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• Imported green e-H 2 is more expensive than e-H 2 produced in Germany and Finland. • Local supply of e-H 2 found to be more economical across all scenarios and years. • Transportation costs constitute 29–63% of the total imported e-H 2 cost. • Pipeline transmission may be cheaper than shipping for distances of 2000–2500 km. Widely available and low-cost solar photovoltaics and wind power can enable production of renewable electricity-based hydrogen at many locations throughout the world. Hydrogen is expected to emerge as an important energy carrier constituting some of the final energy demand; however, its most important role will be as feedstock for further processing to e-fuels, e-chemicals, and e-steel. Apart from meeting their own hydrogen demand, countries may have opportunities to export hydrogen to countries with area limitations or higher production costs. This paper assesses the feasibility of e-hydrogen imports to Germany and Finland from two case regions with a high availability of low-cost renewable electricity, Chile and Morocco, in comparison to domestic supply. Special attention is paid to the transport infrastructure, which has a crucial impact on the economic viability of imports via two routes, shipping and pipelines. This study has found that despite lower e-hydrogen production costs in Morocco and Chile compared to Germany and Finland, additional transportation costs make imports of e-hydrogen economically unattractive. In early 2020s, imported fuel costs are 39–79% and 34–100% higher than e-hydrogen produced in Germany and Finland, respectively. In 2050, imported e-hydrogen is projected to be 39–70% more expensive than locally produced e-hydrogen in Germany and 43–54% in the case of Finland. e-Hydrogen may become a fuel that is mostly produced domestically and may be feasible for imports only in specific locations. Local e-hydrogen production may also lower dependence on imports, enhance energy security, and add jobs. [ABSTRACT FROM AUTHOR]

In Germany, policy-induced energy efficiency improvements typically aim at reducing primary energy consumption. Private households, on the contrary, pursue the maximization of wellbeing or, in microeconomics jargon, the maximization of utility of the occupants. There is a marked difference between upfront-calculated energy performance ratings (EPRs) and actual heat energy consumption (HEC). From an energy and environmental policy point of view, deviations of energy consumption from ex ante calculated EPRs is problematic, as it jeopardizes their usefulness for (prospective) homeowners, policy-makers and researchers relying on EPRs as a guidance. The EPR-HEC gaps reported are, apart from deviations from the mean aggregate values (i.e. heterogeneity), often attributed to anticipated or unanticipated behavioral effects. From an energy economist's point of view, energy rebound induced by lowered costs per unit of energy service due to increased energy efficiency is one explanation. The related literature almost entirely treats building-specific EPRs as universal standards, trying to explain the empirically observed discrepancies. In this paper, we investigate to what extent the current EPR scheme in place in Germany today can address behavioral issues. To this end, based on two different multi-family housing data sets for Germany and regression analysis, we empirically investigate the deviations between EPRs used in the regulatory norms and the HEC levels observed in reality. We find evidence that it is not necessarily the behavioral dimension, but rather the static and mostly technically guided calculation of the EPRs itself that accounts for the major part of the deviations. We conclude that there is indeed a need for further improvements in the field of EPR regulation and methodology. [ABSTRACT FROM AUTHOR]

This paper deals with possibilities of targeting energy efficiency potentials in German companies by delivering information and support within a cooperative management system “Learning Energy Efficiency Networks” (LEEN). Information deficits are pointed out as a relevant barrier to implementing energy efficiency measures in literature that can be aimed at by energy programmes such as audits. Our concept combines aspects of cooperation, shared experiences and moderated learning processes. The programme sought to go beyond the sole provision of consultation, by qualifying companies to decide and act on implementing energy efficiency measures by delivering the individual practical know-how they need. After having analysed evaluation data of several hundred companies, our results show that the participants were mainly motivated by the need for practical knowledge and specific information. The networks could well satisfy this need. The benefit for the participants in such delivered information was also reflected in the decreasing of the barrier of imperfect information and the programme enabled companies to make informed decisions on energy efficiency measures. But the gain of the programme was not solely restricted on an increase in knowledge: The majority of participants reported implementation of suggested measures, which would not have been implemented without the programme. Hence, LEEN can be indicated as a policy instrument enabling informed decisions on efficiency measures and supporting their implementation. Possibly tailoring the programme to different target groups and aiming at dismantling other barriers directly in addition to tackling information deficits could be undertaken to improve the process. [ABSTRACT FROM AUTHOR]

The iron and steel industry is a major industrial emitter of carbon dioxide globally and in Germany. If European and German climate targets were set as equal proportional reduction targets (referred to here as “flat” targets) among sectors, the German steel industry would have to reduce its carbon dioxide emissions from about 60 million metric tons currently to 28–34 million metric tons by 2030. Technical options to further reduce CO 2 that are based on existing production processes are limited. Hence, in the future, the CO 2 emissions of the steel industry could be reduced by alternative and new production processes and variations in production levels. This paper describes four production pathways from 2015 to 2035 that reveal the impact of constant, increasing and decreasing production levels as well as different production processes. The diffusion of energy-efficient technologies, the increase of renewables in the German electricity mix and the age and lifetime of blast furnaces are considered as well. The findings suggest that the German steel sector will only manage to achieve its European CO 2 emissions reduction target for 2030 if it strongly decreases its production levels. Furthermore, it is highly unlikely that the German steel sector will meet its German climate target regardless of the production pathway selected. The findings suggest that efforts to reduce CO 2 emissions in the steel industry should focus on two areas. First, alternative steelmaking processes need to be developed. Besides low-CO 2 process technologies, CO 2 -free processes should be considered as well. Direct reduced iron could be produced based on hydrogen and then fed into an electric arc furnace powered by electricity generated using CO 2 -free sources. Steel could also be produced using electrolysis based on CO 2 -free electricity. However, because these technologies might take decades to develop and introduce, there should be a second focus on incremental CO 2 reductions in the short to medium term. [ABSTRACT FROM AUTHOR]

• Earlier phase-out of coal is not the best answer to achieve energy transition. • The 2050 plan and historical RES investments maxima are not enough to reach climate neutrality. • What is the effect of regional RES limits over Nationwide RES limits. • Where will be the states in Germany having major RES deployment. • Myopic optimization reveals new challenges for energy policy. This paper will introduce the open-source model MyPyPSA-Ger, a myopic optimization model developed to represent the German energy system with a detailed mapping of the electricity sector, on a highly disaggregated level, spatially and temporally, with regional differences and investment limitations. Furthermore, this paper will give new outlooks on the German federal government 2050 emissions goals of the electricity sector to become greenhouse gas neutral by proposing new CO 2 allowance strategies. Moreover, the regional differences in Germany will be discussed, their role and impact on the energy transition, and which regions and states will drive the renewable energy utilization forward. Following a scenario-based analysis, the results point out the major keystones of the energy transition path from 2020 to 2050. Solar, onshore wind, and gas-fired power plants will play a fundamental role in the future electricity systems. Biomass, run of river, and offshore wind technologies will be utilized in the system as base-load generation technologies. Solar and onshore wind will be installed almost everywhere in Germany. However, due to the nature of Germany's weather and geographical features, the southern and northern regions will play a more important role in the energy transition. Higher CO 2 allowance costs will help achieve the 1.5-degree-target of the electricity system and will allow for a rapid transition. Moreover, the more expensive, and the earlier the CO 2 tax is applied to the system, the less it will cost for the energy transition, and the more emissions will be saved throughout the transition period. An earlier phase-out of coal power plants is not necessary with high CO 2 taxes, due to the change in power plant's unit commitment, as they prioritize gas before coal power plants. Having moderate to low CO 2 allowance cost or no clear transition policy will be more expensive and the CO 2 budget will be exceeded. Nonetheless, even with no policy, renewables still dominate the energy mix of the future. However, maintaining the maximum historical installation rates of both national and regional levels, with the current emissions reduction strategy, will not be enough to reach the level of climate-neutral electricity system. Therefore, national and regional installation requirements to achieve the federal government emission reduction goals are determined. Energy strategies and decision makers will have to resolve great challenges in order to stay in line with the 1.5-degree-target. [ABSTRACT FROM AUTHOR]

The Solar Decathlon is a competition for universities from all over the world which focuses on designing, building and operating experimental, solar-powered houses. Participating in the project offers universities a unique and interdisciplinary platform for teaching, learning and research which combines practical experience with research. In 2022, the European edition was held in Germany for the first time. The event took place with a new urban profile to increase both the relevance of the competition and the learning experience. Its main topic was the further development of the European city, and specifically focused on the existing stock of residential apartment buildings. A total of 18 teams from 11 countries with over 500 students took part, with 16 teams ultimately building their houses on a shared solar campus. Demonstrating a balanced or a positive energy balance in practice was one of the essential goals of the competition. This was achieved by 13 of 15 projects in the energy contest. The prerequisites for this were a high level of energy efficiency and the consistent use of solar energy. Both strategies were embedded in convincing architectural concepts. These ranged from the minimised visibility of standard systems on rooftops, through to custom-built systems with full architectural integration in façades. Hybrid solar systems also became a focus, with the goal of making optimum use of the surfaces on the building envelope. This paper focuses on the energy engineering and technical and architectural integration of the solar systems. It also includes the results achieved in the competition linked to the learning experience. [ABSTRACT FROM AUTHOR]

Energy efficiency retrofits are often impeded by high perceived investment risks, long payback periods and a lack of skills. At the municipal level these issues are particularly pronounced as procuring, implementing, and managing retrofits can exceed existing municipal governance capacities. The diffusion of municipal LED street lighting as a replacement for conventional lighting serves as an example. This paper argues that technological (e.g. complexity and maturity), economic (e.g. selling services vs. products and financing costs), institutional (e.g. property situation and contracts) and competency barriers to retrofitting (e.g. lack of measurement capacity and qualified facilitators) translate into transaction costs. We develop a taxonomy of appropriate modes of municipal retrofitting governance based on transaction costs economics. The findings indicate that more market-based solutions, energy performance contracts in particular, can facilitate the procurement of innovative energy efficiency retrofitting solutions and associated investments among municipalities if neutral tenders, open-book accounting, municipal ownership and intermediary organisations allow municipalities to choose appropriate governance structures for particular technologies and retrofits. [ABSTRACT FROM AUTHOR]

Zero Energy Buildings (ZEBs) are considered as one of the key elements to meet the Energy Strategy of the European Union. This paper investigates cost-optimal solutions for the energy system design in a ZEB and the subsequent grid impact. We use a Mixed Integer Linear (MILP) optimisation model that simultaneously optimises the building’s energy system design and the hourly operation. As a ZEB have onsite energy generation to compensate for the energy consumption, it is both importing and exporting electricity. The hourly time resolution identifies the factors that influence this import/export situation, also known as the building’s grid impact. An extensive case study of a multi-family house in Germany is performed. The findings show that the energy system design and the grid impact greatly depend on the ZEB definition, the existing policy instruments and on the current energy market conditions. The results indicate that due to the feed-in-tariff for PV, the cost-optimal energy design is fossil fuelled CHP combined with a large PV capacity, which causes large grid impacts. Further, we find that heat pumps are not a cost-optimal choice, even with lower electricity prices or with increased renewables in the electric power system. [ABSTRACT FROM AUTHOR]

District heating is expected to play an essential role in the cost-effective decarbonisation strategy of many countries. Resource-optimised management of district heating networks depends on a wide range of factors, including demand forecasting, operational flexibility, and increasingly volatile market conditions. However, traditional operations often still rely on static models and rather simple heuristics, while holistic optimisation requires dynamic cross-domain interoperability to allow the consideration of all these factors. This paper demonstrates a proof-of-concept for a knowledge graph based optimisation problem to minimise total heat generation cost for a district heating provider. The optimisation follows a hierarchical approach based on a merit-order principle and is embedded in a model predictive control framework to allow the system to incorporate most recent information and react to disturbances promptly. A detailed sensitivity study is conducted to identify key model parameters and assess the impact of anticipated changes in regulation and market conditions. Simulation-based optimisation is used to determine the short-term heat generation mix based on data-driven gas consumption models and day-ahead forecasts for the network's energy demand and grid temperatures. Seasonal autoregressive integrated moving average models with exogenous predictor variables are found to be sufficiently accurate and precise. The effectiveness of the approach is demonstrated for a case study of an existing heating network of a midsize town in Germany, where a reduction of approximately 20% and 40% compared to baseline operational data is obtained for operating cost and CO 2 emissions, respectively. [Display omitted] • Developed heat generation optimisation framework for district heating providers. • Identified key cost drivers and market dynamics using a detailed sensitivity analysis. • Developed high accuracy time series forecasting models for key input variables. • Assessed optimisation effectivity using a German municipal utility case study. • Improvement potential for operational cost and CO 2 emissions both exceed 20%. [ABSTRACT FROM AUTHOR]

Prosuming combines energy production and consumption on a decentralised level and can contribute to expanding renewable energies and integrating intermittent energy in a decarbonised energy system. This is only one way that conventional electricity consumers can become active agents in electricity systems, but the current literature lacks a comprehensive typology of this field. Furthermore, the literature on prosuming focuses on households and largely neglects organisations. Addressing these two gaps in the literature, this paper first suggests a typology of eight archetypes that encompass electricity production, demand management, and storage as dimensions. Second, it maps the decision-making process for prosuming infrastructure in small and medium-sized organisations based on 14 in-depth interviews from Germany. To better understand the implementation processes of prosuming infrastructure and to identify critical success factors for organisations to become active electricity agents, it outlines a comprehensive collection of motives, drivers and barriers that are shaped by the organisational context and play a significant role when organisations become energy prosumers. [ABSTRACT FROM AUTHOR]

• Linking top-down energy efficiency indicator analysis with bottom-up policy analysis. • Explaining the contribution of energy efficiency policies in Germany and Switzerland. • Analysing the counteracting effects to energy policy of rebound and non-compliance. This paper studies the factors underlying the evolution of the energy consumption for space heating in residential buildings by linking top-down analysis, based on meso -indicators, and bottom-up analysis, based on policy evaluations. The top-down analysis (i.e. the perspective from energy statistics) allows one to separate the change in total energy use into activity level, societal factors and energy efficiency gains. The explanatory power of the resulting meso-(statistical) indicators is often limited, if the underlying factors are not examined (e.g. changes in heating levels and patterns, weather effects, cost of energy and policies regarding insulation and heating system standards). We overcome most of these drawbacks by conducting a bottom-up analysis (i.e the perspective from single policy measures), which enables us to discern the contribution of energy efficiency policies to the changes observed with the meso -analysis. We focus on space heating consumption in the residential sectors for Germany and Switzerland. A major aim of this analysis is to show the contribution of energy efficiency policies (such as thermal building regulation, subsidy programmes, fiscal measures etc.) towards the changes in this indicator. The results show that the progress in energy efficiency (both autonomous and policy induced) in both countries had the greatest effect (-776 PJ for Germany, −42 PJ for Switzerland) regarding the change in energy consumption for space heating in the period from 2000 to 2016. However, the impacts of "technical and comfort" rebounds (+436 PJ for Germany, N/A for Switzerland) and other developments such as societal changes (+316 PJ for Germany, +35.5 PJ for Switzerland) were found to compensate for a significant part of the energy efficiency gains. In both countries, it was possible to link physical energy efficiency indicators to policy evaluation, but limitations were also identified which are primarily related to data gaps. [ABSTRACT FROM AUTHOR]

• A new retrofitting strategy by using prefabricated elements window machine. • Minimization of the renovation costs and speeding up the retrofit action. • A potential in energy saving and improving the Indoor Environment Quality. • Further significance in retrofit and healthy home office working environments. The renovation of existing residential buildings across Europe has become a key factor for energy saving and the improvement of Indoor Environment Quality (IEQ). This paper presents an investigation of IEQ for a typical 1960s single-family house in Germany before and after a new retrofitting strategy (prefabricated element with integrated ventilation and new thermal envelope). In-situ measurements were applied to investigate the energy efficiency and IEQ improvement for the new retrofitting strategy in temperate winter regions of Europe. The simulation model replicates the measured data to be closer to reality and simulates a home office (COVID-19) scenario. The in-situ measurements showed that our retrofitting strategy increases the indoor air temperature during the heating period by up to 2.5 °C, decreases relative humidity by up to 3.8% and increases CO 2 by up to 24 ppm than before. As the simulation results shows, the retrofitted home office scenario allows a reduction in heating energy of up to 77%, an increase in CO 2 concentration of up to 41.8 ppm, 0.5% less relative humidity and 1.6 °C higher indoor air temperature than that without retrofitting. The new approach to retrofit residential buildings thus showed a potential in energy saving and improving the IEQ. [ABSTRACT FROM AUTHOR]

[Display omitted] • Open model-based analysis for 100% renewable and sector-coupled energy systems. • Cost-optimization tool based on Oemof to investigate Germany's energy system in 2050. • Renewable energy is sufficient for electricity and building heat in Germany in 2050. • Investment cost (bn €/yr): 17.6–26.6 (Volatile), 23.7–28.8 (Heat), 2.7–3.9 (Storage). • Energy mix and LCOE comparison validate the developed tool's effectiveness. The ambitious energy target to achieve climate-neutrality in the European Union (EU) energy system raises the feasibility question of using only renewables across all energy sectors. As one of the EU's leading industrialized countries, Germany has adopted several climate-action plans for the realistic implementation and maximum utilization of renewable energies in its energy system. The literature review shows a clear gap in comprehensive techniques describing an open modeling approach for analyzing fully renewable and sector-coupled energy systems. This paper outlines a method for analyzing the 100% renewable-based and sector-coupled energy system's feasibility in Germany. Based on the open energy modeling framework, an hourly optimization tool 'OSeEM-DE' is developed to investigate the German energy system. The model results show that a 100% renewable-based and sector-coupled system for electricity and building heat is feasible in Germany. The investment capacities and component costs depend on the parametric variations of the developed scenarios. The annual investment costs vary between 17.6 and 26.6 bn €/yr for volatile generators and between 23.7 and 28.8 bn €/yr for heat generators. The model suggests an investment of a minimum of 2.7–3.9 bn €/yr for electricity and heat storage. Comparison of OSeEM-DE results with recent studies validates the percentage-wise energy mix composition and the calculated Levelized Cost of Electricity (LCOE) values from the model. Sensitivity analyses indicate that storage and grid expansion maximize the system's flexibility and decrease the investment cost. The study concludes by showing how the tool can analyze different energy systems in the EU context. [ABSTRACT FROM AUTHOR]

When COVID-19 pandemic spread in Europe, governments imposed unprecedented confinement measures with mostly unknown repercussions on contemporary societies. In some cases, a considerable drop in energy consumption was observed, anticipating a scenario of sizable low-cost energy generation, from renewable sources, expected only for years later. In this paper, the impact of governmental restrictions on electrical load, generation and transmission was investigated in 16 European countries. Using the indices provided by the Oxford COVID-19 Government Response Tracker, precise restriction types were found to correlate with the load drop. Then the European grid was analysed to assess how the load drop was balanced by the change in generation and transmission patterns. The same restriction period from 2020 was compared to previous years, accounting for yearly variability with ad hoc statistical technique. As a result, generation was found to be heavily impacted in most countries with significant load drop. Overall, generation from nuclear, and fossil coal and gas sources was reduced, in favour of renewables and, in some countries, fossil gas. Moreover, intermittent renewables generation increased in most countries without indicating an exceptional amount of curtailments. Finally, the European grid helped balance those changes with an increase in both energy exports and imports, with some net exporting countries becoming net importers, notably Germany, and vice versa. Together, these findings show the far reaching implications of the COVID-19 crisis, and contribute to the understanding and planning of higher renewables share scenarios, which will become more prevalent in the battle against climate change. • During COVID-19 spread, energy load dropped significantly in most European countries. • Only some restrictions strongly correlate with load drop. • Generation mix and exchange changed in most countries. • The biggest decrease in generation was from nuclear, fossil coal and oil. • Intermittent renewable generation continued to increase also in 2020. [ABSTRACT FROM AUTHOR]

• A novel metric (DOC) for bidirectional low temperature networks (BLTNs). • DOC describes the balancing potential of heating and cooling demands in a district. • DOC helps to identify building clusters with complementary demand profiles. • Correlations between DOC and KPIs are elaborated based on 63 demand scenarios. • Performance comparison of BLTNs with state-of-the-art building energy systems. Bidirectional low temperature networks (BLTNs) are a promising technology to drive decarbonization of the heating and cooling sector. The energy efficiency of a BLTN strongly depends on the heating and cooling demands of the connected buildings and their simultaneity. In order to evaluate the efficiency of a BLTN, a novel metric, called Demand Overlap Coefficient (DOC), is presented in this paper. The DOC can be calculated for individual buildings or a district and describes which proportion of heating and cooling demands can be balanced inside buildings and between buildings. The DOC is calculated with time series for heating and cooling demands, taking special account of their simultaneity. For a real-world use case in Germany, it is shown that 25% of heating and cooling demands can be balanced in buildings and 45% can be balanced by the BLTN between buildings. The DOC is evaluated for 63 demand scenarios. Correlations show that for districts with a DOC larger than 0.45, BLTNs have lower annualized costs than a state-of-the-art heating and cooling system. BLTNs have higher exergy efficiencies for districts with DOCs larger than 0.3. With the derived correlations, the DOC serves as a practical metric in the planning process of BLTNs in order to identify and assemble building clusters with complementary demand profiles. [ABSTRACT FROM AUTHOR]

The aim of this paper is to provide an overview about the distribution of the environmental impacts arising from different domestic functions (i.e. storing and preparing food, washing dishes, watching television, reading, personal cleaning, washing, drying and ironing clothes, home cleaning, heating, cooling, lighting and mobility) typically performed within a common family home. The method has general validity but for reasons related to the availability of data in the literature it has been applied by way of example only in three EU countries: Italy, Germany and France. The study was performed by using Life Cycle Assessment (LCA) in accordance with international standard ISO 14067 for determining the carbon footprint of different alternative domestic components, mainly appliances, for each function, by exclusively exploiting data from scientific literature. The functional unit is defined comprising all most common referred domestic activities of a family of three members within a house of 100 m2. The study identified an optimal configuration and a worse one of the domestic components in terms of carbon footprint, showing how a wise choice of these can greatly affect the overall impact by reducing it compared to the worst by more than 22% in Italy, 45% in Germany and 56% in France. The average impacts between the optimal and the worst configurations of Germany are higher than Italy (+27%) and France (+44%). Considering the impacts among the domestic functions in the average configuration, mobility was the most impactful in all the three countries (35–48%), followed by heating (17–26%), personal cleaning (10–13%) and washing dishes (8–13%), while cooling is consistent only in Italy (13%), against 5% in Germany and 2% in France. The study also allowed to identify some generic criteria for defining the optimal configuration: the increasing in energy efficiency, the choice of the least impacting energy source depending on the geographical location, ensuring water savings and the early replacement of older domestic components. Finally, by comparing some common measures for improving the domestic sustainability, these criteria proved to be more effective than solar systems and improved electricity mix. The provided outcomes may be used by manufacturers for improving their product in a more sustainable way as well as by legislator and end user, respectively for boosting and choosing the greener domestic components. Image 1 • LCA for estimating domestic environmental impacts based on scientific literature. • Application to three EU countries: Italy, Germany and France. • Assessing Carbon Footprint of different alternative domestic components for each domestic function. • Determining the optimal and the worst configuration of domestic components to minimize the impacts. • Comparing possible improvements for minimizing carbon footprint. [ABSTRACT FROM AUTHOR]

This paper explores the effects of framing a polluting activity in different contexts, i.e. different modes of transportation (bus versus plane) and different travel occasions (holiday versus professional training) on the individual willingness to pay (WTP) for carbon offsetting. For both types of framing, we also study additional contributions from the travel provider (i.e. matching). The empirical analyses with mixed logit and latent class logit models are based on data from discrete choice experiments with a representative sample of about 1000 individuals from Germany. The findings suggest substantial and systematic framing effects resulting from varying the mode of transportation, but not the travel occasion. Furthermore, the individual WTP is significantly higher across all four contexts when offsets are matched by the travel provider at a rate of 100%. In contrast, a lower matching rate of 33% is only relevant for one context, i.e. bus trips to a professional training. In addition, our results indicate that re-/afforestation projects are preferred to renewable energies projects or projects to improve energy efficiency. Likewise, projects carried out in a participant's region are preferred to projects implemented in European countries other than Germany or in developing countries. Finally, the WTP for offsets is found to be significantly higher for individuals with higher income, younger age, and stronger environmental and social preferences, as well as for individuals who believe that offsetting is effective in protecting the climate. [ABSTRACT FROM AUTHOR]