Caldera

Caldera is a UK clean-energy company decarbonizing industrial heat with Warmstone, a thermal battery built from recycled aluminium and volcanic rock inside vacuum-insulated heat cells. Its electric Storage Boiler converts cheap off-peak renewable electricity into industrial steam and hot water up to roughly 200C, offering factories a zero-emissions alternative to gas boilers. Founded in 2017 in Fareham, England, Caldera closed a 10M pound Series A led by Germany's GEA Group in 2025 and landed its first commercial order from the NHS.