What's Going On at Phillips Exeter Lawn?

Those huge green rigs on the lawn are digging hundreds of feet into the ground to make way for an alternative energy system that the school says will give off less pollution.

Crews are installing a geothermal system that will harness heat generated naturally underground.

Plans call for 49 wells that will reach 400 feet underground, according to an overview of the project. A sketch of the project can be found above in the photos.

A pump will push a glycol solution through a pipe system. The solution will be warmed by the earth and shoot back up to a mechanical system that will cool or heat Phillips Hall.

The system is about 30 percent more efficient than a traditional heating/cooling system. There's no air pollution because it doesn't need fossil fuels to operate.

Crews are expected to have the system up and running by the start of fall classes. The grass and trees that have been dug up will be replaced.

The school plans to double the size of system in coming years.

Phillips Exeter already has another geothermal system that powers several faculty housing units. Those units were awarde a LEED (Leadership in Energy and Environmental Design) "Gold" certification by the U.S. Green Building Council.