The impact of weather and of batteries on the investment risk for backup gas power plants in a largely renewable energy system

With an increasing wind and photovoltaic share, the German generation mix becomes more weather-dependent. Backup technologies can help to bridge scarcity moments. These rare moments with high prices are the main events for their cost recovery. However, the uncertain revenue flow combined with long payback periods leads to high investment risks and possibly insufficient investment. A high level of needed backup capacity to cover the load does not necessarily go along with a high level of requested backup energy. Both indicators depend on the renewable output and the availability of alternative flexibility sources. We calculate them for two contrasting weather years and three levels of battery capacity by the agent-based-model AMIRIS. As a result, the demonstrated volatile backup energy request in combination with the same level of requested backup capacity for every scenario supports the idea of an alternative remuneration for the provision of capacity next to the energy-only-market.