Paving the way for a net zero future

Photo by Haneen Krimly on Unsplash

Setting the foundations

It was the middle of summer as we sat on a wooden deck with friends, soaking in the sun and welcoming a refreshing breeze from the Loire.

After a long evening of beer pong and other highly intellectual activities, my friends and I tend to engage in deep conversations as we desperately fight to rehydrate our bodies.

I particularly enjoyed a conversation about individual climate action, guilt and anxiety. I remember telling my friend that we often narrow down our focus on the environmental impact of individuals, which can distract from the broader systemic climate issues.

Regarding air travel, it is true that flights make up a significant proportion of the annual carbon footprint of those fortunate enough to afford them.

However, the aviation industry is responsible for 2.4% of global CO2 emissions, whereas cement accounts for 7%. Have you ever heard someone shaming another person for cement usage?

Don’t get me wrong, I find it extremely important to limit air travel and play a role in reducing demand for flights. However, I’m convinced that individual climate shaming distracts from the need to hold companies and governments accountable for decarbonization in high-emitting sectors.

A hardened environmental criminal

The cement industry emits 2.7 billion tCO2e annually, equivalent to India’s emissions. This makes it the second-largest industrial CO2 emitter, behind iron & steel, and the third-largest industrial energy consumer.

Since 1950, demand for cement has increased 30-fold, and it is expected to be 20% higher than today by 2050 if nothing is done to optimize its use in the construction industry.

China has had high levels of production to address its rapid urbanization. However, Chinese demand is levelling off, and a growth in demand is expected from India and Africa as they develop their infrastructure.

Cement is a carbon-intensive product with a global average of 0.59 tCO2e per tonne of cement, equivalent to a roundtrip flight between London and Rome.

The manufacturing process and chemistry explain why emissions are so high, an impact which can be broken down into three steps:

1. Calcination (50% of emissions): Cement production requires limestone and clay to be heated at very high temperatures to produce clinker, a binding material. However, 40% of the weight of limestone is CO2 which is released when heated.
2. Heating (40% of emissions): Cement kilns are kept at temperatures approaching 1,400°C. Heating equipment at such temperatures is currently heavily reliant on fossil fuels.
3. Fuels (10% of emissions): The remaining emissions arise during the mining and transporting of the materials needed for production.

Once manufactured, cement is mixed with sand, gravel and water to produce the 10 billion tonnes of concrete we use yearly.

Concrete action for cement decarbonization

The emissions from the chemical reaction during calcination cannot be reduced with lower-emission fuels or increased production efficiencies. However, five decarbonization levers present themselves for the cement industry.

• Clinker alternatives: Clinker can be replaced with waste material from the steel and power industries that generate blast furnace slag and coal ash. However, these materials are not always readily available, and their supply will reduce as the sectors decarbonize.
• Fuel switching: The majority of energy from the cement industry comes from fossil fuels. Bioenergy and biomass only account for 4% of thermal energy. In a net zero future for the industry, these alternative energies would account for 14% of the mix in 2030.
• Energy efficiency: While some producers focus on optimizing the shape and intensity of flames in kilns, companies like Cemex are working to electrify the heating process and power it with renewable energy.
• Carbon capture and storage (CCS): Another solution is to deploy CCS technologies to capture CO2 emissions before they are released into the atmosphere. Due to complex technical requirements, it must be economically viable to transport, sequester or sell the carbon.
• Optimizing use: Beyond the manufacturing process, the construction and real estate industry should use concrete more efficiently, minimize material waste in projects and extend the lifetime use of buildings.

How to cement your position as a climate leader

According to the IPCC, our remaining carbon budget to limit global warming to 1.5ºC is 500 billion tonnes of CO2. In a net zero scenario, the cumulative emissions from cement throughout 2020–2050 would be no more than 41 billion tonnes of CO2.

To make this ambition a reality, cement producers should set science-based targets. These targets indicate to companies by when they should reduce their emissions and by how much to align with the goals of the Paris Agreement.

In line with the Science-Based Targets Initiative standard, companies setting net zero targets should aim to:

• Reduce their scope 1, 2 & 3 emissions by a minimum of 90% by 2050, that is, all of the greenhouse gas emissions arising in their operations and value chain.
• Ensure that unavoidable emissions are removed from the atmosphere with technologies such as Direct Air Capture and are permanently stored to ensure these gases do not leak back into the atmosphere.

Building lasting changes brick by brick

As you will have understood by now, decarbonizing cement is no simple task and will require significant collaboration between the public and private sectors:

1. Governments

• Carbon pricing mechanisms such as cap & trade can incentivize companies in high-emitting industries to reduce their emissions.
• Countries with significant oil & gas infrastructure should evaluate how to repurpose pipelines to transport captured CO2.

2. Companies

• Players in the real estate, building materials and construction industry should engage their cement suppliers with environmental requests and use their purchasing power to reward lower-carbon cement producers.
• Cement producers should plan clean energy sourcing through power purchase agreements and on-site renewable energy production in anticipation of the energy-intensive CCS technologies.

In a net zero scenario, a third of emission reductions in the cement industry will come from CCS. Alongside low-carbon clinker production, these technologies need to be commercially available at scale by 2030.

With the mountainous challenge of decarbonizing the cement industry, I believe that change can be driven by voting for politicians who understand climate science and guiding high-emitting companies on their decarbonization journey.

Nevertheless, the climate conversations and debates we have with our friends and family are one step forward in guiding people to create ripple effects of climate action. With the holiday season approaching, now could be the time to start these conversations!