The Project
The Earba Storage project is a proposed pumped storage hydro (‘PSH’) scheme with an installed capacity of 1,800MW.
The Earba project is the largest PSH scheme ever consented in the UK, both in terms of installed capacity (MW) and energy stored (MWh).
Pumped Hydro Storage
The Earba PSH project will store 40,000MWh of energy, making it the largest pumped storage hydro scheme in the UK by energy capacity. Its impressive generation and storage capabilities are matched by site conditions that are ideally suited to pumped storage hydro development. The geology and topography surrounding the existing lochs feature natural bowl-shaped formations, allowing relatively straightforward adaptation into upper and lower reservoirs that can blend sensitively with the surrounding landscape. The site also benefits from close proximity to the National Grid transmission network and excellent existing road access.
Pumped Hydro Storage
The Earba PSH project will store up to 40,000MWh of energy which will make it the largest such scheme in the UK in terms of energy stored. The impressive generation capacity and energy storage figures are matched by the site characteristics which are ideal for a pumped storage hydro project. This includes the geology and topography around the existing lochs which are natural ‘bowl’ shapes, and therefore allow straightforward modification to form upper and lower reservoirs which will blend sensitively into the local landscape. The National Grid transmission network is in close proximity to the site and there is excellent existing road access.
CO2 SAVINGS AND LOCAL EMPLOYMENT
The Earba Storage development would be a major civil engineering project, with construction expected to last approximately six years. During this period, the on-site workforce is anticipated to average around 500 people.
The Earba Storage project would deliver significant benefits to the UK, supporting both clean energy generation and long-term savings for electricity consumers. Its large storage capacity would enable substantial volumes of surplus wind energy, which might otherwise be curtailed, to be captured and reused. In doing so, the project would help reduce reliance on conventional gas-fired generation and lower carbon emissions.
The proposed scheme would also be capable of rapidly supplying clean electricity to the National Grid, enough to power more than 1.4 million UK homes, while helping to avoid over 2 million tonnes of CO₂ emissions each year.
The Location
The proposal is to use Loch Leamhain as the upper reservoir and Loch Earba as the lower reservoir.
A tunnel approximately 3km long will connect the two water bodies.
A powerhouse will be constructed on the shore of Loch Earba which will extend deep underground. The turbines will be located at the bottom of the powerhouse shaft and will generate electricity in times of national demand or pump water for energy storage in times when there is surplus electricity on the national grid.
Location
Loch Earba, Newtonmore, PH20 1BX
Why is Earba a great PSH project?
To make a meaningful contribution to the UK energy system, substantial additional capacity is needed in terms of both power output (measured in MW or GW) and stored energy (measured in MWh or GWh). The grid often requires rapid increases or reductions in power generation and absorption. This can occur when weather conditions change suddenly, during emergencies such as a nuclear power station outage, or when major events, such as a World Cup football match reaching half-time, cause sharp shifts in electricity demand. However, fast-response power alone is not enough to meet the system’s evolving needs.
As the UK moves away from a grid dominated by large, on-demand thermal power stations towards one increasingly reliant on intermittent renewable generation, balancing the system becomes more complex. Weather patterns, particularly changes in wind generation, are becoming a more significant driver of grid balancing requirements than traditional daily fluctuations in demand.
Managing extended periods of low or high wind generation, which can persist for many hours or even several days, requires long-duration energy storage. Long-duration energy storage (LDES) is often defined as storage capable of delivering energy for more than 8 hours. However, our analysis indicates that at least 15 hours of storage is needed to provide an optimal balancing service for the grid. As a result, the UK requires not only greater power capacity, but also significantly larger volumes of stored energy.
The Earba PSH project ticks both boxes:
The Earba project would provide both substantial generating capacity, with 1,800MW of power, and significant energy storage, with 40GWh of capacity. Compared with other pumped storage hydro (PSH) schemes, it ranks among the strongest projects currently proposed in the UK.
The chart below compares Earba (shown as the orange dot) with the UK’s four existing operational PSH schemes (blue dots) and other PSH projects currently in development (green dots), based on their power output and stored energy capacity. Earba’s position in the upper right-hand section of the chart highlights its status as one of the largest and most capable PSH developments in the country.
