Homeowners and self-builders whose projects feature two or more domestic buildings on one site, could be earning themselves a profitable income by utilising a simple district ground source heat pump system architecture to unlock quarterly payments from the Government’s Non Domestic Renewable Heat Incentive (RHI) scheme for the next 20 years.
More commonly associated with commercial projects, the current Non Domestic RHI tariff for ground source heat pumps is very generous in comparison with other renewable technologies. It has recently increased in line with inflation to 9.36p/kWh on the first 1314 hours of eligible energy produced, followed by 2.79p/kWh on any additional heat produced over a 20 year period.
Linking two or more properties to a district system
Paul Dennison, Sales Manager for Kensa Heat Pumps, says:
“If your new build or retrofit project features multiple buildings, you may be able to link them to a shared ground array to cut installation costs and fuel bills. This will qualify as a district heating scheme and allow you to maximise the benefit of the Government’s RHI scheme, whilst delivering the energy savings and efficiency benefits that ground source naturally brings.”
As few as two properties can be linked together in a district ground source heat pump system, opening up the opportunity for self build or renovation projects featuring smaller numbers of residential properties or outbuildings to access the lucrative Non Domestic RHI funding.
As each dwelling features its own individual ground source heat pump, this eliminates the need for a central plant room to be incorporated into the build. Also the occupier has complete control of their own heating and hot water system.
Installation can happen in stages to fit around individual build schedules. And as the ground arrays (typically slinky pipe, pond mats or boreholes), are all part of the same system, they can be sited where practical, rather than individually. Once installed, the district ground source heat pump system infrastructure will last for up to 100 years, and will provide 100% of their heating and hot water needs.
Ground source heat pumps are a popular choice with many self-builders
Ground source heat pumps work by harnessing heat from the ground or water using pipework buried underground or submerged in water, and converting this to a higher temperature. Ground source heat pumps do not require annual servicing or maintenance, and the units typically have a 20 year lifetime.
For every 1kW of power used to run a ground source heat pump, 3-4kW of heat are produced, making them extremely efficient compared to a typical gas boiler. As a result of their efficiency compared to conventional heating options, ground source heat pumps are capable of reducing heating and hot water costs by over 50% compared to electric heating and around 35% compared to LPG, whilst more than halving CO₂ emissions compared to the latter.
More information on district ground source heat pump systems, including example project costs and different ground array configurations, can be found here.