There is growing public concern about the vulnerability of the energy system to ‘shocks’ that go beyond what can be characterised as ‘normal’ disruptions to supply. To explore these ‘concerns’ an integrated energy supply systems model is utilised which allows energy ‘shocks’ to be applied to representations of the existing (2020) and two future energy systems in 2050. One configuration of future energy systems focuses on electrification of both heat and transport (Consumer Transformation), the other sees a majority of heating demand met by hydrogen boilers (System Transformation).
The integrated energy supply systems model includes representation of multi vector energy systems including gas, electricity, hydrogen and heat across transmission and distribution scales. The integrated nature of the model allows assessment of complex interactions between various energy vectors.
The energy shocks modelled are described in terms of magnitude, duration of shock, location and in terms of technology or supply failures. The energy shocks applied include a decline of wind speeds and by extension reduction in wind generation, a loss of nuclear plants, electrical interconnectors, and gas supply.
Given the relatively modest wind capacity connected to the energy system in 2020, a 50 % reduction in wind speeds for one day did not result in energy unserved. However, the impact of a single day gas shock across all supplies including domestic led to energy unserved. Across the peak hours this shock amounted to approximately 12 GW of energy unserved for gas industrial consumers. Currently this gap would be bridged through voluntary demand side measures. Overall, the simulations show that GB has a strong security of supply position and that it has sufficient diversity and capacity to meet the energy demand profiles modelled.
The reduction of wind speeds and loss of generation assets with mitigation measures, such as voluntary demand side response and Vehicle to Grid (V2G) disabled, led to energy unserved in the electrification scenario in 2050 (Consumer Transformation). A shock in wind speeds has a dramatic impact on energy unserved. A five-day shock results in more than 200GWh of unserved energy. With a one-day shock, unserved energy, averages 20-30GW every hour during the typical 3-4 hour peak demand period. This results in a large change in operational costs and energy unserved valued in the billions. The impact of shocks on electrical interconnector and nuclear generation supplies are smaller but still result in energy unserved.
The interdependency between the gas and electricity system in the System Transformation scenario in 2050 is reduced from year 2020 levels but is still significant with annual natural gas demand of 47 BCM. A gas supply shock of duration five days does not lead to energy unserved, as a response is observed with gas fired generation, hydrogen production switching to electrolysis and gas and hydrogen storage facilities withdrawing supplies to meet shortfalls.
The impact of a large reduction in wind speeds results in energy unserved albeit much lower than in the Consumer Transformation scenario. Less than 1GW of voluntary demand response over peak periods would eliminate energy unserved.
Greater storage capacity, battery or hydrogen, performed well in the Customer Transformation scenario although the change (reduction) in total cost of the shock is more pronounced in the case with more battery capacity. The roles are reversed in the System Transformation scenario where higher use of hydrogen for heating and larger reduction in energy unserved reduces overall costs by a larger amount. The simulations showed that Demand Side Reduction (DSR) lacks the capability to reduce all energy unserved, but if available it does provide the ability to shift limited amounts of energy demand to off-peak hours although the reduction in operational costs is modest across both scenarios. In contrast, the implementation of smarter EV charging and V2G services is able to eliminate energy unserved in both scenarios.
Additional authors:
This publication is also authored by Lixun Chi, Cardiff University