Energy storage against interconnection as a balancing mechanism for a 100% renewable UK electricity grid

This study considers generation and demand challenges of a 100% renewable UK electricity grid and how this could be addressed with interconnection or energy storage. Hourly demand and electricity generation profiles for a year have been constructed: Business as Usual (BAU) with a yearly demand of 540 TWh and Green Plus (GP) with a demand of 390 TWh, Two further scenarios based on the above have been considered with electrification of heating (ASHP) and electric vehicle transportation (EV). The resultant hourly imbalances have been used to calculate the interconnection and energy storage requirements. This paper discusses the findings of the BAU scenario. The calculated interconnector capacity required was found to be 60 GW and cost £58 billion. Energy storage capacity requirements vary depending on the selected technology. Rated capacity was estimated to be 14 GW with storage capacity of 3 TWh for pumped storage, 11 GW and 2.3 TWh for liquid air, and 65 GW and 13.6 TWh for hydrogen storage, at a cost of £65, £76 and £45 billion respectively. This paper indicates that storing hydrogen in underground caverns would offer the cheapest solution. However, whilst these technological solutions can address generation and demand imbalance in a fully renewable electricity grid, there clearly remain barriers to each technology.