Long Duration Battery Storage Powers UK Grid Resilience

by David Lewis | published 16 June 2025

In a ground-breaking step toward enhancing the UK National Grid’s resilience, Root Power has submitted plans for four long duration energy storage projects totalling 300 MW/2.4 GWh under Ofgem’s newly launched cap and floor scheme.

Designed to buffer intermittent renewable energy, these 8 hour vanadium flow battery systems – sited across West Yorkshire, North Yorkshire, Buckinghamshire, and Lincolnshire – represent a strategic shift from typical 2-4 hour lithium ion setups to technologies better suited for prolonged grid support.

Balancing the Grid

Such systems can store surplus electricity during periods of high wind or solar output and dispatch it when demand peaks or renewable generation dips. This capability supports grid stability, mitigates volatility, and ensures continuity of supply – a necessity as the UK transitions toward a renewables-dominant energy mix.

Of particular importance is Ofgem’s cap and floor mechanism, designed by the Department for Energy Security & Net Zero (DESNZ), National Energy System Operator (NESO), and Ofgem to de-risk investment in long duration storage. Guaranteed minimum revenue makes these projects financially viable, attracting backing for much needed large scale installations. Vanadium flow batteries, though rare in the UK, are ideally suited for this role given their capacity for sustained energy delivery.

Long Duration Storage

Root Power’s move builds on its 40 plus battery projects, including a 34 MW/68 MWh Highland project in Scotland, underscoring a growing portfolio aimed at tackling grid intermittency. As renewable generation increases, the grid risks periods of oversupply followed by steep demand spikes. Storage assets like these serve as buffer zones – absorbing excess, smoothing dispatch, and furnishing rapid response backup.

By securing large scale, long duration storage deployment, the National Grid bolsters its resilience against both expected energy dips and unforeseen disruptions. Such infrastructure supports frequency response, peak shaving, and ramp rate control – integral to maintaining a secure, clean, and flexible energy system.