Cement is the most consumed manufactured substance on the planet and has an enormous carbon footprint to match. The industry has finally admitted it has an emissions problem and a plethora of carbon reduction projects are in the pipeline. But only with increased pressure is the sector likely to take the radical action needed to move to solely producing low emission cement

“There are some storm clouds gathering on the horizon for the cement industry and we must work together now to repair the roof while the sun is still shining,”warned Zhi Ping Song, president of World Cement Association (WCA), at its climate change forum in June 2018. In an industry plagued by low margins and production capacity well exceeding demand in many countries, finding the resources to invest is not so easy. Stiffer emissions reduction regulations, tighter carbon emissions trading rules and increased lobbying by environmental organisations may, however, leave the industry little choice, but to cough up. Cement, used to make concrete, involves decomposing limestone (calcium carbonate) to produce clinker, a process that accounts for two-thirds of the industry’s total carbon dioxide (CO2) emissions. Reducing the clinker content of cement is therefore a key climate lever. The other third of CO2 emissions are emitted during fuel combustion for the process heat needed for cement production. The whole process means the cement industry’s global share of direct industrial CO2 emissions is 27%, the second largest of any industrial sector behind iron and steel. The industry has been slow to acknowledge the extent of its carbon addiction. Global climate change awareness was triggered back in 1997 with the Kyoto Protocol aimed at reducing greenhouse gas concentrations to “a level that would prevent dangerous anthropogenic interference with the climate system”. Yet, the International Energy Agency (IEA) only released its first cement sector climate analysis in 2009. Nearly ten years later in a 2018 update of its original report, the IEA forecasts that despite increasing efficiencies, cement’s direct carbon emissions are expected to rise by 4% globally by 2050, albeit with an increase of 12% in global cement production in the same period. This scenario is not business as usual, says the agency, insisting that it takes into consideration energy consumption trends and commitments by countries to limit carbon emissions and improve energy efficiency.

Technology gap

Cement manufacturers must clearly do much more to reduce their climate impact. Achieving a sustainable transition to stop global warming at 2°C above pre-industrial levels, let alone 1.5°C, implies a 24% cut in direct CO2 emissions from cement manufacture worldwide by 2050, compared to current levels, while allowing production to grow in line with current forecasts, says the IEA. Emissions reductions greater than those for the 2°C scenario “will be challenging to achieve”, involving a cumulative 3.2 gigatonne drop by 2050, or about a 45% increase in the cumulative carbon emissions reduction effort. Data from the EU Emissions Trading System (ETS) suggest such drastic cuts are mere fantasy, at least in Europe. Preliminary reporting for the cement and lime sector shows European emissions increased to 148 million tonnes in 2017, 5% higher than in 2013, said Sandbag, a non-governmental organisation, in April 2018. Three months later, the WCA acknowledged a “significant technology gap”the cement industry needs to address to transition towards low-carbon production. The cement industry is keen to prove it can step up to the task, though it is less clear about how it will manage the transition. A 2015 roadmap presented by Cembureau, the European cement industry association, predicted that cement’s carbon footprint could be reduced by 32% by 2050 compared with 1990 levels, using mostly conventional means. In a 2018 assessment of progress, the association says the focus is now on reducing direct CO2 emissions by 80% by 2050 with breakthrough technologies, such as carbon capture and storage, and novel cements. It is, however, bullish about the part cement can play in the energy transition, citing, for instance, its potential to help make buildings more energy efficient. Thermally activated concrete, where heating and cooling are delivered through pipes embedded in concrete, can result in energy savings of between 5% for heating and 20% for cooling, says Koen Coppenholle, Cembureau’s chief executive.

In order to protect their position, cement producers may therefore be reluctant to pioneer innovations that would reduce the amount of Portland clinker needed

Clinker progress

Martin Schneider, managing director of the European Cement Research Academy (ECRA), which helps the industry support, organise and undertake research, says a mixture of conventional methods, such as improving energy efficiency, increasing the use of alternative fuels with biomass, and improving clinker efficiency, so less is needed, plus breakthrough technologies, will be necessary. ”Good progress is being reported”on novel cements, he adds.“Some of these novel cements can achieve emissions reductions of more than 90%,”states a report from Chatham House, a London think-tank, “Making Concrete Change”from June 2018. “Others can sequester carbon, theoretically capturing more carbon than is emitted in their production, rendering them carbon-negative.”But the report equally highlights that “the majority of these products have failed to achieve commercial viability”and are unlikely to do so. Needed is “concerted investment in research and large-scale demonstration projects, as well as education and training of consumers to build the market for novel products”. Among the conventional options, clinker efficiency is being paid most attention, says Schneider. “It has the highest lever because it also reduces process emissions.”Materials that are already being used as replacements for clinker include blast furnace slag, power station fly ash and limestone, while calcined clay is close to being used at a commercial scale. But he is cautious about whether the cement sector will ever manage to replace traditional clinker completely. “The reduction and replacement of traditional clinker will have to go hand in hand,”he says, suggesting that standard Portland cement clinker will be indispensable for many applications because of its good strength performance and compatibility with reinforced concrete. Indeed, the Concrete Centre, part of the UK’s Mineral Products Association, says it expects to see novel cements in low-risk applications such as non-structural paving. For reinforced concrete, “durability models and associated test methods will have to be developed and validated before standards can be proposed and adopted”,it warns. Cement producers are also deeply concerned about stranded assets if clinker substitutes and novel cements are rapidly scaled up, lowering the value of thousands of Portland clinker production installations and the companies that own them, says the Chatham House report. “In order to protect their position, cement producers may therefore be reluctant to pioneer innovations that would reduce the amount of Portland clinker needed,”it states.

Climate plan

In an eight-page climate change action plan published inOctober 2018, the WCA says its aim is: transparency around greenhouse gas emissions; optimal use of cement products in construction; an accelerated development of waste co-processing cement kilns to deal with plastic waste and reduce CO2 emissions; to explore innovative technologies; and develop new and innovative business opportunities. Bernard Mathieu, director of the association’s climate programme, says the plan’s commitments are related to the objectives of the Paris climate agreement, but acknowledges that its main focus is on developing methodologies, tools and trainings for WCA members to monitor and report CO2 emissions and establish a carbon footprint of their products rather than ways to actually cut emissions. Indeed, the WCA admits: “We still need to develop 50% of the technologies required to achieve a 2°C degrees scenario”. Mathieu believes better material efficiency could be the way forward. “Training users of cement and concrete, and climate-friendly standards and building codes will reduce average material use, enhance the quality and durability of buildings and thereby massively reduce the climate footprint,”he says. Digital technologies can also help achieve a step-change in process efficiency and trigger the development of low carbon business models.

Producer efforts

In addition to focusing on reducing the use of clinker, LafargeHolcim is also looking at replacing fossil fuels with waste-derived fuels and biomass, and increased energy efficiency. It is cooperating with Solidia Technologies on a new product that sequesters CO2 as the concrete hardens, “reducing emissions by up to 70% for specific applications”. Nonetheless, in 2017, the company‘s average emissions of CO2 per tonne of cement amounted to 581 kilograms, virtually unchanged from the 582 kilograms reported for 2015.Heidelberg Cement has reduced the clinker content in several countries by increasing the proportion of blast furnace slag, fly ash and limestone in cement. In Africa, the company is using ground rock from local quarries to replace imported clinker. It is also busy identifying and developing other alternatives, such as the use of biofuel ash from sugar production, and in the Netherlands, Germany, and France, it is investigating whether fine material resulting from crushing concrete in the recycling process can be used as a cement ingredient to fully close the loop. Another strand being explored by the company is the development of new binders that dispense with conventional clinker altogether. It affirms, though, that these are still being developed and that it will be years until they are ready for wide deployment. It is also investigating the possibility of CO2 capture. Thanks to some of these techniques, Heidelberg Cement has managed to nudge down its average CO2 emissions per tonne of cement to 605 kilograms in 2017, 3% less than in 2015.In addition to exploring the conventional levers of renewable energy, alternative fuels and clinker,Mexican-based company Cemex is involved in four European research projects to directly or indirectly reduce its carbon emissions: Solpart is trialing a pilot-scale high temperature solar process to drive clinker production; Epos aims for “a cross-sectoral industrial symbiosis”to make business and operations more efficient, cost-effective, competitive and sustainable; and Leilac and Genesis are carbon capture projects.Cemex’s average CO2 emissions per tonne of cement amounted to 636 kilograms in 2017, a 1% increase on 2015.Major Chinese producer Anhui Conch Cement Company which reported 855 kilograms of CO2 emitted per tonne of cement for 2017, seems to be concentrating on CCS. Its 2017 social responsibility report highlights a RMB50 million (€6.3 million), 50,000-tonne CO2 capture and purification demonstration project at Baimashan Cement Plant, scheduled for commissioning in 2018. “By capturing CO2 discharged during the cement production process, it will bring economic benefits to enterprises while reducing greenhouse gas emissions and achieving the target of turning waste into value,”the company states.In India, where the cement industry’s capacity utilisation hovers at only some 65%, cement company Ultratechcement has developed a roadmap focusing on reducing energy consumption, increasing its fly ash utilisation rate and improving the share of power from renewable energy sources and from waste heat recovery. Currently, the company’s installed waste heat recovery system capacity stands at around 59 MW, “one of the highest in the Indian cement sector”,it says. Ultratechcement has reduced average emissions of CO2 per tonne of cement to 632 kilograms in 2017, down 2% on 2015.

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Rose tinted vision

The discrepancy between the cement industry’s rosier vision and the more sober forecasts from independent organisations may reflect the latter’s need to see novel solutions ready for use at a commercial level before factoring them in. There is a big difference between picking the low hanging fruit and implementing innovative measures like novel cements or carbon capture. But green regulation and public procurement standards may leave cement companies with little choice. The World Green Building Council has launched the challenge of having 100% net zero carbon buildings by 2050, and from 2019, California will establish maximum carbon emission levels for “eligible building materials”. These will initially be carbon steel bars, flat glass, mineral wool insulation and structural steel, but cement will be next, says the WorldGBC. The EU’s reformed emissions trading system, will also exert pressure for change. “We do not have any detailed information on CO2 allocation for the cement industry for the coming trading period 2021-2030,”says Schneider of ECRA. “It is safe to say, however, that there will be an under-allocation…for the cement industry.”The industry is not believed to have a surplus that can be carried over to the 2021-2030 allocation period, he adds. The additional cost pressure imposed by this situation will probably speed up work on clinker factor reduction, carbon capture and novel cements, predicts Schneider. Switzerland-based LafargeHolcim admits increases in carbon pricing could have a“significant impact”on the company. India’s Perform, Achieve, Trade (PAT) scheme, which has passed the halfway mark of its second cycle (2016-2019), is already having a similar effect. The regulatory instrument is aimed at reducing energy consumption in heavy industries, but it also results in CO2 emissions reductions. Since, April 2017 the energy savings compared with a base line are traded in the form of certificates, leading to impressive results, says the Indian Cement Manufacturer’s Association, which claims some cement production facilities have become global benchmarks in energy consumption. Environment NGOs tend for the moment to be focused on a global exit from coal, but as this battle starts to be won, the cement companies could find themselves increasingly in the spotlight, as many are acutely aware. Germany-based Heidelberg Cement says its range of climate projects is based on the belief that decreasing its CO2 footprint is a “significant step towards safeguarding our future”.

Writer: Sara Knight