At the center of Microsoft’s new East Campus in Redmond, Washington, sits a 6.5-acre field—a park-like setting with sports fields, sprawling trees and roads. At first glance, the space is beautiful and full of activity. But under the surface, this field is a cutting-edge, highly sustainable utility plant.

In the soil underneath the park, nearly 900 bores have been drilled 550-feet beneath the earth’s surface—that’s almost as deep as the Space Needle is tall. These geo-exchange bores act as a giant energy storage system that utilizes the Earth’s geothermal properties to pre-heat or pre-cool the water entering the plant depending on the season.

This bore field is one of the largest in the country and feeds energy to a centralized two-story building, called the Thermal Energy Center (TEC), that acts as a large heat pump, using carbon-free electricity and the earth’s natural geothermal properties to deliver heating and cooling. The highly efficient heat recovery chillers and pumps move energy between the bore field and campus distribution loops powered by clean, renewable energy.

The TEC also houses 7 thermal energy storage tanks for 280,000 gallons of water. The heating and cooling tanks allow the TEC to operate in its most efficient state, rather than constantly adapting to the changing needs of the buildings on campus. The hot and cold energy is sent, via closed loop, to campus office buildings which include all-electric cafes and kitchens.

The TEC, recently awarded Engineering News-Record’s (ENR) Project of the Year, has eliminated the need for individual chillers and boilers in each building. Rather, the TEC centralizes the heating and cooling system making operations and maintenance more efficient. This means no reliance on traditional heating and cooling measures and the associated carbon impacts that come with them.