Going off the Gas Grid.
The Committee on Climate Change recently issued a report describing why the UK housing stock is not fit for purpose and recommended possible changes to improve the efficiency of housing stock and reduce our carbon emissions. This included a recommendation that all new properties should not be connected to the gas grid by 2025.
While not going as far as the Committee on Climate Change, in his spring statement, the Chancellor acknowledged the need to move to greener energy when he stated that “to help meet climate targets, the government will advance the decarbonisation of gas supplies by increasing the proportion of green gas in the grid, helping to reduce dependence on burning natural gas in homes and businesses”.
In this article we consider the Committee on Climate Change’s report, considering the recommendation in more detail and the alternatives to gas central heating.
Who are the Committee on Climate Change?
The Committee on Climate Change (CCC) is an independent, statutory body. They were established under the Climate Change Act 2008 and advise the UK Government on emissions targets and report to Parliament on climate change.
The Committee on Climate Change said: “We will not meet our targets for emissions reduction without near-complete decarbonisation of the housing stock.”
The key messages within the CCC report are:
- UK homes are not fit for the future
• Performance and compliance of new homes falls short of design standards
• There is a skills gap in housing design, construction and installation of new measures
• Existing homes across the UK must be retrofitted and made low-carbon and low-energy
• New homes must be built to be low-carbon, low-energy, water-efficient and climate-resilient. No new homes should be connected to the gas grid
• There are urgent funding needs which need to be addressed with the support of HM Treasury
• Householders must make a big difference with small changes
The report suggests that by 2025, at the latest, new homes should no longer be connected to the gas grid. Instead, they should be fitted with low-carbon heating systems such as heat pumps and low-carbon heat networks. But even before the 2025 target date, the CCC says that newly built homes could be made ‘low-carbon ready’. This could be achieved by, for example, using radiators compatible with heat pumps and low-temperature compatible thermal stores. The space heating demand should also be significantly reduced to 15-20 kWh/m², achieved by the combination of a heat pump and excellent thermal insulation.
UK Energy Use
The report states that according to the Department for Business, Energy and Industrial Strategy (BEIS) 2018 document Energy Consumption in the UK, heating and hot water production for UK homes makes up 25% of total energy use.
While it is clear, from reports such as The Clean Growth Strategy, that the UK has made vast improvements in reducing emissions, especially since 1990, we still have a long way to go to meet our 2030 obligations – to achieve a reduction in greenhouse gas emissions of 40% below 1990 levels. However, the CCC said, “Greenhouse gas emission reductions from UK housing have stalled”.
The graph in Figure 1 shows the differences between the average energy demand for an existing home in comparison to new homes. It shows how drastic reductions in energy use and hence carbon emissions are possible in the domestic sector. The data illustrates how the current build standards will not achieve space heating demand of 15 kWh/m, which is the level of energy use the CCC is proposing, although installing air source heat pumps in new homes will reduce the space heating energy requirement. The data also highlights the need for an insulation first approach. It would be ineffective to have an ultra-efficient heating system if the property is not well insulated. What is also interesting is the different proportions of household energy use and how this varies for new and existing homes. For new-build highly efficient properties the appliance use is more than double the combined space and water heating
energy. Conversely, for existing build properties the appliance use is less than 25% of the overall energy use. This emphasises the need to address the current housing stock as well as new-builds.
Figure 1 – Image Source: CCC
The below chart is from the Department for Business, Energy & Industrial Strategy’s statistical press release for the 2018 UK Energy Statistics and it shows the percentages of fuels used for electricity generation last year, 33.3% of which was generated from renewables which was a record high, 39.4% was generated from gas and coal produced a record low of just 5%.
Figure 2 – Image Source: BEIS
The report confirms that gross gas production decreased by 3.1% compared to 2017 and gas used for electricity production fell by 4.7% as electricity generators made more use of renewable sources.
As clearly illustrated in Figure 1, installing air source heat pumps could be one of the suggested alternatives to the traditional gas central heating system.
Air source heat pumps work by absorbing heat from the outside air to produce useful heat. With an average efficiency of 300% this means that for every 1 kWh of electricity input, 3 kWh of useful heat is produced.
However, retrofitting heat pumps to existing homes can be problematic. Heat pumps operate at a lower temperature than most gas boilers and hence need larger radiators to achieve the same internal temperatures. This is why they are usually installed alongside an underfloor heating system. This makes air source heat pumps a very disruptive solution as a retrofit measure, hence the CCC suggestion that it would be sensible to install the correct emitters in new properties at the build stage if we want to future-proof our homes.
It seems as though the CCC report has ruffled feathers. At the Business, Energy, Industrial Strategy (BEIS) Committee meeting in March of this year, during an oral evidence session on Energy Efficiency, Group Planning Director of UK house builder Persimmon, Peter Jordan, referred to the report stating: “The key issue that came out of the report, for me, is whether or not the solution of air source heat pumps, or rather a gas solution to it, is the correct way to go. The whole industry needs to come together to find the correct solutions to this.”
And, laudable as the ambition is, as Chief Executive Officer of Barratt Homes, David Thomas pointed out: “There is not necessarily the supply chain of all the materials in place that you would need to build carbon-neutral homes on an industrial scale, so that supply chain needs to be addressed.”=
Will heat pump suppliers keep up with demand? Will gas boiler manufacturers evolve and design more electric boilers? We can only watch this space.
Because we live in a society that is used to cooking and heating with gas, the recommendation that all homes should give up gas and go all-electric has been picked up in several news articles. Some articles have suggested that all-electric new homes will struggle to sell in comparison to homes with gas. This is understandable where estate agents’ particulars always list if a property has gas central heating.
Understandably, there is a degree of concern as to how this will impact on consumers and businesses. That said, we are starting to see more incentives to encourage buyers to choose a more energy-efficient home. For example, the Barclays Green Mortgage gives customers a lower mortgage rate if the home has an energy efficiency rating of 81 or above (bands A or B).
The Domestic Renewable Heat Incentive (RHI) is also available. This is a government scheme to promote the use of renewable heat from air and ground source heat pumps, solar thermal and biomass. Those who join and follow the requirements can receive payments based on the amount of clean, renewable heat their system produces.
Changes to SAP
The methodology used for assessing the energy efficiency of buildings is the Standard Assessment Procedure (SAP). The latest version, SAP 10, has recently been published, although a date for its commencement has yet to be decided. Amongst other changes, SAP 10 sees a drastic reduction in the carbon emissions factor for electricity, reflecting the decarbonisation of the grid. CCC state that the emissions factors for electricity in SAP 2012 fail to properly value the benefits of low-carbon technologies. Currently, the carbon emissions factor at 0.519kgCO₂ for electricity is more than double the emissions factor for gas. As new-builds use carbon rather than costs for Building Regulations compliance, this makes gas a more attractive heating fuel. With SAP 10, electricity will be a much more viable heating fuel for new-builds as the electricity carbon intensity will be set to 0.233kgCO₂.
Electricity continues to be more expensive than gas per kWh; however, building homes with excellent thermal insulation will reduce the space heating demand (see Figure 1). This coupled with high efficiency heat pumps will see affordable energy costs for the householder.
We have seen the number of homes with gas central heating increase from 73% twenty years ago to 85% today. This reflects the fact that only 14% of homes in the UK are off the gas network. Will we see a downward shift in this number with a push towards electricity as the main heating fuel? Will householders be happy to give up their gas hobs? These are questions that form part of the ongoing discussion, but one thing we do know is that action needs to be taken so that we reach our emission reduction targets and we must play our part in reducing our carbon footprint.