A Finnish firm thinks it can cut industrial carbon emissions by a third

Fossil fUELLED power stations can be replaced by solar panels or nuclear reactors. Petrol-powered cars can be replaced with ones that use zero-carbon electricity to charge batteries. But not every part of an economy is so easy to decarbonise, even in principle. Three heavy industries—cement, chemicals and steelmaking—are particularly tricky to clean up. One reason is that all rely on chemical processes that need very high temperatures.

Extracting iron from its ore, for instance, is the first step in steelmaking. Temperatures inside the furnaces used to do that can exceed 1,600°C. Cement kilns, which convert limestone into clinker, one of cement’s raw ingredients, can reach 1,400°C. Because it is tricky or impossible to produce such temperatures for some industrial processes using electricity alone, firms rely on fossil fuels.