Investing in infrastructure is vital, but it cannot come at the cost of increasing our net carbon emissions. With net zero targets enshrined in legislation, it’s no longer a peripheral goal, but fundamental to all major infrastructure.
The Lower Thames Crossing (LTC) is acting as a Pathfinder project - pioneering a new era of major project delivery with significantly reduced carbon - not just through low-carbon materials or efficient design, but through a wholelife collaborative approach that embeds carbon reduction across the project and throughout the supply chain.
LTC has three sections: Roads North, Roads South, and the Tunnel itself. A Balfour Beatty led Enterprise (with AtkinsRéalis as Designer) has been awarded the contract for Roads North - but this is not just a design-and-build. This is a pathfinder project leading the way on carbon reduction and management. Our role is to design and build with the lowest carbon cost practicably possible: by reducing carbon in design, in how we build it, and in what we build it with. Yet Roads North presents an unusually significant infrastructure challenge, regardless of carbon, featuring 32 major structures in just 10 miles - far more than your average stretch of road. National Highways LTC estimated that Roads North would contribute almost 600,000 tonnes (600kt) of CO2 equivalent emissions - our goal was to quarter that figure from the outset and then aim to halve it, while balancing cost-time-quality and safety.
Given the size and scale of the challenge, no single solution is enough. Using low-carbon materials or switching to renewable energy sources alone won’t cut it. To make carbon reductions at scale across the project means rethinking traditional approaches from the outset. It means collaborating with the client, the three main works teams and the supply chain, to demonstrably remove carbon. And it means continuously searching for improvements, and empowering staff to do so.
It’s not possible to make significant reductions without understanding carbon holistically across design, process, plant, material, and construction. That’s why we began with ‘What Needs to be True’: elements which must be in place by others in order for us to reduce carbon on the ground. So if we’re going to electrify plant, for example, we will need a good Distribution Network Operator electrical connection to the works coalface and compounds. If we’re to use hydrogen fuel, we will need someone to bulk buy and deliver hydrogen to LTC and we will need to create a ‘last mile’ solution to the works coalface. Without an integrated understanding of carbon reduction, we risk emitting carbon elsewhere, falling short of our aims, or of simply being unable to enact our plans.
For example, low carbon materials will be crucial, and there are already many proven alternatives to traditional materials. However, unless we can obtain such materials in sufficient quantities, they won’t be viable for a project of this magnitude. Which providers (if any) are capable of producing that quantity in the timescales required, and if none, we must collectively (client and main works teams) stimulate the market to provide? We must also understand where it’s coming from: if our low carbon materials are imported from overseas, for instance, potential carbon saving may be negated by the emissions from their journey to the UK.
While there are no ‘one-size-fits-all’ solutions, we can begin to define common protocols across the project. These can be enforced from the start through procurement models, ensuring that all suppliers - no matter size or role - are held accountable (and rewarded) for their role in reducing emissions.
Suppliers must be clear that, if they want the contract, they will be held accountable for carbon - taking responsibility for outcomes, and having these behaviours enforced through contracts. Clear protocols can ensure that, when we are forced to look further afield, we can do so without compromising on our principles and processes. A supplier providing recycled steel from Germany can still be eligible for the project, but only if, for example, they deliver the steel without resorting to road haulage.
If we’re serious about Whole Life Carbon Management, we have to manage all the steps: from the raw material to the semi-produced material to the final material, from its transport to site to its use on site, through to its maintenance and eventual disposal. Anything less is not good enough. LTC Roads North doesn’t begin construction until 2026, so we have time to challenge standards - and in turn this can move our whole industry forward.
In our low carbon route map, we’ve focused on four carbon reduction priority areas: Design, Plant, Steel, Concrete. Approaching these together allows us to enrich each one with insights from the others. For example, reducing carbon in concrete may also yield design efficiencies that would otherwise be forfeited. Similarly, transitioning to fully electric or hydrogen plant reduces emissions markedly but may be significantly more challenging, perhaps demanding a complete redesign of the plant itself, a re-training of operators, and new site operating procedures and possibly redesign. From safety to energy usage, the benefits can be extensive.
By placing carbon reduction at the forefront of the design, traditional structures like viaducts and gantries, for example, can be designed to use materials more efficiently, or to substitute low-carbon alternatives. While designing out carbon is important, so too is using materials in such a way that their construction or assembly is low carbon, too. For example, by establishing a temporary bridge to allow an alternative haul route, we could significantly reduce the on road movements of construction workers and their vehicles.
At the starting point, National Highways LTC estimated a carbon output of almost 600 kilotonnes for Roads North. Now, our route map strategy shows it could be around 275 kilotonnes. While this is prospective, and not finalised (it’s a ‘what’ could be done, not a detailed ‘how and when’), we are continuing to seek significant reductions. LTC is managed following PAS 2080 (2023), which stipulates that carbon reductions must be continuous, not one-offs. All four sprint areas (design, plant, steel, concrete) have contributed to that continuing reduction, and we’re not done yet. Inevitably some of these ideas will fall away (some may be mutually exclusive), but they demonstrate the possibility of significantly reducing carbon for necessary major infrastructure projects.
While LTC has contractualised carbon reduction approaches to all main works contractors, we have then developed procurement and supply chain strategies to ensure that Roads North goes above and beyond existing standards. The procurement contracts specify that carbon must be treated at least equally to other considerations, using a ‘5 pillars’ decision-making process, moving from the usual triangle of quality-cost-time to a square of quality-cost-time-carbon, with safety underpinning them all - and no decision without due consideration to all.
For LTC to be a trailblazing pathfinder project, we must encourage ambitious thinking. Sustainability and innovation must be embedded throughout the workforce as mandatory, in the same way that safety is supported by all across site. This means empowering all suppliers, larger and small, to contribute to sustainable innovations and ways of working. Our procurement strategies have begun to enmesh this through supply chain engagement.
Our integrated design team meets local suppliers as one, presenting a united voice and building confidence in the route to carbon reduction. We host monthly carbon reduction workshops with other main contractors, and quarterly with the whole supply chain under Chatham House rules. AtkinsRéalis and Balfour Beatty are civil engineering behemoths; but innovation demands people with different mindsets and diverse backgrounds, and smaller, nimbler organisations can inject new ideas to break into new areas of low carbon solutions.
Ultimately, our transition to a low-carbon economy cannot depend on a small number of specialists. Sustainability must become everyone’s responsibility in a similar way to safety.
LTC is not about R&D but about ramping up solutions into delivery mode, kickstarting the market, levelling up the supply chain, and establishing a new benchmark for major highways projects hereafter.
LTC is pushing innovators, suppliers, and pioneers to act faster. Through higher expectations, exceeding standards and large orders, LTC is driving the market so that the solutions required will be readily available at scale to achieve our ambitions. Even with all this investment, collaboration, and willpower, LTC will undoubtedly be one of the most challenging infrastructure projects of our time. Yet by establishing better ways of working, by enshrining sustainable standards, and by rolling out collaborative procedures, LTC will be more than just a bridge - it can be a beacon, illuminating the way towards a sustainable future for major infrastructure delivery.
