Plans to build a major hydro scheme on the site of an opencast mine in the south of Scotland have been revealed.
Developers claim the 100MW project at Glenmuckloch, near Kirckconnel, could generate power for more than a century.
It is the latest in a series of renewable energy schemes planned for the site, which is owned by Buccleuch Estates.
They are part of a project to redevelop the opencast mine as Glenmuckloch Energy Park.
The details have emerged in a scoping report for the pumped storage hydro scheme submitted to Dumfries and Galloway Council.
Buccleuch Estates has joined with mining company Hargreaves and 2020 Renewables to draw up the plans.
It will involve creating two reservoirs - one higher than the other - which will be connected by a tunnel with a pump-turbine.
The report states: "When excess electricity exists within the grid the pump-turbines go into pumping mode lifting water to the upper pond and when demand within the network exceeds available supply the pump-turbines reverse and change to generating mode with water released from the upper pond."
If the project goes ahead, the lower reservoir will be created from the existing opencast void, while a second, upper pond will be excavated at the head of Halfmerk Hill.
The higher reservoir will have a water depth of 22m (72 feet), creating 3.3million cubic metres of water storage.
The redevelopment of Glenmuckloch follows the collapse of surface mining firm Aardvark TMC in 2013, leaving a shortfall in the money needed to restore the site to its pre-opencast condition.
However since then Buccleuch Estates and Hargreaves have worked to implement a rolling programme of restoration in parallel with coaling operations.
Later this summer two community wind turbines will be built to the west of the hydro site.