Constellation Energy (CEG) and Pine Creek RNG said Thursday they have signed a long-term agreement under which Constellation will buy a minority equity interest in five Pine Creek production facilities.

Financial details were not provided.

The facilities in Washington, Utah, Iowa and Illinois produce about 1.5 million MMBtus of renewable natural gas a year, the companies said, adding the agreement paves the way for the development of about 3 million MMBtus a year of additional production.