{"id":120270,"date":"2025-02-12T11:05:01","date_gmt":"2025-02-12T11:05:01","guid":{"rendered":"https:\/\/alj.com\/?post_type=spotlight-fadyjameel&p=120270"},"modified":"2025-04-03T08:01:18","modified_gmt":"2025-04-03T08:01:18","slug":"a-concrete-solution","status":"publish","type":"spotlight-fadyjameel","link":"https:\/\/alj.com\/en\/spotlight-by-fady-jameel\/a-concrete-solution\/","title":{"rendered":"A concrete solution?"},"content":{"rendered":"

The world\u2019s go-to building material is among its worst climate offenders. What can we do to reduce its negative impact?<\/em><\/h4>\n

Fourteen billion cubic meters. \u00a0That\u2019s how much cement we produce every year.[1]<\/sup><\/a>\u00a0 By 2050, it will be 20 billion.[2]<\/sup><\/a><\/p>\n

Whether used directly, or turned into concrete, our most consumed human resource is everywhere<\/em> \u2013 from apartments, offices, and schools, to bridges, roads and hospitals.\u00a0 It’s also one of the biggest contributors to climate change, with concrete alone accounting for 7% of global CO2<\/sub> emissions.[3]<\/sup><\/a><\/p>\n

Cement and concrete are prime targets for limiting global warming to 1.5 degrees Celsius.\u00a0 The good news is innovative and improved solutions are appearing, including carbon capture, utilization, and storage<\/a> (CCUS), recycling, and the use of alternative materials.\u00a0 However, huge investment, incentives, regulation, and coordination hurdles lie ahead.<\/p>\n

The future is not set (yet).<\/p>\n

Hard graft<\/h2>\n

Cement production is expected to increase to meet growing global demand.[4]<\/sup><\/a>\u00a0 However, the Global Cement and Concrete Association (GCCA<\/a>) has called for complete decarbonization by 2050 \u2013 with a 20% reduction in CO2<\/sub> per metric ton of cement and a 25% reduction in CO2<\/sub> per cubic meter of concrete by 2030 (compared to 2020 levels).[5]<\/sup><\/a><\/p>\n

According to the MSCI Sustainability Institute<\/a>, the cement industry would need to reduce its revenue-based emissions intensity by an average of 7.2% annually between 2023 and 2050 to become carbon neutral by 2100 as per the Network for Greening the Financial System (NGFS<\/a>) \u20182 degrees Celsius\u2019 scenario.[6]<\/sup><\/a>\u00a0 This conflicts with the industry\u2019s pledged emission reductions (see below).<\/p>\n

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Projections assume that technologies required to decarbonize the industry at scale will not achieve technological readiness or cost parity with incumbent solutions any time soon.[7]<\/sup><\/a><\/em><\/p>\n

As of August 2023, over one third of concrete producers have declared net-zero or carbon-neutral targets.[8]<\/sup><\/a>\u00a0 Thus far, however, only two producers \u2013 Cemex and Holcim \u2013 have set targets validated by the Science Based Target Initiative (SBTi<\/a>) that would align with net-zero by 2050 and the 1.5\u2070C pathway.[9]<\/sup><\/a><\/p>\n

More ways to cut more emissions<\/h2>\n

Until 2030, the most significant gains will come from more efficient and effective use of concrete, cement, and clinker.\u00a0 After that, CCUS is likely to play a more prominent role.<\/p>\n

There are no silver bullets.\u00a0 Reducing CO2<\/sub> from concrete and cement will take multiple, coordinated efforts across the supply chain.\u00a0 As the graphic below indicates, at current rates, 98 gigatons (Gt) of CO2<\/sub> will be emitted from the concrete and cement industry between 2022 and 2050 \u2013 twice as much as the sector can afford to help meet global 1.5\u2070C pathway \u00a0targets.[10]<\/sup><\/a><\/p>\n

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Although long-term solutions are critical, emerging decarbonizing technology could deliver a much steeper decrease in emissions in this decade, by around 40% by 2030, according to some estimates.[11]<\/sup><\/a><\/p>\n

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Let\u2019s unpack the available interventions.<\/p>\n

Use less concrete and cement<\/strong><\/p>\n

An obvious start.\u00a0 The industry should recycle more concrete and use more recycled materials to produce it (as we\u2019ll explore below).\u00a0 Reusable concrete modules, which can be broken down or incorporated into new structures, are proving popular in Nordic countries.[12]<\/sup><\/a><\/p>\n

Also, only build if you have to.\u00a0 Many buildings can be repurposed, such as converting warehouses into social housing.\u00a0 Experts at the World Economic Forum estimate that applying circular solutions for cement and concrete by 2050 could avoid or mitigate around 2.6 billion metric tons of CO2<\/sub> emissions.[13]<\/sup><\/a><\/p>\n

Add more admixtures<\/strong><\/p>\n

Admixtures can make concrete easier to work with and longer-lasting, reducing quantities and costs.\u00a0 They can also make concrete easier to recycle.\u00a0 According to the World Economic Forum, admixtures could reduce concrete’s CO2<\/sub> emissions by up to 30% under current standards and up to 50% under updated standards.[14]<\/sup><\/a>\u00a0 More people must learn about admixtures’ decarbonization potential or how to adapt their concrete mixes accordingly.[15]<\/sup><\/a><\/p>\n

Improve logistics and access to infrastructure<\/strong><\/p>\n

Concrete and cement are heavy, low-margin commodities, typically making them too expensive to transport long distances.\u00a0 Individual plants need easy access to raw materials, low-carbon energy sources, carbon capture infrastructure, and more efficient supply chains.[16]<\/sup><\/a>\u00a0 However, it’s unlikely that all these solutions will be feasible, so the problem must ultimately be solved at the local level.<\/p>\n

Decarbonize production with alternative fuels<\/strong><\/p>\n

One-third of the emissions from a typical cement plant come from burning coal, petroleum coke, and other fossil fuels to heat kilns.[17]<\/sup><\/a> \u00a0Electrifying kilns with renewable electricity will help; high-heat plasma torches powered by renewable energy show promise.[18]<\/sup><\/a>\u00a0 Meanwhile, switching to biomass and waste-based alternatives such as sewage sludge can reduce total emissions by up to an estimated 17%.[19]<\/sup><\/a>\u00a0 There is already a strong use-case for this approach.\u00a0 In 2022, Cemex completed a UK facility that runs on 100% alternative fuels.[20]<\/sup><\/a>\u00a0 In the same year, Holcim reported powering 28% of its thermal energy demand with alternative fuels and aims to hit 50% by 2030.[21]<\/sup><\/a>\u00a0 According to the MSCI Sustainability Institute, alternative fuels could lower emissions far below the cement industry’s stated targets and, owing to their affordability could reduce long-term emissions significantly faster than the current net-zero by 2100 pathway.[22]<\/sup><\/a>\u00a0 Producers are also developing proprietary waste-recycling businesses that target the use of industrial and municipal waste in their kilns.[23]<\/sup><\/a><\/p>\n

Cut the clinker<\/strong><\/p>\n

Concrete’s affordability, versatility, and durability are greatly influenced by the binding capacity of clinker.\u00a0 Clinker is one of the key ingredients of concrete, made from a mixture of\u00a0limestone and minerals.\u00a0 Unfortunately, it is produced by roasting limestone to over 2,552 degrees Fahrenheit in kilns, emitting around 622 kilograms of CO2<\/sub> for every metric ton of cement produced.[24]<\/sup><\/a>\u00a0 Clinker itself accounts for around 90% of the emissions released in cement production.[25]<\/sup><\/a>\u00a0 Two approaches could roughly halve clinker’s carbon footprint: avoid using it or decarbonize production through carbon capture:[26]<\/sup><\/a><\/p>\n

Amp up the SCMs<\/strong><\/p>\n

Clinker can be substituted for less emissions-intensive materials such as fly ash, metal slag, recycled concrete, or calcined clay, which are known as supplementary cementitious materials (SCMs).[27]<\/sup><\/a>\u00a0 Fly ash and ground and granulated blast furnace slag (GGBS) are byproducts of burning coal and iron-making, respectively.\u00a0 Both offer an efficient way to use waste products while avoiding clinker production.[28]<\/sup><\/a>\u00a0 Ironically, these materials will dry up as coal power fades out and steel production becomes greener.\u00a0 Fortunately, there are other options.\u00a0 Calcined clay is a naturally occurring material found worldwide and is abundant in the Global South, where cement demand is peaking.\u00a0 Some estimates indicate that if calcined clay became the go-to for cement, it could reduce the sector’s emissions by 30\u201340%.[29]<\/sup><\/a>\u00a0 SCMs currently comprise around 15% of global cement production, but estimates suggest they could increase to 30%\u201350%.[30]<\/sup><\/a><\/p>\n

Ask the algorithms<\/strong><\/p>\n

Machine learning and control technologies are enabling emerging companies to optimize cement quality while incorporating low-carbon alternatives.\u00a0 US green cement start-up Alcemy reported lowering CO2<\/sub> by up to 50% while improving quality by scaling solutions across Europe and the US.[31]<\/sup><\/a> \u00a0Other start-ups like Fero Labs and AlCrete are helping to optimize cement and concrete production in real-time to enable lower CO2 <\/sub>mixes.[32]<\/sup><\/a><\/p>\n

Capture the carbon<\/strong><\/p>\n

Clinker can be decarbonized by holding onto the CO2<\/sub> emitted during production.\u00a0 CCUS has the largest emissions-saving potential of all options, accounting for 35%\u201350% of emissions savings across all scenarios in the Mission Possible Partnership (MPP<\/a>) report, Making Net Zero Concrete and Cement Possible<\/em>.[33]<\/sup><\/a>\u00a0 In theory, CCUS could even produce clinker with net-zero emissions.\u00a0 However, CCUS is relatively new, expensive, and can be energy and water intensive.\u00a0 If low concentrations of CO2<\/sub> are emitted (around 15%\u201320%), a lot of energy is needed to enrich them to proper levels.[34]<\/sup><\/a><\/p>\n

Due to its high price tag, CCUS has mostly been confined to larger players and those with access to storage capacity and uses for captured carbon, such as industries that use mineralized carbon, government support, and affordable renewable energy.[35]<\/sup><\/a>\u00a0 In some places, incumbents are exploring retrofits to add CCUS.[36]<\/sup><\/a>\u00a0 CO2<\/sub> can also be stored in concrete aggregates when construction and demolition waste is recycled.[37]<\/sup><\/a><\/p>\n

Strategically built megaplants in areas with access to plentiful cheap renewable energy and supportive regulation, such as the US and Europe, could reduce the production cost of lower-carbon clinker by up to 60%.<\/p>\n

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Transporting, storing, and using captured carbon presents challenges, particularly for the Global South.\u00a0 Although CCUS is vital to decarbonization, the industry must avoid overreliance on this underdeveloped technology while research, development, investment, and regulation catch up.\u00a0 To navigate the pathway to decarbonization, a balanced, evolving approach, incorporating the above solutions as they become feasible, is necessary.<\/p>\n

More money, regulation, and cooperation<\/h2>\n

Reaching net zero by 2050 requires a portfolio of policy and financial instruments to create an enabling environment for innovation and decarbonization.[38]<\/sup><\/a>\u00a0 As RMI points out, “The year 2050 is just one investment cycle away, given the industry’s long-lasting capital assets.”<\/em>[39]<\/sup><\/a>\u00a0 The industry must act now to ensure major new investments are net-zero compatible.<\/p>\n

The MPP Concrete and Cement Sector Transition Strategy[40]<\/a> is a roadmap charting a decades-long journey for achieving net-zero in cement and concrete \u2013 requiring substantial technology, finance, and policy interventions.\u00a0 Near-term actions required from industry, government, and finance stakeholders include:<\/p>\n