By Katie Fehrenbacher, Fortune.

One of the largest power companies in the U.S. is doubling down on funding the deployment of fuel cells by Silicon Valley startup Bloom Energy. Fuel cells are large devices that generate electricity through a chemical reaction and are usually installed close to a building that uses the energy.

Constellation, which is owned by Fortune 500 company Exelon EXC 0.18% , plans to provide equity financing to deploy 40 megawatts worth of fuel cells made by Bloom Energy. The forty megawatts would come from 170 fuel cell projects and is enough energy to power 32,000 average homes per year.

Last year Exelon itself entered into an agreement to fund the deployment of 21 megawatts worth of Bloom Energy fuel cells. Now Exelon’s subsidiary is entering into this deal for double that amount.