Build to Zero and the EIC Accelerator: Storing Solar Power as Steam
Build to Zero, incorporated in 2022 and based in Seville, develops ThermalBox, an electro-thermal energy storage system that uses renewable electricity to heat molten salts, stores the heat, and delivers process steam to factories around the clock, replacing gas boilers. Its EIC Accelerator project receives an EU contribution of €2,491,249 and runs from December 2024 to November 2026, according to CORDIS. It targets small and medium industrial users in chemicals, food and drink, paper and textiles that need steam below 400 °C, and aims to validate the system in an industrially relevant environment.
In the first year, the report says, Build to Zero standardised and validated all core components: a redesigned molten-salt electric heater, a once-through steam generator in a vertical helical-coil design, and a modular, transportable storage tank. Industrial manufacturing and pre-testing of all major components were completed, "with factory acceptance tests confirming compliance with design specifications", giving a "FOAK-ready design", according to CORDIS. The steam generator was built with Alfa Laval, which said in October 2024 that the first unit would be deployed at Dekitra, a chemicals maker, according to Alfa Laval.
Company file
- Legal entity
- Build to Zero SL, Seville
- Incorporated
- February 2022
- Chairman
- Joaquín Coronado
- Board investor
- Axon Partners Group
- Product
- ThermalBox molten-salt storage with ETESAI control software
- Partners
- Alfa Laval (steam generator), Dekitra (first site)
- EIC funding
- Blended finance, €2.49M grant
Where Build to Zero Stands Now
The Spanish register lists sales in the €500,000 to €1 million bracket, share capital of €866,410 and a board that includes the venture firm Axon Partners Group, according to Empresia. No equity round, EIC Fund investment or commissioning of the Dekitra installation has been announced. The company's website news section has not been updated since 2024.
The record
From Seville start-up to factory-tested heat battery
Build to Zero completed factory acceptance tests of its ThermalBox components in the first EIC year. The first installation, at the chemical maker Dekitra, has not been announced as running.
- Feb 2022Company incorporatedSeville
- Mar 2024EIC Accelerator cut-offThermalBoxblended finance
- Oct 2024Alfa Laval partnershipSteam generator for Dekitra site
- Dec 2024EIC project starts€2.49M EU contribution
- 2025Components pass factory testsFOAK-ready design
- Nov 2026EIC project endsFirst installation pending
Build to Zero, Alfa Laval, CORDIS and Empresia.
"Our partnership with Alfa Laval marks a major milestone in our mission to accelerate industrial decarbonization."
Joaquín Coronado, chairman of Build to Zero, October 2024The Technology: Solar-Plant Storage in a Box
Sensible heat storage in molten salts is a proven technology, the EIC report says, previously limited to large power plants. Build to Zero's contribution is making it compact, factory-built and transportable for individual factories. Electricity heats the salt when power is cheap or abundant; the stored heat later boils water into steam on demand. The EIC report says this also gives the grid flexibility by shifting industrial demand.
The problem
Heat's share of global energy and emissions
Heat accounted for 50% of global energy consumption and 38% of CO₂ emissions in 2022, and industrial processes for nearly 20% of CO₂ emissions, according to IEA figures cited by Alfa Laval.
Alfa Laval, citing the IEA, October 2024. Per cent.
What the EIC Award Promised, and What the Record Shows
The project runs until November 2026, so it is too early to judge it. The first year delivered a validated design and tested components, which is real engineering progress. The decisive step, a unit supplying steam in a working factory, was described as the next stage and has not been reported.
- Components validatedDeliveredFactory acceptance tests.
- Standardised MVP designDeliveredFOAK-ready.
- Industrial installationNot reportedDekitra planned.
- Market deploymentPendingNo orders public.
The Money
The award was blended finance; no EIC Fund investment has been announced. Build to Zero's financing beyond the EIC grant and its board investor is not public.
The market
Industrial emissions Build to Zero targets
Build to Zero says 56% of industrial emissions come from electricity supply and heat below 400 °C, the range ThermalBox serves, and that long-duration storage could cut industrial emissions by 6%.
Build to Zero website. Per cent of industrial emissions.
What Cannot Be Checked
Questions for the EIC
Whether the EIC Fund invested, whether the Dekitra unit has been commissioned, what steam costs from a ThermalBox compared with a gas boiler, and how much private capital Build to Zero has raised are not public.
Why Europe Should Care
Industrial heat below 400 °C is still mostly supplied by natural gas, while renewable power is increasingly curtailed, the EIC report says. A heat battery that turns surplus electricity into round-the-clock steam addresses both.
What the award promised
A validated, market-ready molten-salt power-to-heat system for industry.
What the record shows
Tested components and a FOAK-ready design; no running unit yet.
The Verdict
Built on paper and bench
Build to Zero has done the engineering. The proof is a ThermalBox making steam in a factory, which the record does not yet show.
Build to Zero and the EIC have not been asked for comment for this article. It is based entirely on public records and published statements, linked throughout.
Industry
EnergyEnergy storage
- Focus
- Thermal energy storage
- Technologies
- Thermal storage
- Keywords
- Molten salt
- Industrial heat
- Process steam
- Gas boiler replacement