But it's an investment the company hopes to recoup within five to ten years because it saves on fuel by taking the warm water from the top of the cavern to the heat exchanger, where its heat is ...

Lost River Caverns is open all year round! Located in Hellertown PA. The Caverns have been open since 1930, Robert Gilman's ...

Carved into the rock beneath a Swedish city, a huge man-made cave system dating back to the Cold War is being used to heat local housing. DW found out how it works ...

Vattenfall, SSAB and LKAB have reached the halfway point in the construction of a rock cavern storage facility in a coastal city in northern Sweden. The 100-cubic-meter facility is being ...