https://arstechnica.com/information-technology/2018/07/monster-energy-project-wants-to-use-loch-ness-as-a-giant-battery/

A company called Intelligent Land Investments (ILI) is proposing a huge 2.4 gigawatt-hour pumped hydroelectric project right next to the shores of Loch Ness in Scotland. The project, called "Red John" after the Scottish name for a source pool in the area, could deliver up to 400 megawatts of power for six hours—a feat that Wired UK says could double Scotland's already-considerable wind capacity.