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The reduction in PV prices and interest in energy independence accelerate the adoption of residential battery storage. This storage can support various functions of an energy system undergoing decarbonization. In this work, operative benefits of storage from the system perspective, namely, generation cost reduction and congestion mitigation, are investigated. Germany is chosen as a case study due to its strong reliance on variable renewable energy. For the analysis, an economic dispatch model with a high spatial resolution is coupled with a pan-European transmission grid model. It is shown that the system's generation costs are highest when the assets are used only to maximize PV self-consumption, and the costs are lowest when the storage also reacts to the market dynamics. This amounts to a 6% cost reduction. Both operation strategies result in an equal level of grid congestion and infrastructure loading. This is improved with a strategy that accounts for regional peak reduction as a secondary objective. The high congestion level emphasizes that grid expansion needs to keep pace with the generation and electrification expansion necessary to decarbonize other sectors. Lastly, policymakers should enable multipurpose utilization, e.g., via the introduction of market-oriented retail electricity prices with intervention options for grid operators. [ABSTRACT FROM AUTHOR]

The decentralization of the energy system in Germany is leading to enormous investments in grid expansion, as the current regulation creates an obligation to expand the power grid to eliminate bottlenecks. Meanwhile, opportunities to leverage grid-friendly control of storage systems are neglected to alleviate the need for investment. For this reason, it is necessary to investigate intelligent alternatives to grid expansion, such as storage systems, to efficiently integrate distributed technologies into the power system and reduce the need for grid expansion. In this work, two representative configurations of a medium voltage grid in Germany are developed for the years 2022 and 2050, and different storage systems are compared economically with the grid expansion in a model-based simulation. Hydrogen storage and battery storage were chosen as storage systems. The results show that grid expansion is the least expensive option if only the grid expansion costs are included in the analysis. However, if additional uses for the storage systems are considered, the battery storage systems are more economical. While in the scenario for 2050 the grid expansion causes costs of approx. 56,000 EUR per year, revenues of at least 58,000 EUR per year can be achieved via the revenue opportunities of the battery storage, representing a 3.5% margin. Heat extraction, arbitrage trading, and avoidance of grid expansion in superimposed grid levels were integrated as additional revenue streams/sources. A robust data basis and cost degressions were assumed for the simulations to generate meaningful results. Overall, hydrogen storage systems are economically inferior to battery storage systems and grid expansion for this use case. The results demonstrate the complexity of analyzing the trade-offs in terms of storage as an alternative to grid expansion as well as the opportunities presented using battery storage instead. [ABSTRACT FROM AUTHOR]

• Techno-economic analysis of battery storage systems providing frequency control. • A stochastic, data-driven optimisation algorithm to optimise the battery controller. • Use of frequency data and detailed, yet computationally efficient battery models. • Case study of Germany shows the highest margins for a battery rated at 1.6 MW/1.6 MWh. • Calendar ageing drives battery degradation, while cycle ageing has less impact. Optimal investment in battery energy storage systems, taking into account degradation, sizing and control, is crucial for the deployment of battery storage, of which providing frequency control is one of the major applications. In this paper, we present a holistic, data-driven framework to determine the optimal investment, size and controller of a battery storage system providing frequency control. We optimised the controller towards minimum degradation and electricity costs over its lifetime, while ensuring the delivery of frequency control services compliant with regulatory requirements. We adopted a detailed battery model, considering the dynamics and degradation when exposed to actual frequency data. Further, we used a stochastic optimisation objective while constraining the probability on unavailability to deliver the frequency control service. Through a thorough analysis, we were able to decrease the amount of data needed and thereby decrease the execution time while keeping the approximation error within limits. Using the proposed framework, we performed a techno-economic analysis of a battery providing 1 MW capacity in the German primary frequency control market. Results showed that a battery rated at 1.6 MW, 1.6 MWh has the highest net present value, yet this configuration is only profitable if costs are low enough or in case future frequency control prices do not decline too much. It transpires that calendar ageing drives battery degradation, whereas cycle ageing has less impact. [ABSTRACT FROM AUTHOR]

We introduce a bottom-up modeling framework that allows both the decentral and central planning of an integrated energy system with high shares of renewable generation. We take into account the distribution network structure as well as the changing local consumption due to high electrification rates of building heat supply and the transportation sector. This approach allows the analysis of pathways in between a cost-optimal system design and an equitable spatial distribution of renewable generation and battery storage capacities within the system. In addition, we investigate the optimal combination of short- and medium-term battery storage technologies, namely lithium-ion and redox flow batteries. Our results for the case of Baden-Wuerttemberg, a state in southern Germany, show that a central planning of renewable generation and storage capacity requirements results in lower levelized costs of electricity than a decentral design, as expected. However, pathways in between the two planning paradigms can lead to a more equitable inclusion of communities in the energy transition at reasonable cost increases, which might increase acceptance. The results of this study are of significance for policy-makers and local stakeholders, as they must address the conflicts that arise on a local level when expansion targets are planned centrally. • Framework for modeling local electricity consumption, considering structural changes • Optimal combination of short- and medium-term storage technologies (LiB and RFB) • Costs, storage and renewable capacity requirements for decentral vs. central planning [ABSTRACT FROM AUTHOR]

Highlights: [•] PV-attached battery unprofitable from German wholesale aggregator point of view. [•] PV-attached battery profitability below utility costs of capital in Italy. [•] Profitability can be reached if energy CAPEX reaches 100–150EUR/kWh. [•] Optimum sizing depends on usage. [•] Maximum 5h of storage and power rating exceeding 40% of PV power required. [ABSTRACT FROM AUTHOR]

• Assessment of profitability and optimal sizing of residential PV and battery storage. • Consideration of heterogeneous household load profiles (e.g., size, employment status, energy efficiency). • Consideration of heterogeneous financial (metrics, parameters, source of financing) and fiscal dimensions (tax treatments, tax rates), within the German regulatory framework. • Battery energy storage increases the profitability of residential PV in many of the considered cases. • Optimal coupling of batteries (as opposite to stand-alone PV) range from 0% to 94% of the analyzed load profiles, following the variation of such finance-related dimensions (e.g., discount rates, debt versus equity financing). • Financial and fiscal aspects may be determinant to understand the diffusion and sizing of renewable energy technologies, especially among heterogeneous investors. The German government, in order to reach its renewable energy targets, has promoted the deployment of solar PV. Small residential PV installations coupled with battery energy storage systems are gaining momentum, as self-consumption has grown in attractiveness. We conducted an economic analysis to assess the profitability and optimal configuration of these technologies from the perspective of heterogeneous households that are subject to the current German regulatory framework. In this regard, we consider heterogeneous potential for self-consumption of electricity (e.g. household size, energy efficiency), as well as heterogeneous financial (i.e., metrics, parameters, sources of financing) and fiscal (i.e., tax treatment, tax rate) aspects. We find that the usage of alternative financial metrics (i.e., payback period, real internal rate of return and net present value), as criterion to evaluate profitability, remarkably affects rankings of system configurations. Secondly, fiscal aspects are crucial to assess profitability and marginally relevant for optimal system configuration, while financial aspects are greatly important for both matters. Our results on optimal battery coupling (as opposite to stand-alone PV) show that rates of adoption range between 0% and 94% of the analyzed load profiles, following the variation of such finance-related dimensions (e.g. discount rates, inflation, debt versus equity financing). We conclude that such findings on the impact of such factors, are greatly relevant to design cost-efficient and effective policies that aim to foster energy transitions, both in Germany and elsewhere, especially in a time of very low interest rates. [ABSTRACT FROM AUTHOR]

In this paper, we analyze consumer attitudes toward and interest in community energy storage (CES) in Germany, based on five focus group discussions and an online survey of private owners of photovoltaic (PV) systems, as well as written surveys and workshops with the residents of two residential developments where CES has been installed. We find that owners of PV systems are generally receptive to the idea of CES but are unfamiliar with it. They assume that CES is more resource- and cost-efficient than residential storage and appreciate the idea of professionally managed operation and maintenance, but are skeptical of whether fair and transparent distribution and billing can be realized. Consumers express a need for ancillary services, such as monitoring, information or energy management, but the interest in such services, however, is strongly dependent on their perception of the costs versus potential savings. [ABSTRACT FROM AUTHOR]