Electrified heat and transport: Energy demand futures, their impacts on power networks and what it means for system flexibility

Demand electrification, system flexibility and energy demand reduction (EDR) are three central tenets of most energy system decarbonisation pathways in the UK and other high-income countries. However, their combined impacts on local energy systems remain understudied. Here, we investigate the impact of different UK energy demand future scenarios on the loading of local electricity networks, and the ability of electrified demand to act flexibly in (i) mitigating the need for network reinforcement and (ii) shifting demand around according to variable tariffs reflecting wider system needs. These scenarios are used to drive spatially- and temporally-explicit technology uptake and energy demand modelling for heating and transport in a localised context, for application to a local electricity network. A particular case study energy network in Scotland, representative of many networks in the UK and Northern Europe, is selected to demonstrate the method. On the basis of the presented case study, which considered a typical winter demand day, energy futures based on EDR policies were found on average to reduce evening transformer loading by up to 16%. Further reductions of up to 43% were achieved with flexible smart charging and up to 69% with the use of vehicle-to-grid. Therefore, we find that policies focused on EDR can mitigate the need for reinforcement of electricity networks against the backdrop of demand electrification. However, flexibility in electricity demand contributes a larger difference to a network's ability to host electrified heat and transport than relying solely on EDR. When used in tandem, policies that simultaneously pursue EDR and electricity system flexibility are shown to have the greatest benefits. Despite these benefits, peak electricity demand is very likely to increase significantly relative to the current baseline. Therefore, widespread reinforcement is required to local electricity networks in the net-zero transition and, accordingly, urgent investment is required to support the realisation of the UK's legally-binding climate goals.