A borefield bid tab lands on my desk. Three drillers, same scope, same site. $28 per foot. $41 per foot. $55 per foot. The developer picks the cheapest number and signs. Six months later the cheapest driller is losing his shirt because the limestone turned into granite at 340 feet. The lump sum contract has no mechanism to share the surprise. The bore gets value-engineered to a shorter depth, or the driller walks, or the project eats a change order that was never supposed to exist.
Every owner and every driller in geoexchange has lived some version of that story. And every owner keeps signing the same turnkey contract.
The Industry That Already Solved This
US onshore land drilling runs 95/5, day work over turnkey. The land rig market is a rental market — operators lease rigs from drilling contractors at a daily rate and carry the hole themselves. The IADC Daywork Contract is the default document on nearly every land well in the country. Turnkey exists for a handful of niche shops; it is not the model the industry runs on.
Geoexchange runs the other direction, and it runs harder. I have never seen a geoexchange borefield built on a day work contract. Not one. The number may literally be zero.
Every vertical bore in the US is sold lump-sum turnkey, with subsurface risk parked on the driller. Some drillers know how to price that risk. Most of them guess. The ones writing for the gap bid light on geology they have never seen and make it up on change orders, warranty dodges, and the next project.
What Happens When the Model Fails at Scale
Subterra Renewables — until recently North America's largest geothermal utility drilling firm, with a fleet of more than 65 rigs and multi-thousand-bore projects on the books — filed for creditor protection in Canada in May 2025. Its drilling subsidiaries were sold at court-approved vesting order in October.
When the lump-sum driller carrying the subsurface risk on thousands of bores runs out of runway mid-job, the owner does not get to finish the project the cheap way it signed up for. The owner gets to find another driller, renegotiate everything, and live with whatever records the first driller left behind.
That is the turnkey model at scale.
Three Reasons Day Work Wins
Risk lands where it belongs. Subsurface uncertainty is the owner's risk. The driller didn't pick the site. The driller didn't write the thermal model. The driller didn't decide the bore had to be 600 feet. Pricing that uncertainty into a lump sum doesn't eliminate the uncertainty — it just hides it inside a contingency the owner is already paying for, whether the surprise shows up or not.
Quality and warranty attach to the work actually performed. Under turnkey, a grout problem, a loop problem, and a heat pump problem all collapse into a single conversation about whether the system "works," and every subcontractor points at the next one. Under day work, the driller warrants the drilling, the pipe manufacturer warrants the pipe, the designer warrants the design. Nobody gets to hide a manufacturing defect behind a driller's signature.
Bidders can be compared on the same axis. When every bid is lump-sum against an uncharacterized site, the cheapest number almost always belongs to the contractor with the thinnest geological understanding. Day work lets an owner compare rig capability, crew skill, and hours-to-completion — the things the owner is actually buying.
The Two Pieces That Have to Exist First
None of that works without two pieces of infrastructure the industry has never quite built. That is the honest reason geothermal still runs on turnkey — and it is the reason we are building both.
The first is a standard. Day work only works when "the work" is defined — what a bore is, what a flow check is, what a pressure test proves, what a completion record has to contain. ANSI/CSA/IGSHPA C449 closes that gap: outcome-based requirements, test-backed acceptance, and a conformance matrix an inspector can walk line by line. It is written so a good driller can pass it and a bad driller cannot hide from it.
The second is recordkeeping. Day work pays for hours, and hours have to resolve into a structured record of what those hours produced. That is a bore construction record — not a field scribble at the end of the shift, but a time-stamped, per-interval, machine-readable log of what was drilled, how, and what happened. OXBO built BIOT‑κ for exactly that purpose: the bore-side equivalent of the mudlog the oilfield has had on every rig for half a century, ported to geothermal and opened up enough that a project owner can actually audit what they bought.