Worldwide, the amount of cement being used for every person in the world has nearly tripled in the past 45 years and demand is projected to increase over 33% by 2050. This demand is driving an exponential growth in cement production - and 'clinker', a key binding agent in cement. Clinker is the main ingredient in most cement mixes, averaging 75% of its content, but can be up to 95% of the content in Ordinary Portland Cement mix (a common type of cement). To make clinker, limestone and clay are heated to around 1450c, creating a chemical reaction. To generate this heat, the industry generally burns fossil fuels - although alternatives exist. Burning the fuel emits an average of 35% of the clinker CO2 footprint, with the remainder (65%) emitted by the chemical reaction of the heated limestone. In total, the cement industry has reduced its reliance on fossil fuels to heat clinker by 22% from 98% in 1990 to 76% in 2023, with post-use mixed waste and biomass increasing their share as alternative fuels. This concrete progress has helped reduce the carbon intensity of the fuel mix by 8% between 1990 and 2023. Unfortunately, this reduction has been outstripped by increases in cement production overall since 1990, so total fossil fuel consumption has actually increased by 100 million gigajoules (GJ), from 1.78bn GJ in 1990 to 1.88bn GJ in 2023.

(Except where specified, figures are sourced from the GCCA, Getting the Numbers Right Project, Emissions Report 2023 - for External Stakeholders industry-reported dataset)

Cementing coal use

Today, 76% of the heat needed to make clinker is generated by burning fossil fuels, with coal constituting 49% of the fossil fuel mix - meaning 37% of cement worldwide is made by burning coal. Consequently, the cement industry consumes around 4% of global coal produced, which amounts to approximately 330 million tonnes of coal per year. UK Government research and commercial examples from around the world indicate that the elimination of fossil fuels in cement production is possible. Thermal coal is the most common fuel burned to produce the high heat required.

Successful, at-scale, examples already exist of cement works burning 100% fuel alternatives to traditional fossil fuels, including pilot projects using combinations of hydrogen and biomass (UK) and hydrogen and electricity (Sweden). Yet, innovations such as use of hydrogen and kiln electrification are forecast to play only a small role, providing 10% of energy needs by 2050. Worldwide, only 24% of cement in 2023 was produced using alternative fuels, with 76% of cement produced using fossil fuels (37% of cement overall is heated using coal). The continuing reliance on burning fossil fuels to generate heat at cement works contributes to its high CO2 footprint – particularly its upstream footprint due to the resources and methane emissions associated with mining coal. Globally, the cement industry is responsible for up to 7-8% of CO2 emissions (but only 1.5% of UK CO2 emissions) – nearly as much as steel.

Coal-free fuel examples from around the world:

Globally, the clinker ratio to cement (Portland and blended) has reduced from 85% in 1990 to 75% in 2023. The use of clinker substitutes has correspondingly increased by 12.7 million tonnes between 1990 and 2023, but much of this increase may be accounted for by the overall growth in cement production. Although most ‘green cement’ works around the world substitute up to 40% of clinker, there is at least one commercial example of a cement works substituting up to 100% of the clinker in their cement production. The use of alternative cementious materials reduce, or even eliminate the needs for clinker. Unlike clinker, these alternative cementious materials don’t require as much, or any, heating – thereby reducing the amount of coal burned. Some of these materials, such as the coal by-products of fly-ash and blast furnace slag, are in increasingly short supply as economies decarbonise. However, other clinker substitutes such as burnt rice husks do not face supply issues, and a lack of acceptance by the construction sector continues to be the most limiting factor in producing more cement with a lower clinker content. One solution to this would be Government mandating that publicly-funded construction projects must use entirely or partially ‘low carbon’ cement products where clinker substitutes have been included.

Clinker substitution examples from around the world:

In contrast to worldwide trends, UK cement production has been in decline since a peak in the 1970s, and roughly halving since 1990. Despite this decline, the UK cement industry still burned just under 400,000* tonnes of coal to make 7.3 million tonnes of cement in 2024 – averaging roughly 1 tonne of coal for every 18 tonnes of cement. To put that into context, around 8,000 tonnes of cement is needed for a new hospital, while between 3-5 tonnes are needed to build a four-bedroom family house.

*There is no cement-specific coal consumption statistics available, but the UK Government reported that 395,000 tonnes of coal were used in the minerals industry in 2024, the vast majority of which would be cement. The burning of this coal alone would have emitted nearly a million tonnes of CO2 in 2024. The UK's cement works emitted 4.2 million tonnes of CO2 overall.