Mark Headshot (2)Mark Howard, project manager at Regen, draws on his experience as an engineer installing and servicing low carbon heating technologies, to discuss why decarbonising heat is as much a people problem as it is an infrastructure problem, and proposes a package of solutions to build this approach into future policy.

I am an engineer by background and have spent many years troubling over the technical details of how we decarbonise our buildings. However, I am increasingly convinced that problems are less technical and more about how we engage people in changing how their homes and buildings are kept warm.

Electricity decarbonisation – did anyone notice?

In the last decade or so, grid electricity has decarbonised, significantly reducing the greenhouse gas emissions associated with every kilowatt hour delivered to homes and businesses across the country.

Figure 1

Whilst many more people are aware of renewable energy sources such as solar PV and wind than previously, research suggests that there is low public awareness of the impact these have had on grid emissions. So, whilst we can celebrate the success of deploying renewable generation and continue our efforts to produce a lower carbon electricity system, we must acknowledge that this transformation has been at a systemic level, and that the decarbonisation of heat is likely to be very different.

The technical challenge – breaking up a (largely) single-fuel nation

There is a big technical challenge with decarbonising heat – natural gas is cheap, easy, and well supported by an industry that pipes it into ~24m homes. Low carbon hydrogen is still very much in the innovation stage and there are major challenges in producing it at a scale to provide a widespread solution to domestic heating. Particularly given the competition with other higher value uses such as industry and transport. The unit price to the consumer of hydrogen will also be 2-3 times that of natural gas. So we are likely to shift away from being a nation largely[1] heated by a single fuel, to one served by multiple technologies. I have created the following diagram to illustrate a hypothetical scenario for future heat, based on the latest CCC ‘Balanced Pathway’ developed to inform the sixth carbon budget.

Figure 2

This represents a lot of systemic change; increased load on electricity networks, disruption in our cities as heat networks are laid, changes to our gas network management as different gases enter the system. What I hear more and more from generators, network operators and engineering consultants is that this can all be achieved, they just need to know ‘where and how much’. I view this problem as identifying the scale and location of possible infrastructure solutions such as heat networks and low carbon gas, then filling the rest with heat pumps. Should this be determined by the energy networks Future Energy Scenarios? There could be a conflict of interests by this route and perhaps there could be a more local approach following Local Area Energy Planning (LAEP)? Local Authorities are better placed to deliver public good and understand local opportunities, but it could take a long time for all Local Authorities to agree a LAEP. These are probably the subject of future blogs/papers.

The big challenge – 28 million decision makers

Acknowledging the systemic change required, key to this second great decarbonisation shift is that at the end of each of these systems lies a consumer, mostly interested in being warm and going about their life, rather than the hidden energy system that serves them[2]. Further, consumer research has shown that people want very different things from their heating, so a ‘good’ system for one household may not match that for another[3]. Most are not aware of low carbon heat, and when they need a new heating system are most likely to ask their gas installer for advice.

If our energy system is unable to offer a like-for-like low-carbon heating system exchange by simply putting compatible gas in the network, and instead will necessitate changes to our homes and buildings, the big challenge is that 28 million decision makers need to be engaged in the decarbonisation shift.

We could regulate and ban fossil appliances. However, for fear of upsetting voters in the 5-year parliamentary cycle, our government has effectively not raised road fuel duty for 10 years, so simply putting up the price of gas or banning it in favour of currently more expensive technologies is unlikely to be on the table.

We could hope for a voluntary shift; by getting consumers to understand why change needs to happen, what the options are and how they will impact each household or business. Awareness of climate change and the need for decarbonisation is at an all-time high, heat pumps have been making the tabloid headlines(!) and with COP26 in Glasgow later this year it will be nearly impossible to not be aware of the need for change. However, many barriers remain and I would argue that one of the largest is to do with risk aversion.

A more collaborative approach is needed, consumers need to be aware of the reasons for change of course, but this interruptive change also needs to offer benefits to each of us and our local communities; eliminating fuel poverty and housing related illnesses; offering improved comfort; and reducing or maintaining current levels of energy bills.

Understanding the consumer perspective – the return of solar thermalFigure 3

Looking at the (now-closed) Green Homes Grant (GHG) statistics, I was intrigued to see that after cavity wall insulation, solar thermal was one of the most popular technologies under the scheme.

At the time of writing over 13,000 applications have been made for a GHG voucher to support a solar thermal installation. That is more applications than have been made for domestic RHI support in the entire six years that the scheme has existed. To date 2,569 systems have been installed under the GHG, more than have been installed in the last five and a half years under the domestic RHI[4],[5].

I have a lot of experience installing and servicing solar thermal, it is a great technology and I see no reason why it shouldn’t be popular under a grant scheme. This got me thinking about what low carbon technologies have proven popular with householders to date, why, and how we might use this to understand the barriers to mass decarbonisation of heat.

What works

From my time spent in the industry designing and installing low carbon technologies for homeowners, it is clear to me that separation of the solution from daily life really helps popularity, this can be broken down into two factors:

The risk factor: for example, if a solar PV system stops working, say the inverter breaks, this is something that needs resolving, but no one is cold, unwashed or in the dark. This has allowed PV to flourish as a popular solution.

The disruption factor: for example, fitting an EV charger requires an electrician to put a box somewhere outside the house and then run some cable internally. The impact on the home is minimal. The same could be said for other popular low carbon techs like PV or solar thermal.

The confusion factor: Something I think those in the sector often underestimate is how ‘obvious’ a technology and its benefits are. It is clear that an EV is a car without the pollution, solar PV provides free electricity when the sun shines, solar thermal provides free hot water when the sun shines.

I think about these key factors as creating a ‘risk’ footprint, the bigger it is, the less likely someone is to go ahead and install a technology. So, we could look at our solar thermal example in this way:

  1. Confusion: It’s pretty obvious what it does.
  2. Risky: Fairly low risk – simple and well established, although the installer base is relatively small, boiler backup in case it breaks.
  3. Disruptive: Low in terms of disruption – it’s mostly on the roof, you’ll just need to move your towels out the cylinder cupboard for a day.
  4. Costly: without a grant, even with the RHI, it is expensive compared to using an existing heat source, and hard to justify on a ‘payback’ basis.

Mapping this out with some slightly arbitrary scores based on my views gives you a risk footprint, with and without the GHG. I’ve given a lower risk score under the GHG on the grounds that the scheme helps the industry grow and therefore support should be better.

Figure 4

To me, this makes it clear why solar thermal has been so popular under the GHG, something with an already low ‘risk footprint’ has the biggest issue, cost, removed and so becomes appealing.

Applying this to replacement heating systems

We can take this approach and apply it to a homeowner currently considering replacing their gas boiler, aware perhaps that they should do something low carbon and invest in a heat pump. Here is how I think a lot of people would rank the decision after they have made a few enquiries with their current gas engineer, some local heat pump installers and perhaps even an energy advisor:

  1. Confusion: high – a fridge but backwards? Low flow temperature heat emitters? You think I should have my heating on 24/7?
  2. Risky: quite high- unknown technology (to most consumers), performs in a different way to gas, reliant on being well designed and installed, a small installer base, same running costs as gas (if all goes well, but could be higher), unknown residual value when selling property
  3. Disruptive: quite high. Longer duration than a boiler swap, new appliances in new locations, probable fabric and radiator changes needed so most of the home impacted.
  4. Costly- without a grant, even with the RHI, it is expensive compared to using an existing heat source, and hard to justify on a ‘payback’ basis.

Figure 5Figure 6

Building this understanding into future policy

So, whilst heat pumps can offer an effective heating solution, there are currently too many barriers stacked against them in comparison to the gas boiler to see mass adoption. Hopefully, this is useful in highlighting why a simple regulation or grant scheme would not drive the change we need to see. A package of solutions needs to:

  • Understand end users, what they want and need from heating systems. e.g. do they want a future built around flexibility to optimise energy networks, or do they want energy networks to be built around human needs and patterns of behaviour?
  • Improve technology awareness and understanding.
  • Demonstrate quality and improve trust – who is trusted?
  • Support consumers until capital cost can be driven down – will the incumbent gas boiler industry deliver this cost reduction or, as with EVs will we see a Tesla/Arrival disrupting the century old production-line approach?
  • Reduce running costs to offer an advantage over fossil fuels.
  • Embed residual value of low carbon in property purchase and rental values – it needs to be as good as a nice bathroom or kitchen.

What am I hoping we can learn from this? Perhaps I am in a bubble, but I often feel that approaches to climate change mitigation are either focussed heavily on what is technically possible, or on convincing ‘early adopters’ to invest in shiny new technology. The difference with net zero is that everyone needs to change, and most consumers have different needs motivations and capacity to effect change. We need to better understand consumers and how we can bring everyone along on the journey to net zero.

In the future I intend to explore issues that the breakdown of a one-fuel nation might bring, and how this might impact a ‘just transition’ – potentially regionalising fuel costs, fuel poverty and exacerbating the north-south divide.

I’m really interested to hear from others in the sector looking at these problems, particularly whether there are historical parallels, such as the shift since the 70’s to most homes having central heating, that we can learn from.


[1] Clearly off-gas heating is also relevant to this discussion. The fact that households currently off-gas are more likely to be in fuel poverty feeds into a separate topic for another day around regulation and the distributional impacts of multi-source approaches to heat decarbonisation.

[2] According to BEIS research 50% of people don’t bother to switch off heating and lighting on when going out for a few hours.

[3] https://www.gov.uk/government/statistics/green-homes-grant-voucher-release-june-2021

[4] https://www.gov.uk/government/statistics/rhi-monthly-deployment-data-february-2021

[5] https://www.gov.uk/government/statistics/rhi-monthly-deployment-data-february-2021

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