Market Snapshot: Pumped-storage hydro – the largest form of energy storage in Canada and a growing contributor to grid reliability
Release date: 2016-10-19
Pumped-storage hydroelectricity (PSH) facilities store gravitational potential energy by pumping water into a reservoir during times of lower electricity demand, and then generate electricity by releasing water through a turbine during times of higher demand. PSH facilities are designed to switch from storage to generation several times a day to take advantage of brief changes in price, but most storage occurs at night and most generation occurs during the day.
PSH is the largest form of energy storage in Canada and helps provide what is known as “load balancing”. This smoothing out of fluctuations in electricity supply and demand is especially valuable in jurisdictions with a large share of renewable intermittent generators that generate according to environmental conditions. For example, PSH can generate power and maintain grid reliability when the wind is not blowing or the sun is not shining.
Source and Description
Source: NEB calculations, Independent Electricity System Operator (IESO): Hourly Ontario Energy Price, 2016 year-to-date
Description: The column chart illustrates typical electricity consumption and generation at a model PSH facility over a 24 hour period. Bars extending below the X-axis represent electricity consumed to pump water into a storage reservoir. Bars extending above the X-axis represent electricity generated by water flow from the reservoir through a turbine. This model assumes 80% round-trip efficiency, meaning only 80% of the power used to pump water can be recovered by the turbine generators.
Superimposed on the bar graph is a line graph showing the average Hourly Ontario Energy Price for 2016, which represents a possible daily price pattern in a deregulated jurisdiction. Generation times at the PSH facility are strongly correlated with high price times.
Canada’s only PSH facility is Ontario Power Generation’s Sir Adam Beck Pump Generating Station. This 174 megawatt facility pumps water from the Niagara River into a 300 hectare reservoir for energy storage. This storage capacity is greater than what currently exists in all of Canada’s newer, emerging storage technologies, such as batteries.
The United States (U.S.) has over 30 PSH facilities with a combined capacity of 22 gigawatts. U.S. facilities generate around 23 000 gigawatt hours (GW.h) per year, and consume 29 000 GW.h to operate their pumps. Despite this net loss of energy, the grid reliability provided by PSH facilities and the ability to generate when demand is strong is highly beneficial and will become increasingly important as Canada and the U.S. integrate more renewable power into their grids.
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