One well, 1,250 metres deep. No fuel, no CO₂.
The deepest single well ever drilled for a public swimming pool. LAGO Bredene Grasduinen heats its pool, sports hall and showers from one borehole — in a subsurface that could never have carried a conventional doublet.
A pool never stops asking for heat
LAGO wanted a sports complex open 360 days a year for 124,000 visitors, without burning fossil fuel. A swimming pool is the hardest building there is for that: the heat demand never pauses — not at night, not in summer, not between seasons.
THE WELL IN NUMBERS
1,250 m · depth of a single borehole
Ø 40 cm · one hole, no second well
± 38 °C · formation temperature
25–30 °C · supply, year round
235 kW · average continuous heat output, with heat pump
500 kW · peak heat output
Jan–Mar 2026 · drilled non-stop
± 1,700 MWh · generated per year
over 50 % · less electricity than an air-source heat pump
0 m³ · gas burned
Why one well, not two
A doublet was never an option here. The coastal subsurface does not deliver the flow two wells need, and there was no room for a second drilling site next to a building under construction.
The NotusPiD system does not depend on an aquifer. Water circulates through a single borehole that stands in pressure equilibrium with the formation, and the well draws heat from the rock along its full vertical length — by conduction and by convection. Nothing is produced from the ground and nothing is injected back into it, which takes injection risk, induced seismicity and the permit debate that comes with them off the table.
Two months, around the clock
The rig went into the ground at the end of January 2026 and reached final depth by the end of March: two months, 24 hours a day, in a hole 40 centimetres across. A domestic ground loop stops at 100 to 150 metres. This one goes roughly ten times deeper.
The well logs from Bredene now serve as the validation set for our simulation model.
What Bredene proves
A swimming pool is only one way to use the heat. Because the system circulates inside its own borehole instead of depending on an aquifer, the same well works where a doublet cannot: industrial process heat, steam production, desalination, and cooling.
Depth, flow and delivery temperature are design choices here — not something the subsurface has to hand you. That is what makes the system flexible, scalable, and applicable on sites a doublet would have to walk away from. And one well is not the ceiling: couple several single wells on one manifold and the installed capacity grows with the site, while the depth of each well is matched to the temperature the process actually needs.
PARTNERS
“LAGO is a pioneering project that puts Flemish sports infrastructure at the forefront of the energy transition in Europe.”
Diether Thielemans, LAGO
LAGO operates the complex. NotusPiD designed, built and delivered the single-well system. Daldrup drilled the well, DMT ran the measurements, and Odfjell supplied the platform for installing the production string. VITO followed the drilling scientifically.
A site with a heat demand that never stops?
Tell us the building, the load and the location. We will tell you whether one well can carry it.
info@notuspid.nl · +31 6 17 95 18 62
