In Germany, wind and photovoltaic (PV) systems dominate renewable electricity generation, with large wind turbines contributing 24.1% and PV systems contributing 10.6% in 2022. In contrast, electricity production from small wind turbines remains marginal (<0.01%). While currently only viable in high-wind locations, factors like rising electricity prices, cheaper battery storage, and increasing electrification could boost their future role. Within this work, a residential energy supply system consisting of a small wind turbine, PV system, heat pump, battery storage, and electric vehicle was dimensioned for different sites in Germany and Canada based on detailed simulation models and genetic algorithms in order to analyze the effect of bidirectional charging on optimal system dimensions and economic feasibility. This was carried out for various electricity pricing conditions. The results indicate that, with electricity purchase costs above 0.42 EUR/kWh, combined with a 25% reduction in small wind turbine and battery storage investment expenses, economic viability could be significantly enhanced. This might expand the applicability of small wind power to diverse sites.

Germany’s energy transition to a higher share of renewable energy sources (RESs) is characterized by decentralization, with citizens, cooperatives, SMEs, and municipalities playing a central role. As of early 2025, private individuals own a significant share of renewable energy installations, particularly PV panels, which corresponds to approximately half of the total installed PV power. This trend is driven by physical, technological, and societal factors. Technological advances in battery storage and sector coupling are expected to further decentralize the energy system. Thereby, the electrification of mobility, particularly through electric vehicles (EVs), offers significant storage potential and grid-balancing capabilities via bidirectional charging, although it also introduces challenges, especially for distribution grids during peak loads. Within this work we present a detailed digital twin of the entire distribution grid of the rural German municipality of Wüstenrot. Using grid operator data and transformer measurements, we evaluate strategic expansion scenarios for electromobility, PV and heat pumps based on existing infrastructure and predicted growth in both public and private sectors. A core focus is the intelligent integration of EV charging infrastructure to avoid local overloads and to optimise grid utilisation. Thereby municipally planned and privately driven expansion scenarios are compared, and grid bottlenecks are identified, proposing solutions through charge load management and targeted infrastructure upgrades. This study of Wüstenrot’s low-voltage grid reveals substantial capacity reserves for future integration of heat pumps, electric vehicles (EVs), and photovoltaic systems, supporting the shift to a sustainable energy system. While full-scale expansion would require significant infrastructure investment, mainly due to widespread EV adoption, simple measures like temporary charge load reduction could cut grid stress by up to 51%. Additionally, it is shown that bidirectional charging offers further relief and potential income for EV owners.

Energy sharing among small- and medium-sized enterprises (SMEs) may improve local use of distributed renewable generation and flexibility, but its effects on distribution grids remain uncertain under participant-oriented rather than grid-optimized dispatch. This study assesses the grid impacts and economic implications of participant-oriented energy sharing for a 2024 reference scenario and a highly electrified 2045 stress-test scenario. The analysis uses measured load profiles from SMEs in sectors covering a 30-day period from 15 October to 15 November. The results therefore represent an autumn-specific comparison rather than annual estimates. For both scenarios, grid operation without energy sharing is compared with participant-oriented energy sharing, and the resulting time series are evaluated in a separate load-flow simulation. Grid impacts are assessed using asset utilization, power flows, and aging-related operating costs. In 2024, energy sharing caused no significant adverse grid effects and reduced aging-related operating costs by 5.6%. In the 2045 stress-test scenario, these costs increase by 11.7%. Nevertheless, based on an energy sharing potential of 22.76 GWh, participating companies retain an economic benefit even if additional grid costs are allocated to them. The results indicate that participant-oriented energy sharing can be economically attractive, while its grid effects depend on future electrification and system conditions.

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