Why Shared GSHP Loop Systems Are Key for Decarbonisation

Steve Wilkinson, Head of Commercial Projects at Cenergist

The UK Government made its intentions clear in March, when it announced its blueprint to deliver the world’s first low-carbon industrial sector. The industrial decarbonisation strategy outlines the government’s goal of cutting the nation’s emissions by two thirds in the next 15 years, with the aim of reaching net zero by 2050.

Decarbonisation has become a top priority for many organisations. Not only would it significantly benefit the environment, but in many cases, the solutions that will help these businesses achieve net zero also prove to be highly cost effective and greatly improve operational efficiency. While much focus is often placed on the decarbonisation of electricity, the true challenges actually lie in heating, ventilation and air cooling (HVAC) systems. However, by optimising existing systems with shared ground source heat pump (GSHP) loops, HVAC technology can be decarbonised effectively.

GSHPs minimise CO2 emissions

GSHPs work by absorbing heat from the ground and transferring that heat into buildings, without the need to burn fossil fuels. By using pipes that are buried underground to extract heat, the system is able to use the extracted heat for radiators, underfloor or warm air heating systems, as well as hot water in homes. With the ground remaining at a fairly constant temperature under the surface across all four seasons, GSHPs provide a viable solution for heating homes year-round.

Defra publishes projections of the carbon grid intensity each year in grams of CO2 emitted for each kWh generated. This includes the relative carbon emissions for different forms of heating, compared to burning natural gas for the same purpose. It shows that combustion methods, such as burning natural gas and coal, produce double the amount of CO2 to that of heat transfer methods like those utilised through GSHPs. It is clear that heating by heat transfer is the attractive alternative.

Scaling the GSHP

GSHPs can be used at scale in a shared ground loop, a heating network where multiple properties have an individual heat pump that can be controlled and connected to a communal ground loop. A shared GSHP ground loop can serve multiple dwellings at once.

Shared ground loop systems can create highly efficient heating system networks. By using boreholes, over 200 properties could be connected by only 5 communal heating systems. Heat pump boreholes are the vertical pipes used to extract heat energy from rock to a GSHP. They save space and minimise disruption in heat pump installation projects – only requiring approximately 150mm width of per borehole. Each property has its own heat pump that is linked to one of the boreholes, and monitoring data shows that homeowners can potentially save 25% to 50% on their energy bills.

With only 5 boreholes provisioning heat to over 200 heat pumps, shared loops can help contractors reproduce GSHPs at scale. Drilling costs can also be reduced by allowing a smaller number of deeper boreholes, those of which can be positioned flexibly across the site, as there is no specific requirement for a borehole within the curtilage of each plot. This is not only restricted to housing properties, but can also be used in flat clusters, bungalows or apartment blocks.

Green energy without the sacrifice

These systems are efficient – a well-designed ground source heat pump installation can provide three or four kilowatts of heat for the consumption of one kilowatt of electricity. Heating is provided without sacrificing comfort, and these efficiency levels provide a significant cost saving.

Before recently, finding a GSHP in the UK was a rare occurrence, this was only because of the taxation and levies that were placed on electricity. Taxes and levies placed on electricity in the UK have received considerable attention in the last decade for their social and distributional impacts. So even though installing and running a GSHP system presented lower upfront costs and running fees than a gas boiler, the taxes were too high to make it sustainable.

It has now become clear these taxations and levies are working against the UK’s need to lower carbon emissions from domestic heating. In response, the government has provided funding and new regulatory measurements in its recent 10 point plan announcement, that counter the taxes and levies. With new government schemes such as the Homes Upgrade Grant and Social Housing Decarbonisation Fund, it is now easier than ever for homeowners and social housing properties to access GSHPs and HVAC systems, benefiting from renewable heating and affordable energy.

With the government making a big push and funding large areas of the country and the industry itself, it is now easier than ever to acquire a GSHP system. Not only are they eco-friendly with low carbon emissions, but they are flexible and scalable to multiple properties, and they have a higher efficiency rate than other methods of heating. Over the coming years, GSHPs will be crucial in the decarbonisation of the housing industry.