Updated

The Boston Red Sox have installed solar water heaters at Fenway Park, as part of an effort to make the ballpark more environmentally friendly.

The Red Sox formally unveiled the rooftop system Monday. They say the heaters will generate enough heat to replace 37 percent of the gas traditionally used to heat water at Fenway Park.

The nonprofit Bonneville Environmental Foundation says the system will help avoid 18 tons of carbon dioxide emissions each year. That's the equivalent of planting 4.86 acres of trees or not driving a car for 43,611 miles.

The club is working on other "green" initiatives, including installing solar-powered trash compactors and collecting plastic soda and water bottles from fans during games.