Utility-Scale Battery Storage Increases Power System Efficiency and Stability – Multi-Billion-Euro Potential from Faster Deployment
The current energy policy debate is overlooking one of the most effective levers for a cost-efficient power system: utility-scale battery storage. A recent study by the Institute of Energy Economics at the University of Cologne (EWI) shows that accelerating deployment could deliver significant cost savings, more stable electricity prices and greater security of supply.
Cologne/Kempten, June 25, 2026
Uncertain regulatory conditions are currently putting the necessary expansion of utility-scale battery storage at risk. Against the backdrop of rising electricity demand, increasing renewable generation and declining conventional generation capacity, this could lead to significant efficiency losses in the German power system.
The EWI study examines the impact of a slower deployment of utility-scale battery storage on Germany’s power system.
The risk is not the expansion of battery storage, but the delay in its deployment,” says Christoph Ostermann, CEO and Co-Founder of green flexibility, summarising the findings.
The analysis is based on a model-driven comparison of two deployment pathways for utility-scale battery storage — rapid versus gradual — in which only battery storage capacity is varied to isolate its impact on system costs and electricity prices.
Four key findings:
1. Up to €2.8 billion in savings for industry and households in 2035: Lower electricity and grid costs, combined with reduced price volatility (of up to 25%), provide greater planning certainty.
2. Up to €1.8 billion in annual system cost savings in 2035: Accelerating battery storage deployment reduces variable power system costs — including electricity generation and power import costs — by up to 7% in 2035, with the impact increasing over time.
3. 11 TWh less market-driven renewable energy curtailment in 2035: This is equivalent to the annual electricity consumption of around 3 million households and represents a reduction in curtailment of up to 48% in 2035.
4. Greater resilience: Battery storage reduces reliance on imports of natural gas and hard coal and acts as a buffer against international energy price shocks. The faster utility-scale battery storage is deployed, the fewer additional reserve power plants — such as new gas-fired power plants — will be required.
“Battery storage is not a cost driver, but a key element of an efficient, resilient and affordable power system,” adds Christina Hepp, Director Strategy at green flexibility.
The Study
The study by the Institute of Energy Economics at the University of Cologne (EWI) was commissioned by green flexibility and is available for download here: Link
