Middlebury College will divest its $1 billion endowment from fossil fuels within 15 years.

The commitment is part of a larger package of environmental reforms the college announced on Tuesday.

The school also promised to transition to 100 percent renewable energy sources โ€” not derived from fossil fuels โ€” for electric and thermal power at its main Vermont campus by 2028, and to reduce its overall energy consumption by 25 percent in that time period. The school also will expand its climate-focused academic and research programming.

On Twitter, environmentalist and Middlebury professor Bill McKibben, who founded 350.org, a nonprofit dedicated to fighting climate change, celebrated the schoolโ€™s โ€œbig beautiful breaking news.โ€

โ€œThis is great news because itโ€™s a billion dollars โ€” but also because itโ€™s one of the first institutions to reject divestment and then change its mind,โ€ he said. โ€œThe school with the first-ever enviro studies program (and the birthplace of @350) is now back among the very greenest institutions in the world.โ€

The initiative, dubbed โ€œEnergy2028,โ€ was unanimously endorsed by the schoolโ€™s board of trustees over the weekend, and follows a multi-year campaign by student activists. Middlebury officials had first considered โ€” and ultimately declined โ€” to divest from fossil fuels in 2013, saying at the time the move was mostly symbolic and too practically difficult. It announced in October it was once again considering divestment, as well as additional environmental initiatives.

Bill Burger, Middleburyโ€™s vice president for communications and chief marketing officer, said the school waited until now because it wanted to advance a broader packet of concrete reforms.

โ€œThis really had to be done comprehensively. Itโ€™s also the case that six years ago, or a little more than five years ago, this would have been mechanically much more difficult to do,โ€ he said, adding that Investure, the schoolโ€™s endowment manager, had since developed new options for managing investments in a more granular way.

Middleburyโ€™s announcement commits the school to divest from all โ€œdirectโ€ fossil fuel investments, which include investments held by specialist managers who maintain an investment focus on fossil fuel companies and specialist fossil fuel index funds.