Hyme and the EIC Accelerator: A Molten Salt Bet Put on Ice

Hyme, founded in Denmark in 2021 as a spin-out of the nuclear power developer Saltfoss, set out to store renewable electricity as heat in molten hydroxide salt, a cheap by-product of chlorine production, and deliver it to industry and power plants. Its EIC Accelerator project, HYSE, received an EU contribution of €2,499,999 towards a total cost of €3,798,250 and ran from April 2024 to December 2025, according to CORDIS. The aim was a 70% cut in total installed cost through better corrosion control, materials and sensors.

In June 2026 Hyme laid off all 32 employees and put its activities into dormancy after heavy losses and weak demand, according to MigogEsbjerg, citing Energy Supply. Chief executive Ask Løvschall-Jensen said the company had been "too early to market" and blamed uncertainty over CO2 taxes, geopolitics, grid delays and slower solar and wind build-out, not technical problems at its Esbjerg demonstrator. Hyme agreed with creditors to cut its debt by about DKK 140 million to allow an orderly wind-down, and was selling its patents and equipment. Its website has since expired.

Where Hyme Stands Now

Hyme's 2025 annual report shows a loss of DKK 135.5 million, negative equity of DKK 78.2 million and cash of DKK 7.9 million at the end of the year. Its capitalised development work, valued at DKK 165.2 million a year earlier, was written down to zero, according to filings with the Danish Business Authority. Over five years the company lost almost DKK 156 million in total, according to Energy Supply as cited by MigogEsbjerg. It had raised more than DKK 150 million from investors.

The Technology: Heat in Molten Salt

Hyme's system heated hydroxide salt with renewable electricity and stored the heat in tanks, releasing it for industrial processes or power. Controlling corrosion was central to the EIC project, which combined oxoacidity and redox control to extend the system's lifetime. In March 2025 it partnered with the Swiss fluid engineering company Sulzer to commercialise the technology, according to ESS News. With the dairy group Arla it planned what it called the world's largest industrial thermal energy storage system, according to Sifted.

What the EIC Award Promised, and What the Record Shows

HYSE promised a 70% cut in installed cost and designs ready for mass production of its sensors. Its interim report records deliverables on cost reduction, corrosion control, salt properties and sensor design, and an application to the EU Innovation Fund for the Arla project, according to CORDIS. The commercial goal failed: no commercial store was built, and the company wrote off the development and stopped operating within six months of the project's end.

1. Technical deliverablesPartialInterim reports filed.
2. 70% cost reductionUnverifiedNo public result.
3. First commercial storeMissedArla store not built.
4. Company continuityMissedDormant, June 2026.

The Money

Hyme's losses grew from DKK 1.9 million in 2022 to DKK 13.3 million in 2024, while it capitalised its development spending on the balance sheet. The 2025 write-down turned that asset into a loss. Long-term liabilities stood at DKK 81.4 million at the end of 2025, before the agreed debt reduction.

What Cannot Be Checked

Why Europe Should Care

Cheap thermal storage would let factories and power plants run their heat on wind and solar power, the decarbonisation Hyme's project targeted. Hyme's collapse shows that a working demonstrator and big-name partners are not enough when the market for decarbonised heat depends on carbon taxes and grid connections that have not arrived.

The Verdict

Hyme and the EIC have not been asked for comment for this article. It is based entirely on public records and published statements, linked throughout.