Climate and Construction: The greening of concrete needs to move forward faster

Cement is the world’s second-most-consumed product after potable water, according to an article authored by McKinsey Global. It’s also a major contributor to global CO₂ emissions. This has to change if global emission targets are to be met.

McKinsey outlines both challenges and possible ways forward for the concrete industry to reduce its 2017-level of emissions by as much as three-quarters by 2050.

It starts by coming to grips with the industry’s high heat, fuel-intensive process called pyroprocessing that produces clinker, a key ingredient in cement, which results in high GHG emissions.

The challenge, as described by McKinsey, is this: Despite pressure from the public and financial investors to reduce GHG emissions quickly, there is no immediate economic rationale for the industry to change, outside of governmental legislation and cross border carbon tariffs.

“Some cement companies have used advanced analytics and other operational tactics to optimize for energy efficiency, while others have experimented with emissions-reducing production methods,” McKinsey says.

But those improvements, some of which have already been undertaken, might only reduce industry emissions by 20 per cent.

McKinsey believes the majority of further progress will come from what it calls “technological innovation and new growth horizons” rather than just energy efficiency improvements.

“More innovative approaches, such as new technologies and alternative building materials, will be indispensable to achieve carbon-reduction targets by 2050.”

However, many of those developments might not be scalable for years.

There is an urgent need for more work to be done now to further develop carbon capture technologies and Carbon Capture Utilization and Storage (CCUS). This is because as the decarbonization of other industries increases, there will be a decrease in the supply of popular clinker replacement materials like pulverized fuel ash (fly ash) and granulated slag.

There are several developments already underway that hold great promise, including new processes that use less limestone and therefore reduce the amount of total energy used to heat kilns.

Using the carbon captured either during the industry’s own processes or from other industry emitters is also gaining momentum around the world. McKinsey foresees future developments in carbon-cured concrete that could sequester as much as 30 per cent of the carbons created during production.

An example of what might be achieved is the engineering design study at HeidelbergCement AG’s upgraded operation in Mitchell, Indiana for the application of carbon capture technology, funded by the U.S. Department of Energy. It’s part of a $30 million DOE program to develop technologies capable of capturing at least 95 per cent of carbon dioxide emissions generated from power plants and other industrial emitters, including steel.

“On the horizon are CCUS technologies,” says McKinsey. “A number of post-combustion carbon-capture pilots are underway, driven by the large cement players. Other companies are testing oxyfuel combustion, a promising but expensive technology that results in high concentrations of CO₂ in flue gas, which in turn allows for near-total carbon capture.”

Other developments include replacing aggregates used in concrete with recycled construction and demolition waste as seen now in the United Kingdom. Another is Energetically Modified Cement (EMC), already used in Texas, which releases less carbon and requires less energy to produce. Prefabrication and increased use of BIM technology would reduce wasteful over-production.

The industry must revisit its processes, McKinsey concludes, and be prepared to make the necessary investments. This will require a change of attitude within the industry as a whole, what they term “a shift in mindset for companies that have become too comfortable with the status quo.”

“Cement makers are approaching a moment of truth,” says McKinsey.

The problem, they say, is that the industry is largely made up of local businesses. Creating changes in the industry’s perspective will therefore require advancements “micromarket by micromarket.”

“The success of such a strategy, however, depends on leaders’ abilities to achieve an organization-wide mindset change that promotes rethinking the current way of working. Leaders should therefore consider the best ways for encouraging the entire organization in their decarbonization journey.”

John Bleasby is a Coldwater, Ont.-based freelance writer. Send comments and Climate and Construction column ideas to editor@dailycommercialnews.com.