Meeting the UK government’s net zero emissions goal for 2050 will only be possible by complete decarbonisation of the building stock (both existing and new). There is uncertainty over the extent to which heating might practically be decarbonised in the future and what the optimal technologies may be. This paper provides some clarity about the pathways forward, focusing on the next 5-10 years.
Almost all of the UK’s 29 million homes will require upgrading by 2050, that is about 1 million homes per year, and is equivalent to more than 19,000 homes per week. Current retrofit rates are inadequate for achieving even a significant portion of the required level of decarbonisation to meet the 2050 targets.
The replacement of fossil fuel-based heating systems is happening at an even slower pace. In 2018 only 27,000 heat pumps were installed in the UK and the vast majority of new build homes were connected to the gas grid. As a result, the proportion of homes heated by gas is increasing.
The well-established UK TIMES model was run to analyse UK futures that span both ambitious emission targets and more liberal technology investment options and includes two pathways, conservative and progressive (which explores increased freedom in choosing heating system options across the sector).
Results highlight the scale of change required in the residential sector. Figure 1 shows how the share of the technologies change with increasingly ambitious carbon reduction targets, depicting conservative and progressive scenarios, relative to 1990 levels.
Taken together, the results highlight the significance of the change that is required to move towards the new net zero emissions target for the UK. Residential heat supplied via natural gas in 2050 is near halved for an 85% emissions reduction target and is non-existent beyond a 95% reduction. Instead, results suggest a dominant role for energy efficiency (termed conservation), community heating (in majority heat pump based), and individual air source heat pumps.
Figure 1. Heat decarbonisation meeting different emissions targets
It is extremely unlikely that heat decarbonisation will be achieved without significant policy interventions. Fundamentally it is important to recognise that the speed and scale of the required heat transformation means that relying on consumer led schemes such as the RHI and the planned Clean Heat Grant, are not sufficient. Incentives for consumers need to be part of a suite of policy measures based around skills, financial support and packages, local area-based planning approaches and cross-industry strategy will be needed.