Return and Engie have agreed a long-term BESS toll in Spain while EnBW and Zelestra have finalised one in Italy, totalling 55MW and 300MW of capacity respectively.
Return and Engie sign 10-year toll for Spanish BESS
BESS owner-operator Return and power firm Engie have signed a 10-year toll for three battery energy storage system (BESS) projects in Spain.
The three projects total 55MW/220MWh, are all in the Basque region, and will come online by the end of 2027.
Under the deal, Return will develop, own and operate the assets, while Engie will optimise their flexibility across Spain’s wholesale and ancillary services markets. It is a full tolling agreement, which generally would mean Engie pays Return a fixed amount and keep all of the potential upside.
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Return said it builds on an existing partnership in Germany, although it hasn’t previously officially announced a toll with Engie there.
Engie is deploying its own large-scale BESS projects globally, including in the US, Chile and across Europe, but is also a major provider of tolls. It recently agreed a toll with BESS platform Flower in Germany covering 657MWh of capacity and then announced one with developer Ignis in Spain for a similar amount.
The toll with Ignis is noteworthy as it only gives Engie the right to the BESS’ dispatch in the day-ahead and intraday market, while Ignis will remain responsible for operating the BESS in balancing services (ancillary services).
Large-scale BESS activity in Spain has picked up since the Iberian blackout in Spring 2025. Notably, the government has accelerated its rollout of EU-backed grants for energy storage, passed a grid resilience decree, and launched a capacity market (CM).
EnBW procuring capacity from Zelestra’s 500MW Italy BESS
Power firm EnBW will procure 300MW of capacity from a 500MW/2,000MWh BESS that IPP Zelestra will build and own in Emilia-Romagna, northern Italy.
The companies have agreed the toll for 60% of the project’s capacity for an unspecified period, only calling it ‘long-term’. Construction will start in 2027 for commercial operation in 2028.
It appears to be the same project that the two companies announced they had agreed a toll for, back in September 2025, based on location and timeline. But at the time they only said it could cover ‘up to 2GWh’ of capacity, so presumably the exact size of the deal was still being negotiated.
The project is not one of the dozen or so that won long-term revenue contracts from Italy’s TSO Terna in the MACSE auction. MACSE is Terna’s way of ensuring there is enough storage to balance solar generation in the south of Italy.
Zelestra’s Italy CEO Eliano Russo discussed the auction, why the company decided not to proceed in it, and what implications it would have for the wider offtake space in an interview with us for the Energy Storage Report 2026, which you can access here.
The IPP has also announced long-term offtake deals for its solar-plus-storage projects in Spain.
BKW has also been the offtaker for Zelestra’s solar projects in Italy, including the Ginosa and Bellomo projects, the latter under construction (pictured above).
