Cement

Tracking Clean Energy Progress

🕐 Last updated Wednesday, 23 May 2018

More efforts needed

From 2014 to 2016, the direct CO2 intensity of cement showed little change, as thermal energy efficiency improvements were offset by a slight increase in the global clinker-to-cement ratio. To meet the IEA SDS objectives, the direct CO2 intensity of cement needs to decline by 0.3% annually through to 2030, even as cement production is expected to grow.


Direct CO2 intensity of cement

The direct CO2 intensity of cement needs to decline by 0.3% annually through to 2030.

	Direct CO2 intensity
2014	0.536
2016 - estimate	0.538
2030 SDS Target	0.516
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Note: Direct CO2 emissions include energy-related and process emissions.


Initial estimates suggest that cement production stayed flat in 2017 relative to 2016 at 4.1 Gt globally, showing a decline since 2014 when it reached almost 4.2 Gt1.

In 2016, it is estimated that the cement sector consumed 10.5 EJ of energy and generated 2.2 Gt of CO2 emissions globally. This represents an annual decrease in energy use of 1% from 2014 while the level of CO2 emissions showed little change due to a slight increase in the global clinker-to-cement ratio, which offset energy efficiency improvements.

Clinker is the main ingredient in cement, and the amount used is directly proportional to the CO2 emissions generated in cement manufacturing due to both the combustion of fuels and the decomposition of the limestone in the process.

Global clinker thermal energy intensity

Thermal energy intensity must fall by 0.1% a year to 3.3 GJ/t to meet the SDS goals.

	Biomass, waste and other renewables 	Natural gas	Oil	Coal
2014	0.19	0.34	0.499	2.419759592
2016 - estimate	0.19	0.26	0.556	2.362131858
2030 - SDS	0.58	0.42	0.481	1.850379154
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Note: Thermal energy intensity of clinker does not include any impact related to other carbon mitigation levers beyond improving energy efficiency (e.g. carbon capture).

Globally, thermal and electricity energy intensities have continued to gradually decline, as dry-process kilns, including staged preheaters and precalciners – considered the state-of-the-art technology – replace wet-process kilns, and more efficient grinding equipment is deployed. The thermal energy intensity of clinker is estimated to have reached 3.4 GJ/t on average globally in 2016, an annual decrease of 1% from 2014.

A life-cycle approach along the construction value chain has recently gained support as a way of further reducing emissions. Emissions can be reduced through actions such as using cement more efficiently, minimising waste in construction, optimising the use of cement in concrete mixes and maximising the design life of buildings and infrastructure, which would result in a reduced demand for cement.

Policy developments

Policy and private-sector efforts are facilitating reductions in energy use and emissions in key cement-producing economies.

  • As part of its 13th Five-Year Plan (2016-20), China has set an ambitious target of reducing the thermal energy intensity of clinker production to 3.07 GJ/t clinker on average by 2020, which would reduce by about two-thirds the existing gap to reach best thermal energy performance levels.
  • In India, 85 cement plants participated between 2011 and 2015 in the first cycle of Performance Achieve Trade, a market-based mechanism to improve energy efficiency. They achieved energy demand reductions equivalent to 9% of India’s 2014 cement sector energy consumption.
  • In Europe, the mandate to develop cement standards within the European Committee for Standardisation was recently widened to allow possible low-carbon alternatives to Portland cement that rely on different mixes or raw materials.
  • In the private sector, 18 key cement companies developed a shared objective in 2015 to reduce their CO2 emissions by 20% to 25% by 2030 compared to business as usual, equivalent to 1Gt CO2.

Tracking progress

Cement faces significant challenges in reducing CO2 emissions while delivering production levels that are expected to resume growth again when approaching 2020, as growing markets start to offset the slowdown in Chinese activity.

The key levers to cutting carbon emissions from cement production are improving energy efficiency, switching to lower-carbon fuels, reducing the clinker-to-cement ratio, and advancing process and technology innovation. The latter two make the largest contribution to direct emissions reductions in the SDS.

To reach the SDS goals, the thermal energy intensity of clinker production must decline by 0.1% a year to a global average of 3.3 GJ/t clinker, and the electricity intensity of cement production must fall by 0.3% to 87 kWh/t cement. Progress is particularly needed in Eurasia, which has the highest thermal energy intensity of clinker production at 5.7 GJ/t, primarily due to continued use of wet-process kilns. (Beyond process technology choice, regional factors affect the thermal intensity of clinker, such as moisture content and burnability of raw materials, typical clinker composition and average capacity of cement plants.)

Energy intensity improvements can be accelerated by increasing public-private collaboration and sharing best practices to facilitate the adoption of state-of-the-art technologies and to develop plant-level action plans that increase the speed and scale of deployment of such technologies.

Global thermal energy consumption for cement production by fuel

The use of alternative fuels in cement production must more than double by 2030 to meet SDS goals.

	2016 (Estimate)
Coal	70
Oil	16.484
Gas	7.796
Biomass, waste & other renewables	5.716
    
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	2030 SDS Target
Coal	55.57516312
Oil	14.43452474
Gas	12.48795517
Biomass, waste & other renewables	17.50235698
    
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The share of alternative fuels (biomass and waste) used, as a proportion of thermal energy use in cement manufacturing, must increase to 18% from about 6% in 2016 to meet the SDS goals by 2030. There is considerable regional variation in alternative fuels use in the SDS, with the highest share in 2030 in the European Union, at almost 50%. Redirecting waste from landfills to the cement sector and cost-competitive access to sustainably sourced biomass are needed to realise these objectives.

The clinker-to-cement ratio must continue to fall to a global average of 0.64 by 2030, through increased use of blended cements and clinker substitutes, including industrial by-products such as blast furnace slag or fly ash. In the long run, alternative clinker replacements that are widely available, such as calcined clay in combination with limestone, become more important, as the decarbonisation of power generation and iron and steel making reduces the availability of these industrial by-products.

By 2030, oxy-fuel carbon capture technologies in cement production should be demonstrated at commercial scale. It will also be necessary to gain experience in large-scale post-combustion capture technologies.

These objectives must all be met while annual cement production continues to grow through to 2030 at an average annual rate of 0.2%. Production is likely to decline in China in the long term, but growth is expected in India, other developing Asian countries and Africa as these regions develop their infrastructure. Adopting material efficiency strategies to optimise the use of cement in concrete would help reduce emissions along the whole construction value chain through reduced demand growth.


Key indicators for the global cement industry in the SDS by 2030

2016 estimate 2030 SDS goal
Cement production (Mt) 4150 4250
Clinker-to-cement ratio 0.66 0.64
Thermal energy intensity of clinker (GJ/t clinker) 3.4 3.3
Electricity intensity of cement (kWh/t cement) 91 87
Alternative fuel use (% of thermal energy) 6% 18%

Notes: Thermal energy intensity of clinker does not include any impact related to other carbon mitigation levers beyond improving energy efficiency (e.g. carbon capture). Electricity intensity of cement production does not include reduction in purchased electricity demand from the use of excess heat recovery equipment or any impact related to other carbon mitigation levers beyond improving energy efficiency (e.g. carbon capture). Alternative fuel use includes biomass, and biogenic and non-biogenic wastes.

Technology Roadmap - Low-Carbon Transition in the Cement Industry

Released: 18 April 2018

This Technology Roadmap provides an update of the Cement Technology Roadmap 2009: Carbon Emissions Reductions up to 2050, and sets a strategy for the cement sector to achieve the decoupling of cement production growth from related direct CO2 emissions through improving energy efficiency, switching to fuels that are less carbon intensive, reducing the clinker to cement ratio, and implementing emerging and innovative technologies such as carbon capture.

The report builds on the long-standing collaboration of the IEA with the Cement Sustainability Initiative (CSI) of the World Business Council for Sustainable Development (WBCSD)

Download the full report

Innovation

RD&D efforts are under way on several technologies and processes that would reduce CO2 emissions from cement production. The European Cement Research Academy has established a pre-competitive research project dedicated to energy-efficient grinding in the cement industry, which involves equipment suppliers and other cross-sectoral stakeholders2.

Between 2013 and 2016, chemical absorption, the most advanced post-combustion CO2 capture technology, was successfully trialled in a cement plant in Brevik, Norway, and became operational in a cement plant in Texas3.

In Dania, Denmark, oxy-fuel capture was successfully piloted in a kiln pre-calciner4. A first demonstration project of oxy-fuel capture technologies is planned in Europe but funding uncertainty makes realisation unlikely before 2020. Carbon capture technologies other than post-combustion and oxy-fuel are also being explored.

Direct separation, which captures process CO2 emissions by applying indirect heating in the calciner, is being piloted at a cement plant in Belgium from 2017 to 20205.

CCUS is likely to be a key way of reducing cement production emissions, particularly after 2030, so RD&D over the next decade is imperative.

Alternative binding materials that rely on different raw materials or mixes are being tested and developed to reduce process CO2 emissions. A number of alternative binding materials are currently commercially available, although their application to date has been relatively limited.

Barriers to wider market deployment of alternative binding materials include technology and raw material costs, technical performance, limited application to a range of possible markets and level of standardisation for such materials. Further process optimisation at the demonstration phase and product standardisation could open more avenues for commercial deployment.


The IEA’s new Innovation Tracking Framework identifies key long-term “technology innovation gaps” across the energy mix that need to be filled in order to meet long-term clean energy transition goals. Each innovation gap highlights where R&D investment and other efforts need improvement.

Explore the technology innovation gaps identified for cement below:

Alternative cement constituents (including natural pozzolanic materials, ground limestone and calcined clay)

Why is this RD&D challenge critical?

Including a larger proportion of alternative constituents in cement - likely possible in the range of up to 15 to 35% mass, and potentially even 50% - reduces the quantity of clinker required along with both process and energy-related CO2 emissions associated with clinker production. Alternative cement constituents will become increasingly important going forward due to the likely decreasing availability of fly ash from coal power plants and granulated blast furnace slag from steel production, which are currently commonly used as alternative cement constituents.

Key RD&D focus areas over the next 5 years

Expand the number of applications that can utilise cement mixes containing alternative cement constituents, through testing and verification. Increase understanding of global alternative material availability and properties.

Key initiatives

  • Commercial applications exist but deployment is limited.
  • Key milestone: expanded use of alternative cement constituents in terms of both the quantity per unit of blended cement and the types of applications. Reach a global clinker-to-cement ratio of 0.64 (2030) and 0.60 (2050).
  • Alternative cement constituents are currently being used to varying degrees by various cement producers around the world; use is not confined to a limited number of key initiatives.


Carbon capture

Why is this RD&D challenge critical?

CO2 capture could enable up to 99% capture yields; widespread application would reduce clinker production process emissions, which have a limited number of reduction options.

Key RD&D focus areas over the next 5 years

Technology scale up to large-scale demonstration, and in a larger number of plants; improved economics to enable broader application.

Key initiatives

  • Successful trial of amine-based absorbants in Brevik, Norway from 2013 to 2016; operation of a chemical capture plant in Texas beginning in 2015, which converts captured CO2 to other chemicals for sale.

Why is this RD&D challenge critical?

CO2 capture could enable up to 99% capture yields; widespread application would reduce clinker production process emissions, which have a limited number of reduction options.

Key RD&D focus areas over the next 5 years

Technology scale up to commercial demonstration

Key initiatives

  • Successful pilot testing of oxy-fuel capture in a kiln pre-calciner in Dania, Denmark.

Why is this RD&D challenge critical?

CO2 capture could enable up to 99% capture yields; widespread application would reduce clinker production process emissions, which have a limited number of reduction options.

Key RD&D focus areas over the next 5 years

Undertake successful pilot testing trials of other capture technologies

Key initiatives

  • Pilot test of calcium looping capture commissioned in 2013 in Chinese Taipei.


CO2 sequestration in inert carbonate materials (mineralisation)

Why is this RD&D challenge critical?

Utilising CO2 for inert carbonates to be used as aggregates in concrete has the potential to improve the economics of carbon capture in cement production and in other CO2 intensive activities.

Key RD&D focus areas over the next 5 years

Technology scale up to higher TRL, depending on the particular process; process improvements.

Key initiatives

  • Currently more than 20 processes are being developed to convert CO2 to carbonate products, ranging from TRL 1 to 9.
  • Key milestone: scale up key processes to large-scale commercial demonstration and/or full commercialisation by 2025.
  • Commissioning in 2018 of a 100 kt/yr plant in Leeds (UK) producing carbon negative aggregate from alkaline wastes from waste-to-energy plants.


Alternative binding material: belite clinker

Why is this RD&D challenge critical?

Belite clinker leads to a reduction in process emissions of 6% relative to Ordinary Portland Cement clinker. Its application is currently limited to massive concrete dams and foundation and confined to a number of countries due to its much lower early-strength development.

Key RD&D focus areas over the next 5 years

Further research and testing of methods to accelerate strength development, such as thermal treatment and incorporating foreign elements, with the objective to possibly expand to greater number of applications.

Key initiatives

  • Currently at TRL 8-9, limited commercial scale market deployment.
  • Key milestone: expanded application.
  • Production in China over the past 15 years, including in the third phase (2003 to 2009) of the Three Gorges Hydropower Project. Japan is also using high-belite cements for mass concrete and high-strength concrete.

Alternative binding material: calcium sulphoaluminate (CSA) clinker

Why is this RD&D challenge critical?

CSA clinker can result in a 44% reduction in process emission relative to Ordinary Portland Cement clinker.

Key RD&D focus areas over the next 5 years

Additional research and testing to verify and improve properties, enabling expansion to a greater number of applications.

Key initiatives

  • Currently at TRL 8-9, limited commercial scale market deployment.
  • Key milestone: expanded application.
  • Commercially produced in China for over 30 years.

Alternative binding material: alkali-activated binders (geopolymers)

Why is this RD&D challenge critical?

The CO2 footprint of alkali-activated binders varies depending on the mix properties, ranging anywhere from less than 10% or 97% emission reduction relative to Ordinary Portland Cement clinker. Its application will likely be limited by material availability as they rely on materials similar to those used in conventional blended cements to reduce the clinker to cement ratio.

Key RD&D focus areas over the next 5 years

Facilitate expanded application through further quality control testing and verification, including addressing sensitivities to varying water contents.

Key initiatives

  • Currently at TRL 8-9, limited commercial scale market deployment mostly in non-structural applications.
  • Key milestone: expanded application to mass production, to the extent that is possible given limited availability of materials.
  • The first industrial plant was built in Australia; commercial scale production in approximately a dozen countries.

Alternative binding material: belite calcium sulphoaluminate (BCSA) clinker

Why is this RD&D challenge critical?

BCSA clinker can result in process CO2 emissions 20 to 30% lower than that of Ordinary Portland Cement clinker.

Key RD&D focus areas over the next 5 years

Further research and testing are needed to develop better clinker formulations, especially with regard to cost competitiveness.

Key initiatives

  • Currently at TRL 7, not commercially produced yet and specific norms for this type of clinkers do not currently exist, with the exception of those BCSA clinker compositions that are within Chinese norms for CSA clinkers.
  • Key milestone: expanded application and increased experience to verify strength development and durability.
  • Globally, a small amount is produced including in China for structural and non-structural applications, as well as in Europe.

Alternative binding material: carbonation of calcium silicates (CACS)

Why is this RD&D challenge critical?

CACS clinker can yield zero process emissions in net terms, since it sequesters CO2 as it cures. However, its application will likely be limited to pre-cast applications since it requires a CO2-rich atmosphere for curing.

Key RD&D focus areas over the next 5 years

Demonstration to verify technical and safety aspects; gain experience in setting up of CO2 curing systems; expansion of pre-cast concrete to new applications in order to increase potential for use.

Key initiatives

  • Currently at TRL 6, first industrial pilot trials have taken place.
  • Key milestone: demonstration and commercialization by 2025.
  • Only solid research and commercialisation effort known is being pursued by a single private venture in the United States, via its patented technology Solidia Cement.

Alternative binding material: pre-hydrated calcium silicates (PHCS)

Why is this RD&D challenge critical?

PHCS clinker has been estimated to achieve emissions levels approximately 40% lower than Ordinary Portland Cement clinker.

Key RD&D focus areas over the next 5 years

Demonstration at industrial scale to optimise processes.

Key initiatives

  • Currently at TRL 5, a pilot plant is fully operational.
  • Key milestone: industrial demonstration plant operational by 2020.
  • Celitement is a patented binder using PHCS processes and is currently at the pilot plant stage.

Alternative binding material: magnesium oxides derived from magnesium silicates (MOMs)

Why is this RD&D challenge critical?

MOMs can in principle counterbalance or even absorb more CO2 than the amount released in the manufacturing process while curing, if magnesium oxides are provided from natural magnesium sources free of carbon.

Key RD&D focus areas over the next 5 years

Pilot testing to improve processes and gain better understanding of properties and feasibility for industrial-scale production.

Key initiatives

  • Currently at TRL 2 to 3, concept stage with research largely limited to academic setting.
  • Key milestone: pilot plant in operation by 2025.
  • R&D largely remains in university labs; a commercial venture to develop an industrial manufacturing process began in 2008 but ended in 2012 due to lack of funding; research at present apparently seems to be largely on hold.
  • UK company Novacem undertook development efforts from 2008 to 2012.


Advanced grinding technologies

Why is this RD&D challenge critical?

Advanced grinding technologies could decrease the electricity intensity of cement production beyond current best practice levels and provide means to manage more flexibly electricity demand. Related CO2 reductions would be dependent on the CO2 intensity of different electricity grids.

Key RD&D focus areas over the next 5 years

Technology scale up to pilot testing, demonstration, or commercial-scale application, depending on the specific technology.

Key initiatives

  • A number of higher efficiency grinding technologies are currently at TRL 6 while others are in earlier stages of development. They include contact-free grinding systems, ultrasonic-comminution, high voltage power pulse fragmentation, low temperature comminution.
  • Key milestone: commercialise new higher energy efficiency grinding technologies by 2025.
  • The European Cement Research Academy has established precompetitive research project on efficient grinding technologies, which includes cross-sectoral stakeholders.


3D printing applied in cement construction

Why is this RD&D challenge critical?

Additive manufacturing processes such as 3D printing have the potential to considerably reduce the quantity of concrete, and in some cases cement, during construction processes. However, some digital fabrication processes use high strength concretes that use considerably higher than normal quantities of cement per unit of concrete, and thus consideration should be given to whether a particular application of digital fabrication actually reduces cement use on net. Wider-spread application of digital fabrication processes that reduce demand for cement would reduce emissions from cement production.

Key RD&D focus areas over the next 5 years

Technology scale up to additional demonstration, in order to exhibit larger number of applications, improve processes, and reduce costs.

Key initiatives

  • Currently at TRL 6-7, with a considerable number of experimental/demonstration projects around the globe.
  • Key milestone: reduction in cement use per application by a considerable proportion by 2030 via additive manufacturing.
  • Many examples exist. To provide a few: The company HuaShang Tengda built a digitally fabricated 400 m2 two-storey house in China in 2016. Winsun built a five-story apartment building also in China that was completed in 2015. The Block Research Group at ETH Zurich has developed an unreinforced concrete funicular floor slab that uses considerably less material than a conventional floor slab.

Explore all 100+ innovation gaps across 38 key technologies and sectors here.


References

  1. United States Geological Survey (USGS), (2018), Cement: Mineral commodity summaries, 2012-2018, https://minerals.usgs.gov/minerals/pubs/commodity/cement/ (accessed March 2018).
  2. ECRA (2017), Development of State of the Art-Techniques in Cement Manufacturing: Trying to Look Ahead, European Cement Research Academy, Düsseldorf, Germany.
  3. Bjerge, L-M. and P. Brevik (2014), CO2 capture in the cement industry, Norcem CO2 capture Project (Norway), Energy Procedia, 2014, 63, pp. 6455-6463.
    Perilli, D., (2015), The Skyonic SkyMine: The future of cement plant carbon capture?, Global Cement Magazine, 2015, (5), pp. 8-12, Epsom, United Kingdom.
  4. IEA GHG TCP (2014), Pilot Plant Trial of Oxy-combustion at a Cement Plant, IEA GHG, Cheltenham, United Kingdom.
  5. LEILAC (Low Emissions Intensity Lime & Cement project) (2017), “Low Emissions Intensity Lime & Cement”, European Union Horizon 2020 Research & Innovation Project, www.project-leilac.eu/, (accessed February 2017).