The drilling is limited to the making the channels for water flow. They are using maneuverable fracking drills and tools to get to the depths they need. They then inject water for use in the heating loop. This water should be used continuously, although it a unclear if it will need to be topped up.

Some of these geothermal startups are creating “natural” cracks via drilling to circulate water, while others are using the drilling to place fixed piping. The latter is hard, more expensive and likely more efficient. The company in the article is doing the former if Im not mistaken.