Life Cycle Sustainability Assessment of the Electrification of Residential Heat Supply in UK Cities

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Abstract

The recent revival of urban living in the UK has been stimulated by many different factors, including life style choices and government policies. This has led to a rapid increase in the number of apartments in the UK cities. This increased density living has also brought about various changes in the city infrastructure, including the way energy is supplied to residential buildings. The recent trend of ‘electrification of heat’ represents one of these changes, whereby electricity rather than natural gas is now typically being used for space and water heating as well as for cooking. Further growth in electricity demand has been predicted in the governments Carbon Plan with the increased use of all-electric systems including heat pumps for domestic heat. This will in turn impact the environment since electricity supplied in the UK is predominantly based on fossil fuels and contributes to significant greenhouse gas (GHG) and other emissions. However, greater penetration of renewable sources in the future would be expected to reduce GHGs. This would also help to improve the security of supply through diversification of energy sources. On the other hand, there are concerns that increasing reliance on electricity could lead to fuel poverty for a greater section of society. Thus, it is not immediately clear whether the change from gas to electricity would contribute to the sustainability or otherwise of energy supply in the UK residential sector.Therefore, this research has set out to understand better the implications of the electrification of heat in the urban residential sector by examining the trade-offs between environmental impacts, techno-economic costs and social aspects. This work therefore goes beyond the previous research that has typically focused solely on GHG emissions and energy pay-back times of different energy options. This is also the first time as far as the author is aware that the sustainability of the electrification of heat in cities are analysed in depth. Various tools have been used for these purposes, including life cycle assessment (LCA), indoor air quality monitoring (IAQ), life cycle costing (LCC), social surveys (SS), scenario analysis (SA) and multi-criteria decision analysis (MCDA).Assuming all sustainability aspects considered here to be equally important, the most sustainable option is the district heating system. All-electric heat-providing systems (electric panel, electric storage, and air source heat pumps) have on average 2.5 times higher environmental impacts than gas-based systems (individual gas boiler, solar thermal and gas, district heating and community CHP systems). The techno-economic costs of all-electric systems are 80% that of the district heating system – however, fuel cost and demand changes increase substantially all-electric system cost vulnerability. Gas-based systems are widely accepted and valued - all-electric systems while a ‘good fit’ for particular city homes - have greater social impacts including affordability.If the proposed decarbonisation of electricity generation is realised, the global warming potential from electric heat-providing systems could be reduced to a 1/10th of present emission levels by 2050 increasing electrification of heat sustainability.Therefore, the choice of the most sustainable heat-providing options in the future, including that of the ‘electrification of heat’, will depend on the extent of the decarbonisation of the UK electricity supply and the relative importance placed on sustainability impacts by different stakeholders.

Keyword(s)

Electrification of heat; Life cycle assessment; Residential heat supply; Sustainability; UK cities

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