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Cement comes clean

21 Dec 21 Cement production is one of the most carbon-intensive industries. But there are now concerted efforts to tackle the problem – and even go ‘beyond zero’. David Taylor reports

The cement industry’s dirty secret ceased to be a secret several years ago when somebody at the Royal Institute of International Affairs calculated the size of the industry’s carbon footprint.

Cement production, we now know, contributes around 8% of the world’s carbon dioxide emissions; if the cement industry were a country, it would be the world’s third-largest emitter of CO2 after China and the US.

Of course, once the news was out the cement industry could not be seen to be doing nothing to clean up its act. Cement substitutes – in the form of waste products from power generation and steel production – were already available, but they have their own substantial carbon footprints and can only contribute so much to carbon reduction.

This article was first published in the November 2021 issue of The Construction Index Magazine. Please sign up online 

But the search for real change is now well under way. In 2018 a new body was launched with the declared aim of ‘developing and strengthening the sector’s contribution to sustainable construction’.

The London-based Global Cement and Concrete Association (GCCA), which represents 40 of the world’s largest cement and concrete manufacturers, says it “aims to foster innovation throughout the construction value chain in collaboration with industry associations as well as architects, engineers, and innovators.” Last month it announced a ‘roadmap’ for the industry to achieving net zero CO2 emissions by 2050.

First stop on the journey is a commitment to cut carbon emissions by up to 25% by 2030. The GCCA says this will reduce the industry’s carbon output by almost five billion tonnes. This is a tall order. The GCCA acknowledges that the global cement and concrete products market will almost double in value from US$333bn in 2020 to US$645bn in 2030.

UK Concrete, part of the Mineral Products Association and a member of the GCCA, published its own version of the roadmap last month setting out how it plans to become net carbon-negative by 2050 – in other words, removing more carbon dioxide from the atmosphere than it emits each year.

UK Concrete says that this goal can be met through decarbonised electricity and transport networks, fuel switching and greater use of low-carbon cements and concretes as well as carbon capture, usage or storage (CCUS) technology for cement manufacture.

The strategy document, entitled Roadmap to Beyond Net Zero, sets out the potential of each carbon reduction measure and the carbon savings that might be achieved. CCUS is vital to delivering net zero manufacturing, it says, and according to the roadmap will deliver 61% of the required carbon savings.

UK Concrete says a net negative-carbon concrete and cement industry can be achieved by 2050 by exploiting the natural, in-use properties of concrete which include its ability to absorb carbon dioxide during use, and the benefit of using the thermal properties of concrete – in other words, heat absorption and storage – in buildings and structures thus reducing operational emissions.

The concrete and cement industry has already taken steps to adopt the use of less carbon-intensive alternatives to cement. The MPA is building on this by undertaking demonstrations of hydrogen and plasma technology, which are being partly funded by the Department for Business, Energy & Industrial Strategy (BEIS). (See Fuel for thought).

The industry is now lobbying government for financial support to help get the technology developed to become an investable proposition in the 2030s.

“Concrete, and the aggregates and cement used to make it, are essential materials for our economy and our way of life,” says MPA chief executive Nigel Jackson. “New homes, schools, hospitals, workplaces, roads and railways, as well as the infrastructure that provides us with clean water, sanitation and energy all depend on these materials.

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“We have already made significant progress to reduce carbon emissions but are under no illusion about the scale of the net zero challenge. Achieving this will require the wholesale decarbonisation of all aspects of concrete and cement production, supply and use.

Jackson concedes that, on its own, the concrete and cement industry cannot achieve net zero, less still net negative-carbon emissions. “We will only be able to go beyond net zero with concerted support from government, as well as with significant changes across the wider construction, energy and transportation sectors,” he says.

“Critically, our roadmap will be delivered without offsetting emissions or offshoring production facilities. We believe that net zero should be achieved by reducing emissions from the construction materials manufactured in the UK, rather than by ‘carbon leakage’ where UK production is replaced with imports that simply moves the emissions responsibility abroad.

“The aim should be to retain jobs and economic value in the UK whilst ensuring that the UK takes responsibility for the emissions it creates,” says Jackson.

This article was first published in the November 2021 issue of The Construction Index Magazine. Please sign up online 

Fuel for thought

A UK cement kiln has successfully been operated using a net zero fuel as part of a world first demonstration using hydrogen technology.

 Led by the Mineral Products Association (MPA) and Hanson UK with funding from the Department for Business, Energy and Industrial Strategy (BEIS), the trial used a mix of fuels, including hydrogen, for commercial scale cement manufacture for the very first time.

The trial followed a feasibility study in 2019 that found that a combination of 70% biomass, 20% hydrogen and 10% plasma energy could be used to eliminate fossil fuel CO2 emissions from cement manufacturing.

 During the demonstration at Hanson Cement’s Ribblesdale plant in Lancashire the proportion of fuels in the cement kiln’s main burner was gradually increased to a wholly net zero mix of approximately 39% hydrogen, 12% meat & bone meal (MBM) and 49% glycerine (by-products from the rendering and biodiesel industries respectively). The trial showed that it is possible to move away from using fossil fuels in cement and concrete production.

The fuel switching trial has used ‘grey’ hydrogen as a proof of concept, but this can be switched for ‘green’ hydrogen in future, says the MPA.

 If fully implemented for the whole kiln system nearly 180,000 tonnes of carbon dioxide could be saved each year at Ribblesdale alone compared to using the traditional fuel of coal at the site.

This article was first published in the November 2021 issue of The Construction Index Magazine. Please sign up online 

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