Taking the lead on low-carbon infrastructure is key for the Environment Agency, says its chief innovation officer, Andy Powell.

“The Environment Agency is a champion of the environment and we encourage others to take action on climate adaptation and resilience, particularly in the event of flooding. But as an owner of infrastructure, we also have to lead by example,” he said.

“Our goal is to be net zero by 2030, which is effectively a 45% reduction in carbon emissions from the baseline we’ve set, with the rest offset. We’re currently carrying out research into what the offset will look like, but it will be primarily focused on planting on our own sites, rather than paying an external organization to undertake the offset.”

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

Net zero commitment

Tackling the carbon linked to building flood defenses clearly had the potential to have a big impact on the Environment Agency’s ability to meet its 2030 net zero commitment. And the crucial organization’s example has been in the spotlight of a number of working groups set up by the Environment Agency over the past few years.

In May last year, the Environment Agency pledged to use low-carbon concrete as much as possible in flood defenses – a direct result of work carried out jointly by the organization and Jacobs.

The concrete focus was on one of the many “task and finish groups” which, in addition to the concrete study, concentrated on the installation and equipment of the site; asset repair and modern construction methods; low-carbon alternatives and steel piles, each involving an external partner working with the Environment Agency. In addition to Jacobs, other partners working in these bands included Bam Nuttall, Volker Stevin, Kier and JBA.

“The categories were taken from previous work that identified them as hotspots in our carbon footprint,” says Powell.

Low carbon concrete saved 215tCO2e on the Hythe Ranges sea defense project in Kent

Powell says having external contractors and design partners was critical to the success of the work as it ensured decisions were based on broad industry knowledge and best practices.

“Essentially, we were trying to capture what’s out there right now in terms of best practices and innovation within our own businesses, as well as those used by other infrastructure customers,” he adds. .

“The goal was to pull it all together to figure out what we could do as if nothing were wrong with our engineering standards and our minimum technical requirements. The end game is to do low-carbon business like usually.

Working and finishing groups began in May 2020, and with results collated at the end of that year, the focus shifted to 11 pilot innovation programs across the country to put ideas into action.

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

Some pilots are still in progress, but Powell points out that the Hythe Ranges sea defenses are operating in Kent where 215 tCO2e was saved by using low-carbon concrete. Other program initiatives saved an additional 1,445 tCO2and achieved financial savings of £2.5 million. The total carbon cost of the £25m program was 9,576 tCO2e.

“The Concrete and Reinforcement Finishing and Working Group looked at concrete standards and the carbon reduction opportunities of the building blocks of concrete, and the blockers around that,” Powell says.

“We used this information to recommend an approach that could be taken within the Environment Agency and the next phase was to put it into practice by changing our standards and creating guidance for project teams. There is a technical report but also a summary guide with an organization chart to guide the teams in the reflection necessary for the adoption of low-carbon concrete solutions. This helps them determine if they are taking the right approach for a specific program and pushes them to consider low-carbon solutions in the early stages of a project. »

Cement substitutes

Much of the focus on the site 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 ordinary Portland cement content, as this can be delivered within existing standards.

“It’s not particularly new though,” admits Powell. “We can do this relatively easily now and we are focusing our efforts on the most innovative products such as Cem-Free and Earth Friendly Concrete in the right applications to further reduce reliance on conventional cement.”

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

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

center stage

BCIA’s win put work center stage, but knowledge sharing was a key part of all task and finish groups, Powell says.

“We learned from the best practices of other infrastructure customers through the project partners and they passed on the knowledge we shared to their other customers as well,” he explains.

The understanding gained from the work will soon be shared more widely and more formally – Powell’s work with Jacobs was instrumental in the development of ICE’s low-carbon concrete roadmap, which should be published soon.

The document is the work of the Low Carbon Concrete Group (LCCG), which was brought together by the Green Construction Board in its role as the Construction Leadership Council’s sustainability task force two years ago.

“The work we’ve done so far with the Environment Agency is an interim situation because ultimately the appropriate solution is to change the standards,” Powell says.

According to Powell, the work of the LCCG is the pathway to changing standards in the construction industry to make it easier to specify and use low-carbon concrete.

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

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