Making Concrete Change: Innovation in Low-carbon Cement and Concrete

As a key input into concrete, the most widely used construction material in the world, cement is a major contributor to climate change. The chemical and thermal combustion processes involved in the production of cement are a large source of carbon dioxide (CO2) emissions. Each year, more than 4 billion tonnes of cement are produced, accounting for around 8 per cent of global CO2 emissions.   To bring the cement sector in line with the Paris Agreement on climate change, its annual emissions will need to fall by at least 16 per cent by 2030.1 Steeper reductions will be required if assumptions about the contribution from carbon capture and storage (CCS) technologies prove to be optimistic. Meanwhile, investors are increasingly expecting companies to report clear information on their exposure to climate risk. The trends all point to regulatory, financial and societal pressures on the horizon, especially for cement companies without a detailed plan for a Paris-compliant pathway.Each year, more than 4 billion tonnes of cement are produced, accounting for around 8 per cent of global CO2 emissionsYet at the same time, cement is expected to play a vital role in the expansion of the built environment, especially in emerging economies. On a ‘business as usual’ trajectory, global cement production is set to increase to over 5 billion tonnes a year over the next 30 years.2 Rapid urbanization and economic development in regions such as Southeast Asia and sub-Saharan Africa will increase demand for new buildings, and thus for concrete and cement. With as many as 3 billion people potentially living in slums by 2050, new rapidly deployable housing solutions are urgently needed.3Moreover, the infrastructure demands of development and urbanization are not limited to housing. Providing clean water, sanitation and energy services typically relies on concrete, whether for transport infrastructure, wind farms or hydro-electric dams. In this context, continuing efforts to meet the UN Sustainable Development Goals (SDGs) are expected to result in $60 trillion being invested in such infrastructure in developing countries by 2030.4The cement sector is thus facing a significant expansion at a time when its emissions need to fall fast. From a technical perspective, there are a number of solutions for reducing the emissions associated with cement production; all will need to be deployed at scale to meet the decarbonization challenge. Some of these solutions are well recognized and common to other sectors: for instance, the energy efficiency of cement plants can be increased, fossil fuels can be replaced with alternatives, and CO2 emitted can be captured and stored.The main focus of this report, however, is on those emissions mitigation solutions that require the transformation of cement and concrete and are thus unique to the sector. More than 50 per cent of cement sector emissions are intrinsically linked to the process for producing clinker, one of the main ingredients in cement. As the by-product of a chemical reaction, such emissions cannot be reduced simply by changing fuel sources or increasing the efficiency of cement plants. This report therefore focuses on the potential to blend clinker with alternative materials, and on the use of ‘novel cements’ – two levers that can reduce the need for clinker itself by lowering the proportion of clinker required in particular cement mixtures. Despite widespread acceptance among experts that these are critical, they have received far less policy focus.Well-known barriers stand in the way of deep decarbonization of cement. The sector is dominated by a handful of major producers, which are cautious about pioneering new products that challenge their existing business models. In the absence of a strong carbon-pricing signal, there is little short-term economic incentive to make changes. Alternative materials are often not readily available at the scale required. Meanwhile, architects, engineers, contractors and clients are understandably cautious about novel building materials. Implementing new practices also implies a critical role for millions of workers involved in using concrete across the urban landscape.Low expectations around the prospects for a radical breakthrough in cement production are reflected in the limited attention given to the sector in key assessments of low-carbon pathways in recent years.5 As one recent report notes, ‘When cement emissions are mentioned at all in public debate, it is typically to note that little can be done about them.’6 There is, however, a growing sense not only of the urgency of the need to decarbonize cement production, but also of the expanding range of technological and policy solutions. The range of major organizations now working on relevant strategies includes the UN Environment Programme (UNEP), the International Energy Agency (IEA) – working with the industry-led Cement Sustainability Initiative (CSI) – and the Energy Transitions Commission, an initiative involving high-level energy experts and stakeholders aimed at accelerating the transition to low-carbon energy systems.For decision-makers, more insight is needed into the potential for scalable, sustainable alternatives to traditional carbon-intensive cement and concrete. For this report Chatham House worked with CambridgeIP, an innovation and intellectual property consultancy, to conduct a major patent-landscaping exercise around innovation in clinker substitution and novel cements – examining where and why laboratory-based breakthroughs are happening, the kinds of firms involved, and which innovations have the potential to cross the ‘valley of death’ (the name given to the phenomenon in which innovations do not make it past the technology-creation stage) and make a meaningful impact on emissions pathways. Along with major global cement producers and technology service providers, Chinese firms and research organizations are among those jostling for pole position.Shifting to a Paris-compliant pathway, with net-zero CO2 emissions by around 2050,7 will require going further and moving faster on all available solutions, as well as making sure that the next generation of innovative technology options is ready as soon as possible.To illustrate the scale of this challenge, Figure 1 shows the decarbonization pathway set out by the IEA and CSI’s 2018 Technology Roadmap.8 This scenario shows action on four mitigation levers – energy efficiency, fuel switching, clinker substitution and innovative technologies (including CCS) – to achieve CO2 reductions consistent with at least a 50 per cent chance of limiting the average global temperature increase to 2°C above pre-industrial levels by 2100. Figure 1: Towards a Paris-compatible pathway – Source: Authors’ analysis of scenario set out in International Energy Agency and Cement Sustainability Initiative (2018), Technology Roadmap: Low-Carbon Transition in the Cement Industry, Paris: International Energy Agency, https://www.wbcsdcement.org/index.php/key-issues/climate-protection/technology-roadmap (accessed 24 Apr. 2018). The B2DS is based on data in International Energy Agency (2017), Energy Technology Perspectives 2017. Note: RTS stands for ‘reference technology scenario’, 2DS stands for ‘2°C Scenario’ and B2DS stands for ‘Beyond 2°C Scenario’. For descriptions of each model, refer to the original source. The ETP B2DS and roadmap models are not directly comparable as they are based on slightly different assumptions as to future demand for cement but they are shown together here as an indicative comparison. Figure 1: Towards a Paris-compatible pathway – Source: Authors’ analysis of scenario set out in International Energy Agency and Cement Sustainability Initiative (2018), Technology Roadmap: Low-Carbon Transition in the Cement Industry, Paris: International Energy Agency, https://www.wbcsdcement.org/index.php/key-issues/climate-protection/technology-roadmap (accessed 24 Apr. 2018). The B2DS is based on data in International Energy Agency (2017), Energy Technology Perspectives 2017. Note: RTS stands for ‘reference technology scenario’, 2DS stands for ‘2°C Scenario’ and B2DS stands for ‘Beyond 2°C Scenario’. For descriptions of each model, refer to the original source. The ETP B2DS and roadmap models are not directly comparable as they are based on slightly different assumptions as to future demand for cement but they are shown together here as an indicative comparison. As recognized in the 2018 roadmap, there is a considerable gap between this scenario and a scenario consistent with countries’ more ambitious aspirations in the Paris Agreement of limiting the temperature increase even further, towards 1.5°C.