Vattenfall has entered into a strategic agreement with international energy storage provider Return to operate and optimize a large-scale battery park storage facility in Waddinxveen, located in the southern Netherlands. The project, featuring a 50-megawatt (MW) output and a total storage capacity of 100 megawatt-hours (MWh), is expected to be commissioned in the first half of 2026.
Under the eight-year contract, Return will deliver the battery system, which will be directly connected to TenneT’s high-voltage grid. Vattenfall will oversee the system’s operation and integrate it into its automated energy trading platforms, leveraging the asset to enhance flexibility, manage grid imbalances, and optimize balancing services.
“Flexible storage systems are becoming increasingly indispensable for a stable, fossil-free, and efficient energy supply,” said Honey Duan, Manager of External Battery Storage Systems at Vattenfall. “Large-scale batteries are essential to the energy transition and support our overarching ambition of enabling fossil freedom.”
This initiative is part of Vattenfall’s broader strategy to extend its expertise beyond in-house developments by optimizing and marketing third-party energy storage assets. The addition of the Waddinxveen battery park will strengthen Vattenfall’s ability to balance the growing share of variable renewable energy sources across its portfolio.
“In an increasingly volatile market, the battery facility from Return offers a highly flexible resource that complements our expanding renewable generation assets,” Duan added. “Integrating this system into our automated trading operations will allow us to reduce portfolio imbalances, optimize balancing costs, and deliver critical flexibility where it is most needed in the electricity market.”
Vattenfall has announced plans to introduce up to 1.5 gigawatts (GW) of external large-scale battery capacity to the Northwest European electricity market over the coming years. The company draws on decades of operational experience from managing pumped storage facilities and hydroelectric assets, including approximately 2.7 GW of installed capacity from pumped storage and run-of-river plants in Germany. In the Netherlands, Vattenfall already operates battery storage systems linked to wind farms such as Haringvliet and Princess Alexia.
