Net Zero in the heating sector: technological options and environmental sustainability from now to 2050

Heating and hot water within buildings account for almost a quarter of global energy consumption. Approximately 90% of this heat is derived directly from the combustion of fossil fuels, primarily natural gas, leading to the unabated emission of carbon dioxide. This paper assesses the environmental sustainability of a range of heating technologies and scenarios on a life cycle basis. The major technologies considered are natural gas boilers, air source heat pumps, hydrogen boilers and direct electric heaters. The scenarios use the UK as an example due to its status as a major economy with a legally-binding net-zero carbon target for 2050; they consider plausible future electricity and natural gas mixes, including the potential growth of domestic shale gas. The environmental impacts are estimated using ReCiPe 2016. Current gas boilers have a climate change impact of 220 g CO2 eq./kWh of heat, which could fall to 64 g CO2 eq./kWh for boilers fuelled by hydrogen derived from natural gas with carbon capture. Heat