Hydroelectricity is the production of electricity through the utilization of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation.
British Columbia is powered predominantly by 21 large scale hydroelectric facilities and 7 small scale hydroelectric facilities, generating a staggering 10,829 Megawatts of clean, emissions-free electricity powering 1.9 million homes across BC.
Large Scale Hydro
Large hydroelectric facilities dam rivers, store the water in a reservoir and then release it as needed to generate electricity. They use the gravitational potential of water held in the reservoir to drive a water turbine and generator when released to flow through the dam. The amount of power in the water depends on the volume and the difference in height between the source of the water and the water’s outflow. Large scale hydroelectric dams’ ability to store ‘firm energy’ for release at peak demand and during periods when water flows are lower make hydroelectric facilities extremely attractive to a power utility.
The biggest concern with any dam project is always the land that must be flooded, bringing the loss of ecosystems, species, forests, farmland, and sometimes (in China) entire villages or towns. The damming of any river creates an obstacle for migrating fish, especially salmon. Large dams are often insurmountable; smaller dams have fish-ladders to help the fish migrate. Large dams do generate methane emissions from the degradation of biological material left in the reservoir, but the amount is countered by the emissions avoided not using fossil fuels to generate electricity.
Small Scale Hydro
Small scale hydroelectric refers to run-of-river facilities and hydroelectric plants that use the kinetic energy of a fast flowing river. Substantial flooding of the upper part of the river is not required for run-of-river projects as a large reservoir is not required. As a result, people living at or near the river do not need to be relocated and natural habitats and productive farmlands are not wiped out.
There are 51 Run-of-River projects operating in BC. Although there are countless rivers in the province, not all are suitable for a run-of-river facility. Potential sites must have cost-effective transmission access, undergo a comprehensive environmental assessment, meet government guidelines and regulations, and be commercially viable.