Hydropower Resources

View this map

Abstract

Hydroelectricity is electricity generated by hydropower, which usually requires the potential energy of water stored behind a dam to drive a water turbine and generator. The map shows 632 large dams and 6 major dams. Major dams are defined as being greater than 150 metres in height and large dams as between 10 to 15 metres and 150 metres. Also, mapped are 479 hydroelectric generating stations. A generating station (power plant) is an industrial facility built and operated to generate electricity. Hydroelectric power is generated from a plant in which the turbine generators are driven by falling or flowing water.

Hydroelectricity is generated from moving water that drives a water turbine connected to an electrical generator. In most large hydroelectric facilities, water enters through a large pipe called the penstock (see Figure 1) through the regulation of water flow and water levels. The generation of electricity depends upon the volume of water flowing through the penstock and the height from which the water falls. The height of a dam is important, as it creates the height for the water to fall and therefore the driving force that makes the turbine blades turn and spin the generator.

[D]
Click for larger version, 21 KB
Figure 1. Hydroelectric Dam

A reservoir is a lake created when a dam is built across a river on what used to be dry land. Hydroelectric plants with reservoirs can store water to generate electricity when river flow may be insufficient to meet demand. There are major dams in British Columbia (the Bennett Dam on the Peace River and the multiple dams of the Columbia River project), Manitoba (dams on the Churchill and Nelson Rivers), Quebec (the Manicouagan and James Bay projects) and Labrador (the Churchill Falls project). Not all hydroelectric projects use dams and not all dams create reservoirs. For example, run-of-river hydroelectric plants generate power by partially diverting a river through a turbine and generator on the side of the river.