Efficient battery control in the German continuous intraday market

On the way towards a green economy with net-zero emissions, electricity storage systems play a crucial role in the transformation process of the energy system. But a few years ago, research repeatedly found that arbitrage in the German electricity spot market does not amortize investment costs. Due to a strong decline in battery prices and an increase in price volatility in recent years, the break-even point might have been exceeded now. This paper compares seven very practical trading strategies with batteries in the particularly volatile German continuous intraday market with hourly products, which take advantage of its multidimensional structure. We find that simple benchmark strategies are outperformed by more advanced decision rules, which apply an alpha-stable, additive, stochastic model to quantify expected short-term developments. Depending on the investment costs and technical conditions, we achieve a net capital return rate between 6.6% and 10.8% in 2024 and the investment amortizes after 4.1 to 6.7 years compared to a risk-free investment; in a sensitivity analysis these prove to be stable values. We also point out the potential for further increase in profit. • A green economy requires extensive flexibility options in the power system. • Battery storage has recently reached profitability in the German continuous intraday market. • We propose explicit trading strategies which apply stochastic forecasting. • Under realistic conditions, we achieve a net capital return rate of 8.4% in 2024. • This value proves to be widely stable in a sensitivity analysis.