Hydroelectric power can be a very efficient way to produce or augment renewable energy. But if you don’t have a nearby river that’s big enough to dam—that’s where pumped storage comes in. Using the power of gravity and a reversible turbine, Toronto’s Northland power wants to convert an old open-pit iron ore mine in Marmora, Ontario, into a waterfall five times the height of Niagara Falls. Water spilling over the new waterfall could generate 400-megawatts of power and allow customers to take advantage of peak-time power prices when demand is high and local wind turbines typically are less active.
In a conventional hydropower plant, the water from the reservoir flows through the plant, exits and is carried down stream. Instead of merely being a checkpoint on the water’s journey, a pumped storage hydroelectric plant has an upper and lower reservoir Water from the upper reservoir flow through the plant to generate electricity. Upon exiting, however the water falls into the lower reservoir where a reversible turbine can pump it back up to the surface to be recycled.
The upper reservoir will be constructed using rock from the waste rock pile, then lined with gravel and an impervious liner, such as asphalt. Monitoring drains will check around the clock for any seepage from the upper reservoir. If seepage is detected, the upper reservoir can be rapidly emptied into the lower reservoir (the existing open pit) from which it cannot go anywhere
As the Globe and Mail explains, “To operate the plant, Northland plans to purchase electricity from Ontario’s grid at night when prices are low and use it to pump water from the mine pit up to a newly constructed reservoir. During the day, the company would release the water for a 258-metre plunge to a powerhouse.” This would help take some of the burden off of wind power plants until a viable grid storage system is perfected, and wind energy captured at night can be properly store for use during the day.
Lead image (cc) Flickr user reiver