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The widely recognised Energiewende, ("energy transition") in Germany has lost its original momentum. We therefore address the question of how the transition process to a new energy system can be reignited. To do so, we developed the "5Ds approach", which lays the groundwork for a process analysis and the identification of important catalysts and barriers. Focusing on the five major fields required for the energy transition, we analyse the effects of: (1) Decarbonisation: How can efficiency and renewable energies be expanded successfully? (2) Digitalisation: Which digital solutions facilitate this conversion and would be suitable as sustainable business models? (3) Decentralisation: How can potential decentralised energy and efficiency opportunities be developed? (4) Democratisation: How can participation be strengthened in order to foster acceptance (and prevent "yellow vest" protests, etc.)? (5) Diversification of service: Which services can make significant contributions in the context of flexible power generation, demand-side management, storage and grids? Our paper comes to the conclusion that German policy efforts in the "5D" fields have been implemented very differently. Particularly with regard to democratisation, the opportunities for genuine participation among the different social actors must be further strengthened to get the Energiewende back on track. New market models are needed to meet the challenges of the energy transition and to increase the performance of "5D" through economic incentives. [ABSTRACT FROM AUTHOR]

The global energy landscape is undergoing a significant shift toward green energy solutions, with Germany leading the way in the transition to renewable energy through its Energiewende initiative. This topic is of great importance as it offers valuable insights for other countries in the European Union and worldwide seeking sustainable and environmentally friendly alternatives for their energy sectors. This paper aims to provide a comprehensive assessment of Germany's green energy transition, focusing on the technological advancements, strategic management, and country economics that drive this transformation. Utilising a bibliometric study research method, the paper analyses data from scientific publications in the Scopus database and employs VOSviewer and Bibliometrix software to develops bibliometric maps of keyword co-occurrences. The analysis reveals the main changes in Germany's green energy transition, uncovering the meaning and important structures of keywords, suggesting new directions for research, and pointing out strategies based on the technological transition toward renewable energy sources and green job creation. By integrating sustainable development and technological changes, this study contributes to the understanding of green energy transition strategies and their impact on adjacent domains, offering valuable insights for business and society. Furthermore, the assessment of Germany's green energy transition serves as a valuable example for governments and policymakers in other countries, helping them to learn from Germany's experience and implement similar strategies in their energy sectors. The full paper will discuss the limitations of the paper and potential directions for future research. [ABSTRACT FROM AUTHOR]

The emerging energy transition is particularly described as a move towards a cleaner, lower-carbon system. In the context of the global shift towards sustainable energy sources, this paper reviews the potential and roadmap for hydrogen energy as a crucial component of the clean energy landscape. The primary objective is to present a comprehensive literature overview, illuminating key themes, trends, and research gaps in the scientific discourse concerning hydrogen production and energy policy. This review focuses particularly on specified geographic contexts, with an emphasis on understanding the unique energy policies related to renewable energy in Brazil, Austria, and Germany. Given their distinct social systems and developmental stages, this paper aims to delineate the nuanced approaches these countries adopt in their pursuit of renewable energy and the integration of hydrogen within their energy frameworks. Brazil exhibits vast renewable energy potential, particularly in wind and solar energy sectors, positioning itself for substantial growth in the coming years. Germany showcases a regulatory framework that promotes innovation and technological expansion, reflecting its highly developed social system and commitment to transitioning away from fossil fuels. Austria demonstrates dedication to decarbonization, particularly through the exploration of biomethane for residential heating and cooling. [ABSTRACT FROM AUTHOR]

The escalating demand for renewable energy solutions and the imperative for efficient energy storage mechanisms have catalyzed the evolution of Power-to-X (PtX) technologies. Germany has the most PtX projects, accounting for 44% of all projects that have been reported. PtX encompasses a spectrum of processes engineered to convert surplus renewable energy into versatile energy carriers or chemical commodities, such as hydrogen, methane, or synthetic fuels. The Paramount to this domain is to synergistically harness renewable energy sources and hydrogen carriers to curtail waste and bolster sustainability. Central to achieving this synergy is the effective control of PtX processes, ensuring optimal performance, cost efficiency, and seamless integration within existing energy frameworks. This paper delves into the control processes and environmental prerequisites within the PtX landscape, elucidating key challenges, and strategies within this dynamic realm. While providing an initial overview of fundamental PtX process chains, this paper accentuates the critical role of geographical considerations. Subsequently, it conducts a thorough analysis of equipment modeling challenges, addressing performance metrics, operational requisites, and capital investments, particularly focusing on methanol and hydrogen production and storage. Through holistic examination, this paper endeavors to delineate the evolving landscape of PtX control processes and conditions, advancing our understanding of this expanding field. [Display omitted] • Comprehensive overview of PtX control process, challenges, strategies, and advancements. • Overview of PtX process chains and geographical conditions. • Analysis of equipment modeling challenges for methanol and hydrogen. • Addressing crucial storage challenges in PtX system. • Exploration of diverse influences on PtX control processes. [ABSTRACT FROM AUTHOR]

The sun's total radiation alone exceeds the world population's entire energy consumption by 7.500 times and ignites secondary renewable energy sources. The end energy consumption buildings use for heating amounts to 28% of Germany's total energy consumption. With the ongoing trend of digitalization and the transition of the German energy supply away from fossil fuels and the consequent political dependency, electric heat pumps and photovoltaic (PV) systems have become increasingly important to the discussion. This has led to an increasing demand for smart control strategies, especially for inert systems such as thermally activated building systems (TABS). This paper presents and analyses a weather predictive control (WPC) strategy using a validated thermodynamic simulation model. The literature review of this paper outlines that the current common control strategies are data intense and complex in their implementation into the built environment. The simple approach of the WPC uses future ambient temperature and solar radiation to optimize the control of the heating, cooling, ventilation, and sun protection system. The thermal comfort and energy demand evaluate the concept. We show that with a WPC for TABS, thermal comfort can improve without increasing the energy demand for the office building in the moderate climate of Munich. Furthermore, this paper concludes that the WPC works more effectively with more thermal mass. This simplified building control strategy promotes the European roadmap goal of climate neutrality in 2050, as it bridges the phenomenon of the performance gap. [ABSTRACT FROM AUTHOR]

Background: Renewable energies are key to reduce CO2 emissions and other environmental impacts of fossil-fueled electricity generation. However, renewable energy systems can also cause negative environmental effects. In this paper, we analyze the potential environmental trade-offs associated with different spatio-technical (de)centralization options for a renewable electricity system. For this purpose, we first review the potential environmental life cycle impacts of key technologies for renewable electricity systems. Subsequently, we develop a framework identifying which factors determine actual environmental effects of renewable electricity systems. We apply the framework to four basic spatio-technical (de)centralization options for the future Germany electricity system. Results: Our analysis shows that all (de)centralization options are associated with potential environmental trade-offs. We find that the (de)centralization of the system is a relevant factor determining these trade-offs. For instance, the two more centralized options considered have lower environmental impacts related to PV, whereas the two more decentralized options have lower environmental impacts related to grid infrastructure. However, we also find that the trade-offs depend on the specific way (de)centralization is pursued. For instance, only in one of the two considered more decentralized development options, there is a potential environmental trade-off between higher impacts related to battery storage and lower impacts related to offshore wind power. Conclusions: Our analysis reveals that the spatio-technical (de)centralization of a renewable electricity system plays a role for its environmental trade-offs while further factors like the institutional and stakeholder management in place also shape the environmental trade-offs. Policy makers should acknowledge the identified potential environmental trade-offs and their influencing factors when making policies favoring certain spatio-technical (de)centralization options. Highlights: Review of potential environmental impacts of key renewable technologies Framework on determinants of actual environmental effects of electricity systems Review of electricity system (de)centralization scenarios for Germany Application of framework to four spatio-technical (de)centralization options Environmental trade-off analysis for the four (de)centralization options [ABSTRACT FROM AUTHOR]

In Germany, there are over 32,000 schools, representing great potential for climate protection. On the one hand, this applies to educational work, as understanding the effects of climate change and measures to reduce GHG emissions is an important step to empower students with knowledge and skills. On the other hand, school buildings are often in bad condition, energy is wasted, and the possibilities for using renewable energies are hardly used. In our "Schools4Future" project, we enabled students and teachers to draw up their own CO2 balances, identify weaknesses in the building, detect wasted electricity, and determine the potential for using renewable energies. Emissions from the school cafeteria, school trips, and paper consumption could also be identified. The fact that the data can be collected by the students themselves provides increased awareness of the contribution made to the climate balance by the various school areas. The most climate-friendly school emits 297 kg whilst the school with the highest emissions emits over one ton CO2 per student and year. Our approach is suitable to qualify students in the sense of citizen science, carry out a scientific investigation, experience self-efficacy through one's own actions, and engage politically regarding their concerns. [ABSTRACT FROM AUTHOR]

The energy sector faces a pressing need for significant transformation to curb CO2 emissions. For instance, Czechia and Germany have taken steps to phase out fossil thermal power plants by 2038, opting instead for a greater reliance on variable renewable energy sources like wind and solar power. Nonetheless, thermal power plants will still have roles, too. While the conventional multistage axial turbine design has been predominant in large-scale power plants for the past century, it is unsuitable for small-scale decentralized projects due to complexity and cost. To address this, the study investigates less common turbine types, which were discarded as they demonstrated lower efficiency. One design is the Elektra turbine, characterized by its velocity compounded radial re-entry configuration. The Elektra turbine combines the advantages of volumetric expanders (the low rotational speed requirement) with the advantages of a turbine (no rubbing seals, no lubrication in the working fluid, wear is almost completely avoided). Thus, the research goal of the authors is the implementation of a 10 kW-class ORC turbine driving a cost-effective off-the-shelf 3000 rpm generator. The paper introduces the concept of the Elektra turbine in comparison to other turbines and proposes this approach for an ORC working fluid. In the second part, the 1D design and 3D–CFD optimization of the 7 kW Elektra turbine working with Hexamethyldisiloxane (MM) is performed. Finally, CFD efficiency characteristics of various versions of the Elektra are presented and critically discussed regarding the originally defined design approach. The unsteady CFD calculation of the final Elektra version showed 46% total-to-static isentropic efficiency. [ABSTRACT FROM AUTHOR]

Achieving national targets on renewable energy poses several challenges, especially in multi-level governance environments. Incentives and specifications on wind energy development might cause uneven progress or even discrepancies. Therefore, governments have commenced adopting 'positive planning' to combine energy targets with spatial and land-use planning. Yet detailed discussions regarding wind energy development remain scarce. In this paper, I explore three explanatory case studies in Germany and Sweden, aiming to provide policymakers and planners with essential knowledge while presenting significant challenges and key lessons learned. Positive planning appears to center on a strong energy target focus, limited space, and a balanced approach, shaped by the sociopolitical context. While Germany has recently embraced positive planning, Sweden started ambitiously but is encountering planning and policy challenges. Planning agencies play a vital role in promoting wind energy targets at mid-scale levels, yet legally binding targets matter. Striking a balance between energy targets and addressing land-use concerns without disregarding them requires managing a delicate trade-off. Early communication and inter-agency collaboration, as seen in Sweden, might facilitate identifying compromises, navigating trade-offs between species protection and renewable energy and offering municipal incentives. Nonetheless, negotiating satisfactory spatial trade-offs for a long-term proof of concept remains a challenge. [ABSTRACT FROM AUTHOR]

Purpose: The study aims to investigate the role of hydrogen technology in sustainable energy in Poland and Germany. It seeks to offer a comparative analysis to fill gaps in existing literature and provide insights for stakeholders in achieving Sustainable Development Goals. Design/methodology/approach: A multifaceted approach is employed, integrating a literature review, tabular analysis, and surveys. Scientific publications, government reports, and research papers are analyzed. Tabular comparisons elucidate differences and similarities in strategies and regulations between the two countries. Surveys among social and professional groups capture public perception and attitudes. Findings: Hydrogen technology has gained significant attention as a sustainable energy source. Germany emerges as a leader with a comprehensive strategy, while Poland aligns with EU objectives but faces infrastructure challenges. Both nations have introduced regulations to promote hydrogen technology investment, although challenges such as high production costs persist. Public support is robust in both countries, with higher awareness in Germany. Research limitations/implications: The study's scope could be expanded for a more comprehensive understanding. Future research could focus on addressing these limitations and offering more granular insights. Practical implications: The study serves as a roadmap for stakeholders, offering insights that can guide policy formulation and investment decisions. It has implications for climate change mitigation efforts and could inform public engagement campaigns. Social implications: The study underscores hydrogen technology's potential in reducing greenhouse gas emissions and fostering economic growth, thereby impacting various societal aspects including environmental protection and economic development. Originality/value: The study's uniqueness lies in its comparative analysis of hydrogen technology in Poland and Germany, contributing to the global discourse on sustainable development by offering practical insights for policymakers and industry leaders. [ABSTRACT FROM AUTHOR]

Recently, challenge-oriented innovation policy has become increasingly popular in political and scientific discussions. However, the extent to which such a challenge-based thinking has entered regional policy making is relatively unclear. This paper examines the scope of the regional level in promoting challenge-based innovation, focusing on the recent renewable energy innovation policy in Schleswig-Holstein, Germany. The results show that while regional innovation policy in Schleswig-Holstein aims to address several structural and transformational systemic failures, many other problems and challenges remain, as they are beyond the capacity of a single region to address. Based on this analysis, we draw four conclusions. First, similar to many other structurally weak regions, policymakers in Schleswig-Holstein are struggling with some of the same key challenges that the policy was originally designed to address. Second, multi-scalar governance and inter-scalar coordination are essential for managing regional sustainability transitions. Third, challenge-driven innovation policy is an extension of, rather than a replacement for, conventional regional innovation policy. Finally, environmental and economic goals should be well balanced in challenge-driven regional innovation policy design. [ABSTRACT FROM AUTHOR]

The expansion of renewable energy infrastructure comes with increasing conflicts at local level that significantly impede the expansion of renewable energy in Germany and impact the realization of national and international climate goals. In some conflicts, rural communities are torn apart and social relations strained beyond the energy conflict. Other projects are realized with no or only minor disruption. To researchers, project developers and local politicians alike, it seems unpredictable as to which way local energy conflicts evolve. Thus, the paper aims to shed light on conflict dynamics and identifies a number of aspects that influence local energy conflicts. The paper applies a conflict theoretical perspective on local energy conflicts. Rather than identifying energy conflicts as a sign of dysfunctionality, conflicts are seen as an important element of a democratic society struggling to find the best way through the transformation towards decarbonization. Based on qualitative research on local energy conflicts in five German municipalities the paper analyzes aspects that encourage constructive conflicts and aspects that impede such developments. With reference to Dahrendorf's conditions of conflict the categories of energy conflicts are systematized within an analytical framework according to conditions of organization, conflict and change. These categories and aspects are embedded in specific local conditions, making conflicts on the one hand typical and on the other very specific. They are also entry points for dealing constructively with the conflicts. [ABSTRACT FROM AUTHOR]

Background: To achieve climate targets, a transition to low-carbon energy production is necessary. However, conflicts between different interests, values and priorities, particularly at the community level, can constrain this transition. This paper aims to analyze lines of conflict and opportunities to build bridges between conflicting interests in the expansion of wind energy in Germany at the local level, to achieve successful implementation of wind energy projects. Results: Our analysis of four cases of local-level wind energy projects in Germany shows that limited local options for action reinforce the need for local actors to maximize the benefits of energy transition projects. In addition to the conflict over scarce space, the lines of conflict at the local level run primarily along the dimensions of costs and benefits, winners and losers. Real or perceived procedural and distributive injustices had the potential to fuel resistance to wind energy projects in the analyzed cases. However, wind energy projects were successfully implemented despite the presence of local opposition. Conclusions: The results show that, by integrating procedural and distributive justice into the project planning and implementation and offering tailored solutions, community support for expansion of renewable energy projects can be enhanced. The paper advances the concept of societal ownership ("gesellschaftliche Trägerschaft"), which suggests the willingness of members of a community to tolerate decisions even when some conflicts related to the decision remain unresolved. Societal ownership is presented as an alternative to the concept of simple acceptance; it implies a more positive, more supportive community attitude, where members aim to address conflict as a normal aspect of decision making. Rather than sweeping alternative opinions aside, the community addresses alternative viewpoints, seeking to achieve greater procedural and distributive justice. In this way, a sense of societal ownership of a project can develop, enhancing its likelihood of success. [ABSTRACT FROM AUTHOR]

The article presents a study which focuses on providing a new method to the validation of modelled Net Primary Productivity (NPP) of forest areas in Germany using the dynamic biomass model Biosphere Energy Transfer Hydrology (BETHY/DLR). It relates that the new method fills important gap for validating modelled NPP. It identifies estimation of the theoretical sustainable energy potentials using the validated NPP as the secondary objective of the study.

Renewables are the greener substitute for the conventional polluting sources of generating energy. For their successful integration into the power grid, accurate forecasts are required. In this paper, we report the lessons acquired from our previous works on generating time-series ARIMA-based forecasting models for renewables. To this end, we considered a consistent dataset spanning the last four years. Assuming four different performance metrics for each of the best ARIMA-based models of our previous works, we derived a new optimal model for each month of the year, as well as for the two different methodologies suggested in those works. We then evaluated the performance of those models, by comparing the two methodologies: in doing so, we proposed a hybrid methodology that took the best models out of those two methodologies. We show that our proposed hybrid methodology has improved yearly accuracy of about 89.5% averaged over 12 months of the year. Also, we illustrate in detail for the four years under study and each month of the year the observed percentage of renewables and its corresponding accuracy compared to the generated forecasts. Finally, we give the implementation details of our open-source REN4KAST software platform, which provides several services related to renewables in Germany. [ABSTRACT FROM AUTHOR]

The energy crisis in Europe in 2022 and its consequences have brought changes to approaches towards the issue of energy security, energy policy, and the ability to react to crisis phenomena in the energy market in a short period of time. European countries that are dependent on Russian fossil fuels have faced numerous dilemmas and challenges in 2022. This paper aims to analyse the instruments and energy policies introduced as the reactions of European countries, specifically with the examples of Poland and Germany, to the ongoing fossil fuel crisis in the context of a short period. Due to the specificity of the energy market, the countries' energy policies mainly concern long- and medium-term goals. In 2022, there was an unprecedented situation in which many European countries had to make significant changes to their fossil fuel imports quickly. We analyse and evaluate how two European countries that are heavily reliant on imported energy resources responded in a short time to the necessity of modifying their patterns of fossil fuel supply and demand. The results of our research are models that illustrate both countries' reactions to the disturbances in the energy market during the initial months of the energy crisis. As part of the research, we conducted an analysis of the energy mix of Poland and Germany, their import energy dependency, and self-sufficiency. We then compared them with the short-term energy policies of both countries. As a result, we elaborate on a comparative analysis of the models of Poland's and Germany's responses to the crisis. The research also assesses the similarities and differences in the response models in Poland's and Germany's short-term energy security policies. The results of our research may help, in the future, to choose the available short-term instruments in the energy policy of countries in the face of a sudden need resulting from disruptions in supply chains. The article contributes to the future discussion on renewed national and regional energy security, as well as efficiency concepts. Our research findings could be valuable in selecting appropriate short-term energy policy tools for countries during supply chain disruptions. This article provides significant input for future deliberations on enhancing national and regional energy security, and also efficiency strategies. [ABSTRACT FROM AUTHOR]

Temporally and spatially resolved data on wind power generation are very useful for studying the technical and economic aspects of this variable renewable energy at local and regional levels. Due to the lack of disaggregated electricity data from onshore and offshore turbines in Germany, it is necessary to use numerical simulations to calculate the power generation for a given geographic area and time period. This study shows how such a simulation model, which uses freely available plant and weather data as input variables, can be developed with the help of basic atmospheric laws and specific power curves of wind turbines. The wind power model is then applied to ensembles of nearly 28,000 onshore and 1500 offshore turbines to simulate the wind power generation in Germany for the years 2019 and 2020. For both periods, the obtained and spatially aggregated time series are in good agreement with the measured feed-in patterns for the whole of Germany. Such disaggregated simulation results can be used to analyze the power generation at any spatial scale, as each turbine is simulated separately with its location and technical parameters. This paper also presents the daily resolved wind power generation and associated indicators at the federal state level. [ABSTRACT FROM AUTHOR]

Increasing emissions of greenhouse gases and increasing prices for fossil fuels have highlighted the demand for CO2 "neutral" renewable energy sources, e.g. short rotation forestry systems used for bioenergy. These systems might be vulnerable to changes in temperature, precipitation and occurrence of extreme weather events. To estimate success or failure of such short rotation coppices in a certain area we need regional climate projections and risk assessment. Changes of water supply patterns in two agriculturally extensively used regions in Central Germany (around Göttingen and Großfahner) with different climate conditions but both in the temperate climate zone are explored. The study is carried out under present conditions as well as under projected climate change conditions (1971-2100) using A1B and B1 climate scenarios downscaled for Europe. Analysis of precipitation bias shows regional differences: a strong bias in Göttingen area and a weaker bias in the Großfahner area. A bias correction approach, Quantile mapping, is applied to the ensemble results for both areas for winter and summer seasons. By using quantile regression on the seasonal Standardized Precipitation Indices (SPIs) as indicator for water supply conditions we found that precipitation is expected to increase in winter in all quantiles of the distribution for Göttingen area during the 21th century. Heavy precipitation is also expected to increase for Großfahner area suggesting a trend to wetter extremes in winter for the future. This winter precipitation increase could trigger runoff and soil erosion risk enhancing the severity of floods. Increasing winter availability of water could enhance local water supply in spring. For both areas no significant change in summer was found over the whole time period. Although the climate change signal of the SPI indicate mild dryer conditions in summer at the end of the 21st century which may trigger water shortage and summer drying associated with above--average temperatures in the future. Even though both study areas are close together Großfahner area was found to be the least affected one by changes indicating that small spatial scale differences matter. These developments were found in all examined simulation runs. This study highlighted the regional differences in the vulnerability to water surplus or deficit risks in a temperate system which emphasizes the need in impact studies to focus on proper consideration of local and regional environmental conditions as well as adaption and mitigation of management for agriculture. [ABSTRACT FROM AUTHOR]

Integrating renewable energies into the electricity grid is a challenge that requires an in-depth investigation. This paper presents a model of the day-ahead electricity market, including wind and photovoltaic (PV) generators, and contingency analysis. The comprehensive day-ahead marketing model is designed as a modular structure so that the individual modules can be easily modified in the future. First, the day-ahead electricity marketing of an electricity grid with and without renewable energies is studied. A market model solves the problem of unit commitment and economic dispatch. A grid model was used to calculate the power flow of the branches and the grid losses. Congestions in the branches were handled by redispatching. For this purpose, the generators were redispatched using mixed-integer linear programming and the power transfer distribution factor. A contingency analysis, investigating the outage of one branch, was applied by using the line outage distribution factor. The redispatch process was operated with these calculated increased power flows, which need to be handled by the grid to achieve N-1 security. The simulations were carried out using 30-bus 118-bus systems. Historic wind speed and solar radiation data of Germany were used as input data for renewable energy production. The load data of the 118-bus system were generated based on a standard load profile from Germany. The results show that both systems were able to meet the demand without violation of the grid capacity during normal conditions, with and without renewable energies. However, when applying the contingency analysis, an outrageous amount of load curtailment is needed. [ABSTRACT FROM AUTHOR]

Generating energy by renewable sources like wind, sun or water has led to the emergence of "clean" energy that is generally available at low cost to the environment and is generated from seemingly unbounded resources. Many countries have implemented schemes to support the diffusion of renewable energies. The diffusion of micro-generation technologies like roof-top photovoltaics is one of the success stories within the energy transition and has been significantly driven—at least in countries such as Germany—by households. As these households usually not only generate energy but also consume it they are often called "prosumers." How does it influence the energy behavior of households if they become prosumers? Are these behavioral changes in line with further goals of the energy transition, e.g., reducing demand? What shapes individual behaviors of prosumers? The paper introduces a conceptual framework based on the existing literature on rebound and spillover effects. It systematizes possible behavioral consequences as well as mechanisms behind them. This framework is then used to code and analyze data from 48 in-depth interviews with prosumer households. These interviews reveal a broad variety of behavioral responses which have their roots in economic conditions and their evaluation by the prosumers, psychological mechanisms like central guiding principles and a clear conscience as well as sociotechnical context and legislative frameworks. [ABSTRACT FROM AUTHOR]

The European Union's ambitious target to achieve zero emissions from passenger cars by 2035 has sparked significant strategic overhauls among European car manufacturers, pushing them towards a 100% electric vehicle fleet. Concurrently, a forthcoming heating law, slated to take effect from 2024 initially in Germany, aims to drastically curtail the installation of gas and oil heating systems in favour of heat exchangers. These legislative shifts are already straining the power grid, necessitating a substantial expansion of renewable energy capacity. Projections indicate an ongoing surge in energy demand, underscoring the imperative of a global transition away from fossil fuels. However, this endeavour poses formidable challenges for nations worldwide. This study delves into the current state of renewable energy and its projected evolution, stressing the imperative of significantly boosting renewable energy deployment to achieve sustainable electrification of passenger vehicles globally. It highlights the need to triple the share of renewable energy sources, quadruple efforts across all transportation sectors, and increase the overall transition away from fossil fuels fifteenfold. While conventional renewables such as solar, wind, hydro, and biofuels remain integral, emerging technologies like nuclear fusion offer promising avenues. Nonetheless, attaining complete independence from fossil fuels may prove elusive, considering non-energy applications of crude oil and other fossil resources. The study also assesses potential ecological ramifications and balances the environmental impacts of these energy transitions. [ABSTRACT FROM AUTHOR]

Low-carbon energy requires more land than the non-renewable resources. This paper balances holistic assessments of the land demands for biomass heating and their ecosystem services. It is predicted that biomass will continue to play an important role in the heating sector in Germany by 2050, as it is one way to increase the use of renewable energy and reduce CO2 emissions. To balance this out, it is important to ensure that the substitution of fossil fuels with fuelwood does not result in losses in biodiversity, natural forest, and agricultural land. Based on the observed types of fuel demand, the need for space in terms of the growing area is characterized as the corresponding land under the consideration of a given land-use type. Formulas have been applied at the federal level in Germany. The area required to supply an average German household is 0.64 ha if all the wood harvested is used for energy purposes, but this is in competition with all other types of timber use. Fuelwood from thinning alone cannot meet the domestic demand. However, a sustainable supply of woody biomass is possible if residues mainly from forestry and the wood processing industry are used, causing a land demand of 2.69 ha per house, possibly in combination with smaller shares of the above-mentioned types of use. Thus, the shares of pellets and wood chips for heating purposes should be expanded, which would also bring ecological advantages. The qualitative consideration of forest ecosystem services shows that changing the forest composition or management may increase the fuelwood supply but does not necessarily decrease forest ecological services. [ABSTRACT FROM AUTHOR]

Fixed feed-in tariffs based on the Renewable Energy Act grant secure revenues from selling electricity for wind turbine operators in Germany. Anyhow, the level of federal financial support is being reduced consecutively. Plant operators must trade self-sufficiently in the future and hence generate revenue by selling electricity directly on electricity markets. Therefore, uncertain future market price developments will influence investment considerations and may lead to stagnation in the expansion of renewable energies. This study estimates future revenue potentials of non-subsidized wind turbines in Germany to reduce this risk. The paper introduces and analyses a forecasting model that generates electricity price time series suited for revenue estimation of wind turbines based on the electricity exchange market. Revenues from the capacity market are neglected. The model is based on openly accessible data and applies a merit-order approach in combination with a simple agent-based approach to forecast long-term day-ahead prices at an hourly resolution. The hourly generation profile of wind turbines can be mapped over several years in conjunction with fluctuations in the electricity price. Levelized revenue of energy is used to assess both dynamic variables (electricity supply and price). The meritorder effect from the expansion of renewables as well as the phasing out of nuclear energy and coal are assessed in a scenario analysis. Based on the assumptions made, the opposing effects could result in a constant average price level for Germany over the next 20 years. The influence of emission prices is considered in a sensitivity analysis and correlates with the share of fossil generation capacities in the generation mix. In a brief case study, it was observed that current average wind turbines are not able to yield financial profit over their lifetime without additional subsidies for the given case. This underlines a need for technical development and new business models like power purchase agreements. The model results can be used for setting and negotiating appropriate terms, such as energy price schedule or penalties for those agreements. [ABSTRACT FROM AUTHOR]

This paper provides an empirical analysis of CO2emissions and economic growth, renewable energy consumption, and energy consumption over the period 1975–2014 in Germany. This paper uses the autoregressive distributed lag (ARDL) approach of cointegration test and vector error-correction models. The unit root and cointegration tests show that the long-run relationship between CO2emissions and its determinants. The empirical results show that the findings do not support the environmental Kuznets curve between real GDP and CO2emissions. To estimate the shocks of renewable energy consumptions, the study applies the dynamic test of Impulse Response Function (IRF) under the VAR method. The increasing portion of renewable energy consumption in electricity generation would have no impacts on the environment. However, the hikes of renewable energy sources would incur more cost to electricity producers and shrivel up the growth of economies through the expansionary effect of industry’s consumption and private capital spending in the Germany’s economy. [ABSTRACT FROM AUTHOR]

The large-scale integration of renewable energy sources requires flexibility from power markets in the sense that the latter should quickly counterbalance the renewable supply variation driven by weather conditions. Most power markets cannot (yet) provide this flexibility effectively as they suffer from inelastic demand and insufficient flexible storage capacity or flexible conventional suppliers. Research accordingly shows that the volume of renewable energy in the supply system affects the mean and volatility of power prices. We extend this view and show that the level of wind and solar energy supply affects the tails of the electricity price distributions as well and that it does so asymmetrically. The higher the supply from wind and solar energy sources, the fatter the left tail of the price distribution and the thinner the right tail. This implies that one cannot rely on symmetric price distributions for risk management and for valuation of (flexible) power assets. The evidence in this paper suggests that we have to rethink the methods of subsidizing variable renewable supply such that they take into consideration also the flexibility needs of power markets. [ABSTRACT FROM AUTHOR]

This paper aims to provide a holistic analysis of the role of hydrogen for achieving greenhouse gas neutrality in Germany. For that purpose, we apply an integrated energy system model which includes all demand sectors of the German energy system and optimizes the transformation pathway from today's energy system to a future cost-optimal energy system. We show that 412 TWh of hydrogen are needed in the year 2045, mostly in the industry and transport sector. Particularly, the use of about 267 TWh of hydrogen in industry is essential as there are no cost-effective alternatives for the required emission reduction in the chemical industry or in steel production. Furthermore, we illustrate that the German hydrogen supply in the year 2045 requires both an expansion of domestic electrolyzer capacity to 71 GW H2 and hydrogen imports from other European countries and Northern Africa of about 196 TWh. Moreover, flexible operation of electrolyzers is cost-optimal and crucial for balancing the intermittent nature of volatile renewable energy sources. Additionally, a conducted sensitivity analysis shows that full domestic hydrogen supply in Germany is possible but requires an electrolyzer capacity of 111 GW H2. • 412 TWh of hydrogen demand in a greenhouse gas neutral Germany in the year 2045. • Hydrogen usage is crucial for defossilization of chemical and steel industry. • 47% of hydrogen is imported from other European countries and Northern Africa. • 71 GW H2 of electrolyzer capacity in Germany with flexible operation. • 35 TWh of hydrogen storage in salt caverns for security of supply. [ABSTRACT FROM AUTHOR]

High level of greenhouse gases emission in fossil fuels has induced a significant transition from conventional energy sources to renewable energy. However, using renewable energy in electricity grids has limitations, such as intermittency and lack of efficient energy storage. This paper focuses on constructing the quanto options contract to help renewable energy producers hedge the risk against low photovoltaic (PV) production and electricity prices. To achieve our objective, we first model the interday PV power production with a combination of a deterministic and stochastic model. We analyse empirical data for daily solar production in three operators in Germany ranging from 1 January 2016 to 31 December 2020. We discovered that all estimated parameters of the deterministic process are highly significant. Meanwhile,we use an autoregressive (AR) process to describe the random behavior in the production. The results demonstrated that AR(2) is suitable enough to explain its stochastic factor. For the error terms analysis, we observed a clear sign of seasonal heteroskedasticity supported by the left skewed density. In addition, we observed a clear seasonal pattern in the squared error terms, where we suggest using seasonal variance and skewed normal distribution to describe its dynamic. As for an application, we embed the PV model in the power price modeling. We found that AR(3) process is sufficient to explain the price behavior and that normal distribution best fits the error terms. Using the suggested PV and power price model, we construct the quanto options contract for renewable energy producers using Monte Carlo simulations. We discovered that the electricity price payoffs are consistent throughout the year, whereas PV and quanto options payoffs vary greatly depending on the season. The quanto options price result shows that the prices vary during four seasons, with the highest variation in July. [ABSTRACT FROM AUTHOR]

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Legislative efforts for renewables-based energy decarbonisation hinge upon the support and commitment from different stakeholders holding often conflicting positions regarding disruptive processes of socio-technical transformation. However, the evolving acceptance of market actors on the policy-driven promotion of renewables over time remains under-scrutinised. Simultaneously, despite growing attention to power and politics in sustainability transitions, limited efforts remain invested for elucidating the political-economic nature of the market-based selection environments they are operationalised through, highlighting the need for a more systematic comprehension of the "politics of selection". To address these shortcomings, this paper provides a more refined understanding of the role of policy-driven markets and its participating agents in facilitating/hindering innovation diffusion and broader (system-wide) sustainability transitions. To do so, it showcases a longitudinal case study of the politics underlying Germany's evolving feed-in policy support framework for orchestrating a market-mediated diffusion of renewables (1980s–2020). Based on policy analysis and semi-structured interviews, the study traces the changing acceptance and ensuing strategic (re)actions of market actors to the emergence and evolution of Germany's market for electricity from renewable energy sources. Results show how different market participants effectively shape the selection environments they operate in by proactively contesting/deluding the design features of the support policies organising their economised relations (e.g., market entry conditions, exchange rules, remuneration levels, pricing schemes, etc.). Such efforts are undertaken through legal means and market framing strategies targeting the affordability of policy support costs, coupled with the strategic use of policy instrumentation as a vehicle to further expand/retain their market shares to the detriment of competing actors. [ABSTRACT FROM AUTHOR]

The present paper considers the problem of choosing among a collection of competing electricity price forecasting models to address a stochastic decision-making problem. We propose an event-based evaluation framework applicable to any optimization problem, where uncertainty is captured through ensembles. The task of forecast evaluation is simplified from assessing a multivariate distribution over prices to assessing a univariate distribution over a binary outcome directly linked to the underlying decision-making problem. The applicability of our framework is demonstrated for two exemplary profit-maximization problems of a risk-neutral energy trader, (i) the optimal operation of a pumped-hydro storage plant and (ii) the optimal trading of subsidized renewable energy in Germany. We compare and contrast the approach with the full probabilistic and profit–loss-based evaluation frameworks. It is concluded that the event-based evaluation framework more reliably identifies economically equivalent forecasting models, and in addition, the results suggest that an event-based evaluation specifically tailored to the rare event is crucial for decision-making problems linked to rare events. [ABSTRACT FROM AUTHOR]

Summary: The transition to an intermittent energy production from renewable energy sources (RES) increases the complexity of providing reliable energy supply in Germany. Yet the growing number of RES impede the necessary effort to control the system. The introduction of digital or smart energy systems is often proclaimed as a logical next step towards coping with this rising complexity. It seems convenient that the manufacturing industry, as one of the major energy consumers, is currently also in a process of a digital transition, the fourth industrial revolution. This paper explores the current state of expert discourse on the role of a digitized industry as a potential enabler for the energy transition using Germany as a case study. For this purpose, we gathered qualitative data through semistructured interviews among industry managers and energy researchers. We identified the three major areas in the expert discourse of industry's future potentials: (1) increasing transparency in the energy system, (2) providing demand flexibility, and (3) increasing energy efficiency. In this paper, we address the internal barriers and explore industry's reluctance to interact with the energy system in order to initiate a transition. [ABSTRACT FROM AUTHOR]

Schools play an important role in achieving climate protection goals, because they lay the foundation of knowledge for a responsible next generation. Therefore, schools as institutions have a special role model function. Enabling schools to become aware of their own carbon footprint (CF) is an important prerequisite for being able to tap the substantial CO2 reduction potential. Aiming at the direct involvement of students in the assessment process, a new assessment tool was developed within the Schools4Future project that gives students the opportunity to determine their own school's CF. With this instrument the CO2 emissions caused by mobility, heating and electricity consumption as well as for food in the school canteen and for consumables (paper) can be recorded. It also takes into account existing renewable energy sources. Through the development of the tool, not only a monitoring instrument was established but also a concrete starting point from which students could take actions to reduce Greenhouse Gas (GHG) emissions. This paper presents the tool and its methods used to calculate the CF and compares it with existing approaches. A comparative case study of four pilot schools in Germany demonstrates the practicability of the tool and reveals fundamental differences between the GHG emissions. [ABSTRACT FROM AUTHOR]

Prediction of weather is a main goal of atmospheric science. Its importance to society is growing continuously due to factors such as vulnerability to natural disasters, the move to renewable energy sources, and the risks of climate change. But prediction is also a major scientific challenge due to the inherently limited predictability of a chaotic atmosphere, and has led to a revolution in forecasting methods as we have moved to probabilistic prediction. These changes provide the motivation for Waves to Weather (W2W), a major national research program in Germany with three main university partners in Munich, Mainz, and Karlsruhe. We are currently in the second 4-yr phase of our planned duration of 12 years and employ 36 doctoral and postdoctoral scientists. In the context of this large program, we address what we have identified to be the most important and challenging scientific questions in predictability of weather, namely, upscale error growth, errors associated with cloud processes, and probabilistic prediction of high-impact weather. This paper presents some key results of the first phase of W2W and discusses how they have influenced our understanding of predictability. The key role of interdisciplinary research linking atmospheric scientists with experts in visualization, statistics, numerical analysis, and inverse methods will be highlighted. To ensure a lasting impact on research in our field in Germany and internationally, we have instituted innovative programs for training and support of early-career scientists, and to support education, equal opportunities, and outreach, which are also described here. [ABSTRACT FROM AUTHOR]

Many countries plan to decarbonise their energy systems by increasing energy efficiency and expanding the use of renewable energy sources (RES). Such actions require significant investments in new energy infrastructures. While people are generally accepting of these infrastructures, opposition sometimes arises when these developments are sited at close proximity to people's residences. Therefore, it is important to understand what actually drives people's preferences for spatial proximity to different energy infrastructure technologies. This study examines the factors influencing people's proximity preferences to a range of different energy technologies using a cross-country econometric analysis of the stated preference data from an unprecedented survey conducted on nationally representative samples of the population in Ireland, the U.S. and Germany. The survey involved more than 4,500 participants in total. This paper presents the data and selected results from a generalised ordered logit model for each energy technology surveyed. These are; wind turbines, solar power technology, biomass power plant, coalfired power plant and natural gas power plant. The results show that, in general, German and Irish citizens are willing to accept energy infrastructures at smaller distances to their homes than their U.S. counterparts. Moreover, attitudinal factors are found to shape people's preferences more consistently than any of the socio-demographic characteristics. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Water & Land Development is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Transformation concepts towards a low-carbon society often require new technology and infrastructure that evoke protests in the population. Therefore, it is crucial to understand positions and conflicts in society to achieve social acceptance. This paper analyses these positions using the example of implementing hydrogen and carbon capture and storage infrastructure to decarbonise the German energy system. The empirical basis of the study are explorative stakeholder interviews which were conducted with experts from politics, economics, civil society and science and analysed within a discursive and attitudinal framework using qualitative content analysis. These stakeholder positions are assumed to represent dominant social perceptions and reflect chances and risks for acceptance. The results indicate different positions while pursuing the common goal of addressing climate change. The general conflict concerns strategies towards a low-carbon society, especially the speed of phasing-out fossil energies. Regarding the combination of hydrogen and carbon capture and storage as instrument in the context of the energy transition, the stakeholder interviews indicate controversial as well as consensual perceptions. The assessments range from rejection to deeming it absolutely necessary. Controversial argumentations refer to security of supply, competitiveness and environmental protection. In contrast, consensus can be reached by balancing ecological and economic arguments, e.g. by linking hydrogen technologies with renewable and fossil energy sources or by limiting the use of carbon capture and storage only to certain applications (industry, bioenergy). In further decisions, this balancing of arguments combined with openness of technology, transparency of information and citizen participation need to be considered to achieve broad acceptance. [ABSTRACT FROM AUTHOR]

This paper presents an econometric analysis of curtailment costs of renewable energy sources (RES) in Germany. The study aims at explaining and quantifying the regional variability of RES curtailment, which is a measure to relieve grid overstress by temporarily disconnecting RES from the electricity grid. We apply a Heckit sample selection model, which corrects bias from non-randomly selected samples. The selection equation estimates the probability of occurrence of RES curtailment in a region. The outcome equation corrects for cross-sectional dependence and quantifies the effect of RES on curtailment costs. The results show that wind energy systems connected to the distribution grid increase RES curtailment costs by 0.7% per MW (or 0.2% per GWh) in subregions that have experienced RES curtailment over the period 2015-2017. The implication of this finding is that policymakers should set price signals for renewables that consider the regional grid overstress, in order to mitigate the cost burden on consumers due to excess generation from RES. [ABSTRACT FROM AUTHOR]

Short-term forecasting of electricity generation from variable renewable energy sources is not an end in itself but should provide some net benefit to its user. In the case of electricity trading, which is in the focus of this paper, the benefit can be quantified in terms of an improved economic outcome. Although some effort has been made to evaluate and to improve the profitability of electricity forecasts, the understanding of the underlying effects has remained incomplete so far. In this paper, we develop a more comprehensive theoretical framework of the connection between the statistical and the economic properties of day-ahead electricity forecasts. We find that, apart from the accuracy and the bias, which have already been extensively researched, the correlation between the forecast errors and the market price spread determines the economic implications - a phenomenon which we refer to as 'correlation effect'. Our analysis is completed by a case study on solar electricity forecasting in Germany which illustrates the relevance and the limits of both our theoretical framework and the correlation effect. • The economics of short-term electricity forecasts are studied analytically and empirically. • The value and the risk of forecast-based electricity trading are evaluated. • We find that the economics depend on the correlation of forecast errors with prices. • Hence, the most accurate forecast is not necessarily the most accurate. [ABSTRACT FROM AUTHOR]

Hybrid micro-grid systems (HMGS) are gaining increasing attention worldwide. The balance between electricity load and generation based on fluctuating renewable energy sources is a main challenge in the operation and design of HMGS. Battery energy storage systems are considered essential components for integrating high shares of renewable energy into a HMGS. Currently, there are very few studies in the field of mathematical optimisation and multi-criteria decision analysis that focus on the evaluation of different battery technologies and their impact on the HMGS design. The model proposed in this paper aims at optimising three different criteria: minimising electricity costs, reducing the loss of load probability, and maximising the use of locally available renewable energy. The model is applied in a case study in southern Germany. The optimisation is carried out using the C-DEEPSO algorithm. Its results are used as input for an AHP-TOPSIS model to identify the most suitable alternative out of five different battery technologies using expert weights. Lithium batteries are considered the best solution with regard to the given group preferences and the optimisation results. [ABSTRACT FROM AUTHOR]

A power system with 80% renewable energy sources (RES) requires significant provision of flexibility to balance the deviations of fluctuating solar and wind power. This paper focuses on how a smart mix of renewable generation technologies can reduce the demand for flexibility and therefore the overall system costs. To measure the demand for flexibility in systems with high RES generation, the term flexibility is defined and described using predictable indicators such as the difference between the highest and the lowest residual demand or the number of hours with negative residual load during a year. This definition is required to determine the optimal mix of RES installations. Optimization is performed for Germany based on the grid development plan of the transmission system operators. In contrast to most studies of the future energy system that foresee a further expansion of onshore wind, this paper shows that higher shares of offshore wind and, to some extent, photovoltaic are better suited to reducing the demand for flexibility and thus the cost of integrating fluctuating RES into the system. • Extended definition of flexibility demand for power systems based on renewables. • Offshore wind and photovoltaic requires less flexibility than onshore wind. • Uncertainty about the future renewable mix increases system integration costs. • Challenge: trade-off between levelized cost of generation and system integration. [ABSTRACT FROM AUTHOR]

This paper identifies socioeconomic factors that are supposed to impact the investment decision of private households in Germany regarding small-scale solar PV (photovoltaic) systems. In 2022, the last nuclear power plant will phase out and the end of coal-fired power plants is fixed for 2038. Thus, the legislator is mandated to foster the addition of renewable energy capacities to close the gap fossil fuels and nuclear power leaves. Some share of the renewable energies could be from private households that mainly invest in small-scale solar PV systems. To stimulate investments, it is necessary to identify factors that are important for the investment decisions of private households. Within this paper, secondary socioeconomic data for the period from 2009–2018 was compiled. In order to identify the latent variables, a factor analysis was conducted. The results state five factors that are supposed to impact the investment decisions of the prosumer in Germany. [ABSTRACT FROM AUTHOR]