Renewable Energy Resources: Hydropower

Hydropower is one of the oldest forms of renewable energy in the province. In fact, in the 1950s, nearly 50% of the province’s power came from hydropower.[1] Although today the proportion of hydro is lower, this is in large part due to increased electricity needs of a growing population and the ready exploitation of fossil fuels. Today, most of the province’s future hydropower potential is located in the Athabasca, Peace and Slave River basins located in Northern Alberta, with only a small percentage coming from the Red Deer River basin and the North and South Saskatchewan River basins.[2]

Hydropower is generated when a power source (in this case moving or falling water) is used to turn a propeller-like piece called a turbine, which then turns a motor that produces electricity.[3] There are two main types of hydropower projects – dams and run-of-river projects.

Hydroelectric dams create artificial lakes or reservoirs by damming up large rivers. When enough water is collected, the generating station harnesses kinetic energy from the falling water to create electricity.[4] Run-of-river projects diver running water from a river and guide it down a separate channel to a generating house.[5] While run-of-river projects have less of an impact on the environment, they also generate less power.

Sounds too good to be true…

Unfortunately, it is. Hydropower is considered to be a renewable resource and is not itself directly polluting but it does come with many environmental pitfalls. For example, hydropower projects can obstruct fish migration, change the natural water temperature, affect the water chemistry, and impact upon river flow characteristics and silt loads.[6]

These large-scale changes can have dramatic effects on the plants and animals that live in the river and on its shores. For dams that create a reservoir, this flooded area may also release a significant amount of methane due to decomposing plants. In turn, this methane contributes to climate change.[7]

The problems with hydropower seem to be consistent regardless of the size of any particular site; and site selection, rather than size, is often seen as the best way to reduce the environmental impacts of hydropower.[8] Proper site selection requires a close look at both the downstream effects of a particular project (for example – is it located near a prominent fishery or town that depends on clean drinking water?) and cumulative effects (how many other hydropower stations already exist in this river system and how do they affect one another?)[9]

You can read about other examples of the environmental and health problems that can occur when cumulative effects are not well regulated in our Toxins & Waste section here.

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[1] Alberta Culture & Tourism, “Hydroelectricity in Alberta Today” online:

[2] Alberta Culture & Tourism, “Hydroelectricity in Alberta Today”.

[3] Canadian Hydropower Association, “Five things you need to know about Hydropower” online:

[4] Energy BC, “Large Hydropower” online:; The USGS Water Science School, “Hydroelectric power: How it works” (2 December 2016) US Department of the Interior & US Geological Survey online:

[5] Energy BC, “Run of River Power” online:

[6] Peter H. Gleick, “Environmental Consequences of Hydroelectric Development: The Role of Facility Size and Type” (1992) 17:8 Energy 735 at 738-745.

[7] United States Environmental Protection Agency, “Understanding Global Warming Potentials” (14 February 2017) online:

[8] Peter H. Gleick, “Environmental Consequences of Hydroelectric Development: The Role of Facility Size and Type” at 735.

[9] Dr. Ute Collier, “Hydropower and the Environment: Towards better decision-making” (Paper submitted to the United Nations Symposium on Hydropower and Sustainable Development, to be held in Beijing, 27-29 October 2004) [unpublished].