Energy that won’t run out
Renewable energy comes from sources that are naturally replaced in a human lifetime: sunlight, wind, flowing water, Earth’s heat and growing plants. Non-renewable energy comes from fossil fuels (coal, oil and natural gas) and uranium, which took millions of years to form and will eventually run out.
Why renewable energy matters
| Issue | Fossil fuels | Renewable energy |
|---|---|---|
| Supply | Limited; will run out | Naturally replaced |
| Greenhouse gases | Release lots of CO₂ | Little or none during use |
| Air pollution | Smog, acid rain | Very little |
| Cost trend | Varies with world prices | Solar and wind costs have dropped dramatically |
Switching to renewable energy is one of the main ways to fight climate change.
Types of renewable energy
Solar energy
Solar energy comes from the Sun.
- Solar panels (photovoltaic cells) turn sunlight directly into electricity.
- Solar thermal collectors heat water or air.
- The cost of solar panels has fallen by about 90% since 2010.
Limitations: no power at night, less on cloudy days and in northern winters.
Wind energy
Wind energy turns the blades of wind turbines, which spin generators.
- Modern turbines can be taller than a 50-storey building.
- Wind farms can be on land or offshore.
- Canada has thousands of wind turbines, especially in Ontario, Quebec and Alberta.
Limitations: wind is variable; some people object to the look and sound; turbines can harm birds and bats if poorly placed.
Hydroelectric power
Hydroelectric power uses flowing or falling water to spin turbines.
- Hydroelectricity provides about 60% of Canada’s electricity, one of the highest shares in the world.
- Quebec, BC, Manitoba and Newfoundland and Labrador get most of their electricity from hydro.
- Quebec’s James Bay hydro project is one of the largest in the world.
Limitations: dams flood land, affect fish and river ecosystems, and have displaced Indigenous communities.
Geothermal energy
Geothermal energy uses heat from inside Earth.
- Iceland heats about 90% of its homes with geothermal energy.
- Geothermal heat pumps use the steady temperature a few metres underground to heat and cool buildings, even in Canada.
Limitations: large power plants need hot rocks near the surface, found mainly near volcanoes and plate boundaries.
Biomass
Biomass energy comes from plants and organic waste: wood, crop leftovers, manure and garbage.
- Wood pellets heat homes and power plants.
- Biofuels like ethanol (from corn or sugarcane) and biodiesel can power vehicles.
- Landfills and farms can capture methane gas for fuel.
Limitations: burning biomass releases CO₂ and some pollution; growing fuel crops uses farmland.
Ocean energy
- Tidal power uses the rise and fall of tides. Nova Scotia’s Bay of Fundy, with the world’s highest tides, is a test site for tidal turbines.
- Wave power captures energy from ocean waves.
Comparing renewable sources
| Source | Works when? | Main advantage | Main drawback |
|---|---|---|---|
| Solar | Daytime, sunny | Can go on any rooftop | Variable; needs storage |
| Wind | When windy | Low cost | Variable |
| Hydro | Constantly, can be stored | Reliable; can respond to demand | Environmental impact of dams |
| Geothermal | Constantly | Reliable | Limited locations |
| Biomass | When fuel is available | Uses waste | Emissions |
| Tidal | Predictable cycles | Very predictable | Expensive; few sites |
Storing energy
Because sun and wind come and go, we need ways to store energy:
- large batteries
- pumped hydro: pumping water uphill when power is plentiful and releasing it later
- hydrogen made from electricity
Using less energy
The cleanest energy is energy we don’t use. Insulating buildings, using LED lights, and choosing efficient appliances and vehicles all help.
Common mistakes
- Thinking renewable means no environmental impact. All energy sources have some impact.
- Thinking solar panels don’t work in Canada. They work well, especially in sunny Prairie provinces; cold actually improves their efficiency.
- Thinking nuclear is renewable. Uranium is a non-renewable resource, though nuclear power produces very low emissions.
Try it yourself
- Find out where your province’s electricity comes from. Make a pie chart.
- Build a small pinwheel turbine or connect a small solar panel to a motor.
- Design a renewable energy plan for a remote northern community. Which sources would you choose and why?
Quick recap
- Renewable energy comes from sources that are naturally replaced.
- Solar, wind, hydro, geothermal, biomass and ocean energy are renewable.
- Canada gets most of its electricity from hydro.
- Each source has advantages and drawbacks; storage helps with variable sources.
- Renewables reduce greenhouse gases and air pollution.