In his analysis, Gaskell starts by pointing out that steel is important for the electrification of industry – 1MW of solar power requires 35 to 45 tons of steel, while 1 MW of wind power requires 120 to 180 tons of steel.
“If steel is to go net zero, this will involve significant green hydrogen build out. Over 306mn tonnes of steel will be required to produce the green hydrogen needed to decarbonise the steel sector alone,” he explains.
“Steel is one of the largest industrial emitters but may be the most straightforward to decarbonise because the technology is understood. What is difficult, is making greener production economically viable. Currently 73% of the world’s steel is produced by predominantly coal-fired blast furnaces, with the remaining using electric arc furnaces. So, the switch to electric still has a significant way to go.”
Producing greener cement is more challenging. Some alternative production routes exist, for example clinker-free cement produced by Hoffmann Green Cement, but currently this is relatively small scale. Scale is a huge challenge – what’s needed to drive change is a shift in building standards.
Gaskell explains: “If these can change from specifying the input material used, such as the percentage of clinker used in cement, to specifying the levels of performance required, this would boost the development of greener, ‘novel’ cements.”
The fuel-intensive, high temperature process of calcination used to produce clinker, cement’s key ingredient, is what causes 50-60% of the emissions. Typically coal and coke (coal that has been processed) are used to produce the 1500C degree temperatures required.
Gaskell says: “Cement producers believe emissions reduction of 40% by 2030 could be achieved by reducing clinker ratios, changing the fuel mix, and using more energy-efficient kiln technology. Some manufacturers are switching to biomass and trialling plasma generators running on wind power/ concentrated solar radiation. But, as yet, there is no clear pathway to net-zero cement which uses clinker because of the emissions released in the clinker production process, so carbon capture will have to be part of future plans. Novel cements using alternative binders to clinker are being developed but scaling these technologies remain a challenge.”
Policy support is crucial. Europe has an existing carbon price which is becoming increasingly material to regulated cement and steel companies. In Norway, the cement company Heidelberg is also receiving government support for its net-zero plans involving carbon capture and green hydrogen. In Sweden, the steel company SSAB is leveraging local advantages, such as access to high-grade iron ore and renewable power to build a green steel value chain.
Gaskell believes policy support is needed to kick start momentum and speed up the research and investment into both greener cement and greener steel. The demand side is also important. “Building developers will need to be incentivised to pay the ‘greenium’ for more sustainable materials,” he suggests.
