job interview | Andy Powell from the Environment Agency on reducing CO2 through material selection

Leading the way on low-carbon infrastructure is key for the Environment Agency, according to its innovation manager, Andy Powell.

“The Environment Agency is an environmental champion and we encourage others to take action on climate adaptation and resilience, particularly around floods. But as infrastructure owners, we also have to set a good example,” he says.

“Our goal is to reach net-zero by 2030, which effectively equates to a 45% reduction in carbon emissions from the baseline we set, with the rest being offset. We are currently researching what the offset will look like, but it will primarily focus on planting on our own sites rather than paying an outside organization to carry out the offset.”

When the Environment Agency set the strategy, it was producing 273,000 tons of carbon each year, of which construction activities accounted for 148,000 tons.

Net Zero Commitment

Clearly, addressing the carbon associated with the construction of flood defenses had the potential to have a major impact on the Environment Agency’s ability to meet its 2030 net-zero commitment. And the vital importance of the organization leading by example has come into the focus of a number of working groups set up by the Environment Agency in recent years.

In May last year, the Environment Agency pledged to use the lowest carbon concrete possible in flood defences, a direct result of the joint work of the organization and Jacobs.

Specifically, it was about one of several “Task and Finish Groups”, which, in addition to the specific study, also concentrated on the construction site facilities and equipment; plant repair and modern construction; alternative low-carbon solutions and steel piles, each involving an external partner working with the Environment Agency. Other partners who worked alongside Jacobs in these groups included Bam Nuttall, Volker Stevin, Kier, and JBA.

“The categories come from previous work that identified them as hot spots in our carbon footprint,” explains Powell.

Low-carbon concrete saved 215 t of CO2e on the Hythe Ranges sea defense project in Kent

Powell says working with outside contractors and design partners was critical to the success of the job, as it ensured decisions were based on extensive industry knowledge and best practice.

“Essentially, we have tried to capture what is currently being used in terms of best practice and innovation in our own operations as well as those of other infrastructure customers,” he adds.

“The goal was to bring everything together to see what our technical standards and minimum technical requirements allow us to do as usual. The end game is to do low carbon business as usual.”

The task-and-finish groups began in May 2020, and after gathering the results by the end of the year, it focused on 11 innovation pilot programs across the country to turn the ideas into action.

The main point is that we use the lowest carbon content concrete to meet the performance requirements

Some pilot projects are still underway, but Powell points to the sea defense work at the Hythe Ranges in Kent, which has emitted 215 tonnes of CO22e was saved by using low-carbon concrete. Other initiatives within the program saved an additional 1,445 tons of CO2e and achieved financial savings of £2.5m. The total carbon cost of the £25m scheme was 9,576 tonnes of CO2e.

“The Concrete and Reinforcement Finishing and Working Group has been looking at concrete standards and ways to reduce the CO2 content of the concrete components and associated blockages,” explains Powell.

“We used this information to recommend an approach that could be adopted within the Environment Agency and the next phase was to put that into practice by changing our standards and creating guidance for project teams. There is a technical report but also a summary guide with a flow chart to guide teams through the thought process required to introduce low carbon concrete solutions. It helps them determine if they are taking the right approach for a given program and pushes them to consider low-carbon solutions in the early stages of a project.”

cement substitute

Much of the on-site focus is now on the use of cement substitutes using secondary cementitious materials such as granular ground blast furnace slag or pulverized fuel ash. These are used to replace 80% of the usual Portland cement content as this can be delivered within existing standards.

“It’s not particularly novel, though,” Powell admits. “That’s what we can do with relative ease now, and we’re focusing on the more novel products like cementless and soil-friendly concrete in the right applications to further reduce our reliance on traditional cement.”

The new approach is risk-based. The technical report recommends adhering to concrete standards for safety-critical applications such as flood walls and using the low-carbon solutions in low-risk, non-structural applications.

“The key point is that we use the lowest carbon concrete to meet performance requirements,” says Powell. It was this drive and focus that secured Jacobs and the Environment Agency the trophy in the Environment and Sustainability Initiative category at the British Construction Industry Awards 2021 (BCIA).

central stage

The BCIA win put work at the center, but knowledge sharing was an important part of all task and completion groups, Powell says.

“We drew on the best practices of other infrastructure customers through the project partners, and they also passed on the knowledge that we combined to their other customers,” he explains.

The understanding gained through the work will soon be shared more broadly and in a more formal way – Powell’s work with Jacobs has played a key role in the development of the ICE’s low-carbon concrete route map, to be released shortly.

The document is the work of the Low Carbon Concrete Group (LCCG) put together two years ago by the Green Construction Board in its role as the Sustainability Working Group of the Construction Leadership Council.

“The work we’ve done with the EPA so far is a transitional one, because ultimately the right solution is to change the standards,” says Powell.

According to Powell, the LCCG’s work is the pathway to changing standards across the construction sector to make it easier to specify and use low-carbon concrete.

“Concrete is a really versatile and important material, so I think we will continue to use it in the future, but its use needs to be optimized,” says Powell.

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