exploration of biodiversity and GHG benefits provided by NWLs, this process could be adapted to examine the effects of management on other important ecosystem services, as well as how management affects equitable distribution of those services. Additional quantitative synthesis is also needed to compare the magnitude of different management activities’ impacts on biodiversity and carbon and to better understand how the intensity of certain activities influences these outcomes.
This report is a collaboration between the Nicholas Institute for Energy, Environment & Sustainability and the Gund Institute for Environment at the University of Vermont. This research was supported by the US Department of Agriculture, Office of Environmental Markets, under a cooperative agreement. The findings and conclusions in this report are those of the authors and should not be construed to represent any official USDA or US Government determination or policy.
... Though, some researchers have studied the environmental sustainability and impacts of aquatic systems, dams, or reservoirs during their operation time. For instance, Song et al. 10 compared the greenhouse gas emissions of different types of dams based on their type of structure, size, primary function, and geographical location during their construction, operation, and decommissioning stages. They realized that compared to diversion dams, dams with reservoirs generally have much higher greenhouse gas emission rates. ...
Environmental sustainability of the Chitgar Lake construction project in Tehran, Iran, was evaluated by a life cycle assessment (LCA) method in two phases of construction and operation using SimaPro 8.2.3 software. The results of analysis by Centre voor Milieukunde Leiden (CML) and IMPACT methods demonstrated that during the construction and operation (assuming 80 years of operation) phases of the lake 0.102 and 0.141 Mt of CO2eq (affects global warming), 0.015 and 0.021 Mt of 1,4-dichlorobenzene (DB)eq (results in toxicity for humans), 657.155 and 807.425 tons of SO2eq (leads to acidification), 150.123 and 69.374 tons of phosphates
eq (causes eutrophication), 1597 and 2265 terajoules of primary energy (damages the resources), 0.1 and 0.138 Mt of CO2eq (impacts on climate change), 18205330.45 and 11424387.32 potentially disappeared function (PDF) × m2 × yr (harms the quality of the ecosystem), and 165.37 and 104.94 disability-adjusted life year (DALY) (threats the human health) are caused, respectively. Electricity consumption has the greatest environmental impact on the operation phase of the lake. Furthermore, the operation phase of the lake is more harmful to the environment and human health compared to the construction phase.
... They also have a major effect on river ecosystems because they change hydrology and aquatic ecosystems simultaneously. Water-air interactions in natural rivers often emit some greenhouse gases (GHGs), although the turbulent river flow and the aquatic ecosystem typically limit GHG generation and keep emissions low (Song et al. 2018). Once a river is dammed, the marine ecology changes from a waterway-type heterotrophic technique dominated by benthic creatures to a lake-type autophytic system controlled by plankton via a process of natural choice, rivalry, and progression. ...
In order to allocate resources and describe progress, frequently nations are grouped together by many international authorities. A variety of pertinent indicators can provide a more useful basis for classification for each specific area of interest. Based on commonalities between various variables connected to the global environmental sector, we developed a novel typology of country clusters. Four indicators were chosen after a review of the literature. In order to optimize data availability across as many OECD nations as feasible, indicators were chosen based on their relevance for all the OECD countries. Countries were arranged into a natural cluster using the hierarchical clustering method. Four groups, covering 31 countries, were the result of two stages of grouping. These four clusters were found to be more compact and clearly divided which gives policymakers a clear-cut idea as to how these environmental indicators are deteriorating day by day and year by year and what needs to be done to be more environmentally sustainable and responsible.
... As governments and businesses increase their attention toward environmental innovations (Dias Angelo et al., 2012;Marrucci et al., 2021), that is, innovative solutions able to reduce intensive consumption of resources as well as sustain economic growth (Geissdoerfer et al., 2017;Ghisellini et al., 2016), CE is becoming central, as it is able to bring economic, social and environmental benefits (Suchek et al., 2021;Barreiro-Gen and Lozano, 2020). It has been argued that the turning point of change is to be found in design and not in economic activity itself, based on the growth of "cradle to cradle" (Lawrence, 2013), thus abandoning the old "cradle to grave" system (Song et al., 2018). Indeed, CE may aid in addressing grand challenges and benefit sustainable development, by creating competitive advantage through innovative and sustainable business models (Kristoffersen et al., 2020;Fernandez de Arroyabe et al., 2021;Ferasso et al., 2020). ...
Purpose:
This study aims to analyze how, under the stakeholder theory, corporate social responsibility (CSR) might favor the emergence of circular economy (CE) in the Agri-food sector, which is a relevant context, as it is technologically dynamic and requires paying attention to all the stakeholders.
Design/methodology/approach:
An exploratory, qualitative research design has been adopted to study the phenomenon in detail, as it facilitates the understanding of complex phenomena such those under investigation and helps enrich existing theory with new insights from real-world cases to add theoretical generalizations to the existing body of research in the field.
Findings:
The results of this study highlight that companies adopting CSR models are oriented toward circularity.
Practical implications:
This study provides useful indications to managers and policymakers as to how to favor the two approaches (CSR and CE) and benefit all the stakeholders.
Originality/value:
While there is wide scholarly and managerial interest toward CSR and CE, previous research has mainly analyzed CE and CSR as two independent phenomena. Therefore, there is a lack of understanding about how the two areas are linked. Following previous studies that have started to theoretically argue an interconnection between CSR and CE, in this research, it has been empirically investigated, and further explored theoretically, whether CSR can implicitly encourage the emergence of CE approaches.
... As governments and businesses increase their attention toward environmental innovations (Dias Angelo et al., 2012;Marrucci et al., 2021), that is, innovative solutions able to reduce intensive consumption of resources as well as sustain economic growth (Geissdoerfer et al., 2017;Ghisellini et al., 2016), CE is becoming central, as it is able to bring economic, social and environmental benefits (Suchek et al., 2021;Barreiro-Gen and Lozano, 2020). It has been argued that the turning point of change is to be found in design and not in economic activity itself, based on the growth of "cradle to cradle" (Lawrence, 2013), thus abandoning the old "cradle to grave" system (Song et al., 2018). Indeed, CE may aid in addressing grand challenges and benefit sustainable development, by creating competitive advantage through innovative and sustainable business models (Kristoffersen et al., 2020;Fernandez de Arroyabe et al., 2021;Ferasso et al., 2020). ...
... Dam releases effectively become the new river regime, modifying natural regimes extensively over multiple timescales (Hwang et al., 2021) and dampening some of the impacts of climate change while amplifying others (Chalise et al., 2021). These operations have major implications for safety (Burgherr & Hirschberg, 2014), health (Steinmann et al., 2006), commerce (Wang & Zhang, 2012), ecosystems (Kennedy et al., 2016;Richter & Thomas, 2007), water quality (Reis et al., 2019), flood control (Boulange et al., 2021), international treaty governance (Cosens et al., 2018), and even greenhouse gas emissions (Song et al., 2018). Many of these constraints are physically insurmountable or have critical safety or legal implications that make them a higher priority than hydropower generation. ...
Hydroelectric power has unusual technical characteristics that could become more valuable as the penetration of variable generation renewables grows, but its use for electricity generation is constrained by complex physical, safety, and socioenvironmental considerations. Hydroelectricity can therefore be difficult to represent in national‐scale energy models, and is frequently presumed to be either overly flexible or inflexible. While a few grid models address this complexity via detailed hydraulic process models, more simplified optimization and dispatch models could benefit from the use of empirical parameter values. In this study, we combine a new data set comprising 7.8 million flow‐hours of data from 2011 to 2016 at 158 dams across the United States with monthly and hourly generation data from the U.S. Energy Information Administration (EIA) to elucidate such empirical constraints for the continental United States. We introduce an approach for estimating power generation from hourly water discharge, then present regionally resolved interannual seasonal and diurnal generation patterns; frequency analyses of ramp rates; minimum and maximum generation rates; daily reversals; and load duration curves, all available interactively with a new data visualization tool. We suggest that due largely to hydropower's role as power generation that also serves non‐energy purposes, it acts as a predictable variable generator with constrained dispatchability, more like a supply side analog to demand response resources than like a battery. This observation is particularly relevant for high penetration renewable energy scenarios, given hydroelectric generators' expected value for grid stabilization and load balancing.
... The eco-efficiency analysis can be utilised in combination with the integration of social impacts into a newly developed economic-input output (EIO-) LCA approach (Hendrickson et al., 1998;Matthews and Small, 2000). Finally, because EIO-LCA does not consider environmental interventions of manufactured products linked to use and end-of-life phases, which might have significant impacts, the environmental impacts of each manufacturing sector are studied from cradle to grave (Song et al., 2018). Notwithstanding that a cradle-to-grave environmental LCA is an essential method for quantifying sustainability impacts, the existing EIO-LCA tool might nonetheless be improved by taking utilisation and end-oflife phases into account. ...
In this research, U.S. manufacturing activities' life cycle-based carbon and energy footprint impacts have been quantified, taking international trade linkages with the rest of the world into account. The U.S economy has been integrated into a multi-region input-output (MRIO) life cycle assessment framework where total of 40 major economies, including the USA, China, Russia, and others, plus the rest of the world (ROW) were modelled to assess global energy and carbon footprint impacts. Each country's economy is assumed to compromise 35 major industries based on the WIOD database classification. A total of 1435 (41 × 35 = 1435) industries has therefore been taken to represent the global structure of the world economy. The novelty of the approach is that the MRIO model has been developed in a stochastic fashion, plus global trade-linked uncertainties have also been taken into consideration. Top carbon emitting and energy consumer industries and countries have been analysed using data analytics and statistical modelling methods. The results show that the USA is the largest contributor to the total carbon footprint (CFP) and the total energy footprint (EFP) with 81.73% and 84%, respectively. Moreover, the agriculture/hunting forestry/fishing sector and the electricity/gas/water supply sectors dominate the overall U.S. carbon footprint, contributing 22% and 21.28%, respectively. The coke/refined petroleum/nuclear fuel sector has the largest share of the total energy footprint, with 47.9% of the total impacts.
... Reservoirs of large hydropower plants located in tropical regions usually generate from 8 gCO 2 eq./kWh up to 6,647 gCO 2 eq./kWh due to the decomposition of biomass and organic matter (Song et al., 2018). However, run of river (RoR) hydropower plants do not need flooding reservoirs and therefore decay of biomass is negligible. ...
The aim of this chapter is to provide an overview of social, economic, and environmental impacts of renewable energy. Based on available literature, this chapter identifies the impacts of key renewable energy sources including solar, wind, hydro, and biomass in addition to solid waste. The most common impacts were identified for these renewable energy sources include impacts on land use, employment generation, and social aspects of quality life. This chapter considered both negative and positive aspects of the impacts and indicates that the impacts of renewable energy generation from different renewable energy sources very in terms of types and extent. The extent of impacts may differ according to the types of renewable energy sources, size of the energy generation plant, technology for energy generation, and socioeconomic context of a country.
... Some studies also paid attention to the indirect carbon emissions or the life-cycle (from cradle to gate or from cradle to grave) carbon footprint of hydropower. A majority of these studies are based on the method of process analysis [9][10][11][12][13]. It is found that the indirect carbon emissions caused by the hydropower project are significant. ...
Hydropower is the largest renewable source of electricity generation, the carbon emissions of which have attracted a lot attention. However, the system boundaries of existing studies are either incomplete or inaccurate. Therefore, this study provides a systems accounting framework for evaluating both the direct and indirect carbon emissions from a hydropower plant. It is based on the hybrid method as a combination of the process analysis and the input-output analysis. To demonstrate the framework, a case study for a typical pumped storage hydropower plant (NPSHP) is carried out. The total carbon emissions are estimated as 5828.39 kt in the life-cycle of the case system. The end-of-use stage causes the largest carbon emissions (38.4%), followed by the construction stage (34.5%), the operation stage (25.6%), and the preparation stage (1.5%). The direct carbon emissions are mainly released from sediments in the end-of-use stage and the surface of reservoirs in the operation stage (94.8%). The indirect carbon emissions are 2.8 times higher than the direct carbon emissions. The material, machinery, energy, and service inputs respectively account for 7.1%, 14.7%, 15.9%, and 62.3% of the total indirect carbon emissions by the case system. The indicator of EGOC (electricity generation on carbon emission) for the NPSHP is calculated as 26.06 g CO2-eq./kWh, which is lower than that of most other power plants.
... Human presence (e.g., accommodation and sanitation facilities for workforce There are also GHG emissions relating to the construction of pump/turbine units, manufacturing of cement and steel, transport of materials and personnel, flooding of forested landscapes, and clearing of vegetation for roads [11,50,51]. ...
Because generating electricity significantly contributes to global greenhouse gas emissions, meeting the 2015 Paris Agreement and 2021 Glasgow Climate Pact requires rapidly transitioning to zero or low-emissions electricity grids. Though the installation of renewables-based generators—predominantly wind and solar-based systems—is accelerating worldwide, electrical energy storage systems, such as pumped storage hydropower, are needed to balance their weather-dependent output. The authors of this paper are the first to examine the status and potential for pumped storage hydropower development in 24 Pacific Rim economies (the 21 member economies of the Asia Pacific Economic Cooperation plus Cambodia, Lao PDR, and Myanmar). We show that there is
195 times the pumped storage hydropower potential in the 24 target economies as would be required to support 100% renewables-based electricity grids. Further to the electrical energy storage potential, we show that pumped storage hydropower is a low-cost, low-greenhouse-gas-emitting electrical energy storage technology that can be sited and designed to have minimal negative (or in some cases positive) social impacts (e.g., requirements for re-settlement as well as impacts on farming and livelihood practices) and environmental impacts (e.g., impacts on water quality and biodiversity). Because of the high potential for pumped storage hydropower-based electrical energy storage, only sites with low negative (or positive) social and environmental impacts such as brownfield sites and closed-loop PSH developments (where water is moved back and forth between two reservoirs, thus minimally disturbing natural hydrology) need be developed to support the transition to zero or low-carbon electricity grids. In this way, the advantages of well-designed and -sited pumped storage hydropower can effectively address ongoing conflict around the social and environmental impacts of conventional hydropower developments. Noting the International Hydropower Association advocacy for pumped storage ydropower, we make recommendations for how pumped storage hydropower can ustainably reduce electricity-sector greenhouse gas emissions, including through market reforms to encourage investment and the application of standards to avoid and mitigate environmental and social impacts.
... This issue appears problematic since one of the purposes of dam reservoir construction is hydroelectricity, which is considered a clean energy source. However, this attribute might become obsolete since a recent study showed that tropical dam reservoirs have greater greenhouse gas emission potential than emissions from electricity generated from fossil fuels (Song et al., 2018). ...
Construction of dams and transformation of rivers, not only affects river-related and adjacent habitats, but also establishes new threats to surface freshwater resources globally. Predicted climate changes and increase of mean annual temperature will affect thermal regimes of dam reservoir ecosystems, severely altering their functioning. Analyzing three projections of representative concentration pathway (RCP 4.5, 6.0 and 8.5) for period of 2061-2080, we found that mean annual temperature at dam reservoir locations will increase by 3.06 °C to 4.74 °C from present. The highest projected increase of temperature was identified for dam reservoirs located in high latitudes of Northern Hemisphere, and therefore dam reservoirs located there will be most significantly affected. Numerous consequences of temperature increase are already recorded. Further increase will amplify unfavorable effects on numerous ecosystems, including dam reservoirs which are built on the purpose of the human population development. Our study indicates a threat for artificially stored water globally, with special attention to high latitudes in northern hemisphere and latitudes close to 200S meridian in southern hemisphere.
... For example, geothermal energy is only available in specific locations, while the LCA emissions of solar power also depend on the duration and strength of sunlight (Ludin et al., 2018). In most areas hydro plants have emissions comparable with other types of renewables (3-70 g CO 2 eq/kWh), but the GHG emissions of those located in tropical regions can reach 8-6647 g CO 2 eq/kWh, a value which is even higher than fossil fuel emissions (Song et al., 2018). ...
Rapid deployment of wind energy plays an important role in China's proposed energy transition to carbon neutrality before 2060. Greenhouse gas (GHG) emissions are, however, unavoidable during the entire life cycle of wind energy from manufacturing to disposal. It is important to estimate these GHG emissions and the emission intensity for programs of energy transition. We developed simplified LCA models and engineering-based models to provide a comprehensive estimate of the GHG emissions intensity and total emissions from onshore wind energy in China at provincial and national scales. We showed that in 2019, the GHG emission intensity per unit power generation was 19.88 g CO2 eq/kWh (provincial intensity ranges from 13.59 to 34.50 g CO2 eq/kWh). The results show that onshore wind energy in China has an emission intensity more than 98% lower than traditional fossil fuels and the mitigation effect can reach 84%–98% compared to the energy mix in 2020. We further investigated the effects on emission intensity of shifting the turbine mix towards larger sizes, reducing wind curtailment and using advanced designs to improve efficiency. Advanced design of turbines can further decrease GHG emission intensity by 21.6%, more than the scenario of reducing curtailment (5.4%), while the emission intensity could be reduced by 2.1% under the scenario of shifting the turbine mix towards larger sizes. The results will aid future energy-mix scenario design and policy formulation.
... Changes in the aquatic environment due to dam construction present new challenges for water quality assessment. Several previous studies have reported that the interruption of river flow due to dam construction resulted in the changes in physical environments (e.g., hydrology, flow regime, sediment, and bed materials, etc.), water quality (e.g., water pollutant load, trophic state, and algae dynamics, etc.), and surrounding ecosystem (e.g., species diversity, community, and vegetation, etc.) (Brainwood et al., 2004;Wei et al., 2009;Wang et al., 2012;Song et al., 2018;Grabb et al., 2021). Especially, the drastic transition from running to stagnant waters by rapid and unnatural changes may have adverse anthropogenic effects on water quality, such as excessive inputs of allochthonous organic matter, increased algal blooms (Winton et al., 2019). ...
This study evaluated changes in the aquatic environment and river water quality due to construction of the Yeongju Multipurpose Dam (YMD) in the Naeseong Stream Basin, Republic of Korea, over eight years. This study evaluated water quality characteristics immediately after dam construction in the target area with aquatic environmental values and important water quality parameters using classification schemes. The drastic formation of new lentic systems in the upstream dammed pool presented exponential algal growth and high potential availability of nitrogenous compounds depending on seasonally. The results of the river system analyzed with the water quality index focused on eutrophication (WQIEUT) and trophic state index of the Republic of Korea (TSIKO) provided adequate complementary information for specific water quality background within the extensive basin for future management. From the results, inflow and accumulation of anthropogenic organic matter as potential eutrophic factors in the upstream dammed pool were significant in the short-term period. However, the downstream lotic systems adjacent to the dam presented the temporary disturbance by physical factors. Furthermore, potential microbial factors were significant in the outlet in the basin depending on seasonally. These results using classification schemes can aid accessible decision-making for water quality management to prevent eutrophication in the dammed pool of upstream or best management practices (BMP) with microbial source tracking (MST) approaches in the downstream area.
... The contribution to GHG emissions related to reservoir construction, meaning those from the activities related to dam construction (raw material extraction, equipment manufacturing, transportation, and building process of dam), is estimated to be (2.3-37.9) gCO2eq/kWh [27]. [28] 235 [28] In paper [26], an average global emission of 173 kg CO2/MWh and 2.95 kg CH4/MWh was estimated after the emissions from over 1400 hydroelectric power plants were analyzed. ...
In order to evaluate the greenhouse gas (GHG) emissions from a reservoir or from several reservoirs in a country or a climatic zone, simpler or more complex models based on measurements and analyses of emissions presented in the literature were developed, which take into account one or more reservoir-specific parameters. The application of the models in the assessment of GHG emissions from a multipurpose reservoir gave values that are more or less close to the average values reported in the literature for the temperate zone reservoirs. This is explained by the fact that some models only consider emissions caused by impoundment and not degassing, spillway emissions , and downstream emissions, or those that use different calculation periods. The only model that calculates GHG emissions over the life cycle that occur pre-impoundment, post-impoundment, from unrelated anthropogenic sources and due to the reservoir construction is the model used by the G-res tool. In addition, this tool is best suited for multipurpose reservoirs because it allocates GHG emissions for each use, thus facilitating the correct reporting of emissions. The G-res tool used to calculate GHG emissions from the Stânca-Costești Multipurpose Reservoir shows that this is a sink of GHG with a net emission of −5 g CO2eq/m 2 /yr (without taking into account the emissions due to dam construction).
... SNG production process using electricity generated from solar photovoltaic (case 4) or onshore wind (case 5) was more sustainable based on CO 2 emissions. Here, although hydropower is renewable energy, relatively high CO 2 emissions were presented because the pump operation requires significant amount of energy in a pumped storage hydropower plant [76]. Scenarios considering degradation in WE had higher CO 2 emissions for all cases compared to those without degradation, implying that technological developments in WE systems for less or no degradation had a positive effect on economic feasibility as well as environmental impact. ...
Synthetic natural gas (SNG) production from captured CO2 and H2 produced by water electrolysis using renewable energy is of increasing interest for low-carbon fuel production, CO2 utilization technology, and unstable renewable energy storage. In this study, the effect of voltage degradation in a water electrolyzer, a core technology for SNG production, on the unit production cost of SNG production and CO2 emissions, with different water electrolysis types such as alkaline electrolysis (AEL), proton exchange membrane electrolysis (PEMEL), and solid oxide electrolysis (SOEL), was identified through techno-economic and environmental assessment. In particular, the energy efficiency, unit production cost of SNG, and CO2 emissions were identified based on the change in the power consumption caused by voltage degradation. Moderate voltage loss results in a decrease in energy efficiency from 53.8% to 48.8% in AEL, 55.3% to 47.0% in PEMEL, and 76.3% to 51.2% in SOEL. Moreover, respective SNG unit production costs of 140.3–170.2 USD MWh⁻¹, 157.5–203.1 USD MWh⁻¹, and 153.1–353.5 USD MWh⁻¹ for AEL, PEMEL, and SOEL, respectively, were obtained, showing an increase in SNG production cost due to the voltage degradation. Furthermore, total CO2 emissions for the SNG production process were investigated considering voltage degradation as well as electricity generation sources.
... The study defines electricity generation per capita as the dependent variable and classifies it into two categories: fossil fuel electricity and lowcarbon electricity (electricity from nuclear, solar, tide, wind, geothermal, biofuels and waste). It excludes hydroelectricity from low-carbon electricity, first considering that reservoir water releases a large amount of carbon dioxide, methane and other greenhouse gases (Song et al., 2018). Second, water-abundant countries have exploited hydro energy because its electricity generation cost is lower than that of fossil fuel. ...
This study focuses on Brazil, Russia, India, China and South Africa (BRICS countries), which contribute over 40% of global CO2 emissions. Using panel co-integration tests, fully modified OLS and seemingly unrelated regressions, the study contributes to the literature by revealing that public debt securities foster the transition from fossil fuel electricity towards low-carbon electricity, whereas private credit is mostly profitless for electricity production transition. The explanation is that environmental pressure urges public capital to play a vital role in electricity transition, while bank loans are reluctant to leave the electricity from fossil fuel for considerable returns. The installed capacity of electricity stations drives the association between financial capital and electricity production. Financial markets in China and South Africa play a more significant role in electricity transition than the other countries. Low-carbon electricity transition requires transformation of financial markets in all these countries.
... However, while there is considerable uncertainty regarding the current emitted quantities [5], the robustness of uncertainty analysis can greatly influence emissions of greenhouse gases from hydropower reservoirs, compared to other non-hydropower reservoirs [28,30]. Given quite a significant number of reservoir-based, non-powered reservoirs highlighted above, it is crucial to understand the relative scale and significance of their GHG emissions [35]. ...
Greenhouse gas (GHG) emissions from reservoirs are responsible for at most 2% of the overall warming effects of human activities. This study aimed at incorporating the GHG emissions of a reservoir (with irrigation/sugar production as its primary purpose), into the carbon footprint of sugar produced from irrigated sugarcane. This study adopts a life-cycle assessment (LCA) approach and encompasses the cradle-to-gate aspect of the international organization of standardization ISO 14040 guidelines. Results show that total carbon footprint of refined sugar could be as high as 5.71 kg CO 2-eq/kg sugar, over its entire life cycle, depending on the priority of purposes allocated to a reservoir and sugarcane productivity. Findings also reveal that the dammed river contributes the most to GHG emissions 5.04 kg CO 2-eq/kg sugar, followed by the agricultural stage 0.430 kg CO 2-eq/kg sugar, the sugar factory 0.227 kg CO 2-eq/kg sugar, and lastly the transportation stage 0.065 kg CO 2-eq/kg sugar. The sensitivity analysis shows that carbon footprint CF of sugar production is largely influenced by the rate of biomass decomposition in the impounded reservoir over time, followed by the reservoir drawdown due to seasonal climatic fluctuations. Significant amounts of GHG emissions are correlated with the impoundment of reservoirs for water resource development projects, which may account for up to 80% of total GHG emissions to the reservoir's primary purpose. Sugar production expansion, coupled with allocating more functions to a reservoir, significantly influences the CF of sugar per service purpose. This study is an indicator for policymakers to comprehend and make plans for the growing tradeoffs amongst key functions of reservoirs.
... Decisions about dams, whether to build, modify, or remove them, are fundamentally decisions about managing trade-offs between different water uses with varying human and ecological impacts and, therefore, feature many of the characteristics of other environmental conflicts (Gleick, 2018). Dam decisions involve complex tradeoffs specific to each river system (Roy et al., 2018;Song et al., 2018), have significant impacts on public resources, and involve many stakeholders with diverse and often conflicting interests . Dam removal proponents cite the benefits of removal for public safety, restoring fish habitat and overall ecosystem health (Mullens and Wanstreet, 2010;Fox et al., 2016;Magilligan et al., 2017). ...
Decisions about dams, like other environmental conflicts, involve complex trade-offs between different water uses with varying human and ecological impacts, have significant impacts on public resources, and involve many stakeholders with diverse and often conflicting interests. Given the many upcoming dam decisions in New England and across the United States, an improved understanding of public preferences about dam decisions is needed to steward resources in the public interest. This research asks (1) What does the public want to see happen with dams? and (2) How do public preferences regarding dam removal vary with demography and politics? We address these questions using data from three random sample statewide telephone polls conducted in New Hampshire over 2018 that asked people for their preferences concerning dam removal versus maintaining dams for specific benefits—property values, hydropower generation, industrial history, or recreation. Respondent age, education, gender, and political party were tested among the possible predictors. We find that majorities (52% or 54%) of respondents favor removing dams rather than keeping them for industrial history or property values, and a plurality (43%) favor removal over keeping them for recreation. A plurality (46%) prefer keeping dams, however, if they are used to generate hydropower. Respondent background characteristics and political identity affect these preferences in ways resembling those for many other environment-related issues: women, young or middle-aged individuals, and political liberals or moderates (Democrats or independents) more often support dam removal. Education, on the other hand, has no significant effects. The results quantify levels of general public support for dam removal in New England, illustrating the use of public opinion polling to complement input from public meetings and guide decisions. More broadly, they contribute a new topic to existing scholarship on the social bases of environmental concern.
... Decommissioning projects in the energy sector can relate to offshore gas production infrastructure [43], dams [44], wave energy [45], heat pumps systems [46] and nuclear reactors [47]. Remarkably, despite their growing importance and their growing costs in several industrial sectors (e.g., nuclear and offshore oil & gas decommissioning), until now, decommissioning projects have been mostly overlooked by scholars working on the economics and management of energy infrastructure. ...
Empirical research involving projects is an important and common way to advance knowledge in the energy sector, and there are well-established approaches for qualitative analysis of single or few cases (1–10 cases) as well as quantitative analysis of large databases (from 50+ cases). However, the “middle-ground” of analysing 10–50 cases is an unknown territory, and very few approaches exist to deal with numbers of cases that lie in the range of 10–50. This paper shows how this “middle-ground” can be explored through Qualitative Comparative Analysis (QCA). This is a method that can be applied to energy infrastructure projects (such as construction, operations, and decommissioning of power plants) in order to study causal inference (e.g. factors associated with outcomes). This paper demonstrates the potential of QCA by showing its application on an energy infrastructure phenomenon with an intermediate number of cases, that of nuclear decommissioning projects. These projects are becoming increasingly important to society and have multibillion US dollar budgets. Moreover, their characteristics need to urgently be matched with their project performance in order to avoid even further cost overruns. The application of QCA to 24 European nuclear decommissioning projects shows that a combination of characteristics (such as a streamlined governance structure and the presence of a storage facility for radioactive material on site) might be contributing to lower cost overruns. This paper concludes by showing how QCA can be applied to other energy infrastructure phenomena with a similar intermediate number of cases.
... In most cases, power plants located in tropical regions generate from 7 kgCO 2 eq/MWh up to 4326 kgCO 2 eq/MWh (Tremblay 2005a, b;Gagnon 1997;Mallia and Lewis 2013;Song et al. 2018). However, reservoir biomass GHG emissions are much lower in boreal and temperate climates. ...
PurposeRivers control biophysical processes that underpin essential ecosystem services. Myanmar’s rivers provide great opportunities for increasing energy supply at low costs from hydropower plants and make important contributions to the national economy. However, associated environmental impacts, as well as input and output flows of hydropower developments, remain less well understood. In this paper, we report on an investigation of the overall environmental effects of five hydropower plants in Myanmar, using a life-cycle impact assessment (LCIA) approach. The primary objective of the paper is to generate detailed life-cycle inventory data and quantify the environmental impacts of the existing five hydropower plants in Myanmar.Material and methodThis paper reports on a “cradle to grave” LCIA for five hydropower plants in which environmental impacts associated with construction, operation and maintenance, transportation, and decommissioning of large-scale hydropower plants in Myanmar were systematically assessed.ResultsConstruction, transportation, operation and maintenance phases are most sensitive to global warming, mineral resource depletion, acidification, freshwater aquatic ecotoxicity, human toxicity and photochemical ozone creation. There is heterogeneity in hydropower plants’ effects on the environment, based on the size of the power plant.Conclusion
Strategic selection of hydropower projects is suggested to enhance resilience in environmentally sensitive areas. It is concluded that more comprehensive and rigorous environmental and social impact assessment (ESIA) is needed, not only for mega-dams but also for the smaller-scale hydropower plants.
Graphical abstract
The unprecedented population and anthropogenic activity rise have challenged the future look up for shifts in global temperature and climate patterns. Anthropogenic activities such as land fillings, building dams, wetlands converting to lands, combustion of biomass, deforestation, mining, and the gas and coal industries have directly or indirectly increased catastrophic methane (CH4) emissions at an alarming rate. Methane is 25 times more potent trapping heat when compared to carbon dioxide (CO2) in the atmosphere. A rise in atmospheric methane, on a 20-year time scale, has an impact of 80 times greater than that of CO2. With increased population growth, waste generation is rising and is predicted to reach 6 Mt by 2025. CH4 emitted from landfills is a significant source that accounts for 40% of overall global methane emissions. Various mitigation and emissions reduction strategies could significantly reduce the global CH4 burden at a cost comparable to the parallel and necessary CO2 reduction measures, reversing the CH4 burden to pathways that achieve the goals of the Paris Agreement. CH4 mitigation directly benefits climate change, has collateral impacts on the economy, human health, and agriculture, and considerably supports CO2 mitigation. Utilizing the CO2 from the environment, methanogens produce methane and lower their carbon footprint. NGOs and the general public should act on time to overcome atmospheric methane emissions by utilizing the raw source for producing carbon–neutral fuel. However, more research potential is required for green energy production and to consider investigating the untapped potential of methanogens for dependable energy generation.
Compared to the increased energy demand in the 21st century, Hydropower (also known as water power) is traditionally considered one of the “Green Energy”. Some advanced researches clarifies that various renewable generations have been performed well to fight back the drastic climate impacts. Though some of them are not as suitable for clean eco-friendly production due to the impacts on eco-system. In recent researches, the Life Cycle Assessment is a great tool to investigate the impact of renewable power plants on eco-system relating upon the whole life cycle based emissions.The Main key function of the paper is to investigate and observe the environmental impacts of the “ITAIPU Hydro-electric Power Plant”, located on the Parana River, between the geographical border area of Brazil and Paraguay”. To identify the environmental impacts CML 2001 have been adapted and the investigation shows that the construction and operation phase has the greater impacts on the eco-system. Through this investigation the identification of environmental hot-spots has been recognized which will help future renewable plant developers to take scientific steps for constructing more environment friendly power plant for sustainable grren electricity production.
The growing demand for clean, sustainable, and viable energy in the twenty-first century prompted researchers to focus their efforts on developing renewable-based technologies. In that context, hydropower energy can be one of the feasible alternatives to meet future energy demands. It has been observed that at reservoir dams, the breakdown of flooded biomass and organic matter produces a significant amount of Green House Gas (GHG), which contributes to global warming. Small-scale hydro-based technologies produces GHG emissions when compared to dam hydropower since they produce most of their emissions during the building and maintenance phases. Small-scale hydro-based technologies such as hydrokinetics can be considered one of the preferable options, which generate energy from flowing water. A complete review of harnessing the power from flowing water by hydrokinetic turbines (HKTs) has been carried out in this article. Information regarding the state of the art and current status of cutting-edge technology has been gathered with the working principles of hydrokinetic turbines, classifications of HKTs and their applications, the terminology used for HKTs, the dam’s impact on the environment, and the selection of turbines, have been discussed thoroughly in this study. Furthermore, a detailed discussion of the design parameters of HKTs like solidity, power coefficient, Tip Speed Ratio (TSR), angle of attack, number of blades, type of blades, performance curve, Reynolds number, aspect ratio, blockage, augmentation and rotor mounting have been included. These parameters will aid in selecting HKT for a given environment condition. A comparison between the wind turbine and the hydrokinetic turbine has also been added. It has been observed that Micro Hydro River (MHR) technology is undergoing continuous R&D as compared to other rural electrification technologies. Various government policies, contemporary civilization, industrialization, and a standard way of life are also important factors that affect the use of HKTs as energy-harnessing devices.
Research on greenhouse gas (GHG; CO 2 , CH 4 , N 2 O) emissions from hydropower reservoirs has attracted widespread attention due to the potential effect on global climate change. However, few attempts have been made to conduct the research progress in this field from a global perspective. In this study, knowledge mapping research was conducted by applying scientometric analysis to explore research hotspots, frontiers and emerging trends of this field from 1993 to 2021, and five research priorities were recommended for the further study. The results showed that the research on GHG emissions from hydropower reservoirs was interdisciplinary, and there was an exponential increase in yearly publication outputs. were the leading contributors with high publication outputs, and the Chinese Academy of Science was the most productive and influential institution. Furthermore, the research hotspots in the field mainly focused on CO2 , CH4 , and N2O emissions and their spatiotemporal characteristics due to great contributions to greenhouse effect and heterogeneities of the GHG emissions from hydropower reservoirs. Research frontiers mainly concentrated on the Three Gorges Reservoir, bubble-mediated gas exchange, GHG emissions across different interfaces and gas transfer velocity. Meanwhile, the first three research frontiers were regarded as emerging trends in recent years. Although great progress has been made in the field, there were still some research challenges. Future research priorities were recommended to strengthen: 1) Application of remote sensing in the research on GHG emissions from hydropower reservoirs, 2) improvement of life cycle assessment research, 3) standardization research on the measurement methods, 4) anthropogenic impacts on carbon dynamics, and 5) international cooperation and database construction. Finally, several mitigation measures were suggested to provide useful insights into the management and control of GHG emissions. In contrast to previous reviews, this paper provides an insight for the visual study of the research on GHG emissions from hydropower reservoirs, helping researchers understand the current research status and future perspectives from a global perspective.
In recent decades, damming has become one of the most important anthropogenic activities for river regulation, and reservoirs have become hotspots for biogeochemical cycling. The construction of dams changes riverine hydrological conditions and alters the physical, chemical, and biological characteristics of rivers, eventually leading to significant variations in nutrient cycling. This review mainly explores the effects of river damming on nutrient transport and transformation, including i) nutrient (N, P, Si, and C) retention in reservoirs, ii) greenhouse gas (GHG) emissions, and iii) interactions between the nutrient stoichiometry ratio and the health of the reservoir ecosystem. The important drivers of nutrient transport and transformation, such as river connectivity, hydraulic residence time, hydropower development mode, microbial community variation, and anthropogenic pollution, have also been discussed. In addition, strategies to recover from the negative effects of damming on aquatic ecosystems are summarized and analyzed. To provide theoretical and scientific support for the ecological and environmental preservation of river-reservoir systems, future studies should focus on nutrient accumulation and GHG emissions in cascade reservoirs.
Introducción/objetivo:
las emisiones de gases de efecto invernadero (GEI) de origen natural han aumentado por las acciones antropogénicas, y amenazan al planeta con un desequilibrio ambiental. Los embalses para almacenar agua, que después se utiliza para mover las turbinas de centrales hidroeléctricas, acumulan sedimentos generando GEI. En este trabajo se analizan los métodos empleados para estimar las emisiones de GEI en embalses, clasificando las publicaciones científicas encontradas en los motores de búsqueda de ScienceDirect y Google Scholar.
Metodología:
el método analítico utiliza una expresión booleana para recopilar información en los motores de búsqueda indicados y extraer la bibliografía relevante, considerando factores como la temperatura del agua, la ubicación geográfica, el tipo y la superficie del embalse, el tipo de gas y la tecnología, lo que atribuye un valor de pertinencia a cada característica para elaborar una matriz de resultados.
Resultados:
los resultados muestran que más del 50 % se basan en estimaciones de GEI y el resto en mediciones directas en los embalses. Además, la contribución de la inteligencia artificial como técnica de estimación es menor al 6 %.
Conclusiones:
finalmente, las regiones mundiales donde se realizan los estudios están distribuidas proporcionalmente y el análisis de literatura científica indica versatilidad en los métodos de estimación de GEI en embalses hidroeléctricos.
Variable renewable technologies are characterized by a large degree of intermittency due to their natural variability, creating a need for exploiting a range of sources. In this context, the use of energy storage systems is often proposed. There are different ways to store and use the overproduced electricity from these technologies. This paper aims to evaluate the global warming emissions savings obtained from storing the surplus electricity from the variable renewable technologies in the Spanish market and later using it in different end use applications, both for the present day and the 2030 time horizon. First, a review of the life cycle assessments of different energy storage technologies published in the scientific literature is performed. Then, selected values from this review, adapted to the emission intensity of variable renewable electricity stored in Spain, are used to compute GHG savings from storing and using this electricity for different end uses. Results show that the highest benefits in terms of GHG emissions avoidance would be obtained in transport applications and in the power sector. However, as the electricity mix becomes decarbonized, the use of batteries behind the meter would lead to no GHG emissions avoidance. Using electricity to produce heat leads to low GHG emission avoidance benefits that will reduce over time. Benefits will improve in time for the chemical sector, as there are few alternatives to decarbonize this sector. A specific storage strategy must be formulated for each particular case.
Dam decommissioning (DD) is a viable management option for thousands of ageing dams. Reservoirs are large carbon sinks, and reservoir drawdown results in important carbon dioxide (CO2) and methane (CH4) emissions. We studied the effects of DD on CO2 and CH4 fluxes from impounded water, exposed sediment, and lotic water before, during, and 3–10 months after drawdown of the Enobieta Reservoir, north Iberian Peninsula. During the study period, impounded water covered 0–100%, exposed sediment 0–96%, and lotic water 0–4% of the total reservoir area (0.14 km²). Areal CO2 fluxes in exposed sediment (mean [SE]: 295.65 [74.90] mmol m⁻² d⁻¹) and lotic water (188.11 [86.09] mmol m⁻² d⁻¹) decreased over time but remained higher than in impounded water (−36.65 [83.40] mmol m⁻² d⁻¹). Areal CH4 fluxes did not change over time and were noteworthy only in impounded water (1.82 [1.11] mmol m⁻² d⁻¹). Total ecosystem carbon (CO2 + CH4) fluxes (kg CO2-eq d⁻¹) were higher during and after than before reservoir drawdown because of higher CO2 fluxes from exposed sediment. The reservoir was a net sink of carbon before reservoir drawdown and became an important emitter of carbon during the first 10 months after reservoir drawdown. Future studies should examine mid- and long-term effects of DD on carbon fluxes, identify the drivers of areal CO2 fluxes from exposed sediment, and incorporate DD in the carbon footprint of reservoirs.
This paper presents the PEACEFULNESS software platform (Platform for transvErse evAluation of Control stratEgies For mULti-eNErgy Smart gridS), an open framework dedicated to multi-energy smart-grids, based on a techno-economic model that integrates economic considerations (contracts). As such, it is mainly oriented towards the evaluation of multi-energy grid supervision strategies, that is, energy management, and the corresponding policies and legal organization. The main goal is then to highlight the various possible behaviors and strategies to organize the probable future interconnections between the different energy carriers. In particular, it aims at investigating how to maximize the use of renewable energy sources (RES), using Demand Side Management (DSM) techniques and energy storage, in a shared economy context. The open-source tool PEACEFULNESS, written in Python, is described here in detail. It combines a top-down description of the energy networks and connections between the various agents (energy providers, distribution system operators, aggregators, consumers, producers, prosumers, etc.), together with a techno-economic bottom-up description for all devices. Here, both public databases and users’ data (basic heating demands or based on building modeling) can be used, as well as generic or more specific models (e.g., PV panels with constant or temperature-dependent efficiency). One of its major unique features compared with other tools is that it extends the use of DSM techniques to various energy grids which can also interact together. Furthermore, different economic models can be set for both the aggregators and the customers, and even within these groups. As a last competitive advantage, PEACEFULNESS allows the user to simulate the operation and supervision of tens up to hundreds of thousands of agents. It also provides a reporting system giving access to all the data, with a configurable granularity and frequency for the retained indicators. Finally, several validation cases are presented, followed by a series of test cases with increasing size: a smart home, a smart district (2 000 dwellings) and a smart community (50 000 dwellings).
Studies of emissions of greenhouse gas (GHG) such as CO2 and CH4 in hydroelectric reservoirs are very important in the debate on whether hydropower can be classified as a ‘clean energy’ source. In this study, GHG emissions in the Topocoro reservoir in Colombia during the first five years after filling were evaluated and related with hydropower generation. The floating static chamber and inverted funnel methodology were used for the collection of GHG and the gas chromatography with flame ionization detector (FID) – methanizer and electron capture detector (ECD) methodology for its detection in the laboratory. The results showed emission values between 256,613 and 654,643 tCO2eq/year. The intensity of gases was also determined in a range between 81 and 148 gCO2eq/kWh, depending on the evolution of the filling and the power generation in the reservoir. The results suggested that as the filling percentage of the surface of the reservoir increases, there will be more GHG emissions, due to the biotic and abiotic decomposition of organic matter. At the same time, higher energy production will be generated. HIGHLIGHTS
A tropical reservoir in Colombia was monitored for five years during the post-filling phase.;
The floating static chamber and inverted funnel methodology were used.;
It analyzed the relationships of the GHG with energy production and power density in the reservoir.;
This is the first investigation carried out in Colombia to determine the net emissions in a reservoir.;
Hydropower, which contributes to around 16% of global electricity and more than 72% of renewable electricity, is expected to play an important role in the deep decarbonization of the energy sector. However, the idea that hydropower is a carbon-neutral energy alternative on par with solar and wind is controversial. Research, mainly from limnology and climate modeling, shows that depending on the characteristics of the hydro project, it could be a significant source of GHG emissions. This aspect has been ignored in most life cycle assessment (LCA) studies, affecting the effective use of LCA results, especially in comparative assessments. This paper aims to provide a comprehensive and critical review on this topic by conducting a systematic literature review on hydropower LCA studies published since 2010. We found that there is inconsistency in how LCA is used for hydropower projects. While the emissions associated with the engineering work are well addressed, efforts to accurately estimate and model reservoir GHG emissions are constrained by limited data availability, difficulties in accurately quantifying highly variable carbon fluxes, and inconsistent modeling approaches. A huge range of emissions values is reported in the reviewed literature, from 1.5 to 3747.8 g CO2 eq per kWh. Reservoir-based hydropower shows high variability, which is mainly dictated by reservoir-related GHG emissions. Reservoir GHG emissions could be more than 90% of the life cycle emissions, especially for hydropower in a tropical region. The regionalized aspect is a key factor to be considered in extrapolating reservoir GHG emissions.
This chapter assesses observed and projected climate-induced changes in the water cycle, their current impacts and future risks on human and natural systems and the benefits and effectiveness of water-related adaptation efforts now and in the future.
This chapter assesses current climate change impacts on the global and regional water cycle, projected water-related risks for human and natural systems, and adaptation options and effectiveness across scales.
Further reservoir-based hydropower development can contribute to the United Nations’ sustainable development goals (SDGs) on affordable and clean energy, and climate action. However, hydropower reservoir operation can lead to biodiversity impacts, thus interfering with the SDGs on clean water and life on land. We combine a high-resolution, location-specific, technical assessment with newly developed life cycle impact assessment models, to assess potential biodiversity impacts of possible future hydropower reservoirs, resulting from land occupation, water consumption and methane emissions. We show that careful selection of hydropower reservoirs has a large potential to limit biodiversity impacts, as for example, 0.3% of the global hydropower potential accounts for 25% of the terrestrial biodiversity impact. Local variations, e.g. species richness, are the dominant explanatory factors of the variance in the quantified biodiversity impact and not the mere amount of water consumed, or land occupied per kWh. The biodiversity impacts are mainly caused by land occupation and water consumption, with methane emissions being much less important. Further, we indicate a trade-off risk between terrestrial and aquatic biodiversity impacts, as due to the weak correlation between terrestrial and aquatic impacts, reservoirs with small aquatic biodiversity impacts tend to have larger terrestrial impacts and vice versa.
Collectively, reservoirs created by dams are thought to be an important source of greenhouse gases (GHGs) to the atmosphere. So far, efforts to quantify, model, and manage these emissions have been limited by data availability and inconsistencies in methodological approach. Here, we synthesize reservoir CH 4 , CO 2 , and N 2 O emission data with three main objectives: (1) to generate a global estimate of GHG emissions from reservoirs, (2) to identify the best predictors of these emissions, and (3) to consider the effect of methodology on emission estimates. We estimate that GHG emissions from reservoir water surfaces account for 0.8 (0.5–1.2) Pg CO 2 equivalents per year, with the majority of this forcing due to CH 4. We then discuss the potential for several alternative pathways such as dam degassing and downstream emissions to contribute significantly to overall emissions. Although prior studies have linked reservoir GHG emissions to reservoir age and latitude, we find that factors related to reservoir productivity are better predictors of emission.
Aging infrastructure coupled with growing interest in river restoration has driven a dramatic increase in the practice of dam removal. With this increase, there has been a proliferation of studies that assess the physical and ecological responses of rivers to these removals. As more dams are considered for removal, scientific information from these dam‐removal studies will increasingly be called upon to inform decisions about whether, and how best, to bring down dams. This raises a critical question: what is the current state of dam‐removal science in the United States? To explore the status, trends, and characteristics of dam‐removal research in the U.S., we searched the scientific literature and extracted basic information from studies on dam removal. Our literature review illustrates that although over 1200 dams have been removed in the U.S., fewer than 10% have been scientifically evaluated, and most of these studies were short in duration (<4 years) and had limited (1–2 years) or no pre‐removal monitoring. The majority of studies focused on hydrologic and geomorphic responses to removal rather than biological and water‐quality responses, and few studies were published on linkages between physical and ecological components. Our review illustrates the need for long‐term, multidisciplinary case studies, with robust study designs, in order to anticipate the effects of dam removal and inform future decision making. WIREs Water 2017, 4:e1164. doi: 10.1002/wat2.1164
This article is categorized under: Water and Life > Conservation, Management, and Awareness
Engineering Water > Sustainable Engineering of Water
Water and Life > Stresses and Pressures on Ecosystems
The character and importance of uncertainty in dam safety risk analysis drives how risk assessments are used in practice. The current interpretation of uncertainty is that, in addition to the aleatory risk which arises from presumed uncertainty in the world, it comprises the epistemic aspects of irresolution in a model or forecast, specifically model and parameter uncertainty. This is true in part but it is not all there is to uncertainty in risk analysis. The physics of hazards and of failure may be poorly understood, which goes beyond uncertainty in its conventional sense. There may be alternative scenarios of future conditions, for example non-stationarity in the environment, which cannot easily be forecast. There may also be deep uncertainties of the type associated with climate change. These are situations in which analysts do not know or do not agree on the system characterisation relating actions to consequences or on the probability distributions for key parameters. All of these facets are part of the uncertainty in risk analysis with which we must deal.
Tropical dams are often falsely portrayed as 'clean' emissions-free energy sources. The letter by de Faria et al (2015 Environ. Res. Lett.
10 124019) adds to evidence questioning this myth. Calculations are made for 18 dams that are planned or under construction in Brazilian Amazonia and show that emissions from storage hydroelectric dams would exceed those from electricity generation based on fossil fuels. Fossil fuels need not be the alternative, because Brazil has vast potential for wind and solar power as well as opportunities for energy conservation. Because dam-building is rapidly shifting to humid tropical areas, where emissions are higher than in other climatic zones, the impact of these emissions needs to be given proper weight in energy-policy decisions.
Interest in the advancement of hydrokinetic energy conversion (HEC) technology has grown substantially in recent years. The hydrokinetic industry has advanced beyond the initial testing phase and will soon install demonstration projects with arrays of full-scale devices. By reviewing the current state of the industry and the cutting edge research this paper identifies the key advancements required for HEC technology to become commercially successful at the utility scale. The primary hurdles are: (i) reducing the cost of energy, (ii) optimizing individual turbines to work in concert considering array and bathymetry effects, (iii) balancing energy extraction with environmental impact, and (iv) addressing socioeconomic concerns.
Turkey’s electricity mix is dominated by fossil fuels, but the country has ambitious future targets for renewable and nuclear energy. At present, environmental impacts of electricity generation in Turkey are unknown so this paper represents a first attempt to fill this knowledge gap. Taking a life cycle approach, the study considers eleven impacts from electricity generation over the period 1990–2014. All 516 power plants currently operational in Turkey are assessed: lignite, hard coal, natural gas, hydro, onshore wind and geothermal. The results show that the annual impacts from electricity have been going up steadily over the period, increasing by 2–9 times, with the global warming potential being higher by a factor of five. This is due to a four-fold increase in electricity demand and a growing share of fossil fuels. The impact trends per unit of electricity generated differ from those for the annual impacts, with only four impacts being higher today than in 1990, including the global warming potential. Most other impacts are lower from 35% to two times. These findings demonstrate the need for diversifying the electricity mix by increasing the share of domestically-abundant renewable resources, such as geothermal, wind, and solar energy.
Abstract
This paper applies a life cycle approach to evaluate for the first time the environmental impacts of renewable electricity in Turkey. There are 305 power plants utilising hydro, wind and geothermal resources, all of which are considered in the study. The results indicate that the impacts from large reservoir hydropower are lower than for the small reservoir (by 45%–72%) and run-of-river hydropower (by 74%–84%). The exceptions are the global warming potential (GWP) and summer smog which are two times and 45% higher for large than small reservoir, respectively. Onshore wind is the worst option overall, with nine out of 11 impacts higher than for hydropower and geothermal. However, its GWP is 9 times and 11% lower than for geothermal and large reservoir, respectively. Acidification from geothermal is 281 times higher than for wind power. Geothermal is the best option for six impacts. Large reservoir has the lowest depletion of elements and fossil resources as well as acidification. Small reservoir and run-of-river plants are the best and geothermal the worst options for the GWP. The majority of the annual impacts from the renewable electricity mix are from hydropower with the exception of acidification which is largely from geothermal electricity.
Environmental life cycle assessment is often thought of as cradle to grave and therefore as the most complete accounting of the environmental costs and benefits of a product or service. However, as anyone who has done an environmental life cycle assessment knows, existing tools have many problems: data is difficult to assemble and life cycle studies take months of effort. A truly comprehensive analysis is prohibitive, so analysts are often forced to simply ignore many facets of life cycle impacts. But the focus on one aspect of a product or service can result in misleading indications if that aspect is benign while other aspects pollute or are otherwise unsustainable. This book summarizes the EIO-LCA method, explains its use in relation to other life cycle assessment models, and provides sample applications and extensions of the model into novel areas. A final chapter explains the free, easy-to-use software tool available on a companion website. (www.eiolca.net) The software tool provides a wealth of data, summarizing the current U.S. economy in 500 sectors with information on energy and materials use, pollution and greenhouse gas discharges, and other attributes like associated occupational deaths and injuries. The joint project of twelve faculty members and over 20 students working together over the past ten years at the Green Design Institute of Carnegie Mellon University, the EIO-LCA has been applied to a wide range of products and services. It will prove useful for research, industry, and in economics, engineering, or interdisciplinary classes in green design. © 2006 by Resources for the Future. All rights reserved. All rights reserved.
Brazil plans to meet the majority of its growing electricity demand with new hydropower plants located in the Amazon basin. However, large hydropower plants located in tropical forested regions may lead to significant carbon dioxide and methane emission. Currently, no predictive models exist to estimate the greenhouse gas emissions before the reservoir is built. This paper presents two different approaches to investigate the future carbon balance of eighteen new reservoirs in the Amazon. The first approach is based on a degradation model of flooded carbon stock, while the second approach is based on flux data measured in Amazonian rivers and reservoirs. The models rely on a Monte Carlo simulation framework to represent the balance of the greenhouse gases into the atmosphere that results when land and river are converted into a reservoir. Further, we investigate the role of the residence time/stratification in the carbon emissions estimate. Our results imply that two factors contribute to reducing overall emissions from these reservoirs: high energy densities reservoirs, i.e., the ratio between the installed capacity and flooded area, and vegetation clearing. While the models’ uncertainties are high, we show that a robust treatment of uncertainty can effectively indicate whether a reservoir in the Amazon will result in larger greenhouse gas emissions when compared to other electricity sources.
Renewable energy systems reduce the greenhouse gas (GHG) emissions associated with energy generation. However, we live in a world with depleting reserves of natural resources, and significant quantities of raw materials are often embodied within renewable energy infrastructure. This paper examines the potential for ecodesign measures to improve the GHG and resource balance of five small-scale hydropower case studies (50-650 kW). A life cycle assessment (LCA) approach compares two specific environmental impact categories: global warming potential (GWP) and abiotic resource depletion potential (ARDP). A number of ecodesign measures were examined for each installation: powerhouse structure, concrete selection, roofing materials, excavation work and transportation. Ecodesign led to cumulative savings of between 2.1% and 10.4% for GWP, and ARDP savings of between 0.1% and 2.6%, for the hydropower installations. Small savings were made with each ecodesign measure applied in all case studies. Furthermore, applying a 1% materiality threshold as outlined by LCA standards was shown to under-estimate the total project burdens, and to neglect opportunities for burden savings through ecodesign. Ecodesign can promote the use of locally sourced materials and some measures can lead to time savings during the construction process. The findings demonstrate the potential for ecodesign to modestly improve the carbon and resource efficiency of hydropower projects.
Purpose
This paper explores the potential to simplify the life cycle assessment (LCA) process for a hydropower (HP) system, without significantly compromising the accurate representation of environmental burdens. Taking five HP case studies, two questions were addressed: (i) Does a 1 % materiality threshold capture at least 95 % of the key environmental burdens from cradle-to-operation? (ii) What is the effect of applying a materiality threshold based on the global warming potential (GWP) indicator for capturing other environmental impacts?
Methods
A comprehensively detailed inventory database was developed for five modern small- and micro-HP case studies (50–650 kW), representing run-of-river and water supply infrastructure installations from the UK and Ireland. Following ISO 14040 standards, the environmental burdens were quantified for these HP projects. Normalised results were compared against a natural gas combined cycle power plant (NG-CCP) reference system for marginal grid electricity generation.
Results and discussion
The adoption of a 1 % materiality threshold as advised by some guidelines led to cumulative omissions of up to 7.5 % of the total project burdens for some HP installations, contravening the 95 % inclusion target. The number of project components differed between the two types of HP projects and target exceedances were more likely for projects with more components. Using a lower materiality threshold of 0.2 or 0.5 % ensured that the 95 % target was achieved for all HP projects. Considering GWP as an indicator burden for assessing materiality thresholds led to significant omissions for other environmental burdens, e.g. abiotic resource depletion potential (ARDP). Omitting a number of small components with low-carbon contributions (e.g. copper wiring) led to a 19 % underestimation for contributors to the resource-based (GWP) impact categories.
Conclusions
A simplified methodology may not capture all environmental burdens for a hydropower system or fossil fuel-based power plant. Basing a 1 % materiality threshold on contribution to a single burden, such as GWP, can lead to omissions of significant contributory components for that burden, and larger omissions for other burdens. ARDP is a particularly important impact category for renewable energy systems and appears to be particularly sensitive to materiality thresholds. It is important that practitioners take care with materiality thresholds when evaluating the environmental performance of all types of renewable energy systems through LCA. Including a materiality threshold to draw practicable system boundaries is necessary; however, reducing the threshold contribution to 0.5 % would be more likely to ensure that at least 95 % of environmental burdens are accounted for.
When carbon credit is granted for projects that would occur irrespective of any subsidy based on mitigation of global warming, the projects generate "hot air," or credit without a real climate benefit. This is the case for tropical hydroelectric dams, which are now a major destination for funds under the Kyoto Protocol's Clean Development Mechanism (CDM). The countries that purchase the credit generated by dams can emit more greenhouse gases without their being offset by genuine mitigation. The limited funds available for mitigation are also wasted on subsidizing dams that would be built anyway. Tropical dams also emit substantially more greenhouse gases than are recognized in CDM accounting procedures. Tropical hydroelectric emissions are also undercounted in national inventories of greenhouse gases under the United Nations Framework Convention on Climate Change, giving them a role in undermining the effectiveness of as-yet undecided emission limits. Brazil's Santo Antnio Dam, now under construction on the Madeira River, provides a concrete example indicating the need for reform of CDM regulations by eliminating credit for hydroelectric dams.
Recognizing the issues of land shortage and growing concerns for protecting natural lands, installers and project developers, with the help of scientists and engineers, continuously try to locate alternative spots for photovoltaic (PV) system installations. In the present paper a novel approach is suggested and analysed: installing solar PV systems on the downstream face of existing dams. This approach provides advantages that could favour even large-scale systems with a capacity of several MWp. First, produced energy could cover water reservoirs' needs supporting energy-intensive processes as water pumping and treatment in a sustainable manner. Moreover, energy provision to inhabited areas near the dams and the subsequent creation of independent mini grids could mitigate energy poverty. In the case of hydroelectric dams, the so-created hybrid system (PV-hydro) could become notably efficient, because the intermittent solar energy would be counterbalanced by the flexibility of hydropower. Finally, we found a notable number of existing water reservoirs in Africa that are either under-utilized or non-powered. That unexploited energy potential can also be amplified by PV-system installation. The analysis included data collection from various sources. Datasets have been cross-checked and extended in the newly created GIS-based model, enabling the selection of the most suitable sites in South Africa, taken as case studies. Following their identification, the selected dams have been analysed using the PVGIS tool in order to estimate the annual energy production. The results have been very encouraging, indicating that PV systems on the face of dams are an advantageous option for renewable energy production.
The two major pathways for energy utilization from biomass are conversion to a liquid fuel (i.e., biofuels) or conversion to electricity (i.e., biopower). In the United States (US), biomass policy has focused on biofuels. However, this paper will investigate three options for biopower: low co-firing (co-firing scenarios refer to combusting a given percentage of biomass with coal) (5%–10% biomass), medium co-firing (15%–20% biomass), and dedicated biomass firing (100% biomass). We analyze the economic and greenhouse gas (GHG) emissions impact of each of these options, with and without CO[subscript 2] capture and storage (CCS). Our analysis shows that in the absence of land use change emissions, all biomass co-combustion scenarios result in a decrease in GHG emissions over coal generation alone. The two biggest barriers to biopower are concerns about carbon neutrality of biomass fuels and the high cost compared to today’s electricity prices. This paper recommends two policy actions. First, the need to define sustainability criteria and initiate a certification process so that biomass providers have a fixed set of guidelines to determine whether their feedstocks qualify as renewable energy sources. Second, the need for a consistent, predictable policy that provides the economic incentives to make biopower economically attractive.
Abstract In this paper, the environmental performance of electricity storage technologies for grid applications is assessed. Using a life cycle assessment methodology we analyze the impacts of the construction, disposal/end of life, and usage of each of the systems. Pumped hydro and compressed air storage are studied as mechanical storage, and advanced lead acid, sodium sulfur, lithium-ion and nickel–sodium-chloride batteries are addressed as electrochemical storage systems. Hydrogen production from electrolysis and subsequent usage in a proton exchange membrane fuel cell are also analyzed. The selected electricity storage systems mimic real world installations in terms of capacity, power rating, life time, technology and application. The functional unit is one kW h of energy delivered back to the grid, from the storage system. The environmental impacts assessed are climate change, human toxicity, particulate matter formation, and fossil resource depletion. Different electricity mixes are used in order to exemplify scenarios where the selected technologies meet specific applications. Results indicate that the performance of the storage systems is tied to the electricity feedstocks used during use stage. Renewable energy sources have lower impacts throughout the use stage of the storage technologies. Using the Belgium electricity mix of 2011 as benchmark, the sodium sulfur battery is shown to be the best performer for all the impacts analyzed. Pumped hydro storage follows in second place. Regarding infrastructure and end of life, results indicate that battery systems have higher impacts than mechanical ones because of lower number of cycles and life time energy.
Purpose
Small hydropower (SHP) in China has experienced soring development in the past two decades and has been assigned ambitious development goals recently, while its environmental performance remains unclear. This study is intended to provide a comprehensive assessment of the environmental impacts of SHP plants in China, to compare the results with its counterparts in other countries, and to identify the key factors in the mitigation of negative consequences.
Methods
A life cycle assessment of a SHP plant in Guizhou Province of China was conducted in a cradle-to-grave manner following the ISO 14040 guidelines. The functional unit is defined as 1 MWh of net electricity produced by the plant. The CML 2001 method was applied to characterize the environmental impacts. The environmental impact categories considered in this study included global warming (GWP), abiotic depletion (ADP), acidification (AP), freshwater aquatic ecotoxicity (FAETP), human toxicity (HTP), and photochemical ozone creation (POCP). Further contribution analyses and sensitivity analysis was performed to identify the key contributors to each impact category during the life cycle of the plant.
Results and discussion
For the case plant, the considered impacts are caused primarily by the construction stage. As for the materials and energy inputs, cement, steel, and electricity are the three dominating ones for the overall environmental impacts. Compared with SHP plants in other countries, the plant performs similar to the MW scale plants in Thailand and Japan but worse than the plant in Switzerland. Further comparison of life cycle inventories (LCIs) revealed that the quality of hydro-energy resources and acquisition of indigenous equipment technology is essential to their environmental performance. The results of the sensitivity analysis suggested that the amount of construction materials and energy consumption as well as the plant output influences its environmental performance significantly.
Conclusions and recommendations
The construction stage of the SHP plant is the most important source of environmental impacts. To minimize the impacts of this stage, optimization of the structural design and application of new construction materials and good construction practices is recommended. In addition, determining suitable installed capacity and advancing equipment technologies to ensure the optimal output is also crucial to improve the environmental performance of SHP plants in China, regarding the current serious problem of unstable operation.
Forty years ago, the demolition of large dams was mostly fiction, notably plotted in Edward Abbey's novel The Monkey Wrench Gang. Its 1975 publication roughly coincided with the end of large-dam construction in the United States. Since then, dams have been taken down in increasing numbers as they have filled with sediment, become unsafe or inefficient, or otherwise outlived their usefulness ( 1 ) (see the figure, panel A). Last year's removals of the 64-m-high Glines Canyon Dam and the 32-m-high Elwha Dam in northwestern Washington State were among the largest yet, releasing over 10 million cubic meters of stored sediment. Published studies conducted in conjunction with about 100 U.S. dam removals and at least 26 removals outside the United States are now providing detailed insights into how rivers respond ( 2 , 3 ).
Globally, the hydropower (HP) sector has significant potential to increase its capacity by 2050. This study quantifies the energy and resource demands of small-scale HP projects and presents methods to reduce associated environmental impacts based on potential growth in the sector. The environmental burdens of three (50-650 kW) run-of-river HP projects were calculated using life cycle assessment (LCA). The global warming potential (GWP) for the projects to generate electricity ranged from 5.5 to 8.9 g CO2 eq./kWh, compared with 403 g CO2 eq./kWh for UK marginal grid electricity. A sensitivity analysis accounted for alternative manufacturing processes, transportation, ecodesign considerations and extended project lifespan. These findings were extrapolated for technically viable HP sites in Europe, with the potential to generate 7.35 TWh and offset over 2.96 Mt of CO2 from grid electricity per annum. Incorporation of ecodesign could provide resource savings for these HP projects: avoiding 800,000 tonnes of concrete, 10,000 tonnes of steel and 65 million vehicle miles. Small additional material and energy contributions can double a HP system lifespan, providing 39 to 47% reductions for all environmental impact categories. In a world of finite resources, this paper highlights the importance of HP as a resource-efficient, renewable energy system.
Tropical hydroelectric emissions are undercounted in national inventories of greenhouse gases under the United Nations Framework Convention on Climate Change (UNFCCC), giving them a role in undermining the effectiveness of as-yet undecided emission limits. These emissions are also largely left out of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Renewable Energy Sources and Climate Change Mitigation, and have been excluded from a revision of the IPCC guidelines on wetlands. The role of hydroelectric dams in emissions inventories and in mitigation has been systematically ignored.
Micro-hydropower (MHP) presents new opportunities to generate electricity from within existing water infrastructure. This paper quantifies the environmental impacts of electricity generation from three MHP case studies (15-140 kW) in the water industry, using a life cycle assessment approach. Environmental burdens were calculated per kWh electricity generated over nominal turbine operational lifespans. Compared with marginal UK grid electricity generation in combined cycle turbine natural gas power plants, normalised life cycle environmental burdens for MHP electricity were reduced by: >99% for global warming potential (GWP); >98% for fossil resource depletion potential; >93% for acidification potential; 50-62% for human toxicity potential. However, the burden for abiotic resource depletion potential was 251-353% higher for MHP than marginal grid-electricity. Different quantities of raw materials and installation practices led to a range in GWP burdens from 2.14 to 4.36 g CO2 eq./kWh. One case benefitted from very low site preparation requirements while others required substantial excavation works and material quantities. Carbon payback times ranged from 0.16 to 0.31 years, extending to 0.19-0.40 years for worst-case scenarios examined as part of a sensitivity analysis. The carbon payback period for future MHP installations was estimated to increase by 1% annually, as the carbon intensity of marginal grid electricity is predicted to decline. This study demonstrates that MHP installations in the water industry have a strongly positive environmental balance.
Massive concrete dam projects will be constructed in the next 10years to respond to the increasing demand for clean energy and water resources in developing countries. Because of their ample use of cement, these projects have a significant environmental impact, including the production of carbon dioxide (CO2) emissions. Rock-filled concrete (RFC) is an innovative dam construction method that promises better environmental performance than conventional concrete (CC) in the material production stage by saving a large amount of cement. However, the environmental loads throughout the entire life cycle of a dam must be quantified. Thus, this paper aims to evaluate the environmental loads in the lifetime of a dam and reveal the environmental impact of RFC relative to CC over the entire life cycle of a concrete dam. Through reviewing the limitations of the existing life-cycle assessment (LCA) models, a hybrid LCA model is applied to achieve this goal. The results from a case study of a concrete dam project in China are presented to demonstrate the environmental benefit of RFC throughout the lifetime of a dam. The results indicate that RFC reduces greenhouse gas emissions by approximately 64% and energy consumption by approximately 55% compared with CC. With regard to each life cycle stage, RFC decreased the CO2 emissions by 72% in material production, 25% in transportation, 51% in construction, and 15.6% in operation and maintenance. The conclusion is that RFC is more environmentally responsible throughout the life cycle of a dam's, and that the environmental benefit of RFC may help to encourage decision makers to select the appropriate methods in the planning phase. (C) 2013 American Society of Civil Engineers.
Human population growth, economic development, climate change, and the need to close the electricity access gap have stimulated the search for new sources of renewable energy. In response to this need, major new initiatives in hydropower development are now under way. At least 3,700 major dams, each with a capacity of more than 1 MW, are either planned or under construction, primarily in countries with emerging economies. These dams are predicted to increase the present global hydroelectricity capacity by 73 % to about 1,700 GW. Even such a dramatic expansion in hydropower capacity will be insufficient to compensate for the increasing electricity demand. Furthermore, it will only partially close the electricity gap, may not substantially reduce greenhouse gas emission (carbon dioxide and methane), and may not erase interdependencies and social conflicts. At the same time, it is certain to reduce the number of our planet’s remaining free-flowing large rivers by about 21 %. Clearly, there is an urgent need to evaluate and to mitigate the social, economic, and ecological ramifications of the current boom in global dam construction.
Improved methods are needed to evaluate barriers and traps for control and assessment of invasive sea lamprey (Petromyzon marinus) in the Great Lakes. A Bayesian state-space model provided reach-specific probabilities of movement, including trap capture and dam passage, for 148 acoustic tagged invasive sea lamprey in the lower Cheboygan River, Michigan, a tributary to Lake Huron. Reach-specific movement probabilities were combined to obtain estimates of spatial distribution and abundance needed to evaluate a barrier and trap complex for sea lamprey control and assessment. Of an estimated 21 828 – 29 300 adult sea lampreys in the river, 0%–2%, or 0–514 untagged lampreys, could have passed upstream of the dam, and 46%–61% were caught in the trap. Although no tagged lampreys passed above the dam (0/148), our sample size was not sufficient to consider the lock and dam a complete barrier to sea lamprey. Results also showed that existing traps are in good locations because 83%–96% of the population was vulnerable to existing traps. However, only 52%–69% of lampreys vulnerable to traps were caught, suggesting that traps can be improved. The approach used in this study was a novel use of Bayesian state-space models that may have broader applications, including evaluation of barriers for other invasive species (e.g., Asian carp (Hypophthalmichthys spp.)) and fish passage structures for other diadromous fishes.
The Xiaowan super-high arch dam has faced challenging construction problems. Here, we provide a scientifically-based reference for applying geomechanical model testing to support the nonlinear design of super-high arch dams. We applied experimental similarity theory and techniques. Based on four 3D geomechanical model tests, the dam stress characteristics, deformation distribution, and the safety factors of the dam foundation were identified and compared. We also analyzed cracking characteristics of the up- and downstream dam surfaces and induced joints in the dam heel, the rock mass failure process of the dam-foundation interface, and the abutments. We propose foundation reinforcement measures for weak rock masses, alteration zones, and other faults in the abutments based on the 3D and plane tests each at a different elevation. The results show that all dam deformations remained normal with no yielding or tensile cracking under a normal water load. The reinforced rock mass increased the crack initial safety in the dam heel and toe by ~20 %. The minimum crack initial safety factor (K
1) of the dam heel was 1.4. The induced joint in the dam heel contributed to a reduction in tensile stress at the upstream dam heel, improving K
1. Compared with similar projects following reinforcement measures, the abutment stiffness and overall stability of the Xiaowan arch dam satisfy operational requirements. Four years of monitoring operations show that key areas near the dam remained normal and the dam foundation is functioning well. Our results may also be applicable to the design and construction of similar projects worldwide.
The Working Group III Special Report on Renewable Energy Sources and Climate Change
Mitigation (SRREN) presents an assessment of the literature on the scientific, technological,
environmental, economic and social aspects of the contribution of six renewable energy (RE)
sources to the mitigation of climate change. It is intended to provide policy relevant information to
governments, intergovernmental processes and other interested parties. This Summary for
Policymakers provides an overview of the SRREN, summarizing the essential findings.
Artificial reservoirs likely accumulate more carbon than natural lakes due to their unusually high sedimentation rates. Nevertheless, the actual magnitude of carbon accumulating in reservoirs is poorly known due to a lack of whole-system studies of carbon burial. We determined the organic carbon (OC) burial rate and the total OC stock in the sediments of a tropical hydroelectric reservoir by combining a seismic survey with sediment core sampling. Our data suggest that no sediment accumulation occurs along the margins of the reservoir and that irregular bottom morphology leads to irregular sediment deposition. Such heterogeneous sedimentation resulted in high spatial variation in OC burial—from 0 to 209 g C m−2 y−1. Based on a regression between sediment accumulation and OC burial rates (R
2 = 0.94), and on the mean reservoir sediment accumulation rate (0.51 cm y−1, from the seismic survey), the whole-reservoir OC burial rate was estimated at 42.2 g C m−2 y−1. This rate was equivalent to 70% of the reported carbon emissions from the reservoir surface to the atmosphere and corresponded to a total sediment OC accumulation of 0.62 Tg C since the reservoir was created. The approach we propose here allows an inexpensive and integrative assessment of OC burial in reservoirs by taking into account the high degree of spatial variability and based on a single assessment. Because burial can be assessed shortly after the survey, the approach combining a seismic survey and coring could, if applied on a larger scale, contribute to a more complete estimate of carbon stocks in freshwater systems in a relatively short period of time.
This study proposes a successive improved dynamic programming (SIDP)
algorithm for hydropower reservoir operation based on an analysis of concavity,
complementarity, and monotonicity of hydropower problems. For single-period
hydropower generation, storage and release have diminishing marginal contributions to
hydropower generation (i.e., concavity), and there is also a complementary effect between
storage and release (i.e., release becomes more productive with increased storage). For
multiple-period hydropower generation, the complementarity is shown to influence the
concavity of objective function and the monotonicity of operation decisions, and is the major
cause of complexity in hydropower operation. With the mathematical derivations, this study proposes a concave approximation to the hydropower generation function and a SIDP
algorithm for hydropower reservoir operation. The efficiency of SIDP is de