How GLP Delivered the World’s First Net Zero Embodied Carbon Building

As record-breaking heatwaves continue to sweep across Europe, and investors become increasingly sensitive to the environmental, social and governance (ESG) impacts of their investments, a growing portion of the commercial real estate sector is shifting the way it approaches the development and operation of properties both new and old.

The opportunity for the environment is significant: the construction sector is responsible for 40% of global carbon dioxide emissions.

That’s why logistics investor, developer and asset and fund manager GLP decided to set a new standard for the logistics industry by building what it claims is the world’s first net zero embodied carbon building: the 314,123-square-foot Magnitude 314 distribution centre in Milton Keynes. Completed in 2020, GLP says the Magnitude 314 project served as a test bed to help define the process of delivering a “net zero carbon” building.

“We wanted to push it as close to net zero as we could, to reduce our carbon as much as possible,” said Steven Alexander, U.K. construction director for GLP Europe, in a conversation with LoopNet. “And as we got further down, we realised, ‘we can go all the way on this.’”

“There's a real race to net zero in the distribution sector,” said Philippa Birch-Wood, director of the Thrive programme at Chetwoods Architects, who designed and delivered Magnitude 314 for GLP, as well as acting as "sustainability champion" for the project by ensuring that all parties involved adhered to the guidelines for net zero. “It's probably one of the sectors that's the most competitive about sustainability.”

Ultimately, the Magnitude project achieved a 25.8% reduction in embodied carbon compared to a standard logistics building, and the rest of the building’s carbon emissions during the construction phase were offset or mitigated using Gold Standard carbon offsets in order to achieve net zero.

Even before the Magnitude project, all GLP buildings were certified using the BREEAM rating system as excellent or outstanding for sustainability. They also had an A-grade Energy Performance Certificate (EPC) for energy efficiency and were designed using WELL principles.

But BREEAM certification doesn’t stipulate a life cycle assessment (LCA) of a building’s cumulative environmental impacts or that a building needs to achieve net zero carbon.

So, GLP decided to follow guidelines set by the U.K. Green Building Council (UKGBC) in its Net Zero Carbon Buildings Framework Definition. In the absence of an official globally recognised net zero carbon certification, the UKGBC framework definition builds on the World Green Building Council’s “Advancing Net Zero” programme to inform the development of building tools, policies and industry best practices for achieving a net zero carbon footprint.

The framework definition sets out three possible approaches to net zero: net zero for construction, net zero for operations and net zero for whole life.

The first approach addresses carbon emissions from construction activities (also known as embodied carbon), which represent roughly 80% of all emissions discharged by the construction industry. The second approach addresses the remaining 20% of emissions known as operational carbon. These are the result of a building’s day-to-day operations: heating, ventilation and air conditioning (HVAC), lighting and any other energy requirements. The third approach combines the first two, while also addressing a building’s end of life.

Since Magnitude 314 was a speculative build – meaning GLP hadn’t secured a tenant before construction began – there was no way to guarantee net zero for operations. So instead, GLP adopted the first approach and set out to achieve net zero for construction, while also putting all the elements in place to ensure that an eventual tenant would be able to reduce their operational carbon as much as possible.

After selecting a standard by which to determine the building’s carbon footprint, the next step was to create a model for how to put those goals into practice in line with the UKGBC’s framework definition.

GLP and Chetwoods set up weekly “eco template” workshops during which key experts and subcontractors, along with the design and engineering teams, were invited to come up with sustainable solutions for each element of the construction process.

“We looked at steel as an element [and] concrete as an element and so on, even down to the paint types we were using and the carpets in the offices,” Alexander said.

The Chetwoods team then created materials passports showing the breakdown of recycled content and recyclability for each building component. Any alternatives suggested during the workshops could then be compared against the sustainability credentials in the passport.

GLP also created a project sustainability information (PSI) document that provided guidance to contractors. But getting everyone on board wasn’t always an easy task, Alexander said.

“I think education was a big part of it,” he said. “Bringing people on board and getting them to buy into the project was probably the biggest challenge. And we were upscaling ourselves to an extent as well.”

As a result of the weekly “eco template” workshops, a list of feasible solutions was compiled and modelled. The projected carbon savings were then determined by third-party LCA consultant Circular Ecology and Dr Craig Jones, who “pretty much wrote the book on carbon content within the UK,” Alexander said.

Cement is responsible for 8% of global carbon emissions, so finding an alternative to the standard concrete mix became a particular area of focus. “We discovered that quite a lot of the carbon was in the slabs in the yard and the foundations,” Birch-Wood said.

The team came up with the solution of substituting cement for ground granulated blast furnace slag (GGBS), a byproduct of the steel production process that performs as well – or better – than cement. The Magnitude 314 project required a minimum of 30% GGBS be used for all concrete elements, with some areas reaching up to 60%.

“When we went to the concrete suppliers,” Alexander recalled, “they said, ‘we've never done this before.’ And we said, ‘well, that's kind of the point. […] We're giving you an opportunity to change the way you work and we’re funding it.’”

“And since then,” he added, “we've done several of these buildings with the same contractor and they're completely on board with it.”

In the end, the concrete mixtures resulted in embodied carbon savings of 786 tonnes of carbon dioxide equivalent (CO2e), a 4.8% reduction from GLP’s distribution centre baseline. The steel roof and wall cladding cut 617 tonnes of CO2e, a 3.7% reduction. The ground stabilisation, pad foundations and cut and fill process saved 985 tonnes, 980 tonnes and 895 tonnes of CO2e, respectively.

Total embodied carbon reduction on the project was 4,263 tonnes of CO2e, a 25.8% reduction from GLP’s standard builds. Carbon savings were determined by Circular Ecology and the numbers were then verified by third-party sustainability certification company Planet Mark.

The remaining embodied carbon was mitigated using Gold Standard carbon offsets, in line with the requirements of the UKGBC Net Zero Framework Definition. The carbon offsets for Magnitude 314 included investing in renewable energy, providing clean drinking water to communities in need and planting over 32,000 trees.

To help reduce operational carbon for the eventual tenant, the team equipped the building with a water-based, refrigerant-free, hydronic air-conditioning system, solar thermal for water heating, a solar photovoltaic-ready roof structure and a 10,000-litre rainwater harvesting tank to reduce the building’s water demand.

Roof lights for natural lighting and optimal airtightness also added to overall energy-efficiency. Electric vehicle (EV) charging stations were installed in 10% of the car park and dock yard, with underground ducts to allow for future expansion without digging up the existing lot.

“All these sorts of things are not typical for even your higher-end commercial development where there is money to spend,” Birch-Wood said.

The 16,415 square feet of office space were also designed to be flexible enough for a variety of different layouts to avoid added carbon emissions from too many future changes.

“We build them with that flexibility, so that the customer can change or add to the building if need be,” Alexander said.

The office fit-out used organic paints, responsibly sourced timber and 100% recycled and recyclable yarn carpets as standard. Material use was reduced by having exposed soffits with ceiling baffles. Energy and water consumption were reduced through ample natural light and LED lighting, water-efficient toilets and spray taps, and low-energy hand driers.

The entire building is also equipped with a Built Environment Analytics (BEA) system that provides tenants with consumption metrics for water and electricity alongside occupancy metrics with environmental well-being monitoring.

As a further incentive to tenants to lower their operational carbon emissions by 5% per year, GLP offers up to a two-year membership to the Planet Mark accreditation service to all their tenants “with the hope that after they get a taste of it, they'll continue with that accreditation themselves,” Alexander said.

For GLP, Magnitude 314 was just a starting point; they’ve continued to apply the same sustainability principles to many of their new builds.

“We've used what we've done at Magnitude, and we’ve pushed the boundaries a bit further to see how we can further reduce that carbon footprint,” Alexander said. “Our last three projects had over 30% [embodied carbon] savings. We've just finished our sixth net zero building, which is nearly twice the size of Magnitude. It's over 600,000 square feet.”

All of GLP’s net zero embodied carbon buildings adhere to the UKGBC’s Net Zero Carbon Buildings Framework Definition and are verified by Planet Mark.

Above all, Alexander and Birch-Wood hope Magnitude and the buildings that followed in its footsteps can serve as an example to others.

“There's a real opportunity for advocacy from distribution centre developers to really shape the industry,” Birch-Wood said, adding that she hoped the lessons learned from Magnitude “will spread out across other sectors, because typically they're all using similar materials.”

After completing Magnitude 314, GLP compiled a detailed case study and distributed it publicly so other developers could see their methodology.

“Net zero [embodied] carbon buildings aren't too much more expensive to build than a normal building,” Alexander said. “The cost increase is negligible, when you look at a big project.”

“We're just trying to share that with others and give people some benchmarks to work towards.”