Decarbonising Cement: Challenges and Opportunities in Asia Pacific

Cement production in Asia Pacific

More than 77% of the world’s cement was produced in countries within Asia Pacific (APAC) region in 2022^[4]. Production levels vary across different regions; some countries, like China and the Middle East, have excess capacity and are expected to lower production while other countries like India are expected to triple their current production by 2050. Overall, the cement production capacity in APAC is expected to be stable until 2050^[5].

Leading cement producers in the region are making significant investments in state-of-the-art production facilities incorporating digital technologies and process automation to improve efficiency. A solid value proposition supports such rapid modernisation and capacity expansion. Moreover, consolidation in the APAC cement industry is a notable trend with major players increasing their market share through acquisitions and mergers. This trend is particularly evident in countries like India, where large players are consolidating capacity, leading to a more concentrated market. This could be good news for driving decarbonisation as large firms are more capable and have better financial support. However, policies and subsidies, in the region, are not yet strong enough to drive major decarbonatisation projects. A tailor- made approach, addressing technical, commercial, and regulatory aspects, is required to develop a strong business case for decarbonisation projects in APAC. Low-carbon cement is an expensive product. While grants and subsidies can support some of the cost increases, achieving financial viability ultimately requires willingness from consumers to pay for green products.

Cement and its carbon footprint

Concrete is the versatile building material whose ingredients are held together by cement, which serves as the vital glue. Although cement accounts for only 15% of concrete by mass, it is responsible for 95% of its CO₂ footprint.

The total global direct CO₂ emissions from the cement sector was estimated to be more than 2.4 giga tonnes of carbon dioxide equivalent (GtCO₂e) in 2023 – this is comparable to the annual emissions from a large country like India. Many cement plants still rely on fossil fuels like coal to generate the significant amount of thermal energy needed for cement production: combustion of these fuels accounts for 40% of the industry’s total direct carbon emissions. Cement is clinker-based and the calcination of limestone during clinker production accounts for the remaining 60% of the direct carbon emissions.

The paradox of decarbonising cement

Conventional cement production is all about transforming low-cost raw materials using inexpensive fuels into cementitious products essential for modern infrastructure development. However, with process emissions accounting for a significant share of total emissions, the cement industry needs to adopt Carbon Capture, Utilization, and Storage (CCUS) to achieve complete decarbonisation. This means the future cement narrative hinges not only on implementing expensive technologies but also on handling CO₂ as an additional product with limited utilisation potential. This shift represents a big change, a challenge involving multiple stakeholders, complex infrastructure, and large amount of investment.

Despite the highs cost as well as various technical and commercial risks, the widespread adoption of CCUS presents an opportunity to achieve sustainable cement production. However, project developers must follow a proactive risk management approach to ensure project success. Ramboll's extensive experience in carbon capture projects has led to the development of six essential guidelines to de-risk CCUS projects at cement plants. These guidelines focus on

1. Preparing of the cement facility for carbon capture,
2. Technology assessment and right sizing for optimal performance,
3. Reducing energy penalty,
4. Early planning for environmental constraints,
5. Robust business case development, and
6. Optimising procurement models to contain project costs and risks
   

Effective implementation of these guidelines requires a joint effort. The cement industry cannot do carbon capture all by itself. CCUS projects will not only require financial and policy support for actual implementation but also need the development and establishment of CO₂ transport and storage infrastructure to effectively handle the captured CO₂. Therefore, this is a long-term solution, especially for the industry in the developing economies of the APAC region.

So, what other options and opportunities exist for APAC?

In the near term, the cement industry in APAC is prepared to adopt CCUS on a trial basis, with several leading companies already taking proactive steps in this direction. It is good to start with feasibility studies and pilot demonstrations to develop appropriate technology options and to evaluate the required infrastructure for future deployment of full-scale CCUS including options for CO₂ offtake. The industry is also looking forward to an enabling policy framework during this period.

However, it is imperative to reduce CO₂ emissions before capture and thus forms the basis for the near-term decarbonisation options. Curtailing the use of fossil fuels is a crucial first move towards reaching net-zero cement. Technologies for the substitution of fossil fuels with alternative waste-derived fuels (e.g., combustible municipal waste, biomass, non-hazardous industrial or commercial wastes) exist today. It is envisaged that the cement industry would increase the share of biomass as fuel. However, often the limitation is a developed supply chain for such low-carbon fuels. Combustion of these fuels presents an economically feasible way in the short-term, before expensive green hydrogen and innovative technologies, such as kiln electrification, becomes viable to decrease energy-related CO₂ emissions. The utilization of alternative fuels in cement plants is projected to rise from the current 5% to 20% by 2030, and further to 50% by 2050, while hydrogen usage and kiln electrification are anticipated to have an impact in 2050^[6]. Supply chain logistics and waste policy to reduce/eliminate waste to land fill are required to support the industry in increasing their use of alternative fuels.

In addition to thermal energy, cement plants also require a limited amount of electric power for activities such as crushing, grinding, conveying and to power other auxiliary systems. Complete decarbonisation of the electricity can be achieved by efficiency improvements in electricity use, maximizing WHR potential and shifting to green electricity with the use of renewable energy. Some cement plants have already started to plan for solar and wind farms as well as Waste to Energy facilities in close proximities.

Addressing the energy related CO₂ emissions is only part of the solution and is not sufficient for complete decarbonisation. Despite the utilisation of green fuels and renewable power, the process emissions resulting from the calcination of limestone during clinker production render cement a hard-to-abate sector. The development of alternative binders that result in lower or zero process emissions during production is an effective approach to reduce emissions. These are cements with reduced clinker content, like geopolymers, carbosilicate and calcium hydro silicate. Reduced clinker content minimizes the amount of limestone required in the raw mix and therefore the amount of CO₂ released in the process.

Another approach will be to substitute part of the clinker in cement with supplementary cementitious materials (SCMs), fillers, and additives which do not release CO₂ when activated. Such cements are called blended cements which will continue to dominate the cement industry. Blended cements are created by mixing clinker with other finely ground materials like pozzolana (Portland Pozzolana Cement, PPC) and granulated blast furnace slag. The abundant supply of fly-ash (from thermal power plants) and blast furnace slag (from steel plants) in developing nations have driven the increased production of blended cement such as the Portland Pozzolana Cement (PPC) and Portland Slag Cement (PSC) in recent years^[7]. Apart from blended cements, it is envisaged that composite cement, Limestone Calcined Clay Cement (LC³) and Portland Limestone Cement (PLC) would play a major role in total future cement production^[8].

Circularity is another opportunity for value creation. Circularity can be attained through recycling concrete and demolition waste either as an alternative building material, such as an aggregate, or as a lever to reduce clinker’s carbon footprint by reprocessing the used cement. Fine fraction of the recycled concrete does not emit CO₂ when activated - as the CO₂ has already been removed.

And finally sequestering carbon in buildings and constructed structures provides an avenue for the cement and concrete industry to close its carbon loop. These solutions include mineral carbonation, concrete curing, and substituting sand with biochar in concrete mixes. Mineral carbonation involves mineralising CO₂ by carbonating metal oxides found in common rocks, a process that can produce both regular and lightweight aggregates as well as carbonated SCMs. Different waste materials can be mineralised and subsequently converted into aggregates. Additionally, CO₂ or carbon can be directly injected into wet concrete during the curing phase. Together, these innovative approaches hold significant potential for reducing the carbon footprint of concrete production and advancing sustainable practices within the construction industry.