Frequently Asked Questions

What is hydropower?

Why is hydropower a clean and renewable source of energy?

Do all hydropower developments include dams and reservoirs?

Do hydropower projects have an impact on the environment?

What is done to mitigate the environmental impacts of hydropower?

What about the impacts of hydropower developments on local communities?

Do hydropower reservoirs emit greenhouse gas emissions?

Do hydropower projects produce mercury?

What are the alternatives to hydropower?

What can I do to promote the use of clean and renewable sources of energy such as hydropower?

What is hydropower?
Hydropower, or hydroelectricity, is a source of energy produced by the fall of water turning the blades of a turbine. The turbine is connected to a generator that converts the energy into electricity.

Why is hydropower a clean and renewable source of energy?
Hydropower is clean because it produces very few greenhouse gases (GHG) and no other air pollutants, and it does not generate any toxic waste by-products. Hydropower is a renewable source of energy because it uses the power of a natural and renewable resource, water, without wasting or depleting it in the production of energy.

Do all hydropower developments include dams and reservoirs?
Not all hydropower developments include dams or reservoirs. Run-of-river projects produce electricity without storing water in reservoirs and without using dams to increase the head (the height from which the water falls). They produce power by partially diverting fast-flowing rivers through a turbine set in the river or off to the side. Of 475 hydroelectric power generating stations in Canada, more than 125 are run-of-river.

Do hydropower projects have an impact on the environment?
All forms of energy production have an impact on the environment. In the initial years of project development, hydropower projects have local impacts on the environment, such as the modification of fish habitat and the flooding of land; however, good site selection, and the careful planning and operation of hydropower facilities can minimize these impacts. Moreover, when the impacts of hydroelectric projects are compared to the environmental impacts of the current alternative large-scale sources of energy (natural gas, coal, nuclear energy), hydropower is the cleaner and more environmentally sound choice for Canadians.

What is done to mitigate the environmental impacts of hydropower?
Reforestation, wetland establishment, and fish reclamation are some of the measures implemented to mitigate the environmental impacts of hydropower. In some cases, wildlife reserves are created around reservoirs providing stable habitats for many species. The hydropower industry continues to invest in the development of innovative solutions to mitigate the negative impacts of hydropower on the environment and to help protect wildlife, rivers and ecosystems, for example, fish bypass systems and fish ladders that allow the passage of fish to their spawning grounds.

What about the impacts of hydropower developments on local communities?
The infrastructure and reservoirs that accompany the construction of hydropower projects do have an impact on local communities. The Canadian hydropower industry therefore works closely with local communities in the planning and development of projects to identify ways to alleviate some of the negative impacts of a project - for example, reforestation, wetland establishment and fish reclamation - and to ensure that local communities benefit from the project - improved quality of life, employment and business opportunities, and long-term revenues.

Do hydropower reservoirs emit greenhouse gas emissions?
Several studies have been published on the question of GHG emissions from hydropower reservoirs. Reservoirs, like natural lakes, emit a certain quantity of GHGs due to decomposing vegetation; however, the scale of these emissions has been shown to be highly variable and more research on a case-by-case basis is required. In a study of a hydropower dam in Brazil, emissions were very high, but in the case of reservoirs studied in boreal regions, Canada for instance, results have shown that emissions are significantly lower than those produced by the combustion of fossil-fuels to generate electricity. In any case, clearing the vegetation in the area to be flooded can reduce emissions.

Do hydropower projects produce mercury?
Hydropower projects do not produce mercury. Most of the mercury found in the environment comes from smelters, incinerators, and coal and oil-fired plants, although some is naturally occurring. By displacing coal and oil-fired electricity plants, hydropower can in fact contribute to the reduction of mercury emissions. The flooding of large expanses of land can contribute to increased mercury circulation and facilitate its absorption by fish. For that reason, fish found in new hydropower reservoirs can contain higher levels of mercury; however, these levels decrease after 20 to 30 years, reaching levels similar to those found in natural lakes. That mercury particles are dispersed in the atmosphere and accumulate in the environment, including water expanses, is a North American issue, which hydropower can help address.

What are the alternatives to hydropower?
At the present time, hydropower is the most reliable, economical, clean and renewable source of energy in Canada. Hydropower supplies approximately 60% of Canada's total electricity production. Although wind and solar power are also clean renewable energy sources, they are intermittent sources that rely on the support of other energy sources. They are also still expensive compared to hydropower. The other alternatives, fossil fuel generated electricity and nuclear power, have their share of environmental problems. Nuclear power must, among other things, deal with the disposal of radioactive waste. The main source of electricity in North America today, that generated by fossil fuel, is one of the major contributors to air pollution and greenhouse gases (GHG), causing acid rain, urban smog, and global warming. In Canada alone, 17% of GHG emissions originate from burning fossil fuels such as coal, gas, and oil to generate electricity.

What can I do to promote the use of clean and renewable sources of energy such as hydropower?
You can find out how your electricity is produced and what energy options are available where you live. You can also write to governments and industry requesting that your electricity supply come from a clean and renewable source of energy, like hydropower.



If you have other questions about hydropower, send us an email at info@canhydropower.org