Large-capacity, long-duration energy storage enhances grid resilience when used in combination with intermittent or highly variable generation. Stored energy can be dispatched when needed, improving grid reliability, especially during periods of high demand or during outages. Energy storage also reduces the need for curtailment of renewable energy during periods of high output and low demand. 

Arup has assessed, designed and delivered pumped storage hydropower, dams and tunnels throughout the world, working on some of the largest and most complicated schemes. As with any major energy infrastructure project, PHES site selection is a complex task that requires careful consideration of the social and environmental characteristics of an area, as well as the engineering challenges. 

A thorough technical understanding of the topography, geology and flood risks is important, but developers also need to appreciate the character and heritage of the landscape while respecting the local ecology and biodiversity, and local community perceptions and aspirations to make each facility as sustainable as it can be. Retrofit assets offer opportunities to use sites that may be already adapted to hydro power and bring additional benefits to the local environment and communities.