Why heat pumps?
It’s a good question to start with as we look at the various options surrounding ‘green’ heat. The main answer is decarbonisation of heat. Since Boris Johnson’s mention of 600,000 heat pumps per year by 2028 in the 2020 10-point plan, the government has continued to press for electrification of heat to achieve our legally binding Net Zero target by 2050. How can heat pumps help us to achieve that goal?
Firstly, it’s important to know that heating buildings produces the greatest carbon emission levels by sector in the UK; 37% of carbon emissions come from heating and hot water [Clean Growth – Transforming Heating, DBEIS 2018]. These emissions come from the combustion of fossil fuels including natural gas, oil and LPG in boilers up and down the country. Heat pumps, on the other hand, use electricity to generate heating, which results in zero combustion at the point of generation; zero combustion of fossil fuels = zero carbon emissions. A second but important benefit of this is improved air quality resulting from reduced combustion. As the amount of renewable electricity being generated on the national grid increases, which we have seen over the last few years, the carbon intensity of the grid decreases, and heat pumps start to become fully decarbonised.
Secondly, heat pump technology is very flexible and can be applied to a myriad of applications. Everything from tiny 3kW ground source heat pumps in small flats to huge multi-MW heat pumps running district heat schemes and industrial processes. Recent advances in refrigerants mean that higher temperatures can be achieved at improved coefficients of performance (COP), anything from 55 – 90°C flow, which helps with retrofitting heat pumps into buildings where gas or oil boilers have been used previously. Heat pumps can generate heating, cooling and hot water from the same unit, sometimes at the same time. The same cannot be said for your humble gas boiler and as the earth starts to warm up, cooling in domestic situations may become more commonplace. Heat pumps can also use all sorts of ‘free’ energy as input including air, ground heat, water sources such as rivers, lakes and the sea, minewater, waste heat from data centres, wastewater, the list goes on. And it is possible to combine different sources if one source is insufficient or too costly.
So, if heat pumps are so great, why are we not just getting on with getting them installed all over the UK?
The reasons for this are varied but there are two or three main reasons that are preventing the industry deploying heat pumps in the numbers required to make a real dent in carbon emissions and achieve Mr Johnson’s 2028 600,000 heat pumps/yr ambition.
Government policy, or lack of it, is one reason for the lack of serious progress. There has been a lot of talk from various government ministers, but no firm plans or roadmap to take us from talk to action. The Heat & Buildings Strategy, which we hope will start to set out the route and regulations necessary to see the heat pump target achieved, was due out in May 2021 but has yet to make an appearance. The Climate Change Committee’s 2021 Progress Report to Parliament, issued on 24th June, presses on this point; bold ambition but no plans to back it up.
One of the main areas where we see policy not matching up with ambition is the spark gap on fuel prices in the UK. This is the difference in price between gas and electricity and is another key reason for heat pumps not being deployed in the numbers we need to see. Gas is cheap, well understood and widespread. At around 3.5p/kWh for a unit of gas, the UK has amongst the lowest cost of gas in
Europe. Conversely, we have around the highest unit cost of electricity in Europe at anywhere between 11 – 16p/kWhe. If we were to replace all gas boilers with heat pumps today, consumers’ bills would increase by around 17%. And that is without the increased capital cost of installing a heat pump over a gas (or oil/LPG) boiler. The costs of gas and electricity are driven by historic levies that load environmental taxes on to the electricity price but not on to the gas price. That was OK when electricity was being generated by high carbon sources such as coal. However, as mentioned above, we are seeing real change in the carbon intensity of the grid, and it therefore makes sense to transition the levies from electricity to gas. In this way, we would start to see the cost of gas and electricity rebalanced to make electric heating systems stand on their own two feet.
To end on a positive note, it is true to say that the heat pump industry continues to thrive and many of the businesses I work with, including my own, are busy with numerous heat pump projects, both domestic and commercial, new build and retrofit. So, there is a great interest and eagerness for people and groups to decarbonise and heat pumps are popular. Now all we need is the government action and strategy to make the ambition become a reality.