HVC Pauses Alton Geothermal Project After Disappointing Well Test

Key Takeaways

• HVC has paused its Aardwarmte Alton geothermal project: the first well reached the reservoir at 2.5 km but delivers less water than expected.
• The result surprised HVC: eight wells 20 km away tap the same aquifer successfully.
• The well will be sealed; HVC is reviewing scenarios, including a restart, with no timeline.
• Alkmaar heat network customers are unaffected; effects on its expansion are under review.
• Alton was part of a six-well programme lifting HVC’s portfolio to 18 wells and around 155 MW.

HVC has paused the Aardwarmte Alton geothermal project in the municipality of Dijk en Waard. A test of the first well showed that the source delivers less water than expected, the company announced on Thursday, 29 October 2026.

“Aardwarmte Alton is currently not delivering the result we had expected,” said Laurien Smies, Director of Heat at HVC. According to Smies, the company remains convinced that geothermal energy can make a significant contribution to the heat transition.

Well Reached the Reservoir at 2.5 Kilometres

Drilling started in September and, according to HVC, proceeded smoothly. The well reached a depth of 2.5 kilometres, where the reservoir is located – the layer from which the hot water is pumped to the surface.

HVC describes the result as unexpected: around 20 kilometres away, eight geothermal wells draw successfully from the same aquifer.

Drilling Rig to Be Dismantled

The drilling rig will be dismantled shortly, and the well will be sealed safely in line with applicable regulations. HVC said the pause gives it time to examine whether drilling the next wells is technically and economically justifiable. Several scenarios are under review, including a restart of the project. The company has not given a timeline.

Existing customers of the Alkmaar heat network are not affected. The network is supplied by HVC’s biomass plant and Waste-to-Wnergy plant on the Jadestraat in Alkmaar. The consequences for the planned expansion of the heat network are still being assessed.

Four Wells in Two Doublets Planned

The site at the Noordscharwouderpolderweg in Heerhugowaard was designed for four wells forming two doublets – two production and two injection wells – according to the explanatory note to the permit application by HVC Warmte B.V. dated 7 February 2025. For the test phase, the application assumed a flow rate of 250 cubic metres per hour per production well. It puts water temperatures at around 45 °C at a depth of 1.5 kilometres and around 120 °C at 4 kilometres. A gas-fired back-up heating plant with 4 × 10 MW thermal capacity was planned for peak and back-up supply.

The municipality of Dijk en Waard granted the environmental permit on 27 February 2026. HVC received SDE++ subsidies for the first doublet in 2023 and for the second doublet in March 2025. The geothermal heat was to feed the Alkmaar heat network and supply households and greenhouse growers in the Alton area.

Part of a Six-Well Drilling Programme

Alton is part of a programme that HVC announced on 28 April 2026: six new wells in three doublets – two at the Wippolderlaan in Westland and four at Alton. The drilling rig was to complete the Wippolderlaan wells first and then move to Alton. Drilling was scheduled to finish before summer 2027, with first heat expected in 2028 and 2029.

Together with its existing projects Trias Westland, Maasdijk and Polanen, the programme would bring HVC’s portfolio to 18 geothermal wells. According to the company, these supply around 155 MW of sustainable heat – the heat demand of more than 175,000 households – and reduce CO₂ emissions by 254,000 tonnes.

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