The cement industry produces a lot of carbon dioxide emissions—on par with the steel industry at around 8pc of the global total based on some estimates—but is less suitable for using green or blue hydrogen to decarbonise for a simple intrinsic reason.

The process of calcination, whereby limestone is heated to break it down into calcium oxide and CO₂, causes almost half of the emissions from cement production and can therefore not be avoided. The combustion of fossil fuels to heat the lime and cement kilns account for only about 40pc of total emissions, while electricity use for other parts of the plant makes up the rest.

“The fast adoption of this new hydrogen-based technology is a clear example of Cemex's innovation efforts and its strong commitment to decarbonise the cement production process," Ponguta, Cemex

As a result, cement companies have so far been placing much greater emphasis on capturing CO₂ emissions, , especially from the calcination process, and either storing them or using them rather than replacing fossil fuels with hydrogen to heat their kilns. For example, LafargeHolcim, the largest cement producer outside of China with 270 plants around the world, is in the early stages of advancing a portfolio of 20 carbon capture, utilisation and storage projects in Europe, Canada and the US.

Major exceptions include Mexican multinational building materials company Cemex, which recently announced a plan to add hydrogen to the fuel mix of all its cement plants, as well as a study and pilot project by UK’s Hanson Cement, a subsidiary of Germany-based HeidelbergCement.

Cemex

On 23 February, Cemex announced it had added its “ground-breaking hydrogen technology” to all of its cement plants in Europe, and was planning to extend programme to all of its plants around the world by the end of this year at an estimated cost of $40mn. Initial trials of this technology, which enhances the cement kiln’s combustion process while significantly reducing CO₂ emissions, were performed at its Alicante Cement Plant in Spain in July 2019.

“The fast adoption of this new hydrogen-based technology is a clear example of Cemex's innovation efforts and its strong commitment to decarbonise the cement production process," says Roberto Ponguta, vice president of global operations, technical and energy at Cemex. "We continue to identify and deploy existing technologies that have a high potential to contribute to our sustainability goals, and hydrogen is a key lever.”

In March 2020, Cemex announced its Climate Action Strategy, with a goal of slashing CO₂ emissions from its global operations by 35pc from 1990 levels by 2030, including a 55pc reduction at its European plants. The company has also provided a longer-term vision of net-zero concrete worldwide by 2050.

Hanson Cement

On 11 February, Hanson announced it had installed a green hydrogen demonstration unit, housed inside a converted shipping container, at the company’s Regen ground granulated blast furnace slag (GGBS) plant in Port Talbot in South Wales. The unit is to produce green hydrogen to replace some of the natural gas the plant consumes to reduce its CO₂ emissions. It is worth noting that Regen GGBS can replace up to 80pc of Portland cement in concrete with only one- tenth of the carbon footprint, even before including hydrogen in the fuel mix.

8pc – Proportion of global carbon emissions from cement manufacturing

In addition, Hanson is undertaking a £6.2mn ($8.58mn) study at its Ribblesdale cement plant in Lancashire, England to determine whether a zero-carbon fuel mix—70pc biomass, 20pc hydrogen and 10pc plasma energy—can successfully be used to power both lime and cement kilns. The study, funded by the UK’s Department for Business, Energy and Industrial Strategy, is to be completed by the end of this year.

“As a company, cutting CO₂ emissions is a key priority for us and we have already made good progress through using alternative fuels in the kiln,” says Gary Young, manager of the Ribblesdale plant. “The prospect of being able to use hydrogen within the mix is exciting and, if successful, will help us and others in the sector on the road to net-zero carbon.”

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Author: Vincent Lauerman