Plans have been unveiled for a 300 MW pumped storage hydropower project on a Scottish island.

Local company Eishken plans to build the project on the Isle of Lewis, the largest island of Scotland’s Outer Hebrides.

Eishken said that the project will store electricity that is principally generated by windfarms on Lewis. It will also double the use of the Western Isles Link, a cable being installed by National Grid to export and import electricity generated from renewables on the islands.Pumped storage planned for Isle of Lewis

The proposed scheme will be adjacent to and form part of the 162 MW Muaitheabhal wind farm, which already has planning consent.

Eishken said that this “will permit part of the output of the wind farm to be stored until required, allowing it to balance the sometimes intermittent nature of wind”.  

Nick Oppenheim of Eishken said: “There are very few pumped storage hydro schemes throughout the UK and what we are proposing is particularly innovative given the use of the sea as the lower reservoir.  This scheme will not only materially enhance the benefits to be derived from the Western Isles link but will make a material difference in the supply of energy to the mainland. It will also be a key element in the Scotland’s renewable energy armoury.”

He added that “although using the sea as the lower reservoir is new to the UK, the technology is proven in Asia”.