On the right grounds

Are ground source heat pumps the answer to the electrification of heat? PHAM News asks James Standley from UK manufacturer Kensa about the potential of GSHP technology to become part of the mainstream. 

Based in Truro in Cornwall, Kensa Heat Pumps is a privately-owned business that has been manufacturing ground source heat pumps for over 20 years. James Standley has been with the company for 12 years and was appointed managing director in January last year.

With the current drive to decarbonisation, do you expect the UK heat pump market to see significant growth in the next 10 years?

“Absolutely. Heat pumps will be an important piece of the net zero carbon puzzle and we are expecting very significant growth as we phase down the use of fossil fuel heating like wet wood burning and gas.

“All stakeholders now accept there needs to be a rapid and sustained increase in the number of heat pumps installed in the UK.  Most credible forecasts predict around 3m heat pumps by 2030, which is a significant uplift on the present installed estate of around 250,000 units, especially as 2019 sales were only around 25,000 units.” 

Do you think growth could be achieved without government legislation and incentives?

“Some growth would be achieved without government intervention but nowhere near enough to achieve our carbon targets, and growth would be limited to the cheapest solutions that aren’t necessarily best for the whole UK energy system.

“Given the requirement for growth, it is concerning that the government has yet to make any announcement on the future of the Renewable Heat Incentive (RHI), which is scheduled to close in March 2021.  Meantime, over half the UK’s local authorities have declared some form of climate emergency, with most setting a net zero target for 2030.  This hugely challenging ambition reflects public opinion, but politicians simply cannot ignore the issue any longer. 

“Local authorities and the devolved assemblies should impose planning conditions which mandate the use of low carbon heating systems.  Ground source heat pumps will provide lower running costs and dramatically lower carbon emissions, so there is no need to fear the change, provided that suitable subsidies are available to handle the upfront costs.” 

Kensa has been involved in the installation of a number of shared ground loop systems in recent years, providing heat pumps for multiple properties. Do you believe this to be the biggest growth opportunity for ground source?

“The durability of ground arrays means there is a fabulous legacy for any subsidy spend so there is a need to install this vital national infrastructure in a street-by-street, town-by-town fashion, which mimics the roll-out of the gas mains in years gone by. 

“Almost certainly, as volumes increase and costs are reduced, new business models will emerge which will offer heat-as-a-service contracts. These asset owners will favour ground source heat pumps as the more efficient, more reliable and more durable heat pump variant, especially as there will be increased opportunity to run the heat pump at times when electricity is both low cost and low carbon, and store heat in thermal stores featuring phase change material.” 

What do you think are the main obstacles to heat pumps becoming the primary source of heating in UK homes?

“The combination of taxes, levies and subsidies on electricity and gas are stacked against the electrification of heat. In order to expedite deployment, there is a need to lobby government for a fairer distribution of the cost of social levies across fuel bills.  Right now, the cost of electricity is inflated by around 18% to cover these costs; the price of gas is hardly affected at all.  It seems rather odd that no action has already been taken, but presumably there was political risk around inflating the cost of the country’s most common heating fuel.  Times are changing.  People want low cost heat but they also want to safeguard the planet and that should become the political priority.  A ground source heat pump delivers both outcomes.”

Could hybrid systems offer a viable way forward for those reluctant to see the end of their gas boiler?

“Hybrid solutions are a niche solution for only a tiny minority of houses. Hybrid (bivalent) systems lumber the consumer with twice the complexity and maintenance of a single technology solution. 

“If the intent is to reduce running costs, when would the air source heat pump ever run given the relative cost of gas and electricity?  They only make financial sense if the relative prices of gas and electricity are different from today.” 

Is there more the industry can do to reduce installation costs?

“Kensa believes the design of the ground array should mimic the approach taken with the gas main. If heat pumps are installed at the same scale, then there are opportunities for reduced installation costs. This is what Kensa Contracting is currently doing across the UK with shared ground loop array installations.

“We don’t ask installers of gas boilers to design the gas infrastructure running down the street and the same should be true for ground array infrastructure. With shared ground loop arrays we are looking to take this complexity away from the installer, and enable the wide-scale adoption of fifth generation ground source heat networks.

“As market conditions improve, heat pump manufacturers who provide products which are designed to be straightforward to install will prosper as the market grows and new plumbing contractors seek to take advantage of the opportunity. And those who offer the best design and technical back-up and take a genuine interest in the performance of the installed system will hopefully prevail over those who are only interested in shifting a box.” 

Are you concerned that there are not enough skilled installers to meet the potential increase in demand?

“Designing a heating system to work with a ground source heat pump is exactly the same design as required for a condensing gas boiler that actually condenses, i.e. runs at 50°C.  So installers who can design and install a gas heating system that runs at the temperatures required for the boiler to condense (and not at the higher, less efficient temperatures) have all the skills they need to install a ground source heat pump. And the best will provide them with all the necessary support to cover the installation of the ground array.”

As a manufacturer of ground source heat pumps, what do you consider to be their key benefits over other heat pump alternatives?

“To achieve the required wide-scale electrification of heat with heat pumps at scale, running a large fleet of air source heat pumps will impose a need for more generating assets due to their lesser efficiency, and that will be financially and environmentally costly.  That need will be magnified once it is generally recognised that air source heat pumps are not suited to operate when winter electricity is most available – through the night.  The temperature is typically cooler at 2am, which further impacts their efficiency.  Worse, most of us are also trying to sleep at that time so won’t want to be disturbed by the circulating fan. 

“There are too many myths around heat pump design and performance.  Too often, fossil fuel boiler manufacturers suggest that heat pumps cannot heat older properties which don’t benefit from excellent insulation.  This is dishonest.  Very simply, any heat pump can deliver a flow temperature at 50°C, which is exactly the requirement for a condensing gas boiler that condenses.  

“Of course, the gas boiler lobby will argue that a heat pump operating at a 50°C flow temperature is not maximising efficiency,  but the pursuit of optimum efficiency is no longer the key metric.  Instead, it is all about running costs and carbon emissions and this places a far greater emphasis on when the heat pump operates rather than the operating efficiency. It is far smarter to accept a little loss in efficiency if the outcome is significantly lower running costs and carbon emissions.”


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