Kraftblock

What they do

Kraftblock builds heat batteries for industry. Its systems take electricity, for example cheap wind power, or waste heat from a furnace, store it as heat in a solid granulate and release it later as steam, hot air, thermal oil or hot water. According to the company, delivery temperatures range from 50 °C up to 1,300 °C, and heat can be held for as long as two weeks. The storage medium is a patented granulate made largely from recycled steel slag, a by-product of steelmaking.

Why it matters

Process heat is one of the hardest parts of industry to decarbonise; it is usually supplied by burning gas. Many thermal storage approaches based on molten salts or concrete top out at roughly 500 to 600 °C, which rules out much heavy industry. Higher temperatures open up uses in steel, glass, ceramics and chemicals. Two projects show the range. At PepsiCo's crisp factory in Broek op Langedijk, north of Amsterdam, operated with the Dutch utility Eneco, the first two modules totalling 70 MWh replace gas boilers that heat frying oil, with a projected cut of around 8,500 tonnes of CO2 a year. At Tata Steel's sintering plant in Jamshedpur, India, two units of up to 20 MWh capture waste heat from cooling and feed it back into the process, with projected savings of about 22,000 tonnes of CO2 and 110 GWh of gas per year.

Products to know

• Kraftblock storage modules: see our product profile.

The German angle

Kraftblock was founded in 2014 by Martin Schichtel and Susanne König and is registered in Sulzbach near Saarbrücken, a former coal and steel region that is now trying to reinvent itself around industrial decarbonisation. Early backing came from Frank Thelen's Freigeist, which took a stake in 2018. In 2023 Shell Ventures led a 20 million euro Series B. It is a small company by venture standards, which makes its two international reference sites the strongest evidence of traction.

Sources

• Silicon Canals: Kraftblock bags 20m
• pv magazine: PepsiCo and Eneco project
• Solarserver: Tata Steel uses German high-temperature storage