The opportunity for green cement and concrete in Africa is driven by four key factors: 1) market demand (the volume of anticipated construction), 2) the youth of the industry, allowing engineers and new cement plants to learn from global best practices,¹ 3) the fact that cement supply chains are highly localized and Africa already has large, well-established cement incumbents, and 4) the limited availability of limestone and the abundance of natural materials suitable for alternative, low-carbon cement production.

Exhibit 1

Africa’s construction sector is racing to build the housing and infrastructure needed for a billion more people by 2050. Of the continent’s projected 2050 building stock, an estimated 80% is yet to be constructed,² and it already faces an affordable housing shortage of at least 50 million units, which could rise to 130 million by 2030.³ Although this article focuses on the cement and concrete used in these structures, it will take many more materials and innovations to build the next generation of better-performing, more affordable, lower-carbon buildings. Similar cases could be made for the role of advanced cooling solutions (both active and passive), carbon-storing building materials, or other innovative materials. These areas are ripe for further exploration and investment.

“We don’t see big barriers in terms of regulation, finances, or market. The [African] construction industry is accelerating — cement consumption is going to be crazy high.”

—Shahrukh Shamim, CEO and Co-founder of EnviCore

The construction boom in Africa will drive an estimated 230% increase in cement demand by 2050 (Exhibit 1), which would produce 4.6 Gt in carbon emissions annually using current methods — roughly comparable to total US CO₂ emissions in 2024.⁴ In today’s cement plants, about two-thirds of cement’s emissions come from the materials — limestone releases CO₂ during calcination in a cement kiln at 1,300°C or more — and the rest comes from the thermal and electrical process energy used to operate the facility and reach these extreme temperatures. Usually coal or other fossil fuels are used for heat. Emergent climate technologies can electrify this heat production with access to low-carbon, low-cost electricity.

Regardless of the underlying process, the new cement plants built to meet growing demand will need reliable sources of electricity, on the order of 100–1,000 GWh/year. This massive power demand can catalyze new investment in low-cost renewables: electric cement kilns need 5x–10x more electricity than traditional processes.⁵ By co-planning with cement producers as anchor offtakers, energy developers can reduce revenue risk and unlock better financing for their projects. Crucially, these projects can do more than power the plant itself. Excess capacity can feed the grid or serve nearby communities and businesses, improving access, reducing system costs, and strengthening reliability for others. The larger the industrial load, the greater the opportunity to scale clean energy infrastructure that benefits everyone.

Even though Africa’s cement and concrete industry is comparatively young, there are already well-established incumbents in place, including Heidelberg Materials, Holcim, and Dangote. Many of them do not have access to enough domestic limestone — the key ingredient in conventional cement — which drives up both reliance on imported cement and the cost of concrete. What they have instead is an abundance of resources suitable as supplementary cementitious materials (SCMs), or for geopolymer concretes.

Lowering concrete costs and emissions starts with using less concrete in buildings, then using less cement in the concrete mix where concrete is necessary, and finally adopting alternatives to traditional cement where possible. Exhibit 2 summarizes several innovation areas in green cement and concrete. In Africa, we see particular promise in three of these: (1) optimization software and education, (2) increasing the use of SCMs, and (3) advancing alternative cements.

Adopting these innovations will require integration into today’s jobsite practices: on most construction sites in Lagos or Nairobi or Pretoria, concrete is being mixed by hand or with small batch mixers. This leads to a wide variation in concrete quality and cement overuse. It also means there is low-hanging fruit in simply introducing ready-mix concrete with consistently proportioned cement and aggregate, which can be taken a step further with optimization or AI.

Software for optimization and education

Beyond physical, “hard-tech” solutions, artificial intelligence and machine learning can help optimize building design, concrete mixes, and cement plant operations. Tools like Beacon (developed by structural engineering firm Thornton Tomasetti) and Generate can be employed to design buildings that need 24%–40% less concrete.⁶ Once the amount of concrete required for the building has been minimized, the next step is to ensure the concrete mix itself is optimized, by combining aggregates and water with only the necessary amount of expensive and emissions-intensive cement.

Around 42% of global cement is sold in bags and then mixed on the construction site in variable conditions, often by personnel who are not trained to ensure the correct proportion of cement.⁷ This means that many concrete mixes use much more cement than structurally necessary. Simply switching from on-site mixing to premixed solutions from a truck or in a bag can reduce wastage by 20%–30%.⁸ Then, solutions like Concrete.ai can further optimize concrete mixes to ensure they only use the amount of cement that is structurally needed, further reducing cement usage and costs while cutting carbon emissions by 30%.⁹ Cement plant optimization tools can take advantage of the development and construction of new cement facilities, making it easier to integrate new solutions.

Exhibit 2

Supplementary cementitious materials (SCMs)

SCMs are materials such as fly ash, slag, and pozzolans that act similarly to cement but don’t have the same carbon price tag. They can replace some of the cement in a concrete mix. SCMs are already in widespread global use and accepted in certain amounts by building codes. This makes them a highly impactful near-term solution that can scale quickly. SCMs are projected to reduce global concrete emissions by 22% by 2050, and by 26%–29% for African countries.¹⁰

African incumbents are already using locally available SCMs such as volcanic ash, slag from steel production, and limestone calcined clay cement. For example, South African firm Afrisam has developed Eco Readymix, which cuts emissions by half compared to typical industry concrete using a blend of high performance cement and carbon neutral mineral components.¹¹ Eco Concrete, a Ugandan startup, is developing novel SCMs, but there is a vast opportunity for other innovators to develop SCMs from abundant and diverse resources across the continent, e.g., lateritic soils rich with kaolinitic clay, volcanic ash, bauxite, industrial waste, and bio-ash from agricultural residues.

Alternative cements

Alternative cements include geopolymers, bio-based cements, and mineral-based alternative cements (e.g., those that use basaltic rock instead of limestone). While they can yield carbon-neutral or even carbon-storing concrete, these solutions have longer pathways to market due to risk aversion and additional testing and validation needs. But in Africa, investing in alternative cement solutions can bypass the development of new conventional cement plants and the emissions lock-in they represent.

Ghanaian startup Theseus Development is working on geopolymer concrete blocks that utilize locally available waste aluminosilicates such as kaolinitic clays and feldspar. The result is pre-cast, interlocking wall blocks with 80% less embodied carbon, that exceeds compressive strength requirements, and can be produced at a price point lower than traditional concrete blocks.

Evans Nartey, CEO of Ghanaian geopolymer concrete startup Theseus Development

Cement is heavy and costly to transport. As a result, cement is typically supplied within a 150km–250km radius of where it’s produced or imported (imports are usually by sea). Establishing local cement or alternative cement production facilities in Africa would lessen regional dependence on imported products and lower costs. However, innovative startups would struggle to obtain the capital and know-how required to build a large factory to commercialize their technology. This is where partnerships with incumbents become vital as a pathway to scale. Corporate cement or concrete producers have facilities in place, supply chains established, and can offer opportunities for testing, piloting, feedback, and potentially licensing or offtake agreements.

For example, last year global cement producer Heidelberg Materials invested in EnviCore, a startup developing SCMs that can reduce the amount of cement needed in a concrete mix. This partnership will involve jointly deploying a pilot SCM production facility close to one of Heidelberg Material’s recycling hubs to validate EnviCore’s technology and optimize the process for production at scale.¹² Similarly, large cement producer Holcim invested in startup SaltX, who has developed a plasma technology that electrifies cement production, to establish the world’s first plant with all-electric cement production.¹³

Policy and regulation

Many African countries have adopted European or US standards and regulations for concrete. While standardization can be helpful, it also means African countries are using codes that have historically resulted in structural overdesign and unnecessary cement use, and that are decades behind today’s best practices. Given the relative newness of their building stock, African countries can set world-leading standards tailored to local conditions.¹⁴ Performance-based standards, for example, can knock down many barriers for innovative startups, which only need to demonstrate that their product meets certain structural requirements rather than try to precisely mimic the chemical properties of ordinary Portland cement.

The power of procurement

Leading real estate developers and corporates can pave the way for more abundant and affordable lower-carbon concrete solutions through pilot projects, company commitments, education campaigns, and even advanced market commitments. For example, Microsoft signed a binding deal to purchase up to 622,500 metric tons of product from low-carbon cement startup Sublime. This deal reduces Sublime’s offtake risk as it seeks to scale up production.¹⁵

Governments can play a strong role here, too, as African nations spend 15%-30% of GDP on public procurement.¹⁶ Public procurement for city infrastructure and social housing development can support the development and growth of innovative solutions, while stimulating economic activity. An emerging priority for African nations is aligning public procurement practices with sustainability goals.

For both procurement pathways, cost will be key. Solutions that are at-cost or lower-cost than incumbents will have much easier adoption rates, as margins in both the construction and concrete and cement industries are low — 10% on average. The number of consumers willing to pay a green premium for low-carbon concrete is small, but a few early movers can help bring promising technologies to market and ultimately lower on the cost curve.

Developing local SCM sources and supply chains

Locally sourced SCMs can replace cement with abundant local resources, quickly reducing cost and carbon associated with traditional cement mixes. For the many African countries still importing cement, SCMs can also reduce dependence on foreign supply chains. Incumbent producers are already developing and selling blended cements that use locally available SCMs, including Lafarge Africa’s UniCem (with calcined clay) and HydroCem (made from recycled steel slag), and Heidelberg Cement subsidiary Suez Cement, which offers a pozzolan (ash) blended cement.

This adoption of SCMs is partly driven by climate commitments, but largely driven by SCMs’ abundance and competitive pricing relative to cement. This opens an opportunity for new SCM producers to sell to incumbents at large volumes. It also means that companies developing alternative approaches, such as Theseus Development, can use abundant, low-cost SCMs in their products and skip traditional cement altogether.

This article is based on research and convening funded by The Rockefeller Foundation. The findings and conclusions contained herein are those of the authors and do not necessarily reflect positions or policies of The Rockefeller Foundation.