Sebastian Lunt, Energy Carbon Programme Manager, Salix Finance
Time is of the essence if we are to meet our decarbonisation objectives, with some organisations, including in the public sector, committed to a net zero target by 2030. Although not the entirety of scope one and two emissions, heating in buildings accounts for a notable amount of carbon emissions. In fact, the built environment accounts for about 25% of our greenhouse emissions in the UK.
Since we all know heat decarbonisation is not a quick fix – the problems mount when attempting to decarbonise at speed and scale in a cost-efficient way. At Salix, we encounter this challenge when supporting our public sector organisations, regardless of their size. Let’s explore whether heat decarbonisation by any means necessary, or a more considered approach is really the best method for buildings in Scotland and the UK more generally.
In nearly all of Salix’s funding programmes we encourage a whole building approach, including the recent round of Scotland’s Public Sector Heat Decarbonisation Fund. This is in keeping with the Net Zero Public Sector Buildings Standard published by the Scottish Government. The voluntary standard is pertinent to new, or large refurbishment construction projects. A whole building approach is a traditional approach to building improvement, following the mantra of refine, reduce, decarbonise. The approach is a holistic assessment of the all the factors that contribute to a building’s energy consumption to identify the most effective suite of solutions.
Recent developments in the heat pump market have attracted a rethink in recent years about whether energy efficiency measures are needed. Novel refrigerants, newer models entering the market and cascading heat pump configurations can operate with flow temperatures similar to current fossil fuel powered heating systems, without changes to the building fabric, and at a reasonable seasonal coefficient of performance (sCOP).
Heat pumps will work in uninsulated buildings and heat pumps will work in cold environments. With all these innovations established in the market, should we still consider heat demand reduction before heat decarbonisation? Well, the answer is not as clear cut as you would hope. No decarbonisation pathway is right or wrong, it is a balance of different factors and priorities. Decision makers will have to weigh the advantages and disadvantages of each pathway to net zero.
A heat pump that can work at a higher flow temperature in a direct swap with end-of-life fossil fuel plant might have a lower capital cost compared to a whole building approach suite of measures but is likely to have a higher operational expenditure. This is in part due to the cost differential between electricity and fossil fuels, but also that the sCOPs of these types of heat pumps aren’t yet as good as more conventional flow temperatures from heat pumps.
On the other hand, investment in improving the insulation levels of the building fabric will reduce the size of low carbon heating plant required, improve thermal comfort, and reduce the need for electrical infrastructure upgrades. The reduction of electricity consumption can reduce the need to upgrade a building’s electrical infrastructure to accommodate the installation of a heat pump. Both of these will reduce the operational energy expenditure of the building, but the upfront cost could well be higher.
To make any informed decisions about the most appropriate pathway, organisations should have a very good understanding of their buildings. A rough list would include, current fossil fuel consumption, heat demand profiles (peak, seasonal and annual), the type of the thermal fabric and its condition, ventilation requirement, local planning permissions, available space, current heating distribution and incoming electrical infrastructure.
With the uncertainties around the energy cost fluctuations, energy security, resiliency of the electrical grid and wider benefits of energy efficiency measures, Salix will continue to promote a whole building, but common-sense, approach to decarbonising buildings. Some energy efficiency measures are simple to implement at a low cost, whilst others have significant cost and deliverability hurdles. In some heritage sites, Salix has seen the successful implementation of low carbon heating solutions without any changes to the building fabric. No one area, or building is the same, so we wouldn’t expect a uniformity in solution either. We have a plethora of case studies showing how solutions can be tailored to the wide breadth of building types in Scotland and the UK.
Have a look at our website area here to find out about the work we are doing in Scotland.
References
https://www.carbonbrief.org/factcheck-18-misleading-myths-about-heat-pumps/
https://es.catapult.org.uk/tools-and-labs/public-sector-decarbonisation-guidance/
AM17 Heat pump installations for large non-domestic buildings, 2022, The Chartered Institution of Building Services Engineers
This article appeared in the September 2024 issue of Energy Manager magazine. Subscribe here.