It's clean, abundant, and will outlast humanity — so why aren't more buildings tapping into the heat beneath our feet?
That question was on Curious Canberran Don Fletcher's mind, after learning about the Geoscience Australia building in the ACT, which is heated and cooled using ambient temperatures in the earth's crust.
"I had this vague memory that Geoscience had done this thing that seemed unusual 20 years ago of drilling all these holes to heat their building from ground heat exchange," he said.
Concerned about Australia's energy future, Don wanted to know why such systems weren't used in other large buildings in the city.
"Here we've got another supply of heat that's constant … it's continuous, it's free, it's clean, there's no surface infrastructure to speak of - it sounds wonderful!"