The effect of a nuclear baseload in a zero-carbon electricity system: An analysis for the UK

This paper explores the effect of having a nuclear baseload in a 100% carbon-free electricity system The study analyses numerous scenarios based on different penetrations of conventional nuclear, wind and solar PV power, different levels of overgeneration and different combinations between medium and long duration energy stores (hydrogen and compressed air, respectively) to determine the configuration that achieves the lowest total cost of electricity (TCoE). At their current cost, new baseload nuclear power plants are too expensive. Results indicate the TCoE is minimised when demand is supplied entirely by renewables with no contribution from conventional nuclear. However, small modular reactors may achieve costs of ∼£60/MWh (1.5× current wind cost) in the future. With such costs, supplying ∼80% of the country's electricity demand with nuclear power could minimise the TCoE. In this scenario, wind provides the remaining 20% plus a small percentage of overgeneration (∼2.5%). Hydrogen in underground caverns provides ∼30.5 TWh (81 days) of long-duration energy storage while CAES systems provide 2.8 TWh (∼8 days) of medium-duration storage. This configuration achieves costs of ∼65.8 £/MWh. Batteries (required for short duration imbalances) are not included in the figure. The TCoE achieved will be higher once short duration storage is accounted for