Cube Hydro Carolinas, an affiliate of Cube Hydro Partners LLC, announced today it has reached an agreement to buy and upgrade Alcoa’s four hydroelectric power plants on the Yadkin River, including the High Rock Dam.

No dollar figure was given for the purchase. Cube Hydro is based in Bethesda, Md.

With its first purchase in North Carolina, Cube Hydro will be buying the facilities from Alcoa Power Generating Inc. (APGI), a subsidiary of Alcoa Inc.

The four facilities are known as High Rock, Tuckertown, Narrows and Falls. They represent a total of 215 megawatts and are expected to produce nearly 800,000 megawatt-hours of clean electricity per year, according to a release from Cube Hydro.

Dr. Kristina M. Johnson, chief executive officer of Cube Hydro Partners and former dean of the Pratt School of Engineering at Duke University, said, “We are excited to expand our presence into North Carolina to operate and upgrade the plants on the Yadkin River.

“We are committed to being good stewards of these well-run hydropower plants that have a long history of generating reliable, carbon-free electricity.”

Ray Barham, APGI Yadkin Relicensing Manager said, “Alcoa has a long history in North Carolina and we are grateful for the strong relationships we’ve formed over the years.

“We will continue to promote economic development opportunities at the Badin Business Park and are confident that Cube Hydro will build on our century-long legacy of generating clean, renewable energy and protecting the natural resources of the region.”

The Yadkin Project, which Alcoa has overseen for nearly 100 years, includes the four hydroelectric stations, dams and reservoirs along a 38-miles stretch of the Yadkin River. Local residents are most familiar with the reservoirs created by the dams: High Rock, Tuckertown, Badin Lake and Falls.

Alcoa’s smelting operation, Badin Works, for which the plants provided power, closed in 2010. Since then Alcoa has tried to transform that property into a business park — Badin Business Park — and one of tis first tenants was Electric Recyclers International.

Alcoa has been working for years toward a federal relicensing of the hydroelectric project.

John Collins, managing director for business development of Cube Hydro Partners, added, “We look forward to partnering with local communities as well as state and federal regulators to preserve the natural beauty of North Carolina and increase the clean electricity generated from these plants.”

Cube Hydro says it acquires and modernizes hydroelectric facilities to demonstrate the value of renewable hydropower and reduce the nation’s reliance on carbon-based energy.

Cube Hydro Partners currently owns and operates 14 plants in New York, Pennsylvania, Virginia and West Virginia with a total capacity of 126 megawatts and 470,000 megawatt-hours annually.

When the Yadkin Project and other pending acquisitions close, Cube Hydro Partners will operate 19 plants on 10 rivers in five states with a combined capacity of more than 373 megawatts, generating 1.4 million megawatt-hours annually, or enough electricity to power approximately 140,000 homes with renewable energy.

Johnson, the Cube hydro CEO, also is former U.S. undersecretary of energy in the Obama administration. Collins spent more than 22 years with Constellation Energy Group Inc. and Baltimore Gas and Electric Company, serving as chief financial officer and senior vice president of integration.

— Mark Wineka contributed to this story.