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This paper delves into an econometric analysis to uncover the differences between Nordic European Countries - NEC (Norway, Denmark, Finland, Sweden) and South-East European Countries - SEEC (Greece, Bulgaria, Romania, Hungary). The focus is on exploring the interplay among electricity generation from Renewable Energy Sources (RES), CO 2 emissions, urban population and GDP per capita in these two European regions. The study employs cross-sectional dependence, first and second-generation panel unit root tests, Pedroni panel and Westerlund panel cointegration tests, ARDL, Dumitrescu-Hurlin causality test to establish the relation among variables. The findings reveal that in both regions, CO 2 emissions are significantly influenced by GDP per capita, urbanization and RES generation. Furthermore, urbanization plays an important role. When examining causality in SEEC, three bidirectional relationships are observed: urbanization and CO 2 , urbanization and GDP, urbanization and generation from RES, and two unidirectional causalities: CO 2 and GDP, generation from RES and CO 2. In contrast, for the NEC, there are two bidirectional causalities: urbanization and CO 2 , urbanization and generation from RES, and two unidirectional causalities: GDP and CO 2 , generation from RES and CO 2. These results highlight the nuanced and varied nature of environmental and economic dynamics across various European regions. • Relationship between CO 2 emissions, GDP per capita and electricity production from RES. • Investigating two groups of EU countries located in the North and SE Europe. • Estimations with Fully Modified and Dynamic Ordinary Least Squares. • Causality and cointegration between variables. [ABSTRACT FROM AUTHOR]

Hydrogen is among the energy carriers, which are most often considered for bringing about a sustainable energy system. Yet, so far, hydrogen has not delivered as an energy carrier. The core objective of this paper is to provide a comprehensive analysis of the state-of-the-art and the future prospects of green hydrogen in the European energy system from economic, energetic and CO 2 emissions point-of-view. The analysis shows that there are some increasing opportunities for hydrogen use in industry and in the transport sector, when electrification is not possible or is too expensive, as well as a storage in the European electricity system. However, a hydrogen-based energy system will remain a vision at least over the next decades. The major reason for this is the unfavorable economics mostly due to high investment costs in the whole supply chain. In addition, the overall efficiencies in the hydrogen chains are moderate in general. The full environmental benignity of hydrogen as an energy carrier is only provided when renewable energy sources are used for hydrogen production. However, in Europe, the potentials for green hydrogen are very limited due to the insufficient expansion of renewable electricity generation. For this reason, many European countries are considering options for green hydrogen import. The future of hydrogen is highly dependent on the supporting policy framework. To reduce the risk in the investment in hydrogen infrastructure, as well as to justify the promotion of green hydrogen, it is very important that Europe works out a very clear and realistic long-term implementation strategy. • Hydrogen might have potential in the European energy system, yet a hydrogen-based energy system stays visionary. • Green hydrogen from renewable electricity via electrolyzers is key for environmental benefits and decarbonization. • Hydrogen should be prioritized for uses where electrification is not feasible. [ABSTRACT FROM AUTHOR]

• Environmental impacts of hydropower plants in Europe is investigated by LCA analysis. • Impacts are estimated by the ReCiPe 2016, Impact 2002+, and Eco-points 97 methods. • Hydropower plants of alpine regions are found least hazardous to the environment. • Plants of non-alpine areas are 10 times responsible for climate change than alpines. Hydropower is the widely used source of clean energy which includes some hazardous emissions that affect human health, ecosystems, and resources. However, in spite of an enormous amount of hydropower generation in Europe, no research has been carried out in evaluating the hazardous emissions from the plants located in alpine and non-alpine areas. Therefore, this paper will analyse the comparative environmental impacts of hydropower plants in alpine and non-alpine areas of Europe by a systematic life-cycle assessment (LCA) approach. The impacts are estimated by the ReCiPe 2016, Impact 2002+, Eco-points 97 methods under a number of effect-assessing indicators such as global warming, ozone formation, eco-toxicity, water consumption, acidification, eutrophication, ionizing radiation, carcinogenic radiation, ozone depletion, and land use. Moreover, the fossil-fuel-based power consumptions and the greenhouse-gas emissions in the life-cycle of hydropower plants in both locations are estimated using the Cumulative Energy Demand (CED) and the Intergovernmental Panel on Climate Change (IPCC) methods, respectively. The outcomes reveal that hydropower plants of alpine regions offer a better environmental profile for the global-warming indicator (2.97 × 10 - 5 kg CO 2 -eq/MJ) than non-alpine plants (3.92 × 10 - 4 kg CO 2 -eq/MJ), but the effects are nearly identical for the other indicators. Overall, the hydropower plants of non-alpine regions are responsible for climate change with a rate 10 times as high as for alpine ones. The findings of this research will play a pivotal role in promoting sustainable production of hydropower, especially the full potentials of the alpine region, and thus leading towards environmentally friendly clean renewable electricity generation. [ABSTRACT FROM AUTHOR]

• Agent-Based Model to emulate real-world performance of microgrid with P2P trading. • Holistic simulation of economic, technical, and ecological metrics. • Validation of Model with urban area of medium-sized German city. • Comparison of microgrid metrics before and during the European energy crisis. • Conclusions for research, practice, and energy policy. The shift towards renewable energy sources (RES) in energy systems is becoming increasingly important. Residential energy generation and storage assets, smart home energy management systems, and peer-to-peer (P2P) electricity trading in microgrids can help integrate and balance decentralized renewable electricity supply with an increasingly electrified power, heat, and transport demand, reducing costs and CO 2 emissions. However, these microgrids are difficult to model because they consist of autonomous and interacting entities, leading to emergent phenomena and a high degree of complexity. Agent-based modeling is an established technique to simulate the complexity of microgrids. However, the existing literature still lacks real-world implementation studies and, as a first step, models capable of validating the existing results with real-world data. To this end, we present an agent-based model and analyze the corresponding microgrid performance with real-world data. The model quantifies economic, technical, and environmental metrics to simulate microgrid performance holistically and, in line with state-of-the-art research, consists of self-interested, autonomous agents with specific load profiles, RES generation, and demand-response potential. The model can simulate a P2P marketplace where electricity is traded between agents. In the second part of the paper, we validate the model with data from a medium-sized German city. In this case study, we also compare microgrid performance in 2022, during the energy market crisis in Europe, with historical data from 2019 to assess the effects of energy market shocks. Our results show how microgrids with P2P trading can reduce electricity costs and CO 2 emissions. However, our trading mechanism illustrates that the benefits of energy-community trading are almost exclusively shared among prosumers, highlighting the need to consider distributional issues when implementing P2P trading. [ABSTRACT FROM AUTHOR]

The increasing share of intermittent Renewable Energy Sources (iRES) in the energy mix leads to a growing need for their accurate representation in energy system models. In this paper, we analyze how the results of generation planning models are impacted by the spatial representation used to model intermittent renewable technologies. It is shown that the spatial resolution, and to a lesser extent the spatial aggregation method used in a planning model, have a significant influence on the obtained system cost. The effect is quantified in a case study of European geographical scale, by varying the spatial resolution from highly resolved (hundreds of sites) to highly aggregated (1 site). A resolution-dependency of the system cost is observed under multiple renewable generation targets, and different renewable capacity restrictions. In doing so, we highlight the importance of implementing an appropriate capacity limit, especially when a high spatial resolution is used. Additionally, basic spatial aggregation methods -to process high resolution input data- are compared. • Isolation of renewable representation effects in a stylized GEP model. • iRES resolution has a strong impact on GEP model results for Europe. • Capacity limits play an important role in this effect, especially in high resolution. • Spatial aggregation method only impacts models with low resolutions. [ABSTRACT FROM AUTHOR]

In light of offshore wind expansions in the North and Baltic Seas in Europe, further ideas on using offshore space for renewable-based energy generation have evolved. One of the concepts is that of energy islands, which entails the placement of energy conversion and storage equipment near offshore wind farms. Offshore placement of electrolysers will cause interdependence between the availability of electricity for hydrogen production and for power transmission to shore. This paper investigates the trade-offs between integrating energy islands via electricity versus hydrogen infrastructure. We set up a combined capacity expansion and electricity dispatch model to assess the role of electrolysers and electricity cables given the availability of renewable energy from the islands. We find that the electricity system benefits more from connecting close-to-shore wind farms via power cables. In turn, electrolysis is more valuable for far-away energy islands as it avoids expensive long-distance cable infrastructure. We also find that capacity investment in electrolysers is sensitive to hydrogen prices but less to carbon prices. The onshore network and congestion caused by increased activity close to shore influence the sizing and siting of electrolysers. • Distance to shore and investment in offshore electrolysis are mutually dependent. • Offshore electrolysis is more valuable for far-away energy islands. • Offshore grids are beneficial for large-scale offshore wind integration. • Electrolyser capacity is sensitive to hydrogen prices but less to carbon prices. • Onshore grid developments influence offshore development significantly. [ABSTRACT FROM AUTHOR]

The green economy policy discourse has devoted a lot of attention to the design of public policy addressing low-carbon technologies. In this paper we examine the impacts of public R&D support and feed-in tariff schemes on innovation in the wind energy sector. The analysis is conducted using patent application data for four western European countries over the period 1977–2009. Different model specifications are tested, and the analysis highlights important policy interaction effects. The results indicate that both public R&D support and feed-in tariffs have positively affected patent application counts in the wind power sector. The (marginal) impact on patent applications of increases in feed-tariffs has also become more profound as the wind power technology has matured. There is also some evidence of policy interaction effects in that the impact of public R&D support to wind power is greater at the margin if it is accompanied by the use of feed-in tariff schemes. These results support the notion that technological innovation requires both R&D and learning-by-doing, and for this reason public R&D programs should typically not be designed in isolation from practical applications. The paper ends by outlining some important avenues for future research. [ABSTRACT FROM AUTHOR]

Following a request of the European Commission in 2012, different bodies within the gas energy sector have been working on a Network Code for transmission tariffs. The final goal is to get a more harmonized structure within the European Union. This paper complements those efforts by developing a formal treatment of some methodological aspects arising in past and present drafts of the Network Code. First, the analysis provides simple formulas for the computation of the tariffs resulting from the application of two of the main methodologies that have been discussed in the official documents: the capacity-weighted distance approach and the least squares approach. Second, it is shown that the tariffs delivered by the two approaches are perfectly correlated with each other. Maybe more importantly, if a natural adjustment is performed to control tariff dispersion, then both approaches lead to exactly the same tariffs. Moreover, the analysis highlights an issue that may have been overlooked by regulators and also by past publications: the difference between weighted and unweighted versions of the methodologies under study and the reasons why weighted versions should be preferred. The paper concludes with a brief comparison with other methodologies and discussing some policy implications. [ABSTRACT FROM AUTHOR]

Highlights • Building internal mass (BaB) is preheated during the afternoon hours for evening heating. • Measured BaB efficiencies of 60–80% for insulated apartments. • Measured BaB efficiencies of 40–70% for low-insulation apartments. • Variable renewable energy as photovoltaic is appropriate for building as battery. • BaB thermal storage can be a viable option for consumers with small reductions in daytime electricity cost. Abstract To increase the penetration of photovoltaic renewable energy (PV RE) in the residential building sector energy mix, the mismatch between mid-day production and evening electrical energy demand must be bridged. The use of heat pumps for space heating of residential buildings creates an opportunity for energy flexible residential buildings that rely on low-cost thermal energy storage systems. This paper explores the 'building as battery' concept (BaB), i.e. the use of the structural thermal capacity as a heat storage medium in winter. In these systems the building internal mass is preheated during solar daytime hours (using a PV RE powered heat pump) and cooled by discharge into the room air after sunset, for space heating. This study presents measured and simulated performance of BaB systems used for thermal energy storage in living rooms of three different apartment buildings with variable thermal insulation levels, ranging from typical southern Europe 1980s construction to a insulated apartment (Passive House certified). To assist in interpreting the results and facilitate their integration in simplified simulation of BaB systems in smart grids the model parameters of a simplified Resistance-Capacitance model were found by fitting the experimental results. The results show that, for apartments with high thermal mass, thermal insulation is the key driver of BaB system thermal efficiency, with the highly insulated apartment reaching BaB efficiencies of 60–80%. For existing apartments with a low thermal insulation, the BaB approach is only effective when space heating is required right after sunset (just when PV RE powered heat pump charging finishes). [ABSTRACT FROM AUTHOR]

As of July 2017, the emissions type-approval of light-duty vehicles in Europe is based on the Worldwide Harmonized Light-duty vehicles Test Procedure (WLTP), introduced to replace the old and outdated New European Driving Cycle (NEDC) test procedure. Since some elements of the European Legislation are still based on the NEDC (2020 CO 2 emission targets, vehicle labelling, national vehicle taxation policies, etc.) in order to allow sufficient lead time to vehicle manufacturers and national authorities to adapt to the new procedure, a simulation-based approach was chosen to calculate CO 2 emissions and fuel consumption according to the NEDC regime in the period 2017–2020. To achieve this objective without significantly increasing the cost and duration of the certification procedure, existing regulation foresees that vehicles are tested over the WLTP for CO 2 emissions, the test results are used as input in a simulation model that then calculates the corresponding CO 2 according to the NEDC test protocol. A dedicated vehicle simulation model (CO 2 MPAS) was developed for the purpose and is currently used for the type-approval of new vehicles in Europe. The development specifications of CO 2 MPAS were challenging, as it had to be highly accurate, exhibit fast operation, and function with a limited number of input data. This paper presents the development principles and process followed, details of the physical models employed in CO 2 MPAS, and provides information regarding its accuracy, validity and in use operation. CO 2 MPAS achieves low errors in the prediction of the NEDC cycle that in the controlled sample used for its development are of the order of 1% with a standard deviation of 3%, while the respective in-use numbers are of the order of 1.5% and 5%. In parallel, random sampling and testing of a 10% of the type-approved vehicles also occurs in order to guarantee the quality of the CO 2 MPAS results and the validity of the process. It is concluded that CO 2 MPAS can be used to accurately estimate emissions of conventional vehicles within a ±4% accuracy range, even when limited input data are available. In addition, the in-use data analyzed suggest that the use of the tool enables the certification of about 2/3 of the new vehicle models without the need of additional experimental tests. This is an important achievement as it reduces the costs and time necessary to certify light-duty vehicle CO 2 emissions during the transitional period. Finally, it can be concluded that the use of CO 2 MPAS does not affect the declared CO 2 emissions of vehicles over NEDC conditions. [ABSTRACT FROM AUTHOR]

Contrary to the U.S., where the Independent System Operator is responsible for electricity balancing, in Europe this is the task of Transmission System Operators. Also in terms of market implementation there are fundamental differences between the U.S. (co-optimisation of day-ahead and balancing/ancillary markets) and Europe (separate bidding and clearing in different market segments). This paper focuses on European electricity markets, where recently the framework for upcoming challenges in electricity balancing has been defined (“Network Code on Electricity Balancing”). In detail, different possible (cross-border) balancing market designs in Europe are evaluated using the model EDisOn + Balancing. We focus on the procurement of up- and downward balancing capacity products (conducted jointly or separately), and how common procurement of frequency restoration reserves influences wholesale electricity market clearings. Different timings and lead-times for the procurement of automatically activated frequency restoration reserve are investigated, starting from weekly off-peak and peak products, leading to daily four-hour products. The quantitative results confirm that in addition to asymmetric procurement of up- and downward balancing capacity, common procurement has significant advantages in terms of cost reductions. The shortening of balancing product timings supports the integration of renewable electricity generation essentially. To achieve these positive effects, the first focus should be on harmonising national balancing markets Europe-wide. A best practise case is the pilot project between Germany and Austria: the two countries have already started common activation of automatic frequency restoration reserve and there are plans for future common procurements. [ABSTRACT FROM AUTHOR]

Renewable energy in Middle East and North Africa (MENA) region, particular solar energy, can be connected to Europe to provide the Northern neighbouring countries with electricity. To achieve this long term objective, it is necessary to understand the local domestic consumption of electricity in the MENA region as the main consumer of energy. The understanding of current and future trends could help to provide a complete picture of the energy situation in MENA region and the feasibility of exporting energy to Europe. For this reason, this paper investigates the domestic energy use and occupants’ energy behaviour in Libya. The aim of this study is to evaluate the effect of domestic energy consumption and householders’ awareness, attitudes and behaviour on the overall energy consumption in Libya and how this could affect the peak demand, capacity, future trends and government energy budget. The paper also investigates the sustainability aspect of consumer products and the awareness and attitude of consumers towards consumption and demand. A comprehensive survey has been conducted to evaluate several aspects of domestic energy demand and characteristics in Libya. The findings have indicated that there is a significant increase in energy demands in the household sector in Libya and it is significant to have a clear strategy to reduce carbon emission and energy use by improving occupants’ behaviour as well as utilising other sustainable measures. Minor adjustment in householders’ energy consumption behaviour and the technology used to generate energy could provide significant financial savings and contribute significantly to the reduction in carbon emission and energy consumption. This will allow significant benefit to the local economy and the energy sector in Libya but at the same time could provide sustainable energy resources for Europe on the long term. [ABSTRACT FROM AUTHOR]

The need to improve the energy efficiency of buildings has introduced the concept of nearly zero-energy buildings into European energy policies. Moreover, a percentage of the building stock will have to be renovated annually to attain high energy performance. Conventional passive interventions in buildings are focused on increasing the insulation of the building envelope to increase its energy efficiency during the operating phase. Often, however, intervention practices imply the incorporation of embodied energy into the building materials and increase the associated environmental impacts. This paper presents and evaluates a comparison of two different proposals for a real-world building renovation. The first proposal was a conventional project for energy renovation, while the second was a low-energy building proposal (following the Passivhaus standard). This study analysed the proposals using an integrated life cycle and thermal dynamic simulation assessment to identify the adequacy of each renovation alternative regarding the post-renovation energy performance of the building, including an evaluation of the introduction of a renewable insulation material into the low-energy building proposal, specifically a specific cork solution. The most significant conclusion was the convenience of the renovation, achieving energy savings of 60% and 80% for the conventional and Passivhaus renovations (ENERPHIT), respectively. The former supposed less embodied energy and environmental impacts but also generated less energy savings. The latter increased the embodied impacts in the building, mainly for the large amount of insulation material. The environmental implications of both proposals can be compensated for within a reasonable period of time, over 2 years in the majority of alternatives and impact categories. However, the ENERPHIT project was 30% better than the conventional proposal when the total lifespan of the building was considered. The introduction of cork did not fit the requirements for competing with the common non-renewable insulation materials because it did not imply better environmental performance in buildings, but cork insulation solutions currently present ample room for improvement. [ABSTRACT FROM AUTHOR]

Biogas upgraded to biomethane can provide a renewable gaseous transport fuel and is one of the proposed solutions in meeting the renewable energy supply in transport targets set under the EU Renewable Energy Directive. The upgrading process for biogas involves the removal of CO 2 . Amine scrubbing is one traditional method of upgrading that is applied due to its low methane slippage and its capability to provide a high purity renewable methane product. However, new technologies such as power to gas (P2G) can also upgrade biogas through biological methanation by combining the CO 2 in biogas with H 2 to produce renewable methane. The H 2 for P2G can be produced through electrolysis of renewable electricity. Through simulation software – SuperPro Designer, the economics of different pathways for upgrading biogas from a grass silage and slurry fed digester are analysed and compared in this paper. Three scenarios were investigated: biogas upgrading through amine scrubbing (scenario 1); biogas upgrading through amine scrubbing with CO 2 directed to ex-situ biological methanation (scenario 2) and biogas upgrading through ex-situ biological methanation only (scenario 3). The results show that at a net present value of zero, the minimum selling price (MSP) per m 3 of renewable methane for scenario 1, 2 and 3 is €0.76; €1.50 and €1.43, respectively (with an electricity price to produce H 2 of €0.10/kWh and a grass silage production cost of €27/t). The electricity price has a significant effect on the cost of renewable methane in both scenarios 2 and 3. The MSP reduces to €1.09 and €1.00 per m 3 of renewable methane, respectively for scenarios 2 and 3, if the electricity price is reduced to €0.05/kWh. Since the renewable methane MSP from scenario 2 is higher than scenario 3, it is suggested that direct biogas injection to the methanation reactor is financially more attractive than capturing CO 2 from biogas and feeding it to the methanation step. The MSP of renewable methane from both scenarios 2 and 3 are significantly higher than that of scenario 1. However, when considering climate change mitigation, balancing of the electricity network and storage of surplus electricity, utilising P2G can offset some of these costs. The cost of H 2 is a significant factor in determining the cost of renewable methane. [ABSTRACT FROM AUTHOR]

Motivated by the increasing integration among electricity markets, in this paper we propose two different methods to incorporate market integration in electricity price forecasting and to improve the predictive performance. First, we propose a deep neural network that considers features from connected markets to improve the predictive accuracy in a local market. To measure the importance of these features, we propose a novel feature selection algorithm that, by using Bayesian optimization and functional analysis of variance, evaluates the effect of the features on the algorithm performance. In addition, using market integration, we propose a second model that, by simultaneously predicting prices from two markets, improves the forecasting accuracy even further. As a case study, we consider the electricity market in Belgium and the improvements in forecasting accuracy when using various French electricity features. We show that the two proposed models lead to improvements that are statistically significant. Particularly, due to market integration, the predictive accuracy is improved from 15.7% to 12.5% sMAPE (symmetric mean absolute percentage error). In addition, we show that the proposed feature selection algorithm is able to perform a correct assessment, i.e. to discard the irrelevant features. [ABSTRACT FROM AUTHOR]

The electricity consumption of non-residential productive sectors represents a significant share of the overall energy consumption in the Member States of the European Union. Therefore, determining the main factors affecting the intensity of such consumption (defined as the ratio of the electricity consumed by the productive system of a given country to gross value added) is a research effort worth undertaking. The aim of this paper is to identify the main factors which affect such intensity with the help of a static panel data model, which is estimated with three different methods. Our results show that a higher degree of technological progress in the production systems and higher retail prices of electricity for non-residential consumers reduce such intensity. Other variables, which are statistically significant, lead to an increase of electricity intensity, including the accumulated stock of physical capital and the lagged gross fixed capital formation. The accumulated capital stock per unit of GDP is the variable with the highest influence on electricity intensity. Whereas the influence of price changes is limited, these results indicate that there is some rigidity to change energy intensity through demand-side policy measures, suggesting that they will need to be complemented with supply-side measures aimed at increasing low-carbon electricity generation capacity. [ABSTRACT FROM AUTHOR]

This paper analyses the energy and economic performance of roof and/or façades Building Integrated flat-plate PhotoVoltaic and Thermal (BIPVT) collectors for residential applications. Aim of the analysis is to assess the active and passive effects due to the building integration of solar technologies on the building energy consumptions. In particular, a comparison among innovative building-plant system configurations, based on BIPVT collectors for the simultaneous production of electricity, thermal energy, and domestic hot water, is carried out. The simulation models of the proposed system layouts are designed and implemented in TRNSYS simulation environment for the dynamic assessment of their energy and economic performance. By means of the developed simulation model, the occurring summer and winter building passive energy effects due to the PVT building integration are also analysed. Several case studies are developed by modelling a representative multi-storey residential building and by taking into account different European climates. For such case studies a suitable energy parametric analysis is performed by varying the thermal resistances and capacitances of the building envelope. By the simulation results interesting design and economic feasibility guidelines are obtained. In particular, by varying the weather location and the building-plant configuration, the adoption of BIPVT panels produces a decrease of the primary energy demands from 67% to 89%. The passive effects of the BIPVT system in both the winter and summer season are also assessed for all the investigated climate zones. The calculated economic profitability resulted slightly better for roof BIPVT panels than for roof and façade applications. For the investigated case studies, the pay back periods appear quite long, varying from 11 years for South European weather zones to 20 for North European ones. [ABSTRACT FROM AUTHOR]

In this paper, the effect of latitude on the performance of different solar trackers is examined. The hourly solar radiation data of different locations around Europe and Africa measured on a horizontal surface is collected and utilized. Widely validated Perez anisotropic model is used to predict the diffuse component of the solar radiation on an inclined surface. Different solar trackers namely, Full/dual-axis, East–West (EW), North–South (NS), Inclined East–West (IEW), and Vertical-axis (V) trackers are considered in calculating the available solar potential of the locations. The performance of the solar trackers in terms of the energy gain is ranked according to the area location latitudes. The results show that the tracking performance is highly dependent on the locations, thus changes with the latitude. The percentage variation among the implemented one-axis tracking options relative to dual-axis trackers ranges from 0.42% to 23.4%. Overall, the increase in the energy gain of dual-axis trackers compared to the optimal fixed panel for the locations varies from 17.72% to 31.23%, thus emphasizes the importance of solar trackers. Finally, the study is expected to aid designers in the selection and installation of appropriate solar trackers in the regions. [ABSTRACT FROM AUTHOR]

This paper investigates how the European electricity and heating system is impacted when medium-scale energy communities (ECs) are developed widely across Europe. We study the response on the capacity expansion of the cross-border transmission and national generation and storage within the European electricity and heating system with and without ECs in selected European countries. The representation of ECs has a special focus on flexibility, and we analyze the difference between flexibility responses by ECs towards local versus global cost minimization. Results show that EC development decreases total electricity and heating system costs on the transition towards a decarbonized European system in line with the 1.5 °C target, and less generation and storage capacity expansion is needed on a national scale to achieve climate targets. We also identify a conflict of interest between optimizing EC flexibility towards local cost minimization versus European cost minimization. • We study investments in the European energy market with energy community roll-out. • We compare flexibility responses with local versus European perspective. • Energy communities partly replace centralized generation and storage capacity. • Energy community roll-out shifts investments from onshore to offshore wind. • There is conflicting interest between local and European flexibility utilization. [ABSTRACT FROM AUTHOR]

Abstract: The paper analyses the issues for consideration listed in the stock taking document “New Energy Strategy for Europe 2011–2020” and explores the impact of their implementation on the use of renewable energy sources. The main objective of the paper is to introduce and provide a summary of the theoretical and methodological achievements required for an analysis of the implications of such an EU level strategy. It also provides a summary of the results of the analysis of the impacts of the Strategy on a specific field; namely, on the use of renewable energy sources. Contradictions inherent in the Strategy are discussed as well, and a proposal is put forward to aid the resolution of these contradictions. The paper also points out that the further development of the theoretical and methodological achievements may result in the creation of a simulation model, the application of which could effectively aid the process of strategic planning and the testing of strategies prior to approval. Finally, the paper discusses how an EU level and/or a global network of energy security centres could promote the development and implementation of an energy policy ensuring the appropriate utilization of renewable energy sources. [Copyright &y& Elsevier]

Abstract: Large scale integration of wind energy poses new challenges to the European power system due to its stochastic nature and often remote location. In this paper a multivariate uncertainty analysis problem is formulated for the integration of stochastic wind energy in the European grid. By applying copula theory a synthetic set of data is generated from scarce wind speed reanalysis data in order to achieve the increased sample size for the subsequent Monte Carlo simulation. In the presented case study, European wind power samples are generated from the modeled stochastic process. Under the precondition of a modeled perfect market environment, wind power impacts dispatch decisions and therefore leads to alterations in power balances. Stochastic power balances are implemented in a detailed model of the European electricity network, based on the generated samples. Finally, a Monte Carlo method is used to determine power flows and contingencies in the system. An indicator is elaborated in order to analyze risk of overloading and to prioritize necessary grid reinforcements. Implications for the Swiss power grid are investigated in detail, revealing that the current system is significantly put at risk in certain areas by the further integration of wind power in Europe. It is the first time that the results of a probabilistic model for wind energy are further deployed within a power system analysis of the interconnected European grid. The method presented in this paper allows to account for stochastic wind energy in a load flow analysis and to evaluate deterministic indicators, such as the N −1 criterion, on a probabilistic basis. Thus, it constitutes an important extension of deterministic models. [Copyright &y& Elsevier]

• Early smart grid R&D advancements can indicate future technological developments. • A method for analyzing the evolution of smart grid technologies is proposed. • The Network theory is used to justify the existence of a main path of technologies. • Four innovation trajectories exist around smart energy applications. • The proposed approach complements existing methods of main path analysis. This paper investigates how the strategic decisions of innovative firms to collaborate with other firms in research and development projects shape the early evolution of smart grid technologies as an emerging technological system across Europe. The early innovations and developments in an emerging technological system are crucial for understanding further developments of the system. This early stage is highly influenced by the strategic decisions and lobbying power of the firms experimenting with different technological innovations, and the policies trying to maintain competition and steer the direction of innovative activities. Therefore, it is important to analyze how innovative firms behave in terms of collaborating with other firms and doing research on specific energy solutions, which reflect their strategic priorities. By taking a complex network approach, this paper investigates a network of smart grid R&D projects to analyze the convergence of smart grid research activities towards a stream of innovative solutions, and the variety of innovative activities branching out from these solutions. The results verify the convergence of smart grid activities towards one specific stream of innovations, and reveal the existence of four variations centered around different technological applications. The results can guide strategy development in innovative firms to take part in research collaborations or focus on specific smart energy technologies, and have implications for policy makers aiming to influence the direction of smart grid research programs, as well as for researchers in the field of smart grid innovation and technological innovation systems. [ABSTRACT FROM AUTHOR]

• Stakeholders see great potential in PEDs for energy poverty reduction. • Energy poverty mitigation needs to be included in PEDs from the onset. • PED replication can synergistically address both decarbonization and energy poverty mitigation. • Increasing levels of energy poverty makes PEDs more financially viable as mitigation tools. • More consideration needs to be given to the social dimension in decisions on new PED creation. 100 Positive Energy Districts (PEDs) are to be created in Europe by 2025, with a stated goal of urban decarbonization. These are highly energy efficient residential urban areas, powered entirely through renewables. PED creation is to be guided by principles of quality of life, sustainability, and inclusiveness (specifically focusing on affordability and energy poverty prevention). Although there is research into the decarbonization aspects of PEDs, there has been little focus on the guiding principles, and their potential to reduce energy vulnerability. Using energy vulnerability factors and an energy justice framework, this article examines how the topic of energy vulnerability mitigation is perceived by professional PED stakeholders. Stakeholders from multiple countries were interviewed in order to determine how and to what extent they approached the topic of inclusivity and energy vulnerability. The contribution of this paper to academic research is in helping to frame energy vulnerability in European smart city urban areas, focusing on the perceptions of key stakeholders. This contributes to research on the identification and evaluation of innovations such as PEDs which offer a potential model for an inclusive transition. Furthermore, this article offers a contribution for policymakers, informing PED replication policies with a focus on the synergistic aims of decarbonization and energy vulnerability mitigation. [ABSTRACT FROM AUTHOR]

The massive data centre energy consumption has motivated significant efforts to use energy efficiency strategies and the implementation of renewable energy sources that reduce their operational costs and environmental impact. Considering that the potential of many of these measures is often closely linked to the climate conditions, the location of data centres can have a major impact on their energy demand. Moreover, from a holistic approach, differences among regions become even more important when accounting for the electricity attributes from the grid. To assess these differences this work compares by the use of energy indicators the behaviour of a data centre located at different representative emplacements in Europe. To do so, a dynamic energy model which incorporates free cooling strategy and photovoltaic energy is developed. The paper concludes by suggesting that future data centre developments could consider site selection as a new strategy to limit the environmental impact attributable to this sector. [ABSTRACT FROM AUTHOR]

• The paper presents NeMo, a model for the simulation of district heating networks. • The thermal inertia of the heat carrier fluid is used to shift the thermal load. • The flow rate regulation allows to shave the peak load during two typical weeks. • Water velocity, heat load pattern and grid topology affect the flexibility figures. • NeMo is released as supplementary material of the article. The possibility of recovering waste and renewable heat in urban areas has made district heating networks one of the key infrastructures for decarbonising the heating sector in Europe. The ability to shift the heat production over time is an important asset to improve the competitiveness of both new and existing networks. To this purpose, the present study evaluates the flexibility potential provided by the water volume enclosed in the network pipelines using the district heating network of Verona (Italy) as a case study. Given the users heat demand in two representative weeks, computer simulations were carried out to calculate the network's thermal response to circulating flow rate variations. The latter were designed to cause an early or late shift in the daily peak thermal load. The local temperature drop at the users substations compared to the current situation was used as a relative discomfort indicator. The simulations were carried out using the model NeMo, which has been attached as supplementary material to this publication. The simulation results show that the network pre-charge strategy achieves significant benefits in terms of both peak shaving and load shifting with a limited impact on discomfort for the users. Furthermore, the paper shows that the available storage capacity of the network is significantly influenced by the duration of the flow adjustment, by the average velocity of the heat carrier fluid and by the daily heat demand pattern. Finally, it is shown that the energy flexibility of the network also depends on its topology. In this regard, the article provides preliminary indications on the number and position of the bypass pipes needed to implement the proposed flow rate variations. In conclusion, the article shows that the thermal inertia of the heat carrier fluid is an interesting source of flexibility for existing networks, and the results highlight its potential and limitations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Methodology to optimize commercial EV pool composition for V2G services. • Simulation of EV pooling to provide balancing power (FCR) and arbitrage trading. • Optimized pool composition enables an increase in revenue per EV of up to 7-fold. • Showcase analysis of battery-specific costs arising from degradation in V2G. The market ramp-up of electromobility is shifting vehicle-to-grid (V2G) issues into the focus of research and industry. Electric vehicles (EVs) have the potential to support the trend towards renewable energies in their role as storage units during idle times. To participate in balancing power and energy markets, EVs are pooled via aggregators. Instead of a random composition, aggregators can smartly compose their pools and add only those vehicles that actually contribute to the pool's performance, gaining advantages over competitors. The optimization methods presented in this paper form optimized pool combinations based on the power and energy capability profiles of commercial EVs. Genetic algorithms are used to determine the revenues of the possible pools per participating EV. The use cases analyzed are the provision of balancing power on the frequency containment reserve (FCR) market of Central Europe and energy arbitrage trading on the European power exchange intraday continuous and day-ahead auction spot markets. The results show that through smart pool composition, an aggregator can increase revenue per vehicle by up to seven-fold across the markets compared to randomly assembled pools. In the Central European market, for example, the potential V2G revenues on the FCR market (380 €) exceeded those of arbitrage trading (28 € − 203 €) in 2020. In a simulation, we show the increased degradation of the vehicle battery in V2G operation compared to sole use for mobility with a smart charging strategy. However, the additional revenue can make V2G financially worthwhile, depending on costs for measuring equipment, bidirectional charging stations, and aggregator costs. [ABSTRACT FROM AUTHOR]

• Road-freight TCO compared for 5 drive-technologies in 3 applications, 10 countries. • A database of costs for road-freight TCO parameters is newly compiled. • Low-carbon vehicles largely competitive in light- and medium-duty segments. • Low-carbon vehicles competitive in heavy-duty segments in selected countries. • Findings indicate three important TCO parameters to drive this competitiveness. In light of the Paris Agreement, road-freight represents a critically difficult-to-abate sector. In order to meet the ambitious European transport sector emissions reduction targets, a rapid transition to zero-carbon road-freight is necessary. However, limited policy assessments indicate where and how to appropriately intervene in this sector. To support policy-makers in accelerating the zero-carbon road-freight transition, this paper examines the relative cost competitiveness between commercial vehicles of varying alternative drive-technologies through a total cost of ownership (TCO) assessment. We identify key parameters that, when targeted, enable the uptake of these more sustainable niche technologies. The assessment is based on a newly compiled database of cost parameters which were triangulated through expert interviews. The results show that cost competitiveness for low- or zero-emission niche technologies in certain application segments and European countries is exhibited already today. In particular, we find battery electric vehicles to show great promise in the light- and medium-duty segments, but also in the heavy-duty long-haul segments in countries that have enacted targeted policy measures. Three TCO parameters drive this competitiveness: tolls, fuel costs, and CAPEX subsidies. Based on our analysis, we propose that policy-makers target OPEX before CAPEX parameters as well utilize a mix of policy interventions to ensure greater reach, increased efficiency, and increased policy flexibility. [ABSTRACT FROM AUTHOR]

This paper presents a multistage adaptive robust generation expansion planning model, which accounts for short-term unit commitment and ramping constraints, considers multi-period and multi-regional planning, and maintains the integer representation of generation units. The uncertainty of electricity demand and renewable power generation is taken into account through bounded intervals, with parameters that permit control over the level of conservatism of the solution. The multistage robust optimization model allows the sequential representation of uncertainty realization as they are revealed over time. It also guarantees the non-anticipativity of future uncertainty realizations at the time of decision-making, which is the case in practical real-world applications, as opposed to two-stage robust and stochastic models. To render the resulting multistage robust problem tractable, decision rules are employed to cast the uncertainty-based model into an equivalent mixed integer linear (MILP) problem. The re-formulated MILP problem, while tractable, is computationally prohibitive even for moderately sized systems. We, thus, propose a solution method relying on the reduction of the information basis of the decision rules employed in the model, and validate its adequacy to efficiently solve the problem. The importance of considering multistage robust frameworks for accounting for net-load uncertainties in generation expansion planning is illustrated, particularly under a high share of renewable energy penetration. A number of renewable penetration scenarios and uncertainty levels are considered for a case study covering future generation expansion planning in Europe. The results confirm the effectiveness of the proposed approach in coping with multifold operational uncertainties and for deriving adequate generation investment decisions. Moreover, the quality of the solutions obtained and the computational performance of the proposed solution method is shown to be suitable for practical policy-making generation expansion planning problems, seeking to evaluate the impact of uncertainty on future system-wide performance. • A multistage adaptive robust optimization model for generation expansion planning. • Key operational uncertainties due to large shares of renewable energy are considered. • Novel solution method based on the reduction of information basis for decision rules. • Significant reduction in calculation time for solving the multistage robust model. • Practical relevance of the proposed approach for system planning under uncertainties. [ABSTRACT FROM AUTHOR]

Involving residential actors in the energy transition is crucial for its success. Local energy generation, consumption and trading are identified as desirable forms of involvement, especially in energy communities. The potentials for energy communities in the residential building stock are high but are largely untapped in multi-family buildings. In many countries, rapidly evolving legal frameworks aim at overcoming related barriers, e.g. ownership structures, principal–agent problems and system complexity. But academic literature is scarce regarding the techno-economic and environmental implications of such complex frameworks. This paper develops a mixed-integer linear program (MILP) optimisation model for assessing the implementation of multi-energy systems in an energy community in multi-family buildings with a special distinction between investor and user; the model is applied to the German Tenant Electricity Law. Based on hourly demands from appliances, heating and electric vehicles, the optimal energy system layout and dispatch are determined. The results contain a rich set of performance indicators that demonstrate how the legal framework affects the technologies' interdependencies and economic viability of energy communities with multi-energy systems. Certain economic technology combinations may fail to support national emissions mitigation goals and lead to lock-ins in Europe's largest residential building stock. The subsidies do not lead to the utilisation of a battery storage. Despite this, self-sufficiency ratios of more than 90% are observable for systems with combined heat and power plants and heat pumps. Social C O 2 mitigation costs range between 147.5–272.8 € / t CO 2 . Finally, the results show the strong influence of the heat demand on the system layout. • System optimisation of distinct operators and consumers in multi-family buildings. • Inclusion of Tenant Electricity Law leads to complex investment and dispatch decisions. • Highest profitability combining photovoltaic, combined heat and power and heat pump. • Combined heat and power is favoured, but profits depend on building's heating demand. • Legislation incentivises energy communities but may offset national CO 2 mitigation. [ABSTRACT FROM AUTHOR]

This paper provides a detailed account of the impact of different offshore wind siting strategies on the design of the European power system. To this end, a two-stage method is proposed. In the first stage, a highly-granular siting problem identifies a suitable set of sites where offshore wind plants could be deployed according to a pre-specified criterion. Two siting schemes are analysed and compared within a realistic case study. These schemes essentially select a pre-specified number of sites so as to maximize their aggregate power output and their spatiotemporal complementarity, respectively. In addition, two variants of these siting schemes are provided, wherein the number of sites to be selected is specified on a country-by-country basis rather than Europe-wide. In the second stage, the subset of previously-identified sites is passed to a capacity expansion planning framework that sizes the power generation, transmission and storage assets that should be deployed and operated in order to satisfy pre-specified electricity demand levels at minimum cost. Results show that the complementarity-based siting criterion leads to system designs which are up to 5% cheaper than the ones relying on the power output-based scheme when offshore wind plants are deployed with no consideration for country-based deployment targets. On the contrary, the power output-based scheme leads to system designs which are consistently 2% cheaper than the ones leveraging the complementarity-based siting strategy when such constraints are enforced. The robustness of the reported results is supported by a sensitivity analysis on offshore wind capital expenditure and inter-annual weather variability, respectively. • Impact of offshore wind power plant siting strategies is analysed. • Method combining siting and capacity expansion planning models is proposed. • Siting schemes maximizing production or spatiotemporal complementarity are studied. • First scheme consistently cheaper across different problem instances. • Results robust to offshore cost assumptions and inter-annual weather variability. [ABSTRACT FROM AUTHOR]

• Sustainability and social justice deserve attention in sustainable transitions. • Responsible research and innovation is used for envision sustainable transitions. • Responsible research and innovation offers tools for policy integration process. • An understanding of the context is vital in terms of replicating an intervention. • Context description must be considered as part of the validation methodology. Aspects of sustainability and social justice deserve special attention in the research and innovation landscape in Europe. In this vein, the inclusion of innovative research and innovation policies, such as Responsible Research and Innovation, devoted to mainstream social outcomes, to deploy democratic governance of science, and to drive innovation into a direction that is ethically acceptable, societally desirable and sustainable are noteworthy. However, substantial efforts are required when it comes to integrate the interactions between renewable energy research and energy and climate policies within responsible approaches. In order to adapt responsible research and innovation approach for the purpose of building an alternative context and assessment approach for sustainable transitions, this paper presents a review of approaches around sustainability and social justice dimensions. The thresholds of this endeavour are detailed in terms of the challenges for the integration, the identification of the inhibitors and facilitators of policy integration and the proposal of the levels for a methodology for this integration. The results show that the different readings and understanding of the contexts and dimensions and the existence of knowledge gaps between policy targets and the outcomes of research and innovation can be considered inhibitors for the integration. In contrast the interlinks between dimensional concepts, backgrounds and rationales appear as facilitators. The innovative contribution of this paper is focused on the contextualization of the dimensions through the use of socio-technical and multi/inter/trans and cross-disciplinary approaches. The authors conclude that the process of introducing a more holistic and alternative approach opens the re-envision of policy elements. Moreover, RRI offers an innovative perspective to the transition approach as well as tools for decision-making and policy processes assessment, in an arena where constant innovation is taking place and new structures, processes and metrics are necessary to guide this process. [ABSTRACT FROM AUTHOR]

Abstract: The aim of Educa-RUE project is to improve energy performance in building sector at local level and with particular attention to educational buildings, by promoting the ability of local players to guide and orient initiatives, designed to encourage energy saving by means of specific measures and integrated tools. The project is therefore focused to speed up the implementation of European Directive on Energy Performance in Buildings, EPBD (2002/91/EC), in Member States at local government level and to ensure its operability, within the various national legislations of reference. Educa-RUE lasted 30months, from January 2008 to June 2010, and involved the following eight partners: for Italy, Provinces of Potenza (project leader), Perugia, Rieti and Palermo; for other Countries, Climate Energy Ltd. Essex and Energy Solutions North West London (UK), Associación Aragonesa de Entidades Locales ASAEL (Spain), Municipality of Prenzlau (Germany). A number of closely interconnected actions were carried on in eight Work Packages (WPs) to face the energy efficiency aspects identified as primary problems by the partners. The project developed a model process, known as “Educa-RUE method”, to assess possible policies of intervention on educational buildings, owned or managed by each Partner. In particular the Province of Perugia, leader of WP 2 and 5, provided guide lines and tools in order to: identify the state of the art of EPBD implementation and the main non-technological barriers, which are preventing its application at local level; select, within the Province/area patrimony, the most suitable educational building, to be used as a shining example to develop the following testing phases of the project; carry on an energy check, or audit, of selected buildings, by involving the educational community as user and active participant in the whole process; elaborate an executive project, concerning the description of all the building elements (structure, roof, heating/cooling plants, etc.) which need to be replaced/improved and the application of an energy/environmental assessment; plan refurbishing interventions for the rest of the school buildings directly managed by each Partner, according to specific priority selection criteria, which represents a guiding and coordinating act for those Administrations directly or indirectly interested in the Project. This paper presents the results obtained by testing and proving Educa-RUE method in different regional areas. Its findings can be extended to other building typologies in order to create a reference model for local planners and responsible. [Copyright &y& Elsevier]

Abstract: This paper estimates supply cost curves for conventional oil and gas in Europe. Oil and gas volumes are distributed across five categories that are based on production costs. The resulting supply figures are intended to be long term representations of how quantities vary with production costs. Both economic and physical measures are used since each provides practical information with respect to the concerns some energy commentators have expressed about oil and gas scarcity in the near future. Supply cost curves incorporating the effect of annual technological advancement (i.e. productivity gains) on production costs to the year 2030 are also estimated. On the quantity side, the curves include volumes from geological provinces not previously assessed. Results indicate that conventional oil and gas in Europe is abundant and can likely be produced at costs below current and projected market oil and gas prices. [Copyright &y& Elsevier]

Abstract: In this paper, per capita CO2 convergence among the EU-25 countries between 1920 and 2007 is analysed using the distribution dynamics approach. Furthermore, the analysis is complemented by investigating the asymptotic half-life of convergence, mobility indices and the continuous version of the ergodic distributions. The novel aspect of this work consists in the fact that it examines whether patterns could differ if weighted by either the population of each country or their economic sizes. The unweighted analysis indicates that the convergence patterns differ strongly before and after World War II, with more convergence being displayed after the seventies. Results of weighting both by population and by economic size show that convergence is much faster when these features are introduced into the model. Conclusions from this analysis are important for the environment policy adopted across the EU-25 countries. [Copyright &y& Elsevier]

Abstract: The presence of price clustering in markets is taken as a sign of market inefficiency that can influence trading strategies. In this paper, we study the presence of a concentration in prices in carbon futures markets. Specifically, we analyze the European Carbon Futures Markets and test for evidence of preference for certain prices above others. Our results reveal the strong presence of price clustering in the carbon market at prices ending in digits 0 and 5. These findings support the attraction hypothesis, which endorses a significant clustering on gravitational prices, but also backs the negotiation hypothesis, which advocates greater clustering when trading costs are higher. [Copyright &y& Elsevier]

Abstract: In this paper, a purposely designed code for the performance analysis of the Water Loop Heat Pump (WLHP) systems is presented. Hourly, daily and seasonal energy system consumptions, operating economic costs and environmental impact assessments are dealt with. For the scope of comparison, the performances of two reference HVAC system are investigated too. For the computation of the building heating and cooling requirements, a suitable dynamic performance simulation model is being developed. All the relevant algorithms are implemented in MATLAB®. A case study of an office building undergoing simulation in different European climatic areas is being presented. Here, different building thermal features are considered. In order to maximize the system performance an additional optimization procedure to the operating devices temperatures is carried out. Results show that primary energy savings and avoided CO2 emissions of the WLHP system vary in relation to the compared reference systems and can be obtained only in several European weather zones. The feasibility of the WLHP system strongly depends on electricity and natural gas national costs. [Copyright &y& Elsevier]

Abstract: In Europe, methyl esters cannot be classified as biodiesel until the EN 14214 Standard specifications are fulfilled. The aim of this paper is to examine the efficiency of removing several impurities in biodiesel from used cooking oils by means of three basic operations under conditions that have been kept as close to commercial operating practice as possible: (a) adsorption (magnesium silicate and bentonite); (b) liquid–liquid extraction (distilled water, tap water, glycerol); and (c) ion exchange (cation resin). The results show that all the purification methods can remove soap, methanol and glycerol effectively, while none had an effect on density, kinematic viscosity, FAME content or glyceride content. However, some of them have shown an influence on FFA and water content. The liquid–liquid extraction with glycerol at 15wt.% and a 2-step contact proved to be the most suitable. [Copyright &y& Elsevier]

Abstract: This paper combines engineering and social science approaches to enhance our understanding of industrial energy efficiency and broaden our perspective on policy making in Europe. Sustainable development demands new strategies, solutions, and policy-making approaches. Numerous studies of energy efficiency potential state that cost-effective energy efficiency technologies in industry are not always implemented for various reasons, such as lack of information, procedural impediments, and routines not favoring energy efficiency. Another reason for the efficiency gap is the existence of particular values, unsupportive of energy efficiency, in the dominant networks of a branch of trade. Analysis indicates that different sectors of rather closed communities have established their own tacit knowledge, perceived truths, and routines concerning energy efficiency measures. Actors in different industrial sectors highlight different barriers to energy efficiency and why cost-effective energy efficiency measures are not being implemented. The identified barriers can be problematized in relation to the social context to understand their existence and how to resolve them. [Copyright &y& Elsevier]

Abstract: Since the turn of the 21st century, the onshore wind industry has seen significant growth due to the falling cost of wind generated electricity. This growth has coincided with an interest in the development of offshore wind farms. In Europe, governments and developers have begun establishing small to medium sized wind farms offshore to take advantage of stronger and more constant winds and the relative lack of landowner conflicts. In the U.S., several developers are in the planning and resource evaluation phases of offshore wind farm development, but no wind farms are currently operational or under construction. In this paper, we analyze the patterns of development in Europe and compare them to the U.S. We find significant differences in the patterns of development in Europe and the U.S. which may impact the viability of the industry in the U.S. We also discuss the policies used by European nations to stimulate offshore wind development and we discuss the potential impacts of similar policies in the U.S. [Copyright &y& Elsevier]

The number of large-scale solar thermal installations has increased rapidly in Europe in recent years, with 70 % of these systems operating with flat-plate solar collectors. Since these systems cannot be easily switched on and off but directly depend on the solar radiation, they have to be combined with other technologies or integrated in large energy systems. In order to most efficiently integrate and operate solar systems, it is of great importance to consider their expected energy yield to better schedule heat production, storage and distribution. To do so the availability of accurate forecasting methods for the future solar energy yield are essential. Currently available forecasting methods do not meet three important practical requirements: simple implementation, automatic adaption to seasonal changes and wide applicability. For these reasons, a simple and adaptive forecasting method is presented in this paper, which allows to accurately forecast the solar heat production of flat-plate collector systems considering weather forecasts. The method is based on a modified collector efficiency model where the parameters are continuously redetermined to specifically consider the influence of the time of the day. In order to show the wide applicability the method is extensively tested with measurement data of various flat-plate collector systems covering different applications (below 200 ° Celsius), sizes and orientations. The results show that the method can forecast the solar yield very accurately with a Mean Absolute Range Normalized Error (MARNE) of about 5 % using real weather forecasts as inputs and outperforms common forecasting methods by being nearly twice as accurate. • Self-learning approach with only very few parameters to be determined. • Automatically considers seasonal changes and pollution of collector fields. • Simple regarding its mathematical structure and straightforward to implement. • Experimental long-term validation with data from various collector systems. • Superior to state-of-the-art forecasting methods regarding accuracy. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to provide a utility eye-view of the European power-sector''s CO2-compliance decision process under a tradable emissions scheme. The cost analysis indicates that, in the medium term, many utilities are likely to consider options based on traditional power technologies such as converting existing coal-fired capacity to burn gas, extending the lives of nuclear capacity, and replacing old coal-fired plants with more efficient gas- or even coal-fired units. The long-term economic potential of future options is highly uncertain, and utilities are likely to respond to this by maintaining flexibility in fuel choices and avoid large investments that lock them into a specific compliance method before more efficient and cleaner technologies have crystallized. Given the multitude of possible CO2-mitigation options, there is a strong case for emissions trading and for refraining from policies that build on mandatory fuel-requirements, higher rates of capital stock turnover and technology standards. [Copyright &y& Elsevier]

Significant economies of scale and scope in the European gas industry make many transmission and local distribution companies natural monopolies in the markets in which they operate. Often, this gives them a strong market power and they experience little competitive pressure. Hence public interventions into the functioning of the market, as seen under the initiatives taken by the European Commission, such as the “Gas Directive” occur. This paper discusses a game between the public authority and the transporters, where various levels of conflict and cooperation will influence how far regulations will go and how they will be designed. [Copyright &y& Elsevier]

An assessment of local wind conditions allows one to predict that about 25percent of the Poland''s territory is advantageous in that respect. Thus the author tries to explain why the development of the wind-power industry in Poland is so slow, especially in relation to the leading European countries such as Germany, Denmark or Spain. At present in Poland, there are wind farms of 27.5 MW total installed power. The Polish wind-turbine of 160 kW power, produced by the NOWOMAG factory, as well as a new approach of the KOMAG Centre aiming at the development of the prototype of state-of-the-art wind turbine of 1 MW power—according to the original technical concept which is a compromise between present multi-gear and gearless solutions in wind turbines — are presented in the paper. [Copyright &y& Elsevier]

This paper analyses the role of sector coupling towards 2050 in the energy system of Northern-central Europe when pursuing the green transition. Impacts of restricted onshore wind potential and transmission expansion are considered. Optimisation of the capacity development and operation of the energy system towards 2050 is performed with the energy system model Balmorel. Generation, storage, transmission expansion, district heating, carbon capture and storage, and synthetic gas units compete with each other. The results show how sector coupling leads to a change of paradigm: The electricity system moves from a system where generation adapts to inflexible demand, to a system where flexible demand adapts to variable generation. Sector coupling increases electricity demand, variable renewable energy, heat storage capacity, and electricity and district heating transmission expansion towards 2050. Non-restricted investments in onshore wind and electricity transmission reduce emissions and costs considerably (especially with high sector coupling) with savings of 78.7€ 2016 /person/year. Investments in electric power-to-heat units are key to reduce costs and emissions in the heat sector. The scenarios with the highest sector coupling achieve the highest emission reduction by 2045: 76% greenhouse gases reduction with respect to 1990 levels, which highlights the value of sector coupling to achieve the green transition. • Sector coupling increases demand flexibility and renewable energy integration. • Electricity-to-heat is a cost-effective way to decarbonise most of the heat sector. • Decarbonisation targets might not be reached without sector coupling. • Restricting onshore wind and/or grid expansion reduces the value of sector coupling. • Detailed variable renewable energy modelling is important in future energy systems. [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]

• Production- and Consumption-based carbon emissions taxation schemes are revised. • Carbon policies are applied to Europe, assessing economic and environmental impacts. • The World Trade Model coupled with Exiobase MRIO database is used for the analysis. • Application of Production-based carbon taxation leads to carbon leakage. • Results of Production- and Consumption-based schemes are comparatively analysed. Policy initiatives towards reduction of CO 2 emissions implemented so far are grounded on the so-called Production-Based paradigm: this approach allocates responsibility of emissions to countries that directly caused such emissions, without taking into account all the indirect contributions to CO 2 emissions caused outside country's borders, eventually leading to the so-called carbon leakage phenomenon. In this paper, the alternative Consumption-Based approach is proposed, and its effectiveness assessed: according to this approach, policy initiatives allocates responsibility for CO 2 emissions proportionally to the CO 2 emissions embedded in goods and services required by industries as inputs for production. Global environmental and economic consequences of carbon emissions reduction policies, applied at the European level based on both Production- and Consumption-Based paradigms, are comparatively assessed based on the World Trade Model with Bilateral Trades. Results of this study suggest that defining CO 2 emissions policies based on a Consumption-Based paradigm seems to be the most effective way to reduce the global carbon emissions, avoiding the carbon leakage phenomenon which may occur in economies regulated by Production-Based policies. Indeed, an imposed reduction in CO 2 emissions embedded in EU final demand through a Consumption-Based Accounting policy would result in a global CO 2 emissions reduction up to almost 1.2 Gton. On the other hand, an imposed reduction in direct EU CO 2 emissions according to a PBA approach would result in an overall increase in global carbon emissions up to almost 0.8 Gton. [ABSTRACT FROM AUTHOR]

• Technical, economic and environmental modeling frameworks are proposed. • Economic and environmental optima of hybrid renewable energy systems are different. • Local climatic conditions highly influence the impacts and the optimal design. • Single- and multi-objective optimization both have advantages and disadvantages. • Installing photovoltaics is the cheapest way to decrease environmental impacts. The rapid spread of renewables made it essential to design optimal hybrid renewable energy systems (HRES) with the distinctive economic and environmental impacts of each technology in mind. According to a comprehensive literature review, very few studies consider life-cycle environmental impacts in small-scale hybrid renewable energy system optimization. This paper aims to fill this gap by providing a multi-objective design framework for household-scale systems based on the technical modeling of several typical components. Solar photovoltaic, wind turbine, solar heat collector, heat pump, heat storage, battery, and as a novelty, heat insulation thickness are considered. Backup power is either drawn from the grid or produced by a diesel generator in grid-connected and off-grid scenarios, respectively. Single objective optimization using genetic algorithm resulted in the least cost and the least environmental footprint options in a case study of three different locations across Europe. Then, Pareto-optimal solutions between the two extremities were explored with a multi-objective genetic algorithm. Single objective results show substantial differences between environmental and economic optima, while multi-objective optimization proved to be an efficient tool to investigate the trade-offs between the two conflicting goals. Solar photovoltaics is proved to be the most competitive technology to reduce environmental impacts in the case of grid-connected systems. Off-grid systems, however, benefit the most from a balanced mix of different renewable energy sources. Life-cycle impacts in the design of systems involving renewables is proven to be relevant while potential applications of the framework are also revealed. Further research areas, as well as the limitations of the methodology are identified in the conclusion. [ABSTRACT FROM AUTHOR]

• Automatic Frequency Restoration Reserve market description and analysis. • Prediction methodology to be used for bidding strategies. • Statistical and machine learning based prediction models. • Derivation of the acceptance probability of a bid. • Machine learning based models do not outperform statistical models. In continental Europe, automatic Frequency Restoration Reserve (aFRR) is the second fastest control reserve market. Due to the complex auction design, market entrance barriers for new players are high and the market is dominated by few operators of conventional power plants. However, a rising share of renewable technologies requires their integration into this market in order to assure future grid stability. Due to the high market complexity, operators and traders of such technologies are currently lacking a tool to estimate earning potentials. Both a market prediction methodology as well as a bidding strategy are required to estimate the earning potentials and to participate in the aFRR market. To encourage participation of new technologies, this paper first provides a detailed market description and then presents a market prediction methodology for estimating revenue potentials and to assist in creating bidding strategies for auction participation. For any potential bid, the acceptance probability within the auction is derived. Both statistical and machine learning based models are used for predicting key market quantities. A model comparison reveals a steadier and usually better performance of statistical models. Exogenous data sources such as weather, electrical loads or market data did not improve the prediction performance. [ABSTRACT FROM AUTHOR]

• Automatic Frequency Restoration Reserve market description. • Operating strategy for a generation pool comprising a Battery Energy Storage Systems (BESS) • Bidding strategy to derive optimal bids and to evaluate economic feasibility. • BESS market participation not economic feasible in 2019 but possibly in 2025. In continental Europe, automatic Frequency Restoration Reserve (aFRR) is one of three control reserve services to counteract imbalances in the electrical grid. The market is dominated by a few operators of conventional power plants since the auction design is complex and new players face various entrance barriers. In order to stabilize the electrical grid in the future, renewable generation technologies need to enter the market. To encourage operators (and traders) of renewable generation facilities to enter the market, this paper presents a bidding strategy based on an optimization approach for deriving an optimal bid and for estimating the revenue potential on this market. The focus is on the participation of Battery Energy Storage Systems (BESS) either in standalone mode or in conjunction with a virtual power plant (VPP). An in-depth cost breakdown and battery ageing model support the derivation of earning potentials. With current costs of containerized BESS, an operation is not economically viable. However, with a predicted cost breakdown for the year 2025 and a pooled operation, profits can be generated. But even for the reduced-cost scenario, profits were found to be lower than on the Frequency Control Reserve (FCR) market. [ABSTRACT FROM AUTHOR]

• Novel integrated model framework of coupled heat and power sectors. • Comprises heat demand model, heat dispatch simulation and electricity market model. • Modeling over 900 district heating networks throughout Europe. • Comprehensive analysis of results (comparison with historical data and benchmarks). • Significant improvement of results (el. prices, plant dispatch, trade balances, etc.). In Europe and other regions of the world, heat and power sectors are highly coupled. Thus, both sectors are interdependent which poses a challenge when modeling these systems. This paper presents a novel and integrated model framework to analyze coupled heat and power sectors. Said framework is designed to assess large-scale/multi-national systems such as the European continent's one. The integral model character derives from a model sequence that first models heat demand at individual district heating network level, then determines the heat supply schedules of individual heat generation units in these networks and finally uses an extended version of a pre-existing large-scale market model, the WILMAR Joint Market Model, for electricity market simulations. All models are embedded in a common database environment. In order to validate the model framework, a historical year is chosen, and model outputs are compared to historical market outcomes. For comparison, two alternative, frequently used modeling approaches are equally tested. Results show that the developed model framework is far superior to the alternative modeling approaches. This statement concerns the reproduction of heat demands, power plant dispatch, electricity prices and net electricity exports. The results also suggest that the developed model can yield improved intra-zonal exchange schedules, which are one major driver for congested transmission network elements. [ABSTRACT FROM AUTHOR]