Cement facilities are among the biggest contributors to greenhouse gas emissions.

Concrete is not just the most common man-made material on earth, and the most widely used material after water, it is also one of the most polluting when it comes to carbon emissions.

“Cement is the vital glue that binds the ingredients of concrete together”, according to the Global Cement and Concrete Association. It is also the source of the vast majority of concrete’s carbon footprint, accounting for 8% of global greenhouse gas emissions.

That’s in part because coal is used in the production process, not just to provide the 1,500C heat needed in cement kilns, but also because that heat is used to release CO2 from limestone to make clinker, a key component of cement. It’s a process that has barely changed in the last 100 years.

It’s clear that we need to decarbonise the cement industry – and fast. A new report outlines some of the technologies that could help to do this, and how soon they could contribute to emissions reductions.

As with many industries, the cement sector is on a pathway to becoming net zero by 2050, but a number of technologies that the industry has high hopes for, such as green hydrogen and CCUS (carbon capture, utilization and storage), are not yet commercial and will make no significant contribution to cutting emissions for many years, if not decades.

But given cement’s contribution to global emissions, we need to start cutting emissions immediately, says Sherif Elsayed-Ali, CEO and co-founder of Carbon Re, a company that uses artificial intelligence to optimize cement production. It is more important to make significant reductions by 2030 than to hit a 2050 net zero target that sees emissions come down mainly after 2040, a report in Nature adds.

Carbon Re has produced a report that identifies 13 technologies that together can reduce the industry’s emissions by more than a third, or 800,000 megatonnes, from 2.5 gigatonnes to 1.7 gigatonnes, by 2030. “There is a lot that can be done to start cutting emissions today while we wait for these other technologies to scale up,” Elsayed-Ali says.

The report says there are three main groups of solutions – those that reduce the use of clinker; those that improve how clinker is made; and those that reduce the use of concrete.

And there are three key technologies that can provide more than four fifths of the emissions savings that are possible by 2030.

The first is to replace clinker with the snappily named substitute cementitious materials (SCMs), which include waste from steel production and coal-fired power stations, as well as limestone calcined clay, which requires a lot less heat to produce and can replace up to half of the clinker used to make cement.

Another significant chunk of savings come from using biomass, refuse-derived fuels (RDF) and municipal solid waste (MSW) as alternative fuels to heat the kilns. It is also possible to recover the waste heat from the production process to generate power that can be used elsewhere in the cement production process.

The final solution is applying AI to the cement production process, to ensure the most efficient use of energy and to blend SCMs into the mix. “When it comes to introducing SCMs, you need to optimize the mix because they are more variable than clinker, and AI is very well-suited to that,” Elsayed-Ali points out.

“To date, AI has predominantly been used in the digital sphere, but we see a huge opportunity to take it to the physical sciences. We’ve seen interesting progress in drug discovery and vaccines, and we’re developing research to understand how it can be applied to the physics and transformation of materials.”

AI tools can be applied in a couple of months and they start to provide benefits instantly, benefits that improve over time as more data becomes available and the tools can be fine-tuned.

Another opportunity comes in the maintenance of plants, says Ian Riley, CEO of the World Cement Association. “There is quite a lot of energy wasted from shutting down and starting up cement kilns to deal with issues such as lubrication failures. Using AI for prescriptive maintenance enables you to build up a pattern related to specific problems and it can save a fortune by reducing unplanned failures.”

The main markets where these technologies will be deployed are Europe, where carbon pricing makes it imperative to reduce emissions; India, the second-largest market for cement in the world; and the US, where the recent introduction of the Inflation Reduction Act has created a huge incentive to decarbonize cement production.

These measures are important because they can be implemented and start reducing emissions very quickly. Many of the longer term solutions will be held back by the long life span of cement plants and the cost of retrofitting them with new equipment to either switch to hydrogen fuel or to capture carbon. AI solutions, SCMs and biomass are not only quick to implement but relatively cheap as well. In many cases, the technologies are complementary and will boost savings even further.

Further emissions reductions solutions will require changes in government policies, standards on the carbon content of cement, more carbon pricing and the creation of a market for low carbon cement to make them viable.

The journey to low carbon cement is a long one and we need to make a start as soon as possible.