The cement industry plays an important role in the global economy, providing the building blocks for infrastructure development and construction projects worldwide. However, cement production is also a major contributor to carbon dioxide (CO2) emissions. It is imperative for the cement industry to address this issue and take proactive steps towards reducing its CO2 emissions. Carbon Capture and Storage (CCS) has the potential for being one of the main solutions to reducing emissions in the cement industry. In this article, we’ll look at where cement plants are located in the world, why process CO2 emissions are a challenge, why cement plants also emit biogenic CO2, and where capture projects are underway.
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The cement industry needs to reduce its CO2 emissions
Cement production is responsible for a substantial amount of global CO2 emissions. According to recent estimates, the cement industry accounts for approximately 7% of global CO2 emissions, making it one of the largest industrial emission segments worldwide.
Over the past decade, the emissions from the cement industry have displayed a concerning trend. Despite advancements in technology and growing awareness about environmental sustainability, CO2 emissions from cement production have continued to rise. This increase can be attributed to the booming global construction sector, particularly in developing countries, where rapid urbanisation and infrastructure development have fuelled the demand for cement. In addition, outdated and inefficient production processes in some regions have also contributed to the rising emissions.
In a meeting in 2019, UN Secretary-General Antonio Guterres stated that “some 75 per cent of the global infrastructure that will be needed by 2050 is yet to be built, and the existing infrastructure will have to be made climate-resilient”. The demand for cement, and in particular cleaner cement, is expected to continue growing in the future.
Cement plants are spread across the globe
Cement is a fundamental construction material used in various infrastructure and building projects across the world. Although cement can be transported across long distances, it is typically produced close to where it will be used, to reduce transportation costs and ensure a timely supply.
Cement production plants are therefore dispersed across the globe, with a notable concentration in Asia, particularly China, which is the world’s largest cement producer.
In CaptureMap, we built one of the most complete overviews of cement plants and their CO2 emissions, spanning sites in 136 countries, and based on 11 different datasets. Our overview includes 2241 plants, with total CO2 emissions reaching 1,92 billion tonnes CO2. China alone accounts for more than half of the global cement production and emits a significant share of CO2 emissions attributed to the cement industry, ca. 40% in our data. Other regions, such as India, the United States, and Europe, also contribute substantially to the overall cement emissions.
Europe and North America is where we have our best data: we combine 9 different datasets with CO2 emissions reported by each individual facility, including both fossil and biogenic CO2 (from the combustion of biomass). In Europe, 198 cement facilities emit a total of 106 million tonnes CO2. In North America, 114 plants emit a total of 82 million tonnes CO2. While the average cement production facility emits 600 000 tonnes CO2 per year, in reality the amount of CO2 emissions varies between facilities, with the largest emitting up to 3 million tonnes, and the smaller ones emitting less than 100 000 tonnes per year.
Carbon capture can be a solution to process emissions
Broadly speaking, over 90 % of the cement production emissions can be attributed to clinker production in which limestone and clay is fused in a kiln at temperatures up to 1450 degrees C. The chemical decomposition of limestone in the kiln releases substantial amounts of CO2, called process emissions.
These typically represent around 60% of the total CO2 emissions in cement manufacturing. The rest of the emissions mainly come from energy production, through the combustion of fossil fuels, such as coal and natural gas, waste and biomass.
Since the largest share of cement production emissions comes from process emissions and is tightly tied to the production process, emission abatement measures such as fuel switching have only a limited effect on the total CO2 emissions from cement plants. Solutions to change the cement production process are being investigated, but this is complex and will take time. This is where Carbon Capture can help the cement industry: by providing an available solution that can abate a large share of the CO2 emissions at existing or new plants.
Cement plants are relatively well suited to most carbon capture technology. Their fumes typically include 15 to 30% CO2 concentration, which is higher than many other industries, making it relatively easier and cheaper to capture the CO2. These values vary depending on the share of emissions from the process and the fuel used. Cement plants often have one to a few emission points, depending on the design of the plant (e.g. number of pre-calciners and rotary kilns), a factor that makes capture design simpler.
Capture costs can be reduced with the use of waste heat, when available on site at the cement plant. This varies from plant to plant. About 70 to 90% of the CO2 can be typically captured, although some plants may choose to capture a lower share of their CO2.
Biogenic CO2 emissions from cement plants can help provide CO2 removals with carbon capture
Cement plants do not only consume fossil energy, some of them also use sewage sludge, wood waste, animal waste and many other types of biomass-based fuels as energy sources. Reporting data in CaptureMap actually shows that on average, cement plants in Europe emit 5% biogenic CO2, while their North American counterparts have an average biogenic share of only ca. 1%. This is most likely due to differences in the energy mix used by the cement plants across different countries. The actual biogenic share varies on a plant by plant basis, and the CO2 emissions from many plants contain from 5 to 15% biogenic emissions, in particular in Europe.
For larger plants, this represents tens or hundreds of thousands of tonnes of biogenic CO2 emitted every year. This provides opportunities to capture and store this CO2, reducing overall greenhouse gas emissions through carbon removals.
Interested in learning more about biogenic CO2 emissions from stationary facilities? Check our article about it.
There are already plenty of projects for carbon capture within the cement industry
Based on the elements described above, it is not surprising that the cement industry is already underway in testing technologies and designing carbon capture projects. The IEA carbon capture project database currently includes 27 projects for carbon capture on cement plants. These are located mainly across Europe and North America, with a few other projects in other regions of the world. The announced capture capacity for these projects vary from 100 000 tonnes per year, up to 2,9 million tonnes CO2 per year.
While most of these capture facilities are at the feasibility stage, some have passed final investment decisions and are or will soon be built. The construction of the Norcem Brevik site in Norway, for example, is well underway and is expected to enter in operation in 2024.