Greening the concrete jungle

Since cement was patented back in 1824, it has been almost universally used in construction as the most common binder in concrete and a vital component of all modern buildings.

However, the production of cement generates significant CO2 emissions. It is estimated that the production of cement and concrete creates 9% of global emissions. Furthermore, concrete buildings add to the ‘heat island effect’ in cities and the material’s lack of permeability is heightening flash flooding during extreme weather events.

The real estate and construction industries need to explore alternative technologies to limit cement’s contribution to emissions and make the built environment more sustainable.

The impact of cement on the environment is only going to grow, as demand is increasing due to population growth and urbanization. JLL estimates the embodied carbon in cement production between now and 2030 could be as much as 18.6 billion tonnes. Infrastructure is the greatest user of cement, but real estate alone will generate 5.4-6.2 billion tonnes of CO2 – greater than the annual emissions of the United States.

More sustainable cement processes could generate significant carbon savings. We estimate reductions of 3.1 to 4.6 billion tonnes of CO2 could be achieved by 2030. Even the lower end of those savings would be the equivalent to eliminating all emissions from the European Union in one year.

Greater regulatory pressure is being applied to cement and concrete in embodied carbon policies, especially in North America and Europe. A variety of policies to reduce cement and concrete use are being applied, such as ‘buy clean’ acts which bar building materials from government funded projects if they surpass a certain embodied carbon threshold. The Netherlands implemented the first buy clean policy in 2010, giving suppliers with a significantly lower carbon footprint priority in government contracts. Similar measures have been introduced in the United States, Canada, Ireland and Finland.

There are three key elements to CO2 emissions from cement: materials, energy and transport. All these elements need to be addressed in order to lower emissions.

• Replacing limestone: limestone is a key ingredient in traditional cement, however the chemical process used to transform it requires a lot of heat energy and releases large amounts of CO2. Supplementary cementitious materials (SCMs) can be used to create cement with low or no limestone.
• Clean energy: it takes roughly 110 kWh to produce one tonne of cement, much of this usage coming from the grinding and crushing process. Using clean energy can remove these emissions.
• Move to local production: cement is heavy and bulky, so its transportation is carbon intensive, using fossil fuel-powered vehicles. Production near the point of use can reduce the carbon impact of transport.

As well as reducing emissions from these three elements of cement production and distribution, producers may also use carbon capture and storage to remove carbon emissions from the process and store it underground or in the cement itself.

The pressure to find alternatives to traditional cement has spawned sustainable solutions for the industry. For example, Colorado-based Minus Materials uses marine algae to create limestone which sequesters carbon, creating a carbon-negative raw material and filler for various low-carbon concrete mixtures which could enable cement producers to cut emissions by up to 60%. The company is supported by JLL Foundation, the charitable arm of JLL.

Other pioneers include Brimstone in California, which is developing a carbon negative process for making cement from calcium silicate instead of limestone. Ecocem, a Dublin-based company, develops cements which use less limestone, and which therefore reduce embodied emissions by up to 50%, while Norway’s EvoZero uses carbon capture and storage to create a net-zero cement-making process.

As so often in sustainability, it is hard to make a difference unilaterally. While there are industry initiatives such as ConcreteZero and the Portland Cement Association’s PCA Roadmap for net zero, more stakeholder collaboration is needed. That’s why the likes of Minus Materials and other innovators have come together to form the Decarbonized Cement and Concrete Alliance to build future infrastructure with low-carbon cement and concrete, and at the same time create jobs. Involvement from real estate developers, the end users of substantial quantities of cement, is required: they have an opportunity to take a lead in decarbonizing their projects and building a network with low-carbon cement producers.

Much of the innovation in sustainable materials has come from start-up companies around the world. These innovators need to be supported by government and by the real estate and construction industries. Investment is needed to foster research and development in low-carbon cement technologies. 

There also needs to be a much greater focus on developing nations, particularly in sub-Saharan Africa and India, where rapid urbanization and population growth mean strong demand for building materials such as cement. Embedding good construction practices and prioritizing sustainability will allow these growing markets to embrace low-carbon technologies. This requires collaboration between international organizations, governments, and local stakeholders to support knowledge transfer and investment in sustainable cement production.

JLL advises clients across the entire property lifecycle, touching every sector across more than 4.6 billion square feet of real estate. Recognising the imperative of decarbonization, JLL advises on the best approaches to reduce embodied carbon, such as retrofits, alternative materials, and clean and renewable energy.

The JLL Foundation is a catalyst for startups and early-stage companies focused on climate mitigation, helping to reduce barriers to scaling up and fostering a collaborative ecosystem of support. The Foundation is supporting startups seeking to replace traditional cement and typical construction materials and reduce emissions in the construction sector. They include Minus Materials (Boulder, USA), Kubik (Nairobi, Kenya) and Thermulon (London, UK).