Mark Hillsdon reports on how venture capital firm 2150 is among those backing technologies that seek to cut construction waste and plastic pollution while reducing embodied CO2 emissions in the built environment
Professor Gabriela Medero is passionate about gravel, and sand, and other building materials that are too often channelled away from construction sites as waste.
In Europe alone, the construction industry contributes over 800m tonnes of waste to landfill every year. “The volumes of materials are huge,” says Medero. Re-using this waste is the thinking behind the K-Briq, which is made from 90% construction and demolition waste.
Rather than being fired at high temperatures, the K-Briq is formed by compressing inert, contaminant-free construction waste. This requires less than a 10th of the energy and uses a 10th of the CO2 emissions of a traditional brick.
Medero works with Kenoteq, a clean-tech spin-out from Heriot-Watt University in the UK, where the K-Briq took more than a decade to develop. She hopes that the low-carbon blocks will start to replace some of the 2.6bn traditional bricks used in the UK every year and help address the fact that globally, around 39% of all CO2 emissions are created by the construction industry.
It is innovative ideas like the K-Briq that can help reduce the embodied carbon within the built environment, believes venture capitalist Christian Gallardo. He is a partner in 2150, a UK-based venture capital firm named after Copenhagen’s newest postcode: a former industrialised corner of the Danish capital that is being redeveloped as a sustainable city of the future.
2150 is looking to invest in technology companies that can sustainably reimagine and reshape the urban environment, building a portfolio of 20 so-called “Gigacorns”, businesses with the potential to reduce or mitigate a gigaton of CO2, which is roughly the amount produced by Japan annually.
But investment comes with a proviso – the companies must be able to stand on their own two feet. “There are a lot of technologies right now that claim to be able to mitigate a gigaton of CO2,” says Gallardo, “but they are not commercially viable [and] they will require subsidies to function for ever."
We need to find technologies that the West can adopt first, and help drive the costs and price down
“The biggest problem is our addiction to cement and concrete,” he says. “We're literally pouring it like water.” So little surprise that 2150’s first investment has been in Canadian company CarbonCure, which injects C02 into concrete as it's being mixed. Not only does this sequester the carbon but it makes the concrete stronger, ultimately meaning that less is needed.
As well as “green” concrete, Gallardo is looking at possibilities around replacing steel in buildings with cross-laminated timber, ways in which AI can be used to control heating in a building, and alternative biodegradable refrigerants for air conditioning units, which won’t contribute to global warming if they leak.
"We need to find technologies that … [the West] can adopt first, and help drive the costs and price down, but that can be globally deployed quickly into these countries that will be building much, much faster,” says Gallardo, particularly in Africa and Asia.
Alongside new technologies, forward thinking also has an important role to play in building for a carbon-free future, says Roland Hunziker, director of sustainable buildings and cities at the World Business Council for Sustainable Development (WBCSD).
“You need to put carbon reduction into the design from the start,” he says, yet when it comes to commissioning a building, the decision-making process is fragmented, and that crucial conversation between the architects, engineers, contractors and the client isn’t happening.
"When a building is designed, nobody looks at whole lifecycle,” he says. "We cannot decarbonise cement or steel [cost-effectively] today, but we can build much more cleverly. It's a question of the design and how these materials are used… which can bring down the overall carbon footprint.”
A joint report from WBCSD and Arup estimates that currently just 1% of building projects calculate and report their full carbon footprint
The idea of adopting a whole lifecycle approach to carbon in the built environment is central to a new joint report from the WBCSD and Arup: Net-zero buildings. Where do we stand? It estimates that currently just 1% of building projects calculate and report their full carbon footprint by taking into account the embodied carbon associated with construction, refurbishment and end-of-life.
The report details six case studies that adopted the WBCSD’s Building System Carbon Framework, a methodology to create whole-life carbon assessments. By setting targets at the start of a project, and through collaboration with the supply chain, the reports says that emissions could be halved in every building project by 2030.
The case studies look at areas such as the role of electrification in cutting a building’s lifetime emissions, how architects can “design light” so that they use fewer materials such as steel and concrete, and the idea of refurbishing and repurposing buildings rather than demolishing and rebuilding with new virgin materials. “Don’t tear it down, reuse it,” advises Hunziker.
The framework helps companies to understand where emissions occur along the value chain and how they can reduce them, with sharing data a key element. “Most developers are just looking for certification, but the problem with certification is it is not data-based... it is tick-box,” says Hunziker.
So what more can be done to encourage the take-up of initiatives such as the WBCSD’s framework? "The biggest lever is urban planning and land-use permitting,” says Hunziker. Several countries are starting to adopt benchmarks for new construction that cover limits on CO2 per square mile, he explains ‒ carbon budgets that developers must to stick to.
Cities including London and Vancouver have introduced life carbon assessment for new buildings, alongside procurement rules that have carbon performances at their core, he continues, while a new law in New York state stipulates the amount of embodied carbon that any state-funded project can have in its concrete. “These regulatory instruments will ultimately move the market,” he says.
If government procurement policies start demanding some of these sustainable technologies, that will create the market
Regulation can also boost innovation, adds Gallardo. “If government procurement policies start demanding some of these sustainable technologies, that will create the market and that will accelerate supply,” he says.
Waste plastic also offers ways to decarbonise the built environment. Around 400m tonnes are discarded a year, with just 9% recycled, yet plastic could be a game-changing new raw material for the construction industry. Its relatively low melting point makes it easy to repurpose, in comparison to the likes of glass and aluminium, while it is also long-lasting and waterproof.
Danish-based automation specialist Robot at Work is using a 3D printer to convert plastic waste into housing units, which are designed with the insulation printed into the wall structures. The company is now able to 3D-print a house in two and a half days. It is also developing a 3D printer that uses soil, bound together by mushroom pores, to create a solid wall.
Plastic building blocks which are easily slotted together are at the core of new homes and classrooms being built by Conceptos Plasticos in Columbia and Côte d'Ivoire. The social enterprise employs local women to collect waste plastic, which is then sold on to recyclers who produce bricks. There are both impermeable and don’t conduct heat, making them perfect for both hot and cold countries.
With their mix of paper and plastic liner, single-use coffee cups are notoriously difficult to recycle, yet the UK alone uses 2.5bn a year. Working in a partnership that includes WRAP Cymru, Nextek has found a way to clean and shred the cups to produce strong polymer composites that can be used to make waterproof building materials such as flooring and decking. By offering a durable, low-maintenance alternative to wood, they can also significantly reduce a building’s carbon footprint.
Plastic also has an important role to play in road building, although standards about how it can be included differ around the world. In India, for instance, shredded plastic is coated with tar to form the road surface. The country now has over 2,500km of “plastic roads”, which are less energy-intensive to produce and require less tar and aggregates to make. However, there are environmental concerns that small particles of plastic can break off and find their way into water courses.
If bitumen is Pritt stick, then adding a polymer makes it like super glue
In Scotland, Lockerbie-based MacRebur has pioneered a different process. Using plastic otherwise destined for landfill, the company produces a polymer that can be added to the asphalt mix, replacing some of the carbon-intensive bitumen that is used to bind aggregates together. At the moment, in order to meet British and European standards, no more than 10% of the MacRebur mix can be used in roads.
Adding plastic to roads in the form of a polymer is nothing new, says company founder Toby McCartney, and bitumen manufacturers have been doing so for decades. “If bitumen is Pritt stick, then adding a polymer makes it like super glue,” he says. "The difference here is that we are using end-of-life plastics."
The polymer makes the roads more flexible and less prone to potholes, which in turn means less maintenance. Resurfacing a one-mile stretch of road with MacRebur also saves approximately 11,320kg of carbon emissions, he says.
With factories in Spain, Estonia, San Diego and one soon to opened in NZ, MacRebur is busier abroad than in the UK, with roads in Australia, all over Europe, Malaysia and the USA. But McCartney hopes this could soon change after the completion of the first long-term, five-year research into plastic roads in the UK. Run by Cumbria Council and the Department for Transport, it has given the technology the green light, says McCartney. "Effectively what that does is free up every local authority to be able to specify that waste plastics can be used in their roads."
Back in Edinburgh, Kenoteq recently received £1m of funding from Zero Waste Scotland to ramp up production of the K-Briq, with the aim of delivering 934 low-carbon homes across the UK over a five-year period, with a number of projects set to be announced at COP26.
Medero points out that K-Briqs are also breathable, making for a better living environment, while they also have nearly double the insulation properties of a normal brick, ensuring they have a positive effect on the building’s long-term energy footprint, too.
“They will show what we can really do to help meet the net-zero targets and to have a more circular approach in construction,” she says.
Mark Hillsdon is a Manchester-based freelance writer who writes on business and sustainability for The Ethical Corporation, The Guardian, and a range of naturebased titles including CountryFile
and BBC Wildlife.
WBCSD K-Briq Kenoteq 2150 embodied carbon CO2 emissions decarbonising construction carbon sapture and storage carbonCure cross-lamminated timber Building System Carbon Framework Conceptos Plásticos MacRebur plastic roads Nexteq