Scotland is pursuing an aggressive offshore wind program that includes groundbreaking technologies like floating wind farms. In fact, sometimes it has too much renewable energy available. Intelligent Land Investments says it has the solution — an enormous 2.4 gigawatt-hour pumped hydroelectric storage installation on the shores of Loch Ness. Once completed, it could deliver up to 400 megawatts of power for six hours — a feat that Wired UK says could double Scotland’s wind capacity and power 400,000 homes.
This pumped hydro proposal will take advantage of the fact that an electric motor can also be a generator. EV fans will be familiar with the concept because of regenerative braking. When we push on the throttle of an electric car, the motor moves the car forward. When we take our foot off the pedal, the motor becomes a generator, putting electricity back into the battery. A properly engineered electric motor is happy to work in either direction.
The key to this pumped hydro facility will be its electric turbines. Flowing water will spin them one way to make electricity, but they can also reverse direction to pump water back uphill from a lower reservoir. That’s exactly what Intelligent Land Investments plans to do on the shores of Loch Ness.
The big advantage of pumped hydro storage is the energy is dispatchability, which means it is available to dispatch when needed to power the electrical grid. A gas-fired generating plant needs time — a half hour or more — to come online. Pumped hydro can’t react nearly as fast as a storage battery, however, and in certain conditions, the cost of battery storage today can equal the cost of building a pumped hydro system.
The other factor storage batteries have going for them is they can be installed fairly quickly with very little time needed for site preparation and permitting. The Loch Ness project will take years to complete, assuming it obtains all the necessary approvals. All storage installations can affect fragile ecosystems but the sheer size of any pumped hydro installation means it will impact a large area. For those Scots who worry the project will disturb the beauty of the hills around Loch Ness, the company assures them it can landscape the upper reservoir to look like the surrounding lochs.
A former gold mine in Australia has been repurposed as a pumped hydro storage facility. Switzerland boasts one of the world’s largest hydro storage installations, one that features a mammoth 1,450 MW of stored power. And China is leading the way with new variable speed generator technology that could make pumped hydro more efficient. Whether or not the proposed storage facility near Loch Ness ever gets built, pumped hydro storage is likely to remain one of the tools that will move the renewable energy revolution forward.