Old quarry near runway now saves airport $430,000 a year

By taking advantage of the quarry reservoir's year-round 50-degree temperature, the airport will be able to halve its cooling costs, said Christine Vitt, the airport authority's vice president of strategic planning and sustainability.

It's a closed-loop system, so the water never leaves the pipes, and the components should last a century or more, said environmental consultant David Rehse of Energy Systems Group, who worked on the system.

[...] unlike solar panels, which are a visible sign that a building uses renewable energy, this geothermal system operates continuously underground, rain or shine.