Small-scale hydroelectric scheme – Glen Shira, Scotland
This scheme is in the mountains of Argyllshire, Scotland. The reservoir is 338m above sea level and was created by building a dam (725m long and 45m high) across Glen Shira.
Water released from Loch Shira passes through the 5MW Sron Mor power station sited on the shore of Lochan Sron Mor, a smaller reservoir just in front of the main dam. The water then travels from this head pond through tunnels and pipelines to Clachan Power Station, more than 7km away at the head of Loch Fyne.
An overhead view of Dinorwig’s lower reservoir, Llyn Peris.
Pumped storage hydroelectric power – Dinorwig Power Station, North Wales
Dinorwig Power Station, located adjacent to the Snowdonia National Park in Gwynedd, North Wales, is Europe’s largest pumped storage hydroelectric power station. It is also one of the fastest, most dynamic power plants in the world, capable of delivering its full station output of 1800 MW in only 12 seconds. This rapid response is strategically important to the GB electricity system in helping National Grid maintain the balance of supply and demand on a second-by-second basis across the network.
The power station complex was built deep underground, inside the Elidir Mountain, and beneath the old Dinorwig slate quarry. It sits between an upper reservoir at the top of the mountain, and a lower reservoir, in the valley below. Water falling from the upper reservoir is used to drive turbo-generators that supply power to the grid. The water is discharged into the lower reservoir, and, during off-peak periods, pumped back into the upper reservoir for future use. It was commissioned in 1984 and took nearly 10 years to plan and construct.
It is now owned by a joint venture of International Power plc (part of the GDF Suez group) and Mitsui & Co., Ltd. This joint venture also owns a second, smaller pumped storage station at Ffestiniog, some 30 miles from Dinorwig.
Community scale – Torrs Hydro Scheme, New Mills, Derbyshire
The local community raised funds and – in partnership with the local Co-op, which also provided funding – installed a reverse Archimedes screw, which avoids fish damage through its slow rolling motion. The installation should continue generating energy long after it has paid for itself. It provides renewable electricity through a private wire to the large local Co-op supermarket. Local residents take it in turns to clear the installation from leaves in autumn and winter. It is reported to have had a positive effect on community interest in the potential of renewable energy. This community scheme is not eligible for hydropower Feed-in Tariffs (FITs) but similar community schemes will be eligible for FITs generation tariffs in the future, making them more cost effective. Those schemes exporting renewable electricity will also be eligible for the additional FITs export tariff.
Micro-hydroelectric scheme – Isle of Eigg, Scotland
Four of the five households that make up the Kildonnan settlement on the east coast of the island are now connected to a shared hydroelectricity scheme. The Isle of Eigg Heritage Trust, which is responsible for the development of the island, installed the scheme.
The small community is not connected to the national grid power supply and the villagers had relied on private diesel generators for their electricity. The generators were noisy, costly and dependent on regular shipments of diesel to the island. They also had to be switched off at night and produced oil waste as a by-product. The Heritage Trust was keen to switch to a cheaper and more reliable source of electricity.
The residents installed the hydroelectricity scheme themselves and they are responsible for its maintenance and repairs. The £40,160 project received £9,200 of funding from Lochaber Enterprise and the Community Economic Development programme, as well as funding from the Scottish Land Fund, the Scottish Clean Energy Efficiency Demonstration Scheme and the Gordon Fraser Trust.