Dig Energy completes first project with novel geothermal drilling tech

A startup called Dig Energy has finished its first commercial job, drilling seven boreholes for a geothermal heating and cooling system at a Boston office building. Geothermal systems use heat pumps to draw on temperature stored underground, and they're considered one of the most efficient ways to heat and cool a building. The catch has always been cost: installing one can run up to five times more than a standard air-source heat pump, which is a big reason only about 1% of U.S. buildings use geothermal today.

Dig's pitch is a new drilling method that could change that math. Instead of the usual approach, which drills a hole, lines it with a protective casing, then inserts a heat-exchange pipe, Dig's rig uses a high-pressure water jet to bore through soil and rock, leaving the drill pipe in place to serve as the heat exchanger. Because there's no need for a casing, the holes can be narrower, which the company says cut water use by 90% and leftover debris by 75% on the Boston job, while also making the process much quieter and easier to fit into a tight city site. Dig says the method could eventually cut drilling costs by as much as 80%.

None of this changes what's available to homeowners right now, but it points toward geothermal heating and cooling becoming more affordable and practical in tighter spaces over time. Dig already has projects booked into mid-2027 and is working on an updated rig meant to speed up drilling further.