Abstract
The transition to net-zero electricity systems requires an effective integration of energy storage across multiple timescales to balance renewables intermittency and provide flexibility. However, the impacts of large-scale multi-timescale storage deployment on power system under evolving technology and policies remain unclear. Through hierarchical modelling of short-(battery), medium-(pumped hydro, compressed air, thermal), and long-duration (hydrogen) storage, this study develops a multi-period optimisation framework to explore how grid-level multi-timescale energy storage integration affects the United Kingdom's power system performance and configuration in 2035 and 2050 under different scenarios of technology advancement, renewable energy availability, and emission reduction pathways. Results reveal that power systems with multi-timescale storage outperform those with only short-duration storage in terms of both cost and carbon emissions, with 22% lower cost and 25% lower emissions in 2050. In a power system with different energy storage types of varying storage durations, advancements in storage technology that lower storage costs reduce electricity costs in 2050 by 7% under the fast technology advancement level compared to the base level. A more ambitious emission reduction target in 2035 increases electricity costs (18%) but significantly lowers carbon emissions (73%) compared to the base target. With unlimited renewable capacity caps, system's electricity costs decrease by 23% and carbon emissions fall by 13%, in 2050 compared to the base cap level. These findings highlight the crucial role of multitimescale energy storage in achieving cost-effectively net-zero power systems and underscores the importance of integrated planning that jointly considers technology improvement and the policy environment.