One year after launching an industry-leading embodied carbon target, British Land’s development pipeline is ahead of schedule – with embodied carbon already over a third lower than the industry standard.
Juliette Morgan, Head of Sustainable Development, joins colleagues from across the business to look at how this has been achieved, lessons for other projects and the challenges that lie ahead.
Marginal gains and big leaps
Juliette: To support global efforts to keep warming below 1.5°C, our 2030 target for embodied carbon (all the emissions generated to produce a building) is 500kg CO2e per sqm – half the 2020 industry average and confirmed as ambitious by the Science Based Targets initiative. If we were progressing incrementally, our target this year would have been 950kg. Instead, we’ve reached 640kg across our portfolio on average; so, we’re ahead of schedule.
That doesn’t mean we’re complacent or that further reducing to 500kg will be easy. Most carbon is saved at the design stage and 2030 buildings are being designed today, which is why we have urgency now. We’re also currently delivering several major refurbs, which have lower embodied carbon than new builds. As more new builds come on stream, such as Canada Water, embodied carbon is likely to go up. So, we’ll need to push the boundaries on every project to achieve our portfolio target.
What’s needed is a landscape of incremental improvements and huge innovations in materials and supply chain – marginal gains and big leaps. In his book ‘How to Avoid a Climate Disaster’, Bill Gates highlights that steel and cement account for roughly 10% of all global emissions. That’s massive. How are we, as an industry, going to make structures dramatically lower in embodied carbon, at scale?
Embracing new ideas
Juliette: As an industry, we need to be more willing to refurbish first to retain carbon and gain circular economy savings – committing, collaborating and sharing learnings. British Land has signed up to Architects’ Journal’s RetroFirst pledge and we now make investment decisions against this refurbish first policy. Then, in the design and commissioning stages, we embrace innovation and new ideas.
What everyone will see on projects for the next few years will often be the legacy of decisions taken five years ago. British Land is benefiting from years of stewardship, but many of our current projects predate our ambitious 2030 targets. So, we’ve spent a lot of time on gap analysis and seeing where we still have opportunities to reduce embodied carbon, in some cases saving over 100kg of CO2e per sqm in later design stages.
Our industry-leading Transition Vehicle includes a mechanism to invest in research and development with partners, so we can advance our own projects and the industry where we see impact. We’re already switching to Earth Friendly Concrete with cement replacement (GGBS), using recycled steel and investigating steel created with electrolysis as opposed to blast furnacing. We’re also working with project teams, planners, insurers and legislators to advance timber and lighter structures. And we’re considering the de-constructability of our buildings so that, in 60 years, we can dismantle and re-use them. But it’s not enough to recycle in 60 years’ time, so we’re working with global chains in demolition and deconstruction to recycle as much material as possible in its highest value state, to preserve resources now and in the future. We’ve saved hundreds of tonnes of CO2e this way.
Significantly, the progress we’ve seen this year isn’t the result of actions by one small team, but activities right the way through our business and supply chain – people finding carbon savings on every project. From beginning to end, this is what we do, as shown by these insights from colleagues who are driving change across our portfolio.
100 Liverpool Street – halving embodied carbon at scale
Gareth Roberts: The biggest impact on embodied carbon at 100 Liverpool Street came from retaining 50% of the existing structure. Here, sustainability went hand in hand with the commercial case. Looking at the four project fundamentals – cost, programme, value and risk – retaining the structure benefited all these, while dramatically cutting embodied carbon.
Charlie Horne: Our structural engineers, AKT II, used as-built information to establish that the existing foundations had the capacity to take an additional three floors. Sir Robert McAlpine and our supply chain partners also made huge efforts to cut embodied carbon where new materials were required. This included using recycled steel and concrete that has cement replacement (GGBS).
Find out more in our recent blog here.
1 Triton Square – pioneering a circular façade
Tim Downes: Once we identified that the existing frame at 1 Triton Square had capacity to take additional floors, our first port of call became a refurbishment, which immediately meant massive carbon savings. We then sought to re-use other parts of the building that would usually be replaced after a 20-year lease.
We worked closely with contractor Lend Lease to dismantle, refurbish and re-use the façade, saving extra carbon. Initially, we planned to return the façade to Germany, where it was manufactured, but we saved even more carbon and supported UK jobs by creating a pop up factory here. This was the first time we’d followed circular economy principles on a façade and we’re now taking learnings onto other projects.
Find out more in Arup’s blog here.
Norton Folgate – where old meets new
Matt Secker: Norton Folgate is another project where retaining existing structures and façades has significantly reduced embodied carbon. It also keeps authenticity and creates a characterful space for customers and the local area.
Where we are building new, we’re working with our supply chain to increase the use of low carbon materials, such as 40% cement replacement (GGBS) in concrete mixes and we’re keeping waste as low as possible. We tried to introduce Cross Laminated Timber but there were technical challenges that the industry needs to solve.
Operationally, Norton Folgate will be one of British Land’s first all-electric office developments. It’s unusual for a scheme this size not to use gas heating, but as part of our net zero strategy we’re moving away from reliance on fossil fuels and working towards 100% electricity from renewable sources.
1 Broadgate – an urban garden
Gareth: At 1 Broadgate, embodied carbon falls below the industry benchmark but above some of our other projects, due to site specific considerations and structural decisions made years ago. There’s over an acre of terraces, which is great for occupier wellbeing, but it also means big beams, which add carbon. In addition, the retail and leisure floors need a big grid for flexibility. Long term, this adaptability will extend the building’s lifespan (avoiding future emissions), but it impacts embodied carbon now.
Charlie: We are making huge carbon savings on materials, achieving an estimated 13% reduction over the last year; and we hope to get this down even further. We’re using high recycled content steel wherever possible and maximising use of concrete that has cement replacement (GGBS). Where we can get embodied carbon down, we will.
Gareth: Operationally, 1 Broadgate will be highly efficient, targeting a 5.5 star NABERS UK rating. As soon as net zero was on the horizon, we engaged with occupiers and revisited the services strategy to introduce more air source heat pumps. There’s mixed mode ventilation too, so people working in the building will be able to open windows, cutting operational carbon and promoting wellbeing. This will be a truly productive workplace.
5 Kingdom Street – a mixed use oasis
Tim: We recently secured planning consent for 5 Kingdom Street. This is a cleared site, so there’s no opportunity to refurbish and re-use an existing building. However, we have managed to find embodied carbon savings before even putting a spade in the ground, by maximising the benefit from Crossrail groundworks. With significant structural work to safeguard tunnels below Paddington Central, our engineering partners tested thoroughly to make sure we only add what’s needed.
To cut embodied carbon in the superstructure, we’re learning from innovations in materials and design on other British Land projects. We’ve introduced pre-made openings into the concrete floor slab, which we’re infilling with Cross Laminated Timber. This will add flexibility, allowing occupiers to easily add staircases, and cut embodied carbon, so we don’t use any more concrete than essential.
Read a blog on Cross Laminated Timber here.
Canada Water – sustainable urban regeneration
Phil Tait: Embodied carbon is part of a much broader picture at Canada Water, where we’re innovating with partners to create one of the most sustainable urban regeneration schemes in the UK. With few existing structures to recycle, most buildings are constructed from scratch, which adds challenges for embodied carbon. We looked long and hard at timber structures for several of the first buildings – making great headway in de-risking design from the perspective of building regulations, fire brigade and construction insurance; and making the impacts of timber on area and costs work. However, the risk of not being able to obtain property insurance proved too great. This is an issue for the industry.
As a result, we’re now looking closely at cement free/low carbon concrete, which may end up having lower carbon than some hybrid construction techniques with concrete and timber. We’ve already used Earth Friendly Concrete for the piles in one building, saving 240 tonnes of carbon.
Hannah Farahar: As well as low carbon materials, we’re looking at efficient, lean design and intelligent use of emerging technologies. This involves rethinking the traditional relationship between architectural form and performance function, as well as greater use of prefabrication to eliminate superfluous materials. We’re engaging main contractors earlier than usual too, so together we can apply their expertise to minimise carbon at the design stage. Operationally, we will use NABERS UK modelling to optimise efficiency and BRE has already awarded the project credits for innovation. For example, our first two buildings will capture and re-use heat from the office cooling systems, which would otherwise be wasted. Our partners have really bought into our net zero goal, which is driving a mindset shift across the whole consultant team.
Looking forward to consistency
Karina Williams: What we’ve seen across the portfolio is that reporting on embodied carbon triggered positive competition among project teams. Colleagues immediately began investigating why some structures perform differently in carbon terms, and this promoted cross-project collaboration to increase knowledge sharing and improve performance. It became clear that, though you should be able to compare two office buildings like for like, it’s not always that simple.
We already align to the RICS framework for whole life carbon, which helps drive consistency. However, it doesn’t provide measurements for every element, such as mechanical and electrical services, and the metrics consultants use can vary substantially. Plus, there are a range of tools and models, making comparison even harder.
We’re therefore rolling out One Click LCA lifecycle assessment software on all our projects to bring data together so, together with our consultants, we can benchmark performance. We’re also introducing consistent metrics at early stages for elements such as building systems, where there may not be much detail available.
We look forward to further progress across the industry to standardise carbon measurements, enabling benchmarking. In the meantime, we’ll continue driving consistency wherever we can. And we’ll feed everything we learn into our Sustainability Brief and the wider industry to continue improving performance.
After driving the embodied carbon as low as possible, British Land offsets through certified, nature-based solutions. More here