HS2 testing building piles that can suck heat out of the ground

A test is being carried out by an HS2 contractor that could see heat being extracted out of the ground to heat buildings and railway stations.
Extracting heat from the ground is not a new technology, but it has struggled to be incorporated into large commercial construction sites. Considering that a heat pump needs lots of pipes drilled into the ground to pump cool water down, and warmed water back up, and as most construction sites dig large deep piles into the ground to support the building, i