BSEE-FEB22-PG22.qxp_Layout 1 21/01/2022 10:09 Page 22
BSEE
BUILDINGS CONTROLS & TECHNOLOGY
Digital twin modelling provides a treasure trove of building information
For existing and heritage buildings, the journey towards Net Zero emissions can seem complex, but it doesn’t need to be according to Sarah Peterson, director, Harley Haddow, the multidisciplinary engineering consultancy
be achieved.
When it comes to the infrastructure of our towns and cities, we can’t build our way to Net Zero, we need to address the impact of existing buildings. What then? 80% of current buildings will still be around in 2050, and with the energy consumption of these accounting for around 40% of the UK’s annual carbon emissions, successful decarbonisation of existing assets will be essential, as will a new approach to managing these buildings.
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As one of the biggest contributors to the UK’s CO2 emissions, the building sector is a pivotal agent for meaningful change. Failing to improve our existing stock is not an option. The good news is that decarbonisation is completely possible and can still encourage a thriving industry whilst cutting down on emissions.
Every journey starts with a single step
The UK has set carbon reduction targets – with the target of reaching Net Zero by 2050 and Scotland aiming for five years earlier. They’re not the only ones with ambitious targets, many local authorities, organisations and public bodies also believe they could be ‘Net Zero-ready’ by 2030.
Into a new landscape
An essential part of any Net Zero carbon strategy is limiting the amount of energy buildings need to run. With buildings, this relates to operational energy related to the
t’s widely acknowledged that this decade needs to be one of climate action. Without taking drastic steps now, the Net Zero carbon target set for 2050 will not
energy used to run them – so heating, lighting, hot water plus any energy used for plug-in equipment and the associated carbon emissions.
There’s also whole life carbon which looks at the materials used to build with and calculates the total embodied carbon, including the carbon used to manufacture and transport the material. This element is not currently included in legislation for buildings but will be gradually considered for new buildings. Existing buildings will already have a lower embodied carbon as the building is being re- used.
The route ahead
For existing and heritage buildings there is little or no published guidance on Net Zero demand targets, something we think is urgently needed.
It is clear that we have the skills and technology to build new Net Zero buildings in the UK already, but this needs to be covered by legislation to ensure our existing buildings are included in the Net Zero journey. Legislation for new buildings needs to catch up with the demands being asked of those within the industry and become more stringent quicker.
Heritage listed buildings are some of the hardest to improve for a Net Zero future and despite the challenges of the pandemic, most people will still occupy, operate, or own an existing building.
While getting existing buildings to Net Zero may be challenging initially, it also gives the greatest potential savings in the long run. Stakeholders in existing buildings should not be asking whether to get on the Net Zero journey, but rather how quickly they can work towards achieving this target.
22 BUILDING SERVICES & ENVIRONMENTAL ENGINEER FEBRUARY 2022
Stepbystep solutions
As well as setting building energy demand targets, the other essential requirement is to stop using gas as a fuel. The electrical grid is decarbonising – so we’re moving away from gas and coal-fired power stations and onto a grid powered by renewables.
If electricity is your primary fuel supply in coming years, you’ll become Net Zero by default. But while electricity is undoubtedly greener, it’s not always cheaper. Electricity currently comes in at five times the cost of gas per kWh, although with an uncertain gas supply network this cost difference may start to shift.
It calls into questions whether hydrogen could be one of the Net Zero solutions. While there’s been a lot of hype there needs to be a serious revolution in the way it’s produced with the majority currently made from natural gas or coal. The best solution is to reduce energy demand first, and then provide an efficient electric heating system.
Best way forward
Data and digital twin modelling can reveal a treasure of information within existing buildings. It allows for various options to be tested, including steps to work out what and where savings can be made. At Harley Haddow we create a digital twin model of the building using dynamic simulation software and compare this with measured utility consumption. This can then be used to understand where and how energy is used and if the building management systems are working as efficiently as possible.
A digital twin model gives an accurate baseline to measure and test options on, with the following steps:
1. A hierarchy multi-level approach is used to see what savings can be made; e.g. can the building’s fabric be improved to reduce heating demand.
2. Reduce demand by looking at the building’s management systems e.g. can controls be optimised.
3. One of the most important steps is the replacement of the gas heating which reduces the carbon further and limits running costs. This could be a heat pump – ground, water, air as that gives efficiency, reduces the carbon further and limits running costs. Developments in heat pump technology mean that in many buildings heat pumps can already meet the peak heating demand without the need for backup gas systems.
These steps, with a strong emphasis on the removal of gas, can be carried out in a phased and tailored approach and will set your building on its journey to becoming Net Zero. While it is a long term venture it is important to know that from the start of the project, your carbon impact will continue to reduce alongside the implementation of each step. Experts can help guide the way and at Harley Haddow we are pleased to have helped deliver projects including comprehensive improvements and expansion of the British Academy of Film and Television Arts headquarters at 195 Piccadilly in London.
A final view
Net Zero can seem overwhelming at first, but it’s totally achievable. While every business has a role to play in tackling climate change, it also makes commercial sense with benefits including reduced costs, enhanced reputation, competitive advantage and investor confidence.
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