By Jo Clarke, Head of Design
The first question we need to ask is what do we mean by decarbonise?
Applied to buildings, it means reducing the emissions from energy used through operation as well as the embodied carbon of their structure, materials and technologies. To achieve the government’s 2050 net-zero target, we must also remove carbon from the process of building construction – from transport, site set-up and site activity. While this will be difficult enough to achieve in new housing, decarbonising existing housing stock is the greater conundrum.
Retain, retro fit and decarbonise
Retaining existing housing is itself a significant step towards decarbonisation. Demolition, material removal and disposal and replacing with new stock should be avoided where possible. However, much of the UK’s existing housing was built before thermal performance standards existed, and are incredibly difficult to heat. Recent housing stock is also riddled with problems, mainly due to the ‘performance gap’ between housing design and construction.
Fortunately, there are solutions for improving existing housing stock. Although, there is no one panacea; a mix of technologies is needed.
Where existing gas transmission networks are concerned, repurposing needs to be considered for example. Instead of supplying homes with natural gas, they could distribute a low carbon source of energy such as hydrogen. This would enable existing infrastructure to be retained and reused, rather than becoming obsolete and requiring costly replacement.
While hydrogen can be produced from fossil fuels, it can also be produced via electrolysers that convert energy generated from solar or wind. Hydrogen could also be used directly in buildings via hydrogen boilers or fuel cells for storing renewable energy.
How active buildings are offering a low carbon approach
Active Buildings offer a low/zero carbon approach, combining renewable energy generation with storage and electric vehicles to manage a building’s interaction with energy networks. Combining reduced energy demand with use of renewable energy generation technologies can significantly lower carbon emissions from buildings and decrease pressure on the National Grid.
Originally developed in the Netherlands, the Energiesprong model addresses whole-house retrofits by providing a new insulated envelope and energy system, including solar panels. It’s a great solution for decarbonising the operational energy for houses. However, it doesn’t address embodied carbon.
Decarbonising the built environment is about more than just material solutions. We also need to do more around education to upskill the existing industry; educate designers on designing for climate resilience; attract the younger generation into construction; and develop strategies to improve occupants’ understanding of their houses’ operation.
Furthermore, the industry needs to adopt a different mindset. Currently, procurement tends to focus on initial capital project cost, rather than focusing on whole life costs of buildings or carbon cost. Unless decarbonisation is regulated or incentivised, it will be very difficult to change this.
There are still challenges to be overcome: the costs of implementing solutions, the skills shortage and the industry’s understanding of retrofit, to name a few. Additionally, some building types are more difficult to retrofit than others – terraced or semi-detached houses with rear extensions and heritage buildings, for example. However, with a concerted effort from the top down, clear policy and regulation and a willingness to explore and implement new technologies, I don’t believe any of this is insurmountable.