Spain's Battery Storage Boom Faces Price-Spread Cannibalization

Spreads at high levels

The average monthly one-hour intraday spread in Spain reached 215.37 euros/MWh in September, according to figures from the specialist energy press. That tops August's 195.29 euros/MWh, even though August usually offers strong solar resources, albeit with high demand. A wide spread attracts more companies to the market and raises the value of storage, which is why Europe is betting heavily on batteries in its energy transition strategies.

The cannibalization problem

Today's spread does not guarantee income over a battery's whole life. Consultancy AleaSoft Energy Forecasting notes that profitability also depends on how much energy can be shifted, on battery degradation and lifespan, and on operating constraints.

The bigger risk is cannibalization. Batteries charge when prices are low, which lifts demand at those hours, and discharge when prices are high, which adds supply. Both effects narrow the price gap. Projects whose revenue forecasts rely on current spreads could overestimate long-term returns, and that makes banks less willing to see some investments as viable.

What comes next

This does not mean batteries will stop being profitable or that installations should slow down. It means the business cannot rest only on the price differences seen today. To be financeable, projects will need coherent assumptions about installed capacity and operation, plus hourly forecasts covering different paths for the power system, including the least favorable ones. Only then can developers present long-term proposals that win funding and keep the renewables market moving.