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27/07/2020

To deliver homes fit for the future, we may have to redefine ‘zero-carbon’

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Parc Hadeau housing

Our current methods for measuring carbon emissions in housing are inadequate, argues Andy Sutton from Sero. What's really needed is to view houses as a component of the energy grid

Calls for a ‘green recovery’ and ‘building back better’ push for economic stimuli, but they also support a step-change tackling the climate emergency and the biodiversity crisis.

The impacts from these will make Covid-19 look like a minor blip. The UK faces three waves of crisis – the virus, its economic consequences and then the ongoing environmental crisis.

Demands to address climate issues must be based on strong factual foundations. One current flaw is the way that ‘zero-carbon building’ is used to mean whatever a developer, politician or lobbyist wishes. In the absence of government clarity, the Net Zero Carbon Buildings Framework published by the UK Green Building Council sets out the best definition.

Beyond a definition we can rely on, the tools and framework we have then co-opted to service the work towards zero carbon are also failing us. For residential properties, the Energy Performance Certificate (EPC) and its Standard Assessment Procedure (SAP) were conceived to satisfy the EU requirements for a National Calculation Methodology: a minimum standard for the energy performance of buildings. 

“Regarding a building as part of the energy grid allows us to factor in the impact of decarbonising the grid”

This might sound like it fits with zero carbon, but it doesn’t. The SAP demonstrates that the regulated components of a building (such as heating and lighting) perform no worse than a notional standardised equivalent. It does not show how the building actually works in practice, let alone take into account what the occupants of that building get up to. 

Although this is technical detail, the consequences are huge. In the next ten years, it will be possible to build a truly zero-carbon building without any renewables installed whatsoever. To plan them correctly requires us to change the tools we use to determine the right outcomes, and to begin to think of our buildings as an integral part of the UK’s energy network.

Right now, we see buildings as independent from the energy grids that supply them power. Our buildings demand power whenever they wish, and the energy grids rush to provide it – but, as renewable power generation is not at our beck and call, the carbon footprint of this energy varies hugely. We therefore need a more sophisticated approach to our buildings that integrates smart energy management and storage, as well as generating and passing energy to the grid. 

Regarding a building as part of the energy grid allows us to factor in the impact of decarbonising the grid. It means we can anticipate how the grid will continue to decarbonise and allow for this in the future design and retrofit of our buildings.  

In practical terms, that means we can build or refurbish buildings that are zero carbon by a specified future date – by undertaking the physical works to the building and then waiting for the energy grid (combined with automated intelligent building management) to meet the building halfway. For example, creating a building that can have a zero-carbon operation in a 2035 energy grid is easier and cheaper than building one that is zero carbon today. Whilst zero carbon today would be fantastic, zero carbon by 2035 might just be enough.

Andy Sutton is an architect and co-founder of sustainable energy service provider and zero carbon homebuilder Sero

Images l iCreate (main image), Andy Sutton/Sero

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