Impacts of volatile and uncertain renewable energy sources on the German electricity system

The paper quantifies the indirect system costs of renewable energy sources for the German electricity system with a model-based energy system analysis approach. The stochastic and volatile character of renewable energy sources and the market mechanisms used in Germany to compensate the forecast errors are considered. The results of the system analysis point out that the indirect system costs are currently quite small. However, the indirect system costs are increasing in coming years. Results show that photovoltaic has smaller indirect system costs than wind energy and photovoltaic reduces the costs of volatility which arise by using wind energy. In other words, model results indicate that several intermittent resources lead to a positive portfolio effect.