Fraunhofer-Institut für System- und Innovationsforschung ISI

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  • Publication
    Towards improved prosumer participation: Electricity trading in local markets
    ( 2022)
    Kühnbach, Matthias
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    Bekk, Anke
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    Weidlich, Anke
    Local energy markets are a promising way to involve prosumers in the electricity system and activate demand-side flexibility. In this paper, we develop a modeling framework consisting of an optimization for prosumer home energy management systems embedded in a local energy market simulation. To enable an integrated assessment, the local market is linked to a central spot market. For each prosumer, we consider the individual flexibility potential, home storage systems, and demand response of electric vehicles. Using this model, we analyze the costs and benefits of a local market for prosumers in an energy system with a high share of renewable energy. We compare the systemic effects and the potential economic benefits of this local market for prosumers to pure self-consumption and prosumer participation in a central spot market. Applying our model to a case study of 480 prosumers, we show that a system including a local market is beneficial compared to self-consumption from a systemic perspective. However, allowing prosumers to participate directly in a central spot market is more profitable and facilitates the system integration of renewables.
  • Publication
    Investigating the impact of smart energy management system on the residential electricity consumption in Austria
    ( 2022)
    Mascherbauer, Philipp
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    Kranzl, Lukas
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    Yu, Songmin orcid-logo
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    Haupt, Thomas
    This paper addresses the following question: How can smart energy management system (SEMS) influence the residential electricity consumption at both individual household and national level? First, we developed an hourly optimization model for individual households. The energy cost of an individual household is minimized under given assumptions on outside temperature, radiation, (dynamic) electricity price, and feed-in tariff. By comparing the optimization to the reference scenario, we show the impact of SEMS on grid-electricity consumption and photovoltaic (PV) self-consumption at the individual household level. Second, to we aggregate the results to the national level, we constructed a detailed building stock taking Austria as an example. By aggregating the results of 2112 representative households, we investigate the impact of SEMS in the residential building stock on the national electricity system. As a result, we found that for individual single-family-houses (SFHs) with PV (no battery) and heat pump adoption, SEMS can significantly reduce the grid-electricity consumption up to 40.7% for a well-insulated building. At the national level we found that, for the buildings with 5 kWp PV but without hot water tank or battery storage, SEMS can still reduce the grid-electricity consumption by 7.4% by using the building mass as thermal storage.
  • Publication
    Cross-border concentrated solar power projects - opportunity or dead end? A study into actor views in Europe
    ( 2022)
    Burghard, Uta orcid-logo
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    Dütschke, Elisabeth orcid-logo
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    Caldes, Natalia
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    Oltra, Christian
    Cross-border renewable energy projects (in particular those based on concentrated solar power (CSP)) could play an important role in the future EU energy systems. Be it by contributing to enhanced energy security, improving the management of the energy system or meeting the EU renewable energy target in a cost-effective manner. However, despite the expected benefits associated with the use of cooperation mechanisms set up under the Renewable Energy Directive, several barriers and, possibly, lack of active support have prevented a wide use of these mechanisms among Member States. This paper explores whether social acceptance, or lack there of, can explain some of this lag in development. Collecting actor views on CSP cooperation mechanisms between EU Member States forms the basis of this analysis. The empirical basis consists of 43 interviews from Spain as a potential host for and Germany and the Netherlands as potential consumers of renewable energy (off-taker countries). The data analysis outlines that overall CSP cooperation mechanisms are seen positively; however, the complexity of implementation, heterogeneity of actor views, as well as high costs for CSP are perceived as downsides. Thus, overall, a societal impetus is missing and interest in further development seems limited.
  • Publication
    Impact of sector coupling on the market value of renewable energies - a model-based scenario analysis
    ( 2021)
    Bernath, Christiane orcid-logo
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    Deac, Gerda orcid-logo
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    Sensfuß, Frank
    Decarbonizing the energy supply by substituting fossil fuels with renewable energy sources (RES) is a key task for the coming decades in order to achieve the EU's ambitious climate protection targets. Information about the possible development and marketability of RES in the electricity sector is essential for assessing future funding needs. However, rising shares of fluctuating RES generation in the energy system reduce the average market prices and increase price volatility. Balancing price variations requires a considerable degree of flexibility. Additional flexibility in the electricity market through closer interconnection between the electricity sector and other demand sectors makes it possible to keep the market values of RES closer to the general market price level, irrespective of their shares. Such sector coupling can thus contribute to a cost-efficient transition to a low-carbon energy system. This paper examines the impact of efficient sector coupling on the market values of RES in a European energy system with ambitious decarbonization. We analyze different scenarios by applying the Enertile model, which uses an integrated cost optimization approach with flexibility options due to sector coupling and provides a detailed future development of RES. In our analysis, we examine three flexibility options: smart charging of electric vehicles, decentralized heat pumps in buildings, and multivalent district heating grids. We show that the flexible use of electricity in district heating has a significant impact on market values, while the impact of both flexible electric vehicle charging and flexible heating with heat pumps is rather small. Short-term flexibility due to load shifting of the charging or heating process shows only a limited effect on market values. Fuel switching in district heating, however, offers the possibility to change the absolute demand for electricity in direct response to RES feed-in and drastically reduces the curtailment of RES.
  • Publication
    Factors affecting the calculation of wind power potentials: A case study of China
    ( 2021)
    Franke, Katja
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    Sensfuß, Frank
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    Deac, Gerda orcid-logo
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    Kleinschmitt, Christoph
    ;
    Ragwitz, Mario
    In order to mitigate global climate change and air pollution, the Chinese government has assigned high priority to expanding low-carbon power generation in China. Recent studies have shown that wind power is one of the most promising renewable energy option in China. Although many studies have estimated the generation potential of onshore wind power, their results vary widely from 1783 TWh to 39,000 TWh. Therefore, we examine the different assumptions in these papers and identify three main factors influencing the results. The three influencing factors are: weather data set, land utilisation factor, and wind turbine configuration. For our model-based analysis, we define a reference scenario which is used to compare the results. Our analysis shows using a different weather data set increases the generation potential to roughly 35,000 TWh. This is 54% higher than the generation potential of the reference scenario. The land utilisation factor also has a large influence, ranging between -10% and -51%. The studies' assumptions and data should be subjected to careful scrutiny, as the calculated wind power potentials are widely used to develop decarbonisation strategies for the energy system.
  • Publication
    Energy efficiency and the direct and indirect effects of energy audits and implementation support programmes in Germany
    ( 2021)
    Schubert, Torben orcid-logo
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    Breitschopf, Barbara orcid-logo
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    Plötz, Patrick orcid-logo
    Energy audits help to increase energy efficiency in industry and have proven effective in many studies. Additional implementation support programmes providing financial incentives have been developed to not only support audits but also to overcome financial barriers to energy efficiency investments. Because the different types of programmes coexist, we argue that a precise analysis of their effects must explicitly model them together, demonstrating non-trivial direct and indirect effects of both audits and financial programmes on the adoption of energy efficiency measures. We corroborate the presence of these direct and indirect effects with data on German firms, all of which have participated in an energy audit programme and some of which have additionally received financial implementation support. Audits not only affect the adoption of energy efficiency measures directly, they also increase the likelihood of receiving financial implementation support, which in turn increases the adoption rate. Furthermore, our findings highlight that consultancy during implementation is an important factor for adoption. Accordingly, additional supporting policies should be considered in future energy audits, for example to ensure assistance during implementation.
  • Publication
    Nachhaltigkeitsbewertung für Kleinwasserkraftwerke in China
    ( 2020)
    Tettenborn, Felix orcid-logo
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    Sartorius, Christian
    In China besteht ein hohes hydroenergetisches Potenzial an dezentralen emissionsarmen Lösungen in Form von Kleinwasserkraftwerken. Deren Nutzung kann helfen, soziale Ungleichgewichte abzubauen, gleichzeitig resultieren daraus international kontrovers diskutierte deutliche Eingriffe in Natur und Landschaft und damit in die Gesellschaft. Zur Erfassung und Bewertung der systemischen Auswirkungen der Nutzung von Wasserkraft wurde ein multikriterieller Ansatz erarbeitet, mit dessen Hilfe Planungsprozesse unterstützt und innovative Finanzmittel mobilisiert werden können.
  • Publication
    Zellen demonstrieren das zukünftige Energiesystem
    ( 2020)
    Haller, Birgit
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    Kießling, Andreas
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    Pelka, Sabine orcid-logo
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    Wohlschlager, Daniela
    Die zelluläre Organisation des Energiesystems wird im SINTEG-Projekt C/sells nicht nur konzeptionell vorangetrieben, sondern auch vielfältig demonstriert. Die enge Verzahnung von Konzept und Praxis ist ein Erfolgsfaktor des transdisziplinären Verbunds von Forschung und Industrie. Der Artikel beleuchtet die Genese des Begriffs ""Zellularität im intelligenten Energiesystem" im Projekt und zeigt die Diversität verschiedener Zellfunktionen auf - dokumentiert während der ""AcCEUerator Tour" zu den Projektstandorten.
  • Publication
    A supply curve of electricity-based hydrogen in a decarbonized European energy system in 2050
    ( 2020)
    Lux, Benjamin orcid-logo
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    Pfluger, Benjamin
    Alongside substituting fossil fuels with renewable energies and increasing energy efficiency, the utilization of electricity-based hydrogen or its derived synthetic fuels is a potential strategy to meet ambitious European climate protection targets. As synthetic hydrocarbons have the same chemical properties as their fossil substitutes, existing infrastructures and well-established application technologies can be retained while CO2 emissions in energy conversion, transport, industry, and residential and services can be reduced. However, the conversion processes, especially the generation of hydrogen necessary for all e-fuels, are associated with energy losses and costs. To evaluate the techno-economic hydrogen production potential and the impact of its utilization on the rest of the energy system, a supply curve of electricity-based hydrogen in a greenhouse gas emission-free European energy system in 2050 was developed. It was found that hydrogen quantities of the order of magnitude envisaged in the 1.5 °C scenarios by the European Commission's long-term strategic vision (1536-1953 TWhH2) induce marginal hydrogen production costs of over 110 e2020/MWhH2 and electrolyzer capacities of more than 615 GWel. Although the generation of these amounts of hydrogen using electrolysis provides some flexibility to the electricity system and can integrate small amounts of local surplus electricity, an additional 766 GWel of wind power and 865 GWel of solar power must be installed to cover the additional electricity demand for hydrogen production. It was furthermore found that the most important techno-economic properties of electrolyzers used in an energy system dominated by renewable energies are the ability to operate flexibly and the conversion efficiency of electricity into hydrogen. It is anticipated that the shown analysis is valuable for bothpolicy-makers, who need to identify research, subsidy and infrastructure requirements for a future energy system, and corporate decision-makers, whose business models will be significantly affected by the future availability of electricity-based fuels.
  • Publication
    How much energy autonomy can decentralised photovoltaic generation provide? A case study for Southern Germany
    ( 2020)
    Kühnbach, Matthias
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    Pisula, Stefan
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    Bekk, Anke
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    Weidlich, Anke
    Energy autonomy, the desire to become independent from a centralised supply system, is a core motivation for the development of decentralised energy systems, even if it does not have tangible economic or ecological benefits. For the case of electricity, we introduce a regional system model which optimises the capacity expansion and operation of photovoltaics and battery storage. We quantify cost-efficient regional degrees of electricity autonomy for 166 regions in Southern Germany and assess how increasing the degree of autonomy beyond the optimal level affects the economic viability of a decentralised electricity system. We find that the average optimal degree of autonomy reached is 44%. Thus, our results show that a substantial increase of photovoltaic capacity is economically beneficial in all the regions examined. However, achieving a predefined degree of autonomy causes additional costs for the region and results in a large overcapacity, while all regions still rely on the superordinate electricity system to some extent.