Sainsbury’s, a massive supermarket retail chain in the UK, recently announced plans to install geothermal energy systems for heating, hot water and cooling in 100 of its stores. The drastic switch is part of the corporation’s 20 by 20 Sustainability Plan which it says will help customers make more nutritious, sustainable and ethical purchasing decisions.

Geothermal energy systems work by pumping water down below the Earth’s surface, where it is quickly heated to very hot temperatures. The warmed water is then returned to a heat pump, which extracts the heat and delivers it to the building, where it cools over time. Eventually, the cold water is pumped into the ground again, and the process starts all over again.

Sainsbury’s already uses a geothermal system to provide power to its Crayford store in southeast London, and claims that it supplies some 30 percent of the store’s energy requirements. If this can be duplicated across 100 chain locations, the company says it will deliver up to 100 MW of renewable energy by 2016 and cut carbon emissions 30 percent by 2030.

“The roll out of this technology with our partners is an important milestone in our renewables commitment,” says Sainsbury’s property director Neil Sachdev. “We were the world’s first to use geothermal technology in a supermarket to tap natural, renewable energy trapped 600 feet under the ground.”

Sainsbury’s is also installing biomass boilers, which run off wood chips or pellets, and is the largest UK user of anaerobic digestion with all of its food waste from stores not donated to food charities being used to generate electricity for the grid.

Corporations in the U.S. have been somewhat slower to embrace geothermal energy, although there are a few brave enough to give it a try. In 2010, Ikea announced that its Centennial, Colo., location would be the first U.S. Ikea store to utilize geothermal heating and cooling. Fifteen of the company’s stores worldwide are using geothermal energy. The same year Walgreens opened the nation’s first drug store chain location utilizing geothermal energy in Oak Park, Ill.

Main photo credit: Sainsbury’s