Yesterday the UK Prime Minister set out his “ambitious ten point plan for a green industrial revolution which will create and support up to 250,000 British jobs.”
The plan, which is fleshed out in a more detailed booklet, covers offshore wind, hydrogen, nuclear, electric vehicles, public and active transport (walking, cycling), jet zero and greener maritime, homes and public buildings, carbon capture, nature-based solutions and innovation and finance.
Our response focuses on energy efficiency, standards gone AWOL, the hydrogen red herring and the problem with heat pumps.
Whither energy efficiency?
As we recently explained in our response to the BEIS Strategy Committee Inquiry on decarbonising heating in homes, heating is part of a wider system that delivers comfort. As a result:
“If a policy is targeting saved carbon as its metric then it will need to focus on delivering affordable comfort. This means that we need to consider both the de-carbonised provision of heat/cool and also vastly improved building fabric performance. Undertaking the latter will require less energy to attain comfort and so make the former much easier to achieve.”
The role of energy efficiency in significantly decreasing the (avoidable) costs of transitioning to a low-emissions energy system is recognised by the to-be extended £3bn Green Homes Grant programme, the Social Housing Decarbonisation Fund and the Future Homes Standard.
However, a clear strategy and effective mechanisms to deliver these upgrades at the scale and depth required is currently missing and urgently required. Guidance on the minimum standards for retrofit to be achieved, along with triggers for improvements are also needed. Following the collapse of the green deal, innovation within supply-chains and large-scale training and skills development is also urgently required to deliver retrofits at the required scale with minimum inconvenience to occupants (e.g. see Energiesprong).
We have previously estimated that we need to spend ~£330bn (~£11bn a year for 30 years) on the investments required to bring the UK housing stock up to an appropriate standard. Doing so could reduce heat and hot water energy demand by 55% and go a very long way to avoiding the need for costly energy supply-side techno-fixes and over-build.
We should not be put off by the apparent scale of the capital investment required:
- £11bn/year represents only ~10% of the annual NHS budget or ~3 times the recently announced annual uplift to the MoD budget;
- the £, CO2e, health and well-being co-benefits ROI are close to inarguable (Committee on Climate Change, 2019);
- as a result, significant private (green) capital could be mobilised – although expecting £3-4bn public investment to leverage a further £325bn private capital is a big ask.
Since low carbon comfort is synonymous with highly efficient buildings, it is therefore crucial that the UK legislates, via the forthcoming Future Homes Standard, to ensure that both new builds and refurbishments should have the highest fabric-first standards possible through mandating the lowest practically achievable energy intensity. Options include the PassivHaus new build space heating standard of 15 kWh/m2 alongside their equivalent 25 kWh/m2 retrofit (EnerPhit) standard (Passivhaus Trust, 2019). It is worth noting that New Zealand has just closed a consultation on exactly this approach for new builds as a pathway to a similar standard for retrofits.
At the same time, it is important to resolve rebound and pre-bound issues (Teli et al., 2016; Aragon et al., 2018; Bardsley et al., 2019) and to ensure that building retrofit strategies do not result in a transition from winter heating to summer overheating risk.
The hydrogen red herring
Point 2 of the plan covers low carbon hydrogen and highlights the impact: “lower carbon heating and cooking with no change in experience for domestic consumers through hydrogen blends and reducing the emissions of the gas used by up to 7%”. This speaks for itself; while hydrogen may have an important role in many aspects of industry and transport in the future, in terms of providing heat to homes it is at best a niche application and at worst a red herring (Lowes et al., 2020). The existing gas transmission, distribution and combustion infrastructure cannot handle a high proportion of hydrogen without significant changes.
We do however see a role for hydrogen in cities where there are heat networks supplying heat through combined heat and power engines and geothermal plants. Converting the engines to hydrogen is now feasible in the short term and offers a low-carbon solution if low-carbon hydrogen production can be achieved. Such systems could also be coupled with large-scale ground source heat pumps to augment heat supply. These options could address hydrogen-based heating at scale and provide the needed demonstrators for the UK.
The trouble with Heat Pumps
Air Source Heat Pumps (ASHP) offer a decarbonised heat pathway attractive for deployment at scale, in both retrofit and new build contexts. Where ASHP is to replace heating systems in existing dwellings, a whole-house approach will be required to maximise the benefits of the technology with respect to performance, customer experience and wider energy system-scale benefits (e.g. reduced peak demand, increased flexibility).
Unfortunately, analysis of the use of heat pumps, especially when used to heat air inside a dwelling or when the buffering potential of a hot water storage cylinder is absent, suggests that they may add substantially to morning and evening peak electricity demand peaks in some areas (Anderson et al., 2018; Eggimann et al., 2019). Even without this extra demand, these peaks are problematic for a renewables-based electricity system. As a result, sufficient energy storage whether thermal, grid (or local) based or through system flexibility will be needed to ensure that air source heat pumps do not inadvertently increase the carbon intensity of supplied electricity as the CIBSE response to the Future Homes Standard consultation made clear. Again, upgrading the thermal envelope of existing dwellings to reduce heat demand should be prioritised to minimise the impact of electrifying heat on peak demand (and low-voltage distribution networks). In addition, charging mechanisms which support the flexible aggregation of domestic loads by electricity providers to maintain grid demands within limits will be required. Households may have to accept third party control of significant loads (electric vehicles, heat pumps, hot water – as has historically been the case in France and New Zealand), and scheduling / dynamic control by their energy provider in return for a preferential tariff.
In other words, heat pumps as a solution to low-carbon heat implies more than just a ‘simple’ heat-source switch – there will be a multitude of second order consequences for the system that delivers low-carbon comfort.
Recognising that low-carbon comfort (Chappells & Shove, 2005; Shove et al., 2008; Ormandy & Ezratty, 2012) is a systemic problem (not just a heat technology problem) matters because it can only be fixed by a combination of:
- Stringent fabric-first design and retrofit standards via the Future Homes Standard to significantly reduce the amount of energy required to achieve comfort and…
- Reducing the carbon intensity of the (reduced) energy that is still required.
We therefore welcome the integrative aspects of the 10-point plan that respond to this systemic view by setting out both fabric-first efficiency and low-carbon energy supply interventions. This must not, however, be compromised during the plan’s implementation period. This is particularly the case when we recognise the labour-intense nature of energy efficiency retrofits and their potential to radically reduce the scale and cost of the energy supply-side transformations required for zero-carbon comfort. There is always a risk that ‘easy’ techno-solutions, such as many of those foregrounded in the 10-point plan, will find themselves prioritised over more difficult and less newsworthy fabric efficiency programmes. This must not be allowed to happen…
Anderson, B., Rushby, T., & Jack, M. (2018, November). Electrifying Heat: Patterns of electricity consumption in electrically heated households in the UK and New Zealand. 8th International Conference on Energy and Environment of Residential Buildings. 8th International Conference on Energy and Environment of Residential Buildings, Wellington, New Zealand.
Aragon, V., Teli, D., & James, P. (2018). Evaluation of retrofit approaches for two social housing tower blocks in Portsmouth, UK. Future Cities and Environment, 4(1).
Bardsley, N., Büchs, M., James, P., Papafragkou, A., Rushby, T., Saunders, C., Smith, G., Wallbridge, R., & Woodman, N. (2019). Domestic thermal upgrades, community action and energy saving: A three-year experimental study of prosperous households. Energy Policy, 127, 475–485.
Chappells, H., & Shove, E. (2005). Debating the future of comfort: Environmental sustainability, energy consumption and the indoor environment. Building Research & Information, 33(1), 32–40.
Committee on Climate Change. (2019). Net Zero—The UK’s contribution to stopping global warming.
Eggimann, S., Hall, J. W., & Eyre, N. (2019). A high-resolution spatio-temporal energy demand simulation to explore the potential of heating demand side management with large-scale heat pump diffusion. Applied Energy, 236, 997–1010.
Lowes, R., Woodman, B., & Speirs, J. (2020). Heating in Great Britain: An incumbent discourse coalition resists an electrifying future. Environmental Innovation and Societal Transitions, 37, 1–17.
Ormandy, D., & Ezratty, V. (2012). Health and thermal comfort: From WHO guidance to housing strategies. Energy Policy, 49, 116–121.
Passivhaus Trust. (2019). Passivhaus the route to zero carbon?
Shove, E., Chappells, H., Lutzenhiser, L., & Hackett, B. (2008). Comfort in a lower carbon society. Building Research & Information Volume 36, 2008 – Issue 4: Comfort in a Lower Carbon Society
Teli, D., Dimitriou, T., James, P. A. B., Bahaj, A. S., Ellison, L., & Waggott, A. (2016). Fuel poverty-induced ‘prebound effect’ in achieving the anticipated carbon savings from social housing retrofit. Building Services Engineering Research and Technology, 37(2), 176–193.