Optimal distributed hybrid-storage and voltage support of photovoltaic systems

Due to climate change and limitations of fossil energy sources, political goals that lead towards a massive increase in renewable and distributed generation, e.g. photovoltaic (PV), wind power, etc. have been proposed. However renewable generation units increase the volatility of electricity production, are only conditionally controllable and are characterized by low full load hours. These negative aspects challenge the integration of renewable energy sources into the electrical grid. Remedial measures that can be applied are the integration of hybrid energy storage in the existing energy system and the use of installed PV systems for voltage support. Hybrid energy storage balances deviations in generation and load. By providing reactive power, PV systems can limit the increased voltage level, which can be observed especially in weak grids in case of a reversed load flow due to a high power production. This paper is going to describe how to achieve a decentralized generation-load-balance by coupling the existing infrastructures (electrical, gas and thermal networks), using decentralized hybrid storage, enabling a massive integration of renewable energy sources into electrical distribution systems, as examined in the project “Symbiose”. Parallel to the work of “Symbiose”, benefits of voltage support by PV systems in the German distribution network will be presented.