Supporting National Highways on the road to net zero

The UK’s National Highways is the first roads and highways owner-operator in the world to be accredited to PAS 2080, the newly updated international specification for managing infrastructure carbon. Accreditation was gained in December 2022 alongside a first annual review of progress in delivering National Highways’ Net Zero Highways 2030/2040/2050 Plan.

National Highways’ plan involves:

• By 2030, reducing its direct emissions to net zero from 82,000tCO₂e in 2020
• By 2040, reducing emissions from construction and maintenance to net zero from 734,000tCO₂e in 2020
• By 2050, reducing road user emissions to net zero from 32.9MtCO₂e in 2020

“Our core purpose is to support transport for people and the economy, by creating a well-connected country. But we also need to get to the point where our highways emit net zero carbon, have a positive impact on nature, and avoid local environmental pollution,” says Stephen Elderkin, director of environment and nature at National Highways. He says that the organisation has come a very long way since he joined in 2015, reflecting the sea change in industry, with organisations moving from aspirational target setting to implementing detailed decarbonisation route maps. “As an industry we’re recognising that if we don't get a firm grip on emissions neither civil engineering nor the highways sector has a healthy future,” he says.

Decarbonisation has strong corporate support, assisted by the “heroic efforts of passionate and dedicated people.”

This already shows. In 2021-22 National Highways cut its direct emissions by more than two thirds, from 82,000tCO₂e to 26,300tCO₂e. These impressive savings were achieved by making National Highways’ energy supplies fully renewable, switching petrol and diesel vehicles for plug in hybrids, and replacing road lighting right across the network with low energy, long-life LEDs. “This alone has been a major investment of more than £100M,” says Stephen.

Tackling construction

Our role in National Highways’ journey to net zero has been in creating a route map for reducing construction and maintenance emissions. “That started by taking stock of project-related emissions and setting a baseline for 2020,” says Alicia Winter, Mott MacDonald principal carbon consultant. The team began by collecting carbon data for product types. This revealed that materials including cement, concrete, steel and asphalt were responsible for over 40% of annual emissions.

2020 baseline carbon emissions

• Concrete and cement: 28%
• Materials transport: 25%
• Construction machinery: 22%
• Steel: 10%
• Asphalt: 9%
• Aggregates: 3%
• Other materials: 2%
• Operational energy: 1%

We then looked at legislative requirements and highways engineering specifications and standards, which revealed constraints and opportunities for decarbonisation. We also examined the technical development of materials including manufacturing and design innovations that could reduce carbon intensity in future.

While we were developing the route map, National Highways made a 2040 commitment to transport materials using net zero emission HGVs and began trialling low carbon reinforced concrete on the M42 and bio-asphalt on the A590.

Supporting suppliers

An important part of our work was integrating carbon into the project control framework (PCF), helping organisations in National Highways’ supply chain understand their role and obligations. “A new document, the Carbon Management Report, has been added to the PCF. All projects will need to complete it, detailing the carbon impacts at every stage of design and construction,” says Alicia.

We have helped create a repository of low carbon design and delivery options called the Low Carbon Opportunities Register “Every project is required to demonstrate it has considered appropriate opportunities,” says Stephen.

Our core purpose is to support transport for people and the economy, by creating a well-connected country. But we also need to get to the point where our highways emit net zero carbon, have a positive impact on nature, and avoid local environmental pollution.

Stephen Elderkin

director of environment and nature at National Highways

PAS 2080 cascade

Having gained PAS 2080 accreditation itself, National Highways expects its suppliers to follow suit. “It’s time for our tier one contractors and material manufacturers to get accredited too,” says Stephen. They have three years to do it – by the end of 2025.

Meanwhile the priorities for National Highways in 2023 include strengthening procurement, with clear and effective means to assess carbon in tender evaluation and incentivise emission reductions.

A world first

National Highways is the first roads organisation in the world to be PAS 2080 accredited. “Mott MacDonald have supported us in coming from a relatively low base to being industry leading,” says Stephen.

National Highways organised its decarbonisation programme into six contracts. Contract three was delivered by us working directly for National Highways. We delivered contracts four, five and six in partnership with consultant WSP, and contributed to contracts one and two.

1 – Implement PAS 2080

• ​Gather evidence and conduct gap analysis against PAS 2080 clauses. Develop systems to estimate carbon emissions, identify reduction opportunities and record progress against targets.
• Prepare for PAS 2080 audit, including staff training.

2 – Develop National Highways’ approach to estimating whole life carbon emissions

• Work with National Highways’ cost estimating team to establish the viability of integrating carbon assessments into a new cost estimating tool.
• Report on how carbon estimates should be built and integrated into the carbon management process.

3 – Develop a carbon management reporting process

• Consistently estimate emissions and measure carbon reductions throughout the project lifecycle.
• Create report template that walks users through the steps to be completed at each stage, creating a comprehensive record of the estimated whole life GHG emissions at each PCF stage.

4 – Develop a low carbon opportunities register

• Create a central repository of low carbon design and delivery options.
• Embed this into the new carbon management processes.

5 – Develop net zero roadmaps for concrete, steel and asphalt

• Align new route maps with European standard for sustainable construction, BS EN 15804.
• Investigate the technical feasibility of decarbonisation technologies and products, and the practicality of incorporating them into designs.

6 – Develop National Highways’ low carbon construction innovation programme

• Identify interdependencies and scope for innovation and collaboration to remove blockers and unlock enables of decarbonisation.
• Develop a process for innovation management capable of immediate application.