Spanish oil and gas company Repsol has struck a deal to buy a stake in Hecate Energy to gain a platform to expand in the growing U.S. renewable energy market, it said May 13, confirming an earlier Reuters report.

Repsol will buy 40% of the Chicago-based business, which is one of the largest privately-owned developers and operators of solar power plants in the United States.

No financial details were given, but a source familiar with the matter told Reuters on May 12 that Repsol would pay “a few hundred million dollars.” It has the option to buy the rest three years after the deal closes.

European oil and gas companies are buying up wind farms and solar plants and building expertise in the sector in the face of pressure from investors and governments to tackle climate change.

The Hecate deal helps Repsol with its plan to boost renewable generation capacity to 15 gigawatts (GW) by 2030, from the 1 GW of hydropower and wind capacity it had installed at the end of last year.

Repsol is also in talks with potential partners to take a stake in its low-carbon business before a possible market listing.

Until now, Repsol’s business in the United States has focused on hydrocarbon production. It produces gas at the Marcellus shale field in Pennsylvania and oil from the Buckskin production block in the Gulf of Mexico.

Hecate Energy, meanwhile, manages more than 20 solar projects that are either operating or at late stages of development in countries including the United States, Canada and Jordan.

Owned by a group of private investors, it has a pipeline of more than 40 gigawatts of capacity, including 16.8 GW of solar photovoltaic and energy storage projects at an advanced stage of development.