An initiative to manage carbon on a major infrastructure project has resulted in an upfront emission reduction of more than 35%.
When consultant Sweco was appointed as engineer and designer for the infrastructure development of Renfrewshire Council’s £130M City Deal, it decided to seize the initiative to apply the PAS 2080 standard to its work.
The British Standard Institute’s “PAS 2080 – Carbon Management in Infrastructure” specification was developed following the Treasury’s Infrastructure Carbon Review in 2013. It aims to encourage collaborative working to manage and reduce carbon in the infrastructure sector.
Worst carbon emitter
To date, transport has been among the worst carbon emitters. But as the number of electric vehicles on the roads increases, reducing transport’s carbon footprint, the relative proportion of emissions caused by construction and operations in the infrastructure sector will increase.
One recommendation of the review was that there should be a systematic way to lower carbon in infrastructure, and this became PAS 2080.
Renfrewshire Council’s City Deal has two elements: the Glasgow Airport Investment Area, including the realignment of Abbotsinch Road and a new bridge across the White Cart Water; and the Clyde Waterfront and Renfrew Riverside, which includes a new opening road bridge across the River Clyde and the Renfrew North Development Road. The two areas are geographically connected.
When Sweco was bidding for the work, it was asked to put a price on the sustainability it could achieve and explain its approach.
“We decided to frame this approach around the United Nations Sustainable Development Goals (SDGs) and apply these through PAS 2080,” says Sweco UK technical director Lewis Barlow.
The approach identified which SDGs would be tackled, either indirectly through the project being built, for example through regeneration, as well as directly meeting the climate action SDG in terms of the whole-life carbon on the project.
“We said: ‘There’s a new standard and this will be ideal for this project to make sure that we’re really reducing carbon all the way through it.’ We explained that to the client and it hadn’t heard of these things before, but it understood the value,” says Barlow.
You can reduce most cost and carbon at the earliest stage of the project
During the tender process Barlow provided backed-up information on carbon reduction to give the client the knowledge that the project would be delivered in the most carbon-efficient way, using cutting-edge methodology.
Sweco also focused on designing the project to be resilient to future climate change, for example looking at Environment Agency and Met Office predictions.
So, with the client on board, what did Sweco do to fulfil its pledge on carbon reduction, and eventually win the NCE100 Low Carbon Leader Award as a result?
Lifecycle carbon reduction
Applying the standard to the scheme meant reducing carbon throughout its lifecycle: from the design and construction process to operations, and ultimately by cutting end user emissions.
“We have cut carbon from the outline design baseline by 35%. You can reduce most cost and carbon at the earliest stage of the project,” says Barlow.
Carrying out a detailed carbon accounting process during the specimen design stage and sharing this feedback across all design teams ensured a focus on carbon reduction.
The team used a detailed traffic modelling output analysis, which had information such as estimated type of vehicle, speed and distance of travel. Taking the Department for the Environment, Food and Rural Affairs’ spreadsheet-based Emissions Factors Toolkit, Sweco translated traffic data into carbon emissions at various life stages of the project.
We have cut carbon from the outline design baseline by 35%
For example, it took traffic modelling data from the new bridge across the River Clyde and translated it to carbon data to demonstrate the immediate improvements the scheme would bring in terms of air quality, emission reduction and congestion mitigation.
“We wouldn’t have known that if the client hadn’t wanted us to have a spotlight on carbon,” says Barlow.
For the construction phase, carbon reduction by the supply chain started with the procurement process. However, there was no precedent for measuring carbon reduction this way.
Through research, the Sweco team adapted the prequalification questionnaire to include a section which looked specifically at contractors’ understanding of carbon reduction in infrastructure and their understanding of PAS 2080. This was given a 5% weighting during the tender assessment.
20% carbon baseline cut
At the tender stage bidders were asked to cut up to 20% of the carbon from the project’s carbon baseline which Sweco worked out was around 10,000t. It developed a methodology for demonstrating carbon reduction, by drawing on what the team saw as the best bits of the carbon management models across the UK.
“If we just said to contractors, ‘go away and reduce carbon by 20%’ they could do all sorts of things and we would have to spend half our time working out if they were right or not,” says Barlow. “I think this is the first time it has been spelt out to contractors [how it should be achieved].”
The 20% figure aims to push contractors to reduce carbon, without pushing them to cut costs so far that the quality of the scheme was impacted, as there is a strong relationship between carbon and cost. Bidders have to demonstrate how they have already used the tools they are proposing for carbon management. The bidders’ carbon score will be based on how far they can achieve that target – for example looking at how they can alter the bill of quantities, or the design, or by using recycled materials or reducing waste. This is currently still in the procurement process.
Barlow is now awaiting the “acid test” of carbon reduction projections in final tenders from contractors, but he is optimistic about the supply chain’s ability to step up to the bar.
A contractor is expected to be appointed at the end of 2018, with construction beginning in January 2019 and completion in 2020.
Now the work is bearing fruit, Sweco is keen to share its learning with the industry. It is particularly keen for clients to follow Renfrewshire Council’s lead in carbon reduction.
“We can’t wait two years for people to slowly get their heads around PAS 2080. The standard is best applicable to large projects and they take years, but we don’t have years,” says Barlow.