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STUDY: EXECUTIVE SUMMARY
& DOWNLOAD

EWI (2026). Benefits of large-scale battery storage in the German electricity system and the costs of delayed expansion

Key findings at a glance

Uncertain regulatory frameworks are currently putting the necessary expansion of large-scale battery storage at risk – and, against the backdrop of growing electricity demand, increasing renewable generation and declining conventional generation capacity, could lead to significant efficiency losses in the German electricity system. The EWI study examines the impact of a slower ramp-up of large-scale battery storage on the German electricity system.

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“Expanding storage is not the risk – delaying it is,” says Christoph Ostermann, CEO and co-founder of green flexibility, summarizing the results.

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The approach is based on a model-supported comparison of two expansion pathways for large-scale battery storage systems (fast vs. slow), in which only storage capacity is varied in order to isolate the effects on costs, electricity prices, the grid and security of supply.

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Four key findings:

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1. Up to €2.8 billion in relief for industry and private households in 2035: Lower electricity prices and grid costs, reduced price volatility of up to 25%, and improved planning certainty.

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2. Up to €1.8 billion in annual system cost savings in 2035: Accelerated expansion of battery storage reduces variable electricity system costs (electricity generation costs and electricity import costs) by up to 7% in 2035, with increasing impact over time.​

 

3. 11 TWh less curtailed renewable electricity in 2035: This corresponds to the electricity consumption of around 3 million households and represents a reduction in electricity curtailment of up to 48% in 2035.

 

4. Greater resilience: Battery storage reduces import dependencies on natural gas and hard coal and acts as a buffer against international energy price shocks. In addition, the faster large-scale battery storage is expanded, the fewer additional reserve power plants, such as new gas-fired power plants, will be needed.

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“Storage systems are not cost drivers, but a central element of an efficient, resilient and affordable electricity system,” adds Christina Hepp, Director Strategy at green flexibility.

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DOWNLOAD THE STUDY

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