Grenergy has signed a 10-year financial tolling agreement for its 150 MW / 600 MWh stand-alone battery energy storage project in Oviedo, Spain. The agreement, effect from January 2028, was signed with an international utility rated Investment Grade by Moody’s. Construction is underway, with commissioning targeted for H1 2027. The project forms part of the 31 GWh Greenbox European storage platform and represents Spain’s largest announced stand-alone BESS to date.
PROJECT SNAPSHOT
Spanish multinational clean energy producer, Grenergy has signed a 10-year financial tolling agreement for its 150 MW / 600 MWh stand-alone battery energy storage project in Oviedo, Spain. The agreement, effective from January 2028, was signed with an international utility rated Investment Grade by Moody’s, with Grenergy retaining responsibility for asset operations and battery trading management.
Under the terms of the tolling agreement, Grenergy will retain responsibility for asset operations and battery trading management throughout the contract period. The Oviedo project is designed to provide 4-hours of storage capacity and is positioned as the flagship Spanish asset within Greenbox, the company’s stand-alone storage platform in Europe.
The construction of the Oviedo project is already underway on a former industrial site next to the La Estrecha substation in La Corredoria, with operations expected to begin in H1 2027. This location enables direct grid connection, reducing the need for additional transmission infrastructure.
The Oviedo project forms part of Greenbox, Grenergy’s European stand-alone storage platform, which was introduced during the company’s Capital Markets Day in London in May 2025. Greenbox currently includes a development pipeline exceeding 31 GWh across six European markets: 5 GWh in Poland, 7 GWh in Romania, 3 GWh in Germany, 5.8 GWh in Italy, 6 GWh in Spain, and 4 GWh in the United Kingdom.
In Poland, Grenergy has secured capacity agreements totaling 2.1 GWh for stand-alone storage projects and has received nearly €8 million (approximately $8.7 million) in grant funding from the Polish government to support additional 136 MWh of stand-alone battery projects. The company continues to evaluate further tolling agreements and pipeline expansion opportunities across its active European markets.
With a capacity of 600 MWh, the Oviedo facility is currently the largest stand-alone battery project announced in Spain. The project reflects the expansion of utility-scale energy storage in the Spanish market.
David Ruiz de Andrés, CEO of Grenergy, stated that the transaction marks Spain’s first financial tolling agreement of this type and could be extended to other Greenbox projects across Europe.