Irizar e-mobility, public transport operator EMT Madrid and Iberdrola España have launched a pilot project to reuse electric bus batteries in a stationary energy storage system at EMT’s Fuencarral depot, as part of efforts to improve charging efficiency and extend battery lifecycles.
The project involves a container-based static storage unit that integrates second-life batteries previously used in Irizar e-mobility electric buses. While the batteries no longer meet the capacity requirements for vehicle operation, the partners said they remain suitable for stationary energy storage applications.
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The system has been integrated into EMT Madrid’s smart charging platform and is designed to charge during off-peak hours and discharge during periods of high demand. This approach is intended to reduce power peaks during bus charging, optimise energy use and lower electricity costs at the depot.
The container has a maximum energy capacity of 1 megawatt-hour and can deliver charging and discharging power of up to 500 kilowatts. It comprises 15 battery racks recovered from three Irizar e-mobility buses and is fully managed through EMT’s existing smart charging system, which is already used daily to charge the electric fleet at Fuencarral.
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Irizar e-mobility said it has been developing and manufacturing its own batteries for more than seven years and has prioritised reuse as part of its circular economy strategy. “The reuse of batteries has been a priority within our approach to circular economy solutions,” the company said, noting that stationary applications allow batteries to remain productive after they are replaced in vehicles due to capacity degradation.
The partners said extending battery lifespans through second-life use reduces the need for new battery production, lowering demand for raw materials and associated environmental and social impacts. The storage system is intended to provide a practical and cost-effective solution for large-scale electric bus charging while supporting sustainability goals.
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The project is part of Spain’s PERTE VEC programme and aligns with EMT Madrid’s broader strategy to decarbonise public transport through zero-emission vehicles, upgraded infrastructure and smart energy management technologies.
