Evaluating carbon emissions reduction due to the uptake of heat pumps

Air source heat pumps are one of the most promising solutions for decarbonising domestic heating in the UK. However, the extent of their decarbonisation potential is dependent on a number of factors. This study aims to explore the greenhouse gas reduction capabilities of a  heat pump uptake, in the houses currently using gas boilers for specific local authorities. Three different regions in England and Wales were chosen for this study: South Wales, North East England and South England. Furthermore, within each of these regions, at least one predominantly urban local authority was selected. This is to account for the difference in housing characteristics such as floor area. Therefore, local authorities selected were Powys, Cardiff, Vale of Glamorgan, Newcastle upon Tyne, Northumberland, Reading West Berkshire.

In this study, three different house models, including terraced, semi-detached and detached were created within each local authority for calculating heat demand and % reduction in carbon emissions. The annual heating demand for each local authority was then estimated using modelling techniques, alongside temporal, housing and heat flow data. For households with natural gas boilers, the annual greenhouse gas emissions were calculated using typical boiler efficiency (84%). For households with heat pumps, the annual carbon emissions were computed using regional carbon intensity data.

The heating load for the year 2022 (in GWh) for local authorities was calculated as 210 for West Berkshire, 180 for Reading, 680 for Northumberland, 410 for Newcastle, 170 for Powys, 230 for Vale of Glamorgan, and 450 for Cardiff. Seasonal performance factor was observed in close range of 2.3 for all the local authorities in the same year. Finally, the carbon emissions reduction for replacement of 5% of boilers with heat pumps was noted to vary from 2.2 to 2.6% for all the local authorities.

Furthermore, this study revealed that the Carbon Reduction of a local authority was linearly related to the overall heating demand in that local authority, which is an expected result. When considering the base model conditions, the biggest factors influencing the heating demand between different local authority were the number of houses, the split of houses (between detached, semi-detached and terraced) and the average outside temperature. The local authority which performed best on both metrics mentioned was Northumberland, which had many of the prior factors working in its favour. However, it was also determined that other strategies should be implemented to reduce heating demand, alongside the deployment of heat pumps, such as insulation or demand side reduction.

The preliminary results for this work were obtained as part of the ‘Barocaloric materials for zero carbon heat pumps’ project funded by the Engineering and Physical Sciences Research Council (EP/V042262/1).