Scottish and Southern Energy (SSE) has submitted an application to the Scottish Government for consent to construct the Coire Glas pumped-storage hydropower scheme at an increased capacity of up to 1500 MW. The UK multi-utility was granted planning approval for an £800 million, 600 MW plant in the Scottish Highlands in late 2013 but to maximize the potential of the site, located northwest of Loch Lochy in the Great Glen, it is now seeking permission to more than double its capacity.
The project, which would be the largest capacity hydropower project to be built in Scotland, and the first new pumped-storage scheme in the UK since the Dinorwig plant in Wales in 1974, would help meet the UK’s electricity needs, and act as “a natural complement to a low carbon energy system based on renewables”, SSE said in a press release on 18 April.
“Pumped storage can and does play a significant role in making the UK’s electricity system more efficient, reliable and secure for the future. Our Coire Glas project would more than double the total amount of current pumped-storage energy capacity in the UK,” it said. The Coire Glas scheme would have a storage capacity of up to 30 GWh, more than doubling the UK’s existing pumped-storage capacity of 24 GWh. SSE said it would take 20 hours to release the stored energy with the proposed 1500 MW capacity, compared to 50 hours for a 600 MW scheme, adding that the higher capacity would mean water could be moved in larger quantities, allowing for more “flexible operational options” to help either store energy or generate power depending on demand.
Pumped storage can and does play a significant role in making the UK’s electricity system more efficient, reliable and secure for the future.
Scottish and Southern Energy
Despite the obvious benefits that pumped storage offers, SSE said that progressing the Coire Glas scheme requires overcoming a number of commercial and regulatory challenges. These include changes in the existing transmission charging regime for pumped storage and a satisfactory and supportive long-term public policy and regulatory framework. Since obtaining consent in 2013, SSE said it had been working with key stakeholders including the Scottish Government, Department for Business, Energy and Industrial Strategy, OFGEM and other bodies with the aim of achieving recognition of the benefits that pumped-storage hydro will bring to the electricity market and its wider socio-economic benefits. According to a report commissioned by SSE, the UK consultancy Baringa found that Coire Glas would deliver benefits in social welfare of about £70 million per year and a reduction in customers’ bills of about £215 million per annum.
Moreover, SSE said the increase to the scheme’s capacity would entail “little change” to the current external elements of the project as the majority of changes would occur under-ground with an enlarged powerhouse to house the larger turbines and pass the increased flow rates of water. External elements, such as the dam, upper reservoir, construction access, jetty and administration building, will be similar in size and nature to that of the already consented development. Changes would include the inclusion of a surface intake tower and a surge shaft to respond to fluctuation in pressure, as well as expanded tailrace and outlet structures. The project design currently envisages the construction of an upper reservoir in a bowl-shaped valley, which would be impounded by a dam with a height above ground level of 92 m and a crest length of approximately 650 m. The nearby Loch Lochy would act as the lower reservoir, with an elevation of around 500 m between the reservoirs.
SSE owns and operates 1150 MW of conventional hydropower capacity at 50 stations in Highland, Perth and Kinross and Argyll and Bute, as well as the 300 MW Foyers pumped-storage facility.