Concrete Has an Emissions Problem. Thankfully, Startups Are Queuing Up to Solve It

In 2021, global construction projects consumed 30B tonnes of cement to make concrete — with every tonne emitting almost a tonne of CO2. The good news is, technologies already exist to reduce the impact of concrete production.

By Tom Idle | Published 1 year ago | About a 6 minute read

Image: Paris 2024

The world’s Olympians will descend on Paris, France next Summer — with the organisers not-so-quietly-confident this will be the most sustainable Games ever staged. The 2024 Olympics will be unlike any other Games in history, with a wealth of energy-conservation projects and creative innovation designed to halve the amount of greenhouse gas emissions (GHGs) that usually arise from hosting the global event. The organisers have promised to trial and help develop solutions across food sourcing, energy generation and transport.

In the newly constructed Athletes’ Village, just over four miles from the centre of the French capital, an example of this innovation is clearly on display. The new neighbourhood, which comprises the Olympic Village Plaza — which opens onto the Seine, a residential area and an operational area connected to the main road networks — is dominated by concrete. But this isn’t just any concrete. It is ultra-low carbon cement by Ireland-based Ecocem — an alternative to traditional material that significantly reduces the CO2 footprint of the project. Known as Ecocem Ultra, the cement was developed over four years in partnership with global construction business, VINCI Construction. It is a hydraulic binder — produced in a way that does not involve a high-heat, high-emissions combustion process.

Ecocem is one of many companies to start up in recent years to deliver much-needed, low-carbon cement. Concrete is one of the most important substances in the world. Other than water, concrete is the second-most consumed substance we have — dominating urban environments all around the world. As Ecocem Managing Director Conor O’Riain has said: “[It] is almost ubiquitous to the point of anonymity. It is everywhere; and yet, concerningly, many fail to notice its environmental impact.”

As the linchpin of the built environment, demand for concrete has almost tripled during the past 20 years. In 2021, global construction projects consumed 30 billion tonnes of the stuff. That’s 3 million times the weight of the Eiffel Tower. Today, cement production is responsible for 8 percent of the world’s GHGs — with every tonne of cement made emitting almost a tonne of CO2.

The primary source of these emissions is the chemical reaction known as calcination, where limestone (calcium carbonate) is heated to produce lime (calcium oxide) — a process that releases substantial amounts of carbon into the atmosphere. The high-temperature kilns (reaching as high as 1,450°C) used to heat the raw materials to produce clinker — cement’s main component — burn through a significant amount of coal and petroleum coke. These are fossil fuels that not only contribute to CO2 emissions but also release other pollutants — including sulfur dioxide and nitrogen oxide — causing air pollution and poor health.

A finger can also be pointed to the mining and quarrying of limestone and clay as a cause of deforestation and loss of biodiversity.

The good news is that the technology already exists to reduce the impact of concrete production. Of course, reducing our use of clinker is easier said than done — especially with huge infrastructure projects all around the world showing no shows of slowing down. But substituting traditional cement for a less harmful alternative that does exactly the same job could well be the answer.

“We can’t really do without concrete — so we had to figure out a way to make it more environmentally efficient at scale, at a reasonable cost,” Grant Quasha, CEO of Eco Material Technologies, told Sustainable Brands®. His business is blazing a trail for concrete substitutes across North America; its roughly seven million tons of “supplementary cementitious materials” account for half of all sales.

The majority of these materials are being recycled from fly ash — the waste material left over in many power plants and commonly just thrown away.

“Several decades ago, our predecessor companies realized you could repurpose that material and use it in concrete. Not only does it reduce the amount of emissions and the cost of the concrete, it also actually makes it stronger and better,” Quasha says. “There’s two billion tons of fly ash in the US and it’s an environmental hazard. So, we dig the material out of the ground, clean it up, beneficiate it with our technology, and then sell it to put it in concrete.”

Eco Material Technologies continues to experiment with its production — finding new ways to increase the percentage of carbon-free cement in its concrete products.

“With our proprietary technology, we can upgrade the reactivity so that the glue takes the same amount of time to set and you can set your concrete and drive over it the next day. You don’t have to wait a week,” he adds.

In the US alone, other potential startup solutions that are gaining ground include:

Watershed Materials’ clay-based cement alternative, which is twice as strong as ordinary concrete.
More novel still, Fortera has created a cement-like material that actually converts CO2 into cement — reducing CO₂ emissions by more than 60 percent. And it’s 10 percent cheaper than conventional cement, according to the company.
Solidia has staked claims on its carbon-absorbing concrete. Using a chemical process licensed from Rutgers University, it uses less limestone and therefore requires less heat. Instead of curing the concrete with water, the process has been tweaked to use carbon dioxide instead.

According to McKinsey, cement companies that adopt circular business models — such as using digital marketplaces for waste and taking on circular technologies to adjust to evolving business risks — will reap undeniable benefits: A recent analysis suggests such a move could deliver an extra €110 billion in net value and avoid two billion tons of CO₂ emissions by 2050.

But if low-carbon cement and concrete are to become the norm — and companies such as Eco Material Technologies are to dominate the building sector — policies, legislation and standards will need to be tweaked. The Alliance for Low-Carbon Cement and Concrete (ALCCC) — a coalition of European innovators and construction firms — is calling on the European Union to set ambitious targets for low-carbon, resource-efficient and circular construction products; using laws, standards, and financial tools to reduce the environmental burden of concrete.

“A crucial first step would be replacing the existing, recipe-based standards on cement and concrete with a performance-based approach — finally allowing the uptake of all low-carbon cement and concrete solutions on the market,” it says. “The legislative framework should incentivise low-carbon solutions in the industry — never discourage them — as this gives a competitive advantage to traditional, polluting, carbon- and energy-intensive technologies.”

As the crowds gather in the City of Lights next Summer, low-carbon concrete will proudly take a bow. With so many viable solutions available, could the days of heavy-polluting cement production finally be coming to an end?

Tom Idle

Content creator extraordinaire.

Tom is founder of storytelling strategy firm Narrative Matters — which helps organizations develop content that truly engages audiences around issues of global social, environmental and economic importance. He also provides strategic editorial insight and support to help organisations – from large corporates, to NGOs – build content strategies that focus on editorial that is accessible, shareable, intelligent and conversation-driving.

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