National Grid completed its $100 million acquisition of renewables developer Geronimo Energy, launching another deep-pocketed European utility into the business of building wind and solar projects in the U.S.

Separately, National Grid entered a joint venture to acquire 379 megawatts of operating wind and solar capacity from Geronimo alongside the Washington State Investment Board, which manages pensions for public employees in the Pacific Northwest state.

National Grid is among the most important energy companies in its home market of the U.K., where it operates the electricity and gas transmission networks. But its U.S. business is even larger, including transmission and distribution infrastructure in the Northeast, and an increasingly active non-regulated arm, known as National Grid Ventures.

NGV is the unit that acquired Geronimo, which was among the last major U.S. wind developers not already backed by a utility group or investment fund. The deal was first announced this spring.

Minneapolis-based Geronimo claims to have developed more than 2.2 gigawatts of renewables capacity since being founded in 2004, with its historical focus on wind in the Upper Midwest having blossomed into a more geographically diversified portfolio that increasingly includes utility-scale solar. The developer will remain headquartered in Minneapolis.

The deal adds to an already long list of U.S. renewables developers acquired by European utility groups and energy companies, including Enel Green Power’s acquisition earlier this year of Tradewind Energy, Ørsted’s recent purchases of Lincoln Clean Energy, and Engie’s acquisition of Infinity Renewables.

In National Grid’s last annual report, chief executive John Pettigrew said the Geronimo deal represents the company’s “first meaningful step into renewable generation in the U.S.,” offering a potential pipeline of more than 6 gigawatts of onshore wind and solar projects.

Late last year National Grid launched a San Francisco-based VC arm known as National Grid Partners, with the stated intention of "disrupting itself." Its portfolio of investments ranges from solar software startup Omnidian to data analytics firm AutoGrid.

National Grid's traditional U.S. utilities business has played an important role in the emerging American offshore wind market, having built the subsea cables that connect the Block Island Wind Farm to the onshore grid and signed on to buy power from an 800-megawatt project off Massachusetts.