Bechtel is supporting its customers to reduce the carbon impact of projects. Some case studies from a selection of UK projects is below.
Crossrail/Elizabeth Line
Bechtel supported the Crossrail carbon model to measure, and track reduction of the overall carbon footprint through Scopes 1, 2, 3 for construction and 120 years of operation. During design, Crossrail’s carbon footprint was expected to range between 9.6 and 14.9 million tonnes. We were challenged to reduce the embodied carbon to help Crossrail’s sustainability theme of addressing climate change and energy. We worked with contractors to use the Environment Agency embodied-carbon tool to achieve further carbon reductions in the materials used. To do this the embodied carbon footprint was broken down into: embodied carbon in materials at 58%, construction site activity at 28%, tunnel boring machinery at 9%, waste removal and delivery at 5%, plus smaller sources.
Construction carbon emissions formed during the construction phase were calculated to be approximately 1.5 million tonnes which was a reduction from 1.7 million tonnes. The exercise reduced 15% on construction baseline carbon footprint the target was 8%. This was achieved by increasing cement replacement in concrete, in some cases from 50% to as much as 72%.
With regards to scope 3 emissions, we worked with contractors to ensure recycling and reuse rates were high. We achieved 95% of the construction material and 97% of the demolition material generated was reused or recycled. Our environmental advisers identified that the bulk of the excavated material could be sent to Wallasea Island (Essex) to create a wildlife habitat and wetlands reserve; additional materials could also be beneficially reused. Through careful planning at Bond Street and Tottenham Court Road, almost 128,000 tonnes of waste was removed via tunnels and rail instead of by road transport, avoiding more than 71,000 vehicle movements through busy central London streets, as well as reducing related fuel usage and carbon emissions.
Additionally, our Bechtel Sustainability Manager established a carbon working group that brought together the client, supply chain and partners organizations into a forum to identify technology options and determine project applications. Initiatives trialled and adopted on site, as a result of working group, included hybrid and fuel cell lighting, LED lighting, hybrid excavators, noise monitoring equipment, and power cube generators. Carbon reduction measures integrated during construction resulted in an 11% (Greenhouse Gases) GHG saving. For example, on one station, a more efficient 100t crane was introduced, saving 764 kg CO2/week and £22,300. Through this working group we established the Green Footprint Award, a Bechtel Environment and Sustainability Award Scheme with the purpose of ‘making best practice business as usual’ in construction execution. Introducing the award ensured best practise on the Crossrail project and led to a reduction in the amount of energy used and carbon emitted. Therefore, reducing the railways climate impact over its lifetime. Learn more.
Reading Station Area Redevelopment
Whilst working with National Rail on Reading Station, the customer identified a requirement for a value engineering exercise to be carried out to deliver cost and embodied carbon savings. The value engineer highlighted three major design changes which realized cost and carbon savings through reductions in the volume of concrete and reinforcing steel.
Some of the design changes included: concrete slabs designed out of box structures, resulting in less concrete and less piling; savings achieved were approximately £3.3 million and 2,600 tCO2e. The use of a portal frame box structure (replacing heavy fill and concrete slab), saving approximately £1.9 million and 2,900 tCO2e. Increased viaduct articulation from 15m in-situ simply supported concrete spans to 25m.
Pre–cast, pre–stressed beams, saved approximately £6 million and 8,500 tCO2e. Through collaborative working with the customer and designe, the rationalized design was technically acceptable. Value engineering achieved £12 million cost savings and 15,000 tCO2e embedded carbon reduction. Learn more.
High Speed Rail 2
On the HS2 project there is a target to achieve net zero Scope 1 and Scope 2 carbon emissions by 2025. By 2029, HS2 has a target to remove diesel on all HS2 construction sites; and by 2030 to achieve a 50% reduction in carbon emissions from concrete and steel compared with 2021.
In Bechtel's role as Development Partner, the team has set up a carbon working group which creates a space for collaboration with both internal and external stakeholders. The group’s objective is to research and integrate innovative carbon reduction ideas within Phase 2b. The working group is focused on the delivery of the targets and actions within the Phase 2b Carbon Action Plan.
The group facilitates communication and engagement between stakeholders who play a key role in HS2’s endeavour to become net zero. The findings of the working group influence the Phase 2b Carbon Action Plan which is reviewed and updated every two weeks.
Bechtel supports the target to achieve diesel free construction sites. The lead civil engineer carried out a review with a contractor on a critical scheme development to assess the impact meeting the diesel-free targets on the West Leg of the project. This review was essential for identifying next steps including a cost-benefit analysis and an exercise on capturing lessons learned from previous phases.
A Bechtel apprentice on the project supported research into low carbon concrete alternatives,. Research like this will play a pivotal part in HS2 fulfilling its net zero ambition.
Since April 2022, contractors were required to submit two opportunities for carbon reduction each month, including an assessment of potential impact. This activity led to the development of a formal Carbon and Cost Reduction Programme. Prior to this, Carbon reduction opportunities before were not specifically part of the KPI incentive programme for the contractors. The Bechtel led Phase 2b Carbon and Cost Reduction Team, drove the incentive programme with help from the commercial team to review progress, assess submissions and approve the contractor’s monthly submissions. The KPI process ensures that a consistent flow of carbon opportunities is being pursued and recorded each month to contribute towards Phase 2b’s Carbon Reduction Programme. To date, there has been many opportunities submitted and going through the process of being actualised. These provide a significant amount of carbon savings that will help HS2 reach its net zero targets. Incentivising the contractors has enabled an increase in productivity and a better attitude towards carbon. Learn more here.
London City Airport Expansion Project
The City Airport Development Programme had targets on controlling the amount of carbon the project would emit. Bechtel's team advised on and implemented carbon focused elements in the project such as directing the use of precast concrete segments for the concrete apron over the piles. This initiative promoted the use of the river Thames infrastructure for transport, reduced congestion in the compound and local roads and reduced air pollution. This mitigated 3,105 tCO2e through efficiencies in material usage, waste reduction and the carbon savings resulting from the construction of the 6000+ precast components with high proportion of cement replacement.
Another initiative Bechtel supported was transporting 29,196 tonnes of piling arising to a local ecology restoration project via barges on the river Thames. This equates to 1622 lorry journeys removed from local roads. It avoided the use of 1650 muck wagons, reduced CO2, and NOx emissions by up to 80% and reduced noise to local residents. There was a saving 103.4 tonnes of carbon emissions which led to a cost savings of £307,995.
On the airfield we advised the switch from the use of Hydrotreated Vegetable Oil (HVO) to power temporary generators, this saved the project 59 tons of CO2 (equivalent to 12 single flights to Sydney). The innovative alternative biofuel, using hydrogen rather than methanol, also reduced PM, NOx, and aroma. Learn more here.
Sellafield Pile Fuel Cladding Silo Retrieval
The Pile Fuel Cladding Silo (PFCS) is a legacy waste storage project of 6 silos with hazardous waste on the Sellafield site. The Bechtel Cavendish Nuclear solutions joint venture are working on the safe removal and long-term storage of the waste, and in August 2023 started the retrievals process.
In 2022, PFCS created a carbon management plan (CMP) and a sustainability management plan (SMP) as part of its commitments to multiple stakeholders for Net Zero 2050. This plan included calculating the project’s carbon footprint and then highlighting the risks and opportunities for where carbon saving and sustainable switches could occur. Examples of this include, embedding sustainability checks into the ITT, a sustainable construction checklist and a sustainability process in the engineering kick off meetings. From the CMP and SMP, the team created an implementation tracker, where all the carbon savings from different initiatives were recorded. To make sure everyone on the project engages with these initiatives, the team has carried out carbon literacy training with all department leads, the whole engineering team and the client’s supporting projects team. The project also has a green travel plan, green office plan, the Bechtel office has also switched to a green energy tariff. The team is assuring that carbon reduction carbon reduction is embedded across the organisation, not limited to siteworks.
Furthermore, the team is continuously working with the customer to understand their needs in the carbon and sustainability space. This includes attending monthly sustainability working groups with the client, sharing innovation with them, and presenting at their sustainability groups as an exemplar project on Sellafield site. To continuously improve our sustainability and carbon management processes, the team has a 'Learning from Experience' monthly meeting with department leads. Learn more here.
Click here to learn more about Carbon Reduction Plans in the UK.