Gonna need a roadmap for all that concrete

In the age of Google, road maps are pretty much obsolete. So it's fitting that the concrete industry is so big on road maps. While it is not obsolete, it is facing an existential carbon crisis, with the industry responsible for roughly 8% of worldwide emissions of carbon dioxide (CO2).

Treehugger recently wrote about the American Portland Cement Association's (PCA) road map. Now the Global Cement and Concrete Association (GCCA) has released its version. The GCCA is international and represents close to 50% of the world's cement production capacity, and is run out of London. In advance of the United Nation's COP26 in Glasgow, Scotland, the GCCA isn't pulling punches about hitting tough targets:

"Our roadmap sets out a net-zero pathway to help limit global warming to 1.5OC. The sector is committed to producing net-zero concrete by 2050 and is committed to acting now."

The approach taken by the GCCA is pretty much the same as that taken by the American industry, in a much prettier package with better graphs that are much easier to understand. Unlike the PCA, it is also going after intermediate targets for 2030:

"The industry has already made progress with proportionate reductions of CO2 emissions in cement production of 20% over the last three decades. This roadmap highlights a significant acceleration of decarbonisation measures achieving the same reduction in only a decade. It outlines a proportionate reduction in CO2 emissions of 25% associated with concrete by 2030 from today (2020) as a key milestone on the way to achieving full decarbonization by the mid-century. The roadmap actions between now and 2030 will prevent almost 5 billion tonnes of CO2 emissions from entering the atmosphere compared to a business-as-usual scenario."

It's actually all laid out in this one chart, with savings in clinker production, meaning mainly the heat required by the chemistry of cement manufacture. besides thermal efficiency, they will use "alternative fuels" like waste materials, some of which are problematic.

"Alternative fuels are derived from non-primary materials i.e. waste or by-products and can be biomass, fossil or mixed (fossil and biomass) alternative fuels. There are current examples of cement kilns operating with 100% alternative fuels which demonstrates the potential of this lever."

The GCCA is a bit more upfront about the elephant in the room: what the PCA called the "Chemical Fact of Life," or in other words, the CO2 emitted in calcination or turning calcium carbonate into calcium oxide. That's the big purple square, 36% of emissions, 1,370 metric megatons in 2050 to be dealt with through carbon capture and utilization/storage (CCUS). The GCCA doesn't try to sweep it under the rug.

"CCUS is a cornerstone of the net zero carbon roadmap for cement and concrete. The technology has been shown to work and is close to maturity but an industry-wide roll out of CCUS will require close cooperation between the industry, policymakers and the investment community. While the technology is advancing, the economics remain challenging. The development of a ‘carbon economy’ is therefore an essential step in the move from a number of successful pilots across the world to widespread and commercial scale deployment."

The GCCA shows all the CCUS projects happening now, with a lot more action in Europe than in North America. It is not clear if they all work, or how much CO2 is actually being stored. As they say, it is early in this game.

But here it is, a plan for serious reductions in carbon emissions from almost every step of the process. The green wedge at the top is the savings from "Efficiency in Design and Construction":

"Designers of buildings, with support of clients, can achieve CO2 emission reductions through their choice of concrete floor slab geometry and system, choice of concrete column spacing and optimisation of concrete strength/element size/reinforcement percentage. This can be achieved whilst still obtaining all the performance benefits of concrete construction. Infrastructure projects offer analogous opportunities. Across all projects globally, the CO2 emissions reductions achievable through design and construction levers is forecast as 7% and 22% in 2030 and 2050 respectively."

This is where it seems like wishful thinking. Can good design really deliver 22% savings? That kind of low-hanging fruit would have been grabbed already.

Being the GCCA, it does not suggest we use less of the stuff. In fact, it predicts that its use will grow from 14 billion cubic meters per year today to 20 billion cubic meters in 2050. The GCCA doesn't tell us where in the world we will find enough limestone, sand, and aggregate to make that much concrete.

The GCCA is really good at this. It talks about how cement and concrete align with the U.N.'s sustainable development goals and will save the world. It states: "Durable and cost-effective buildings and infrastructure are central to the transformation of communities out of poverty, providing education at all levels and combatting food waste" and how "transport infrastructure made with concrete provides market access for local food producers, promotes access to education and creates economic opportunities and well-being."

But it also claims that "the unique reflective properties and thermal mass of concrete contribute to the energy efficiency for our built environment" which is questionable. And "the cement and concrete industry is at the heart of the circular economy, using by-products from other industries as raw material or fuel, and by providing a product that can be repurposed or recycled," which is almost laughable.

Like the PCA, the GCCA has done a serious amount of work to address the issue of getting to net-zero by 2050. Is it plausible or realistic? Or should we just look at alternatives that have it easier? After all, timber is renewable. The steel industry has figured out new chemistry, as has the aluminum industry. The concrete industry has to chip away at every step of its process and still can't get there without vast amounts of CCUS.

There is just no way around the fact that in the end, we have to just use less of the stuff, fewer new highways and parking garages, fewer new buildings when we can fix old ones. Twenty billion cubic meters of net-zero concrete in 2050? It's just beyond my comprehension.

View Article Sources

"Making Concrete Change: Innovation in Low-carbon Cement and Concrete." Chatham House, 2018.

Lloyd Alter

Global Concrete Industry Releases Road Map to Net-Zero Carbon