This week, Costain announced that it has been trialling a carbon tracker, developed to collect carbon emission data from its supply chain. So far, it has trialled the new tracker on several road, water and integrated transport projects and aims to roll it out to other projects in the coming months.
Supply chain emissions, known as Scope 3 emissions, account for the biggest piece of the carbon pie for construction projects. Scope 1 emissions, which cover sources owned or controlled by a company and Scope 2 emissions which come from purchased energy, are far more straightforward to measure and reduce.
Costain’s latest carbon report, published in September 2023, said that Scope 3 emissions accounted for 73% of its total emissions. That’s because Scope 3 includes all the embodied carbon due to the manufacture of raw materials, with concrete, steel and asphalt being big contributors.
Most tier 1 contractors have already cut the low-hanging fruit of carbon emissions, for instance switching the fuel in their company car fleets and moving to renewable energy tariffs for their offices. Now they must turn their attention to the many smaller companies in their supply chain.
Some supply chain members are already collecting the data that will be needed for their own purposes. Thermal Road Repairs, for instance, gained PAS 2080 accreditation for its carbon management system which covers Scope 1, 2 and 3 emissions in February 2024.
One of the first hurdles for Costain, and for any company looking to reduce carbon emissions, was to work out what its current – or baseline – emissions were. It is not uncommon for companies to report that their emissions are rising in the first few years, even with carbon reduction measures in place, simply because they are getting better at collecting the right data.
Costain set itself some pretty ambitious carbon reduction targets back in 2020, which included achieving net zero carbon – including Scope 3 – by 2035. Its initial plan was to use 2020 figures as a baseline; however in 2023 it said that it was going to now use 2021 figures as its baseline, since the Covid pandemic meant that 2020 had been untypically low in terms of emissions.
There may have been some other tweaks too: its 2020 ‘Climate Change Action Plan’ can no longer be found on its website, so we can’t check. However, Costain does state that its re-baselining activity was independently and externally verified through the Achilles’ Carbon Reduce Scheme.
Comparing 2022 with 2021, Costain has cut its Scope 1 and Scope 2 emissions, but Scope 3 emissions have increased. That could be because Costain and its supply chain got better at measuring them and because it delivered more work in 2022, and hence used more concrete, steel, asphalt and other materials.
Companies sometimes express carbon emissions as carbon intensity: carbon emissions per unit of output or activity. Expressing carbon emissions per turnover, Costain says that its total emissions dropped by 10% between 2022 and 2021 against the baseline. It has not yet reported on its 2023 emissions.
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