On the banks of the Rhine in north-west Germany sits Thyssenkrupp’s Duisburg plant, Europe’s largest integrated steel mill. The hulking facility churns out about 11m tonnes of steel a year — along with roughly 20m tonnes of carbon dioxide, close to 2.5 per cent of the country’s CO2 emissions.

With EU nations committed to a 55 per cent reduction in greenhouse gas emissions by 2030, companies like Thyssenkrupp need to decarbonise fast. Its plan eventually to convert Duisburg’s furnaces to hydrogen is among the most ambitious in heavy industry.

Sectors such as steel, cement and petrochemicals that require extreme heat during production have huge carbon footprints. Steel is responsible for 7-9 per cent of all direct emissions from fossil fuels, with each tonne produced resulting in an average 1.83 tonnes of CO2, according to the World Steel Association. Cement accounts for about 8 per cent of all global emissions.