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The European Union launched a set of policies as part of its 2020 climate and energy package aimed at meeting its 20/20/20 headline targets for smart, sustainable and inclusive growth. This paper evaluates how successful new-to-the-market climate change mitigation technologies (CCMT) are in helping EU member states (MS) reach these goals and, furthermore, whether there are differences between sectors subject to EU-wide polices. To do so, we relate CCMT patent counts to two specific headline targets: (1) achieving 20% of gross final energy consumption from renewables, and (2) achieving a 20% increase in energy efficiency. Our results provide the first ex-post evaluation of the effectiveness of these technologies for combating climate change. Moreover, our sectoral impact assessment points to significant differences in the way in which these technologies contribute to policy goals across the sectors. [ABSTRACT FROM AUTHOR]

Water is a prime element both for sustaining life on Earth and for complex human activity. In 2015 in Romania the average electricity production was of 7343 MW h and the average consumption was of 6590 MW h. The average hydropower generated was of 1894 MW h, which is equal to 26% of the total production. In this paper, we aim at reviewing the hydropower system in Romania from its beginnings, in 1884, to its present development. The first hydropower plant in Romania was in Sinaia and had an installed capacity of 4×250 kW. Now, Romania has more than 200 HPPs, with a total installed capacity of 6.443 MW. In Romania, hydropower is the first main source of energy among RES, followed by wind energy. Between 1950 and 1990 were built 115 hydropower stations. This period is characterized by the construction of most of the hydroelectric power plants in Romania, including the largest. The development of the hydro potential has begun in Bistrița basin. After 1990, in the transition period, after the fall of communism, the number of installed hydropower plants decreased, by 2010 totaling an installed capacity of only 838 MW, which means less than 14% of what was done before 1990. About 54% of Romania's hydropower potential is now arranged, and there are plans to reach 63.5% by 2025. The largest artificial lake of Romania is Lake Iron Gates I (Porțile de Fier I), constructed between 1964 and 1972 behind a 60 m’ dam. Iron Gate I rank position 52 out of 66, in the list of largest hydroelectric power stations in the world. Iron Gates I system is one of the largest hydro constructions in Europe and the largest on the Danube. [ABSTRACT FROM AUTHOR]

Renewable energy is an important piece of the puzzle in meeting growing energy demands and mitigating climate change, but the potentially adverse effects of such technologies are often overlooked. Given that climate and ecology are inextricably linked, assessing the effects of energy technologies requires one to consider their full suite of global environmental concerns. We review here the ecological impacts of three major types of renewable energy – hydro, solar, and wind energy – and highlight some strategies for mitigating their negative effects. All three types can have significant environmental consequences in certain contexts. Wind power has the fewest and most easily mitigated impacts; solar energy is comparably benign if designed and managed carefully. Hydropower clearly has the greatest risks, particularly in certain ecological and geographical settings. More research is needed to assess the environmental impacts of these ‘green’ energy technologies, given that all are rapidly expanding globally. [ABSTRACT FROM AUTHOR]

Reducing fossil fuels use while promoting the adoption of clean and renewable energy sources is crucial for mitigating climate change and attaining the sustainable development goals. This study investigates the driving forces of the share of non-hydroelectricity sources in total electricity generation. Using panel data of forty-six developed and developing countries over 1980–2011 and employing panel cointegration estimation techniques, we examine the key factors that influence the share of non-hydro renewable energy sources in the short and long run. The results of the study show that the driving factors have different impacts on the size and share of non-hydro renewable energy; and these impacts are mostly in the long run. Oil price increase and financial development has a significant positive effect on the amount and share of non-hydro renewable electricity generation. The impact of trade openness is ambiguous. Economic development enhances the size of non-hydro renewables but undermines its share in total electricity. Foreign direct investments, ratification of the Kyoto protocol, gross fixed capital formation and resource rent have no significant impact on non-hydro renewable electricity generation. Based on the results, appropriate policy recommendations are proffered. [ABSTRACT FROM AUTHOR]

The residential sector is the third largest energy-consuming sector in Mexico and an important contributor to energy related carbon dioxide emissions after transport and industry. The objective of this study is to evaluate the implementation and social acceptance of energy efficient technologies and renewable technologies in the so called sustainable social housing program in Mexico City, and compare the real reduction of CO 2 emissions to the theoretical potential. To do so, two estimations are developed: 1) the technical and economic CO 2 emission reduction potential of energy efficiency and renewable energy technologies in new social housing in Mexico City, and 2) the real avoided emissions based on social acceptance of technologies obtained by housing surveys and physical revision of performance status of implemented technologies. We found that due to lack of information and training to households an important part of dwellers ended up rejecting mitigation technologies developing what we called the socially neglected effect of mitigation technologies. These results were used to estimate three scenarios for year 2025: baseline, mitigation and neglected effect. Due to the neglected effect a reduction of 25% with respect to the baseline scenario was obtained instead of 45% of emission reduction in year 2025. In the case of efficient lighting and refrigerators, where Minimum Energy Efficient Standards are in place the socially neglected effect disappears once the replacement of old to new technologies takes place. This result shows that minimum energy performance standards are the main mitigation policy to eliminate socially neglected effect in the long run. Obligatory standards for installation of solar water heaters can be developed as well, although it is important to develop additional follow-up policies for adequate installation of these technologies. [ABSTRACT FROM AUTHOR]

Energy shortages and CO 2 emissions reductions are critical contemporary challenges for Thailand. A consumption-based analysis provides crucial information that enables policymakers to more comprehensively understand the hidden contributors of energy demand and CO 2 in the economy. The other manufacturing, construction and food and beverage sectors were amongst the five largest contributors to energy use and emissions in both 2000 and 2010, based on a consumption perspective. However, these sectors have been neglected by energy conservation and climate change mitigation policies in Thailand because they were the least energy-intensive sectors per government energy reports from 1995 to 2015. The CO 2 emissions burden from exports was almost 50% of Thailand's national CO 2 inventory in 2000 and 2010. The embodied CO 2 emissions results revealed that Thailand could reduce its emissions inventory by 12% and 13% if embodied imports replaced exports in 2000 and 2010, respectively. Furthermore, the leading gross domestic product-generating industries in Thailand are seriously vulnerable to natural gas and crude oil shortages despite some sectors using them in small proportions in their production processes. Energy and emissions policies should better reflect consumption characteristics to increase the potential of energy-saving interventions and CO 2 mitigation. [ABSTRACT FROM AUTHOR]

Reducing local and global emissions is one of the drivers behind the promotion of renewable energy technologies (RETs). Some RET projects (e.g. solar, marine power, and some biomass and wind) usually require supplemental income from carbon credits in order to make them economically viable. This paper presents the mathematical development of nodal marginal CO 2 emission metrics for hydrothermal systems. These metrics are obtained from optimal power flow and hydrothermal dispatch models considering hydro uncertainty. The proposed model allows a more accurate assessment of the emission reduction effect of RET projects and the provision of efficient carbon signals to the system. Modeling of hydro reservoirs and intertemporal constraints also allows incorporating the emission mitigation potential of water storage. The concepts of marginal CO 2 emissions for hydrothermal systems are first exemplified using a small test system, and then simulations on a real hydrothermal system illustrate how these metrics can inform investment and operational decisions. Theoretical and simulation results show that transmission and hydro storage constraints neglect may provide wrong signals for RET investors, missing the incentives to install in areas where the potential for emissions reduction is higher (where renewable energy displaces a larger amount of coal or diesel). Policy makers can use the proposed model to assess the cost-effectiveness of emission reduction policies. [ABSTRACT FROM AUTHOR]

With the growing literature related to climate change mitigation measures and policy interventions, a systematic review of the application of computable general equilibrium (CGE) model is inevitable. Therefore, this article aims to characterise the relevant studies, define a comparative framework to identify the current state-of-the-art and the gaps in applied general equilibrium models. Firstly, the systematic review found a total of 301 research articles from Scopus and Web of Science databases and finally analysed 154 articles based on inclusion and exclusion criteria from 67 refereed journals. The review analysis found that application of CGE model is very vital in addressing climate change mitigation issues at the national, regional and global levels. However, China attracted the most substantial research interests followed by the USA, India and Australia, among others, which are in line with their share of greenhouse gas emissions in the world. Most of the research themes focus on the carbon tax, emission reduction target, emission trading, renewable energy, energy efficiency, and carbon capture and storage as primary drivers of low carbon economy. Nevertheless, there is a trend of employing more static CGE model compared to the dynamic CGE, although application of the latter has a limitation of providing right inputs to the macroeconomic policy. Finally, research directions and gaps envision other complementary models such as dynamic stochastic general equilibrium (DSGE) and agent-based model (ABM) for proper policy interventions. [ABSTRACT FROM AUTHOR]

The importance of three-dimensional (3D) graphene-based macrostructures (GBMs) is increasingly being recognized over the last five years for diverse clean energy-related applications and global climate change mitigation. With exceptionally large specific surface area and highly interconnected pore networks, 3D graphene scaffolds manifest extraordinary nanoscale effects that result in materials with unusual electrical, mechanical, and electrochemical properties. A global multidisciplinary research effort focusing on the development of innovative 3D GBMs with hierarchical microstructures and novel functionalities has therefore recently emerged. This review provides a comprehensive account of the key design principles in preparing high performance 3D GBMs and discusses their application as advanced electrode materials in a range of energy storage and conversion devices, including lithium-ion batteries, supercapacitors, fuel cells, dye-sensitized solar cells, and photoelectrochemical water splitting units. In addition, the review provides insights into newer and emerging sustainable energy applications of 3D GBMs, such as adsorbents for high-density hydrogen storage and selective capture of CO 2 from flue gases, as well as catalysts for photoconversion of CO 2 into clean fuels and value-added chemicals. The current state of knowledge is highlighted for each of the applications, followed by a discussion of our own perspectives on each topic. Finally, the future outlook on practical deployment of 3D GBMs is suggested as concluding remarks. [ABSTRACT FROM AUTHOR]

Synthetic fuels are increasingly discussed when considering solutions to climate change mitigation. However, it is rather unclear what synthetic fuels are and their scope in replacing regular fossil fuels. Here, we propose a definition for synthetic fuels and discuss their classification based on production methods. These technologies are considered based on their scalability and extent of sustainability, along with the advantages they provide for overcoming renewable energy challenges. [Display omitted] • Synthetic fuels offer novel solutions to energy and environmental challenges. • Synthetic fuels can be grouped based on their synthesis strategies. • Intermediate molecules can play an important role in achieving new syntheses. [ABSTRACT FROM AUTHOR]

Anthropogenic activities and advancements in industries boost global energy demand and increase fossil fuel consumption, causing several global environmental problems, such as climate change. As a climate change mitigation strategy, the use of renewable energy technologies has gained unprecedented interest. In particular, the thermochemical processing of lignocellulosic biomass integrated with other renewable energy technologies has emerged rapidly. It is critical to select appropriate integrated renewable energy system configurations for sustainable and feasible power generation towards higher environmental benefits. Understanding the possible configurations of thermochemical lignocellulosic biomass processing technologies (gasification, pyrolysis, hydrothermal gasification, or hydrothermal carbonization) integrated with renewable energy technologies (solar thermal, fuel cell, fusion power, or energy storage) is crucial for the further development and propagation of the integrated renewable energy system. Hence, we provide a systematic review of the thermochemical conversion of lignocellulosic biomass integrated with the other renewable energy technologies. Finally, the challenges associated with the implementation of these systems and suggestions for future research on the systems are discussed. • Renewable energy technology is integrated with thermochemical biomass conversion process. • The integrated bioenergy systems help overcome limitations of single-source energy systems. • Challenges and prospects for the integrated systems are highlighted. [ABSTRACT FROM AUTHOR]

[Display omitted] • We propose criteria for siting Solar-Wind Hybrid Renewable Energy Systems. • Integration of fuzzy logic and the Best-Worst Method in GIS is consistent and efficient. • Chittagong is the most suitable area for Solar-Wind Hybrid Renewable Energy Systems. • Current land-use policy is a barrier to meeting renewable energy and climate targets. • GIS-based techniques can facilitate integrated geospatial decision-making. Solar-Wind Hybrid Renewable Energy Systems (SWHRESs) provide more reliable and efficient power than single systems and are, therefore, regarded as a promising tool for achieving SDG 7. However, the performance of SWHRESs in large-scale implementations is highly subject to the site selection method, which is subsequently crucial to achieving the goals of the transition from fossil fuels and climate change mitigation. To address this issue, this paper, based on a case study in Bangladesh, proposes a GIS-based BWM-Fuzzy Logic Method to select optimal sites for SWHRESs. The results show that SWHRESs are preferable to wind and solar systems alone. Totals of 11% and 25% of the area were suitable and moderately suitable, respectively, for SWHRESs, and the most suitable area for installation was Chittagong. The most influential criteria are solar irradiation, elevation, distance to rivers and waterbodies. The results of three sets of sensitivity analysis have demonstrated the robustness of the proposed method, and the comparative study has further shown that the proposed method performs better than methods proposed in previous studies. Hence, this study has provided a powerful tool for supporting decision-making regarding SWHRESs, thus offering a useful tool for achieving SDG 7. [ABSTRACT FROM AUTHOR]

This study conducted a comparative assessment and a meta-analysis of 48 greenhouse gas (GHG) emissions reduction scenarios based on bottom-up energy system analyses for 2030 reported in seven studies published between 2011 and 2015 to obtain insights into the ambition level of Japan's official mitigation target for 2030. First, the scenarios were categorised into four mitigation effort levels and assessed the GHG emissions range (excluding land use, land use change and forestry: LULUCF) as well as key underlying energy-related indicators for each effort level category. Second, a multiple regression equation was derived and applied to project GHG emissions with selected energy-related explanatory variables. Using the derived regression equation, we calculated the levels of low-carbon energy supply and end-use energy savings required to achieve different levels of GHG mitigation. In the first analysis, GHG emissions levels ranged between 16% and 39% below 1990 levels for scenarios that are categorised to have the highest level of mitigation efforts including those consistent with the 2 °C target, with the nuclear power share ranging at 0–29%. The second analysis indicated that regardless of the future nuclear share, GHG emissions reductions of more than 25% from 1990 levels may be considered a minimum effort required in the global efforts towards the 2 °C target. In this view, Japan's official 2030 target (15% below 1990 levels excluding LULUCF) is suggested to be insufficient, especially in light of the UNFCCC Paris Agreement. Strengthened pre-2020 targets and efforts to reduce energy end-use are essential to achieve such mitigation targets. [ABSTRACT FROM AUTHOR]

Fossil fuel subsidies are a key barrier for economic development and climate change mitigation. While the plunge in international fuel prices has increased the political will to introduce fossil fuel subsidy reforms, recently introduced reforms may risk backsliding when fuel prices rebound − particularly if they fail to address the underlying mechanisms that create demand for low fossil fuel prices. Extant literature has mostly focused on the consequences of fossil fuel subsidies, including their economic or environmental impact, and the social contract that make their reform difficult. In this paper, we complement the extant literature with a socio-technical perspective of fossil fuel subsidies to explore the systemic mechanisms that often keep subsidies in place and how these mechanisms can be weakened. Specifically, in case studies of the electricity sectors in South Africa and Tunisia, we trace the socio-technical foundations of their fossil fuel subsidy regimes and the potential of renewable energy policy in disrupting this regime We discuss the relevance of our results for national policymakers wishing to implement and international actors wishing to support fossil fuel subsidy reform. In particular, we highlight that the socio-technical perspective of fossil fuel subsidies offers new intervention points for subsidy reform and that policy designs and assistance should strengthen technologies and actors that are most likely to destabilize the fossil fuel subsidy regime. [ABSTRACT FROM AUTHOR]

• Feasibility of net zero-energy (nZE) for residential and commercial building stock. • Accommodation of nZE conditions by current power distribution network. • Proposed framework integrated synthetic population and activities. • Case study on dense urban area in noncold climate. • nZE transformation pathways explored as different from those for cold climate. The transformation to net zero-energy (nZE) building stocks involves harvesting of renewable energy, enhancement of building energy efficiency, incorporation of various supply-side options, and advanced energy management. Although several studies have evaluated the feasibility of nZE for residential areas in cold regions, only a few studies have been conducted on dense urban regions in noncold climate. Additionally, the accommodation of such building stock transformation by the current power distribution network has not been clarified to date. Thus, this study proposes a novel framework integrating synthetic population, activity, building stock, and power distribution network to explore transformation pathways. This was further demonstrated by a case study on a densely populated region covering four cities in Tokyo, Japan. The results signified that complete dissemination of popular energy efficiency measures can reduce the energy demand by 40%. With the reduction in energy demand, nearly nZE condition can be realized only if the building roof area is completely covered by photovoltaics. In particular, one half of the generation would be utilized locally, whereas the remaining would be exported. Moreover, the power distribution network can accommodate the transformation with a slight increase in power distribution loss up to 1% and a modest reinforcement requirement owing to line overloading. Conclusively, this study revealed that the transformation and reinforcement requirement are significantly distinct from those required in cold regions. [ABSTRACT FROM AUTHOR]

• Material, substance, energy flows of the agricultural biogas system are quantified. • Today the system provides about 1300 TJ/a biogas and could reach 15,500 TJ/a by 2050. • Nutrient coefficients transfers through AD to fertilizers are over 80%. • Biowaste anaerobic digestion could spare over 10 kt/a DM nutrients (38 kt/a CO 2 -eq). • Agricultural biogas cannot rely on co-substrate to use the full manure potential. Today's agro-food system is typically based on linear fluxes (e.g., mineral fertilizers importation) when a circular approach should be privileged. The production of biogas as a renewable energy source and digestate as an organic fertilizer is essential for the circular economy in agriculture. This study investigates the current utilization of biomass in agricultural anaerobic digestion plants in Switzerland in terms of mass, nutrients, and energy flows to assess its contribution to the circular economy and climate change mitigation through the substitution of mineral fertilizers and fossil fuels. We quantify the system and its benefits in detail and examine potential future developments using different scenarios. Today, agricultural anaerobic digestion provides 1300 TJ/a of biogas. Our results demonstrate that the system could be largely expanded and provide ten times more biogas by 2050 while saving significant mineral fertilizer amounts (over 10 kt/a of dry mass nutrients yielding 38 kt/a of CO 2 equivalent). [Display omitted] [ABSTRACT FROM AUTHOR]

As climate change is exacerbated and existing resources are depleted, the need for sustainable industries becomes ever so important. Aviation is not an exception. Despite the overall carbon dioxide emissions related to the aviation sector accounts for 2%–4% currently, forecasts for air travel indicate an annual growth of 3%–5% and other industries present more potential to reduce carbon emissions once they recur to an increasing use of renewable energies. This option is more difficult in aeronautics since an efficient and lighter energy storage system is required and the current state of the art in battery technology is far from the specific energy densities of fossil fuels and its production is not friendly to the environment. Thus, a herculean effort to integrate several promising mitigation strategies in an efficient way is required. In this paper, a review of the most upfront solutions towards greener aviation is presented and categorized as follows: concepts of operations, energy storage, propulsion systems, aerodynamics, structures, materials, and manufacturing processes. In the end, potential synergies between the different technologies to achieve green aviation are proposed. [ABSTRACT FROM AUTHOR]

Renewable energy resources have garnered considerable attention owing to concerns regarding climate change mitigation and sustainability. The performance of renewable energy resources varies based on weather conditions, which is an important consideration in power system planning as renewable energy penetration increases. In this study, a probabilistic approach for the potential estimation of renewable energy resources based on augmented spatial interpolation was proposed. The proposed algorithm was verified using empirical data obtained from wind farms in Jeju Island. Wind power output scenarios were modeled through ordinary kriging and Monte Carlo simulations. Moreover, the point and cause of line overload according to the seasonal wind power output and power demand were analyzed through transmission security analysis, and the frequency and scale of the curtailments were estimated. This can be used to estimate potential renewable energy resources and establish a power system operation plan. Further study includes the development of stable power system operation plans for large-scale renewable energy resource-integrated power systems. [ABSTRACT FROM AUTHOR]

Climate change mitigation has been a global effort and energy generation is one of the primary sources of GHG emissions. There is a need to transition from fossil-based energy to renewable-based energy. One of the platforms to nourish the work is Eco-Industrial Park (EIP) which it promotes resource efficiency, industrial symbiosis, and circular economy practice. There is a need to explore an optimal configuration of multiple renewable energy (RE) systems in a centralised EIP facility that generates electricity for internal consumption and exports the excess energy to the grid. This model developed a mixed-integer non-linear programming (MINLP) model that considers RE from biogas, biomass, micro-hydro, and solar sources for a centralised water hub. The energy generated is primarily used for the main processes involved in the facility as the excess energy will be supplied to the grid. A case study and two scenarios were assessed, and the results offered simultaneous technical, economic, and environmental benefits, which are in the forms of multiple RE generations, additional yearly profit, and GHG emission avoidance from fossil source. This will further strengthen the envisioned role of EIP as it is also capable of supporting the United Nations Sustainable Development Goal (UNSDG) and RE100 agenda. • A MINLP model to optimise renewable energy generation for Total Site was developed. • The model is a part of a framework to optimise energy, water, and material streams. • The model considers energy generation via solar, micro hydro, biomass, and biogas. • The proposed installation could suffice the core processes energy needs. • Additional profit is up to 39% and GHG emission reduction can be up to 70%. [ABSTRACT FROM AUTHOR]

The Spanish national energy and climate plan (PNIEC) has recently been published, leading the worldwide task of climate change mitigation towards a net zero-carbon economy by 2050. The objective scenario of the PNIEC expects to reach a renewable share in the power system of 74% by 2030. In this context, three contributions are developed: i) providing an analysis of how Spain is facing the energy transition; ii) conceptualizing the link between an hourly energy model (EnergyPLAN) and a yearly integrated assessment model (MEDEAS); and iii) proposing a transparent policy agenda for the Spanish benchmarking in line with the official report. The results clarify the decreasing role such technologies as the combined heat and power facilities, as well as the pressure of biomass in Spain. Coherency in translating common variables in the energy chain of IAMs to the energy model is effectively reflected in the tables as an output of the research. Positive conclusions are found for Spain. The commitment of 74% might well be completed and the Spanish economy could run with a 100% renewable energy system by 2050, with requirements of sixteen and six times more installed capacity of solar-PV and wind onshore, respectively, by 2050 related to 2017. [ABSTRACT FROM AUTHOR]

With the progressive implementation of Low-Carbon Policies based on Life Cycle Assessment (LCA) methodologies to assess climate change mitigation, biofuels' potential environmental advantages could finally be translated into economic revenues, especially for residue-based production chains. This implies, however, tackling environmental hotspots along the Life Cycle, such as the use of enzymes, an important input in cellulosic ethanol production. While relevant, however, aspects of enzyme manufacturing, crucial to the LCA results, are often oversimplified in databases or even undisclosed, which might render the accounting for this flow unreliable. A potential solution for this is to model enzyme production, disclosing aspects such as carbon source uptakes, energy consumption and purification steps, all of which may carry significant environmental burdens, especially for fossil-reliant procedures. Integrating these steps into the biorefinery process design as an on-site operation, however, would allow access to renewable energy and carbon sources for enzyme production, potentially reducing their burden in the final biofuel LCA profile, when compared with off-site supply. This work, then, aims to evaluate the effect of inserting on-site enzyme production within a stand-alone second-generation (2G) biorefinery, using sugarcane straw as feedstock, to produce ethanol and electricity, as opposed to off-site enzyme supply from manufacturers. The results show that adopting on-site production can reduce the overall environmental impact profile for cellulosic ethanol, in comparison to off-site supply, even though off-site data present significant variability among databases and literature. This trend persisted for varied enzyme dosages in the saccharification process and for different inventories to model off-site supply. The reference inventories for off-site supply lack transparency and details, while also displaying large discrepancies between impact indicators, indicating the need to pursue more consistent, reliable, and complete inventories for its modelling in LCA. Compared to first-generation (1G) sugarcane ethanol, 2G-ethanol (with on-site enzyme production) demonstrated a reduction in the Global Warming Potential category of around 80%. However, relevant trade-offs for 2G ethanol (with off-site enzyme supply) were observed – regarding ecotoxicity, mineral scarcity, eutrophication and even the potential GHG reduction – when different enzyme inventories are used. [Display omitted] • On-site enzyme production leads to lower environmental impact. • Enzyme dosage and off-site inventory choice do not alter this previous conclusion. • With on-site production, enzymes cease to be the major hotspot within the life cycle. • On-site production leads to a 53% GHG emissions reduction, compared to off-site. • There are trade-offs among impact categories for cellulosic ethanol production. [ABSTRACT FROM AUTHOR]

In the context of climate change mitigation and sustainable energy infrastructure development, this paper focuses on the successful implementation of microgrids supplied by renewable energies in very diverse environments. Taking into account the challenges of reaching economies of scale, this paper is targeted at identifying success factors for microgrid implementation. The success factors are derived from case study analyses of microgrids implemented in the Global South and in communities of Germany. The goal of the research is to develop a mutual understanding of common values and so support future developments. The analysis covers the categories of ownership and participation; technology and system design; and policy and financing. The results show that microgrids in the Global South and renewable-energy-based communities in Germany share a number of success factors. The results demonstrate that a high share of ownership by users and the flexibility to expand the microgrid with user needs are particularly promising features. To verify the application of the identified success factors, the latter are applied to analyze the microgrid concept of “swarm electrification”. The analysis concludes that the concept of swarm electrification is consistent with the success factors, making it a high-potential approach for renewable-energy-based electrification. [ABSTRACT FROM AUTHOR]

To mitigate climate change, substantial investments are needed in emerging renewable energy technologies. However, developers of the technologies – both capital goods suppliers and utilities – lack the capital to make the required investments, and other investors hesitate because of the high risks and low returns involved. This article analyses the challenges of financing the development and large-scale diffusion of biomass gasification and offshore wind power in Europe. Biomass gasification needs to take the step from public to private finance and find investors willing to make a sizable investment with high risk. Mobilising the amount of capital needed to bring about large-scale diffusion of offshore wind power will require innovative financial solutions. To overcome these challenges, changes are needed in both the financial sector and in firms in the energy sector. Amongst other suggestions this article points to bonds specially designed for renewable energy as one way to increase investment. [ABSTRACT FROM AUTHOR]

In order to mitigate the effects of climate change, a lot of research has been devoted to reduce carbon dioxide (CO 2 ) emissions, develop capture and storage technologies (CCS), as well as direct carbon dioxide removal (CDR) from the atmosphere. The 2014 “Summary for Policymakers” of the Intergovernmental Panel on Climate Change 5th report (working group III) preponderantly mentions CCS and CDR. Although many scientific publications cite “greenhouse gas removal“, to our knowledge none of them has yet proposed innovative solutions to effectively remove greenhouse gases other than CO 2 from the atmosphere. This article proposes a combination of disrupting techniques to transform or destroy the halogenated gases in the atmosphere, which are harmful for the ozone layer, and possess high global warming potential as well as long atmospheric lifetimes. [ABSTRACT FROM AUTHOR]

Climate change mitigation requires sustainable energy transitions, but their political dynamics are poorly understood. This article presents a general dynamic model of renewable energy policy with long time horizons, endogenous electoral competition, and techno-political path dependence. We calibrate the model with data on the economics of contemporary renewable energy technologies. In doing so, we discover transition dynamics not present in economy-energy models, which ignore politics, or in formal political economy models, which ignore long-term technological dynamics. We show that the largest effects of partisan ideology on policy occur when the competing parties disagree on the importance of energy policy. In these cases, the less ideological party appeases the more ideological one, while the more ideological party attempts to appease the electorate. The results demonstrate that political dynamics could have large effects on the development of renewable energy and carbon dioxide emissions over time, influencing the ability of countries to reach various climate mitigation trajectories. [ABSTRACT FROM AUTHOR]

Anthropogenic global climate change has large and mounting negative economic impacts. Companies and nations responsible for greenhouse gas (GHG) emissions are thus acquiring considerable potential liabilities. If litigation becomes widespread, renewable energy technologies (RETs) potentially offer emitters reduced liability for climate change. This benefit has been ignored because of the lack of knowledge of potential liabilities. To overcome this information deficit, this paper reviews recent literature on the potential for climate change litigation and methods to quantify liability for climate change. Next, the top 10 emitters in the U.S. are identified and their potential liability is quantified using standard GHG emission costs. Potential liabilities are explored in depth with a single case study company comparing the results of the fractional liability from only natural disasters within the U.S. for a single year to a sensitivity of the future costs of carbon emissions from other sources of emission-related liability. Then classes of potential climate change litigants are identified and their capacity to bring such lawsuits is evaluated. The results show that the net income available to shareholders of large companies could see a significant reduction from the emissions liability related to only natural disasters in the U.S. from a single coal-fired power plant. Finally, a rough estimate of the economic risk associated with future scenarios and existing organized international potential litigants is quantified. The results show that potential liability for climate change for the Alliance of Small Island States is over $570 trillion. It is concluded that as emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change, a high value for liability mitigation would provide additional powerful incentives for deployment of renewable energy technologies. [ABSTRACT FROM AUTHOR]

Solar photovoltaic systems are considered vital renewable energy sources for mitigating climate change and reducing dependency on fossil fuels. However, in some countries, the diffusion rate of photovoltaic systems is decreasing. A case in point is Germany, the country with the highest installed capacity of photovoltaic systems. Given the new conditions in the German market, the diffusion rate continuously declined in both 2012 and 2013. Whether the diffusion rate will again take off is not known. While the recent literature has pointed out that local solar companies have a vital driving role in diffusion, not many studies have yet discussed the business models and challenges such local companies may have. Through an extensive case study, this paper explores the business model of a local solar company in a town of 43,000 habitants in Southern Germany. The case of this company tells about an important business model challenge. Overcoming such challenges may not only let the company survive but also drive the diffusion of solar photovoltaic systems in the region. The results include implications for both industrial actors and policymakers. [ABSTRACT FROM AUTHOR]

Mixed sugars, which are often obtained from renewable biomass, can be converted into biofuels and chemicals by microbial conversion. This sustainable production process can also mitigate man-made climate change when used to petroleum-based fuel and chemical production. In contrast to single sugar fermentations, such as corn-based or sugarcane-based ethanol fermentations, mixed sugar fermentations present significant challenges for cost-effective production of the target products. In particular, inefficient and slow microbial fermentation of non-glucose sugars, such as galactose and xylose from the depolymerization of marine and terrestrial biomass has been a major obstacle. Nonetheless, simultaneous utilization of mixed sugars has recently been demonstrated through innovative metabolic engineering strategies and the discovery of transporters, and metabolic pathways which are necessary for co-fermenting glucose and non-glucose sugars. [ABSTRACT FROM AUTHOR]

Access to energy can significantly contribute to the development of the living standards of the energy poor. Also if the provision of access to energy is sustainable, i.e. via renewable energy sources, there is an added benefit of contributing to mitigation of climate change. Currently, the percentage of population with access to energy varies significantly between countries and across regions. This is due to the nature of national socio-economic situations and energy resource availability in differing settings. This article addresses issues and hindrances to energy access in regional contexts and also examines, in particular, the prospects of how regional cooperation initiatives linked with climate change mitigation objectives could assist in widening energy access. Existing relevant regional cooperation initiatives that may be upscaled or used as models to widen access to modern energy services are evaluated. Findings are that regional cooperation initiatives linked with climate change mitigation can potentially facilitate widening energy access. However, in order to realise such potential, synergies from regional cooperation that are indirectly linked to energy and wider climate change mitigation programs should be harnessed. Recommendations are made for development of sustainable energy programs in energy deprived regions that will also mitigate climate change impacts. [ABSTRACT FROM AUTHOR]

We introduce a new method for incorporating short-term temporal variability of both power demand and VRE (variable renewables) into long-term energy-economy models: the RLDC approach. The core of the implementation is a representation of RLDCs (residual load duration curves), which change endogenously depending on the share and mix of VRE. The approach captures major VRE integration challenges and the energy system's response to growing VRE shares without a considerable increase of numerical complexity. The approach also allows for an endogenous representation of power-to-gas storage and the simultaneous optimization of long-term investment and short-term dispatch decisions of non-VRE plants. As an example, we apply the RLDC approach to REMIND-D, a long-term energy-economy model of Germany, which was based on the global model REMIND-R 1.2. Representing variability results in significantly more non-VRE capacity and reduces the generation of VRE in 2050 by about one-third in baseline and ambitious mitigation scenarios. Explicit modeling of variability increases mitigation costs by about one fifth, but power-to-gas storage can alleviate this increase by one third. Implementing the RLDC approach in a long-term energy-economy model would allow improving the robustness and credibility of scenarios results, such as mitigation costs estimates and the role of VRE. [ABSTRACT FROM AUTHOR]

Sustainable energy transition, air pollution reduction and climate change mitigation are the most challenging themes in nowadays energy sector. Microgrids (MGs) are one of the most effective ways to integrate Renewable Energy Sources (RES), and among them PhotoVoltaic (PV)-Storage (ST) configuration is relevantly promising. Focusing the attention on the PV and ST converters primary control, the main needs are to properly regulate voltage and frequency and optimally exploit the energy coming from the sun and manage the ST operation without any communication among the converter controllers. The conventional converter control approach presents several drawbacks and thus a strategy based on Higher Order Sliding Mode (HOSM) is presented in this work. The HOSM converter control strategy is fully analysed defining its control laws and the control schemes. A comparison between the HOSM and conventional control is performed with dedicated simulations on a common benchmark MG in order to highlight the advantages of the proposed strategy. • Decentralized control of islanded photovoltaic-storage microgrids. • Higher-Order sliding model application to microgrids. • Robust control approach for islanded power systems. • Combined results of primary and secondary frequency regulation without communication. [ABSTRACT FROM AUTHOR]

The progress made in the penetration of renewable energy (RE) sources in most parts of the world is not fast enough for achieving the international climate mitigation targets. Furthermore, there is a lack of energy planning strategies, methods and tools for assessing the implementation of RE technologies which considers the social support. In this work, we present a replicable multi-criteria spatial approach based on geographical information system to estimate the potential of solar photovoltaic (PV), wind and biomass energy technologies that could be implemented in the short-term in a given territory. This potential includes environmental, technical (with economic attributes) and geographical (with social-acceptability attributes) constraints, together with existing local power plants considerations for calculating the electricity generation by technology, and then estimating its jobs creation and greenhouse gas emissions reduction. The approach was applied to the province of Jaén (Southern Spain), which has a pronounced unbalance between its inner electricity production and consumption and apparently is a territory with great technical potential for the aforementioned technologies. Results show that this province has a short-term implementable potential that would annually produce 8.9 TWh from solar PV, 911 GWh from wind energy and 683 GWh from biomass plants; which is 3.8 times greater than the current electricity consumption and would require 1.5% of the total surface of Jaén. This potential can create about 92,800 direct jobs and avoid the emissions of 3.78–8.61 MtCO 2 to the atmosphere. The proposed approach can be useful for energy planning processes and for allowing decision-making to accelerate the implementation of RE power plants in order to achieve the climate mitigation goals. • A multi-criteria GIS-based approach with local consideration is proposed. • A renewable energy potential with economic and socio-acceptability attributes was estimated. • 6.6 GW of photovoltaic (PV), 0.6 GW of wind and 88 MW of biomass energy can be installed in the near-term in Jaén. • PV and wind energy installed capacity would occupy 1.5% of the total surface of Jaén. • About 92,800 direct jobs can be created and 3.78–8.61 MtCO 2 emissions avoided. [ABSTRACT FROM AUTHOR]

Transforming and expanding the electricity sector are key for climate change mitigation and alleviation of energy poverty. Future energy systems based on renewable energy sources may reduce greenhouse gas (GHG) emissions but could require more materials during construction. We assess this trade-off by quantifying the requirements of the main bulk materials used in electricity infrastructures for 281 global electricity sector pathways until 2050. We identify main determinants for material requirements and gauge the relevance of socio-economic framework conditions and climate change mitigation regimes. Five selected, highly diverse scenarios are analysed in detail by quantifying their respective annual material stocks and flows, and cumulative GHG emissions to 2050. We find robust evidence that scenarios in line with the 1.5 °C target are associated with significantly higher material requirements than scenarios exceeding a global temperature rise of 2 °C. Material stocks in 2050 differ by up to 30% for copper, 100% for concrete, 150% for iron/steel and 260% for aluminium (3rd quartiles of Monte Carlo simulations), even when the particularly material-intensive "Below 1.5 °C″ scenarios are excluded. Although power plants account for the largest part of the material requirements, grid expansion and reinforcement, necessary to accommodate large shares of volatile power generation and provide universal access to electricity, also cause substantial material demand. In the absence of future GHG mitigation in the processing industries, GHG emissions related to bulk materials (primarily iron/steel and aluminium) could amount to one tenth of the remaining carbon budget for a 50% chance of limiting global warming to 1.5 °C. However, if preference is given to material-efficient technologies, low-carbon processes are applied in the industries and increased material recycling is achieved, GHG emissions related to bulk materials in decarbonisation pathways will not significantly exceed those in largely fossil fuel-based scenarios. • Global electricity sector pathways to 2050 require large amounts of bulk materials. • High-renewable scenarios that meet climate targets are most material-intensive. • Future iron/steel and aluminium requirements imply large greenhouse gas emissions. • Without mitigation, cumulative GHG emissions could be 10% of the 1.5° carbon budget. • Mitigation options include material efficiency, technology development & circularity. [ABSTRACT FROM AUTHOR]

Pyrolysis can be used to produce renewable energy and offset greenhouse gas emissions. While the biopower potential of pyrolysis has been widely analyzed, agronomic and environmental benefits under competing pyrolysis modes have not been investigated and compared. This study reviews the properties and characteristics of major pyrolysis technologies including fast, intermediate, slow, gasification, and torrefaction, and then investigates and compares their biopower potential and the biochar-induced agronomic and environmental benefits so that the fundamental figures for future large-scale biopower development can be explored. The results indicate that (1) revenues from energy sale generally outweigh the agronomic and environmental benefits, but the extent depends on the commodity price and emission price; (2) if biochar is not used as an energy source, 10.58%–26.73% of biopower generation is decreased for fast pyrolysis and a 90%–97.44% decrease would occur for torrefaction; (3) biochar-induced agronomic benefits and emission offsets from torrefaction can greatly recover the loss of energy sales; and (4) with torrefaction the emission offset can be up to 2.82–3.19 tonnes carbon dioxide, on a per tonne biomass basis. We also discuss how biochar application might alleviate surface water eutrophication and groundwater pollution. • Mitigation potential of torrefaction is up to 3.19 MT per ton feedstock. • Without the use of biochar, power generation of fast pyrolysis declines by 26.73%. • Torrefaction benefits agronomic mostly but yields least biopower. • Changes in energy and emission prices would cause technology transitions. • Slow pyrolysis balances biopower production and mitigation effects. [ABSTRACT FROM AUTHOR]

Urban areas play a key role in climate change mitigation. We investigate here energy systems design to increase the use of renewable electricity (RE) such as photovoltaics and wind power in cities. We analyzed the hourly temporal and spatiotemporal energy demand and supply patterns in Delhi, Shanghai and Helsinki to understand how energy systems respond to high RE shares, and to determine realizable levels of RE power. The results indicate that if limiting the RE output to the instantaneous power demand, a 20% yearly share of electricity could be reached. Increasing the RE beyond this limit without a smart design adds only limited benefit. Adding short-term electrical storage could increase the RE share of power in Shanghai to 50–70%, in Delhi to 40–60%, and in Helsinki to 25–35%. An electricity-to-thermal conversion strategy in which surplus RE power is utilized for heating, enables to increase the wind power use in Helsinki up to 64% of the yearly electricity demand, but in addition, to cover 30% of the yearly heat demand. Such a scheme would add ca 10% to the overall wind power investment. A high RE share affects the existing power mix and the plant capacity factors, which need to be re-optimized. In the above cases, RE replaces fossil fuel and coal power plants and therefore the CO 2 emission reductions from smart design are proportional to the RE shares shown. Smart energy system design could help mainstreaming renewable electricity as part of the cities' carbon reduction strategies. [ABSTRACT FROM AUTHOR]

As the use of plug-in electric vehicles (PEVs) further increases in the coming decades, a growing stream of batteries will reach the end of their service lives. Here we study the potential of those batteries to be used in second-life applications to enable the expansion of intermittent renewable electricity supply in California through the year 2050. We develop and apply a parametric life-cycle system model integrating battery supply, degradation, logistics, and second-life use. We calculate and compare several metrics of second-life system performance, including cumulative electricity delivered, energy balance, greenhouse gas (GHG) balance, and energy stored on invested. We find that second-life use of retired PEV batteries may play a modest, though not insignificant, role in California's future energy system. The electricity delivered by second-life batteries in 2050 under base-case modeling conditions is 15 TWh per year, about 5% of total current and projected electricity use in California. If used instead of natural gas-fired electricity generation, this electricity would reduce GHG emissions by about 7 million metric tons of CO 2 e per year in 2050. [ABSTRACT FROM AUTHOR]

Mitigating climate change is driving the need to decarbonize the electricity sector, for which various possible technological options exist, alongside uncertainty over which options are preferable in terms of cost, emissions reductions, and energy security. To reduce this uncertainty, we here quantify two questions for the power system of Great Britain (England, Wales and Scotland): First, when compared within the same high-resolution modeling framework, how much do different combinations of technologies differ in these three respects? Second, how strongly does the cost and availability of grid-scale storage affect overall system cost, and would it favor some technology combinations above others? We compare three main possible generation technologies: (1) renewables, (2) nuclear, and (3) fossil fuels (with/without carbon capture and storage). Our results show that across a wide range of these combinations, the overall costs remain similar, implying that different configurations are equally feasible both technically and economically. However, the most economically favorable scenarios are not necessarily favorable in terms of emissions or energy security. The availability of grid-scale storage in scenarios with little dispatchable generation can reduce overall levelized electricity cost by up to 50%, depending on storage capacity costs. The UK can rely on its domestic wind and solar PV generation at lower renewable shares, with levelized costs only rising more than 10% above the mean of 0.084 GBP/kWh for shares of 50% and below at a 70% share, which is 35% higher. However, for more than an 80% renewable generation share to be economically feasible, large-scale storage, significantly more power imports, or domestic dispatchable renewables like tidal range must be available. [ABSTRACT FROM AUTHOR]

Abstract/Summary Expansion of renewable energies (=RE) is a key measure in climate change mitigation. For this expansion mountainous areas are regarded as specifically suitable because of their high-energy potential. However, mountains also are biodiversity hot-spots and provide scenic landscapes and therefore offer high natural and cultural value. Preserving this natural and cultural value whilst intensifying RE, is expected to increase land use conflicts. This is of great concern in particular for vulnerable areas such as the Alps. Reconciling RE expansion with the preservation of natural and cultural values and thus minimizing environmental impacts represents one of the most important challenges now. For this a systematic assessment of the wide range of impacts is needed. This literature review scrutinizes RE resources which are relevant in the Alpine region and their effects on the environment by applying the Ecosystem Service approach. Thereby, we identified possible environmental constraints when exploiting Alpine RE potentials and generated recommendations for future strategies on expanding RE. The outcomes highlight the strong need for interdisciplinary research on RE and environmental conflicts. Interdisciplinary approaches such as the concept of Ecosystem Services can help to cover the wide range of aspects associated with these particular human–environment interrelations. [ABSTRACT FROM AUTHOR]

Merging climate change mitigation and sustainable development in developing countries is pivotal for the transition towards low carbon growth pathways. This paper combines the field of technology transfer and technology-specific aspects with sustainable development objectives. The general climate change mitigation paradigm has shifted from project oriented mitigation action to more strategic, country-wide, cross-sectoral mitigation plans, in order to explicitly take into account also economic development goals. Local technology needs and socio-technical circumstances are important towards economic development induced by technology transfer. Yet, this approach is not sufficient for the success of technology transfer, which shall also deliver on economic development. A strategy for the adoption of technologies, as well as the broadening of the domestic technology manufacturing base, needs to consider also the technology properties itself in greater detail. The technology transfer process should emphasize the economic developmental purpose as well as the properties of technologies. Thus, I propose a detailed assessment of the technology and its potential of being adopted by suggesting that technology complexity assessments should be integrated into technology transfer mechanisms. By using CSP, PV and wind technology as examples, I describe how the evaluation of technology complexity and of potential economic development, determined by demand for manufactured goods and services within domestic economies, which could lead to job creation and value added, could be used to inform policy makers. [ABSTRACT FROM AUTHOR]

Renewable energy can play an important role in India's climate change mitigation, as India has great potential for renewables, especially solar and wind. This paper analyses the role of renewables to meet India's possible 2050 climate change mitigation targets using a multi-region global energy system model called TIAM-UCL, where India is explicitly represented as a separate region. TIAM-UCL is a cost optimisation model. The climate policy is applied to all regions in the model based on equal per capita emissions of 1.3 tCO 2 by 2050. Analysis shows that renewable energy can play an important role to decarbonise the economy, especially the power sector. Two low-carbon scenarios are explored, the first allowing for carbon capture and storage (CCS) technology deployment and the second excluding this technology. In the first low-carbon scenario (LC1), the most critical renewable energy technologies in the power sector are biomass with CCS, solar and wind. In the second low-carbon scenario (LC2), without CCS, there is an even greater role for solar and wind. Over the whole Indian economy, by 2050 renewables contribute 57% of the total CO 2 reductions in LC1 (relative to a reference scenario with no CO 2 target) and 63% of the CO 2 reductions in LC2. [ABSTRACT FROM AUTHOR]

The threat of climate change and other risks for ecosystems and human health require a transition of the energy system from fossil fuels towards renewable energies and higher efficiency. The European geographical periphery, and specifically Southern Europe, has considerable potential for renewable energies. At the same time it is also stricken by high levels of public debt and unemployment, and struggles with austerity policies as consequences of the Eurozone crisis. Modeling studies find a broad optimum when searching for a cost-optimal deployment of renewable energy installations. This allows for the consideration of additional policy objectives. Simultaneously, economists argue for an increase in public expenditure to compensate for the slump in private investments and to provide economic stimulus. This paper combines these two perspectives. We assess the potential for renewable energies in the European periphery, and highlight relevant costs and barriers for a large-scale transition to a renewable energy system. We find that a European energy transition with a high-level of renewable energy installations in the periphery could act as an economic stimulus, decrease trade deficits, and possibly have positive employment effects. Our analysis also suggests that country-specific conditions and policy frameworks require member state policies to play a leading role in fostering an energy transition. This notwithstanding, a stronger European-wide coordination of regulatory frameworks and supportive funding schemes would leverage country-specific action. Renewed solidarity could be the most valuable outcome of a commonly designed and implemented European energy transition. [ABSTRACT FROM AUTHOR]

• Large synergies of different energy models, but few practical integration studies. • Merging of a techno-economic optimisation and a socio-technical simulation model. • Model convergence shows the feasibility of soft-linking very different models. • Pace of technological change is critical for climate change mitigation. [Display omitted] Transforming global energy systems is critical for climate change mitigation and requires overcoming not only techno-economic, but also socio-technical hurdles. The main tools to analyse challenges in these two domains are integrated assessment models (IAMs) and transition theories or models, respectively. Despite a surging interest in integrative research that leverages complementarities in order to include social constraints into IAMs, both approaches are often confined to their own disciplinary background and practical integration studies of existing models are scarce. Here I demonstrate the feasibility of model integration by a bi-directional soft-link that merges the strengths of a neoclassical intertemporally optimising IAM with one global region, and a technologically and regionally highly resolved, evolutionary simulation model of S-shaped technology diffusion in the power sector. The new model iteratively converges to a stable equilibrium via two time-dependent coupling variables: carbon prices and renewable energy shares. The results for a 2 °C scenario show that due to gradual technology diffusion, energy transition challenges are exacerbated and incur higher economic losses. I discuss the potential of coupling existing models as an option to combine insights from different disciplinary perspectives to energy transitions. [ABSTRACT FROM AUTHOR]

Space-based geoengineering is gaining attention, if not necessarily traction, as a possible "break the glass" solution to mitigate the worst impacts of climate change and facilitate the transition to a low-carbon future. Though still on the periphery of discussions around climate mitigation and geoengineering, space-based methods that would deflect or block incoming sunlight, and thereby diminish how much radiation ultimately reaches the Earth, could offer advantages, notably, by avoiding the need for difficult trade-offs and decisions in terms of land and resource use on Earth. Aside from a few specialist-oriented studies, the literature on space-based geoengineering remains limited. In this study, we utilize a large and diverse expert-interview exercise (N = 125) to provide a first critical examination of the promise and relevance of space-based geoengineering for tackling climate change, including perhaps as a source of renewable energy, its feasibility and prospective risks, as well as key actors and issues related to commercialization and governance. To our knowledge, no other study has employed empirical data of any kind to examine perceptions of space-based geoengineering, let alone in relation to other kinds of climate-intervention technologies. Not only does the current research represent the first of its kind, it also provides a foundation for more informed, comprehensive deliberations around this interesting, possibly even necessary solution to climate change. • Space-based solar geoengineering is a radical proposal for tackling climate change. • No study has so far employed empirical data to explore perceptions of space-based proposals. • Our data is derived from a diverse set of 125 original interviews with key experts. • The promise, feasibility, and risks for climate mitigation are critically examined. • We also engage with the potential of sunshades to provide significant amounts of renewable energy. [ABSTRACT FROM AUTHOR]

Energy futures and the case for renewables and cleantech can be framed in terms of their contribution to mitigation of climate change, as well as cleanliness and absence of carbon emissions. By contrast, energy security is generally discussed in terms of access to fossil fuels. In this paper we make a different case for renewables: we contrast the extraction of energy (fuels), which - in spite of technological change - takes place under diminishing returns, with the harvesting of nature's renewable energy, which takes place in a process utilizing manufactured devices, where manufacturing generates increasing returns and costs decline along steep learning curves. This gives a fresh perspective on both renewables and energy security. We argue that energy choices can be framed as choices in favour of increasing returns (based on manufacturing), vs. choices in favour of diminishing returns activities, which usually involve extraction of fossil fuels. Such a framing does not entail assumptions as to whether the entire energy system can be converted to renewables, but simply as choices made at the margin - whose effects will cumulate over time. Energy security through renewables manufacturing therefore promises to be a fruitful area of futures studies. [ABSTRACT FROM AUTHOR]

Green financing has been proposed to stimulate and promote environment-friendly products such as low-carbon building and renewable energy to mitigate climate change since 2013; however, Taiwan's energy security is fragile and vulnerable to fluctuations of fossil prices. This study investigates how the promotion of green bonds benefits Taiwan's bioenergy production and emission reduction, as well as the development efficiency under various green-bond rates and volumes. We propose a price-endogenous, mathematical programming framework that incorporates the entire agricultural sector to simulate net bioenergy production, emission reduction, and overall profitability in the face of alternative bioenergy technologies and market conditions. The results show that if biopower and biofuel are eligible for low-cost bond financing, bioenergy production would be more stable. An increase in the emission trade price is favored to biopower technology, but this advantage will be partly recovered by a low borrowing rate because biofuel production will also be at a low production cost. In the face of energy price changes, we estimate that with an increase in green volume of US$0.61 to US$1.02 billion, a meaningful transition to bioenergy technology could occur. • A price endogenous, mathematical programming is applied. • We analyze the effect of bond rates and bond volume on bioenergy development. • Lower bond rates encourage the development of biopower. • Transitions among bioenergy technology occurs under various market conditions. • Capital required for biopower is relatively stable than for biofuel. [ABSTRACT FROM AUTHOR]

• Renewable energy quotas incorporating equality and efficiency are allocated at regional level. • The methods combined entropy and ZSG-DEA models are proposed. • The quota allocation results have achieved the goal of transferring the responsibility of renewable energy quota from western to eastern. Renewable energy policy plays an important role in achieving carbon neutrality which is main goal for climate change mitigation. China is striving to promote the implementation of renewable portfolio standards under the goal of carbon neutralization in 2060. Thus, based on the principles of equality and efficiency, we apply zero sum gains data envelopment analysis (ZSG-DEA) model combined with entropy model to allocate China's renewable energy quota from provincial perspectives. Further, we introduce an environmental Gini coefficient to evaluate the rationality of allocation results. The allocation results show that Guangdong, Jiangsu, Sichuan and Shandong are four provinces with the most renewable energy quota, while Hainan, Guizhou, Gansu, and Xinjiang are four provinces with the least quota. In addition, the quota allocation results have achieved the goal of transferring the responsibility of renewable energy quota from western provinces to eastern provinces. Last, managerial suggestions in promoting renewable energy development are discussed. [ABSTRACT FROM AUTHOR]

Currently, it is believed that the share of renewable energy in the overall balance of electricity production should increase in view of the climate change mitigation needs. Analysis of the current capacity of renewable energy shows that the hydropower constitutes the largest part. In this article, the authors undertook the assessment of the impact of hydropower plants on the hydromorphological conditions of the rivers on which they are located. Research sections located upstream and downstream of the facilities and on reference sections were investigated and compared for selected rivers in Poland (Oder, Bystrzyca, Ślęza Rivers) and Belgium (Meuse River). Impacts of the hydropower plants were studied based on 42 indicators, including physical conditions, coastal habitats, morphology, and hydrological regime. It was also determined which hydromorphological indicators influenced the hydromorphological conditions. Results show that in the sections upstream of the hydropower plants, the average hydromorphological state is moderate, whereas it is poor downstream of the plants and very good in the reference stations. From the 42 analyzed indicators, 26 show a deterioration in the hydromorphological state, and 14 show an improvement. The hydromorphological conditions are mostly influenced by anthropogenic pressures, the presence of transverse and longitudinal obstacles in the riverbed, river regulation, and changes in the hydrological regime and flow conditions. The presented methods used in individual EU countries (HIR, HEM, QBR, and MC) complement each other well and their results show a high convergence of the findings for the general hydromorphological state, with an average level of agreement of 82.14%. • Hydromorphological studies within hydropower plants in Poland and Belgium were shown. • Impacts of the hydropower plants were studied based on 42 indicators under 4 methods. • Hydropower plants have an ambiguous effect on the hydromorphology of rivers. • The most pronounced influence concerned the impacts on the hydrological regime. • There was a deterioration in 62.9% of the indicators, and an improvement – in 33.3%. [ABSTRACT FROM AUTHOR]

The development of renewable energy sources (RES) is considered to be a key instrument in addressing climate change. However, different RES have different potential and economic feasibility depending on country-specific conditions and mitigation ambitions. Understanding the relative importance of each RES could help policymakers focus their efforts on the most promising options. In this paper, we focus on Ukraine and explore the potential of biomass use under two mitigation scenarios – with 68% and 83% of greenhouse gas emissions reduction in 2050 relative to the 2010 level. First, using the TIMES-Ukraine energy system model, we show that biomass would play a major role in the future climate mitigation. If constrained at the baseline scenario level (due to political or other reasons), mitigation costs would be substantially higher – by 14.0–19.6 B € or 10.8–14.3 €/tCO 2 -eq., over the 2020–2050 time frame. Second, we quantify the importance of each biomass source. We show that woody biomass and bioliquids are the most important biofuels under the high-ambition climate scenario, while biowaste and bioliquids play a key role in the lower ambition pathway. Finally, we analyse the current policy environment in the context of future biomass development and conclude with a set of policy recommendations toward the realization of the biomass potential in Ukraine. We believe that findings presented in the paper would be relevant not only for supporting the decision-making process in Ukraine, but could also provide useful insights for other countries with similar conditions. • Two scenarios with 68% and 83% reduction in GHG emissions in 2050 relative to 2010. • Over 50% of all renewable energy is coming from biomass under both scenarios. • Bioenergy constraint increases mitigation costs by 10.8–14.3 EUR/tCO 2 or 2.4–3.2 times. • No significant impact of the biogas availability on the mitigation costs. • Constraining biowoods , bioliquids or biowaste increases costs by at least 35% each. [ABSTRACT FROM AUTHOR]

European energy landscape is currently undergoing significant changes shifting from fossil to renewable energy sources. Biomass will continue to play a significant role in decarbonisation efforts. As a pioneer in climate change mitigation, the European Union (EU) can also greatly benefit not only from the wide deployment of bioenergy, but also from Bioenergy coupled with Carbon Capture and Utilization (BECCU). BECCU is a key enabling technology for the energy transition addressing simultaneously the renewable feedstock-based circular economy. Biomass utilization in existing and future power and heat applications addresses the decarbonisation of power and heat sector, while the integration of CO 2 -utilization technologies in these plants enables the valorisation of waste streams via conversion to fuels and chemicals. The current status of bioenergy deployment in Europe is reported, along with a review of the main BECCU technologies and a special focus on valuable recycled bio–CO 2 –derived transport fuels. BECCU enables the decarbonisation of power, heat and transport sector leading to a net zero or even negative emission energy system by 2050. • Review of regulatory framework for Bioenergy with Carbon Capture and Utilization. • Alternative configurations in biorefinery applications are presented. • Implementation of BECCU in combined heat and power plants and in biofuel production. • Applications, carbon capture costs and technology readiness level are assessed. • Use of biogenic CO 2 for transport fuels can boost EU circular economy. [ABSTRACT FROM AUTHOR]

Strengthening capacity for cross-sectoral coordination has a crucial role in enabling ambitious climate mitigation. This research work integrates the Sustainable Development of Energy, Water and Environment Systems Index into a policy framework with three main components to compare possibilities for improving urban system performance. Tiers of integration are defined and compared with the index results for more transformative action. The levels range from unintegrated urban sectors and emerging integration, including those with urban land use and spatial planning, to advanced integration across the urban system. The case study is based on a municipality that is benchmarked to receive an index score of 27.783, placing the urban area in rank 79 among 120 other cities. The measures in the existing action plan are compared with opportunities that would support the municipality in reaching higher tiers of urban integration in the future. Policy learning from other urban areas to which the index is applied is foreseen to support collective action in addressing synergistic opportunities for mitigation. The results have implications on considering urban system integration in the transition to net-zero targets, missions for climate-neutral cities, and the realization of 100% renewable energy systems. • Urban climate mitigation action can focus on integrating across the urban system. • A framework that involves benchmarking is developed in a broader policy context. • The case study receives a benchmarked score of 27.783 as a solution-seeking city. • Tiers of urban system integration are defined with comparisons to opportunities. • Net-zero emission targets can be supported with more transformative urban action. [ABSTRACT FROM AUTHOR]