Electricity generated using the flow of water
How it works
- Water flows from high to low elevation (kinetic energy of water)
- The water flow is so strong that it is able to push the turbine blades (Kinetic energy of turbine blades)
- The turbine blades are attached to a rotor, which is a magnet that spins when the turbine spins
- When the rotor rotates, an electric current is produced in the coil of wires (stator) that surrounds the rotor (electrical energy)
Pros of Hydroelectricity
- Water is free to use (not costly to get- unlike oil which has to be pumped out of ground)
- Renewable: water is recycled back using water cycle
- Clean: doesn't release greenhouse gases in atmosphere during energy production
- With a dam, production can be halted at anytime when electricity is not needed
- Reliable- the equipment used (ex. turbine, dam, generators) is very precise and advanced and rarely breaks down
Cons of Hydroelectricity
- Initial cost of construction is expensive (building reliable dams is costly).
- Weather dependent: if drought or dry seasons happen, it could significantly reduce electricity production
- Building the hydroelectric power plant requires lots of machines that release pollutants in the atmosphere.
- Negative Environmental Impacts (see below)
- Presence of a dam creates flooded areas due to the unequal elevations of water (see How it works diagram). Those areas produce methane, another greenhouse gas, from the decomposition of plants.
- Presence of a dam disrupts the natural river flow (slows it down) due to unequal elevations of water. This creates many problems for the fish population. For example, many fish species, such as salmon, depend on steady flows to flush them down river early in their life and guide them upstream years later to spawn. Slow reservoir pools disorient migrating fish and significantly increase the duration of their migration.
- Bacteria in decaying vegetation that's caused by the presence of a dam can convert mercury (found in rocks underlying reservoir) into form that’s soluble in water. The fish that swim in that water will accumulate this mercury in its body. If other animals eat the fish, they will also be poisoned by the mercury. After eating many fish, the animals will have accumulated a large concentration of mercury. This may harm the animals.
Can we use this to power our school?
- There are no nearby bodies of water that could support a dam for hydroelectricity.
- It's unreasonable for a school to build their own dam for hydroelectricity (it's very costly and will take a long time).
- Building a dam for hydroelectricity has so many negative impacts (ex. methane production, mercury bio-accumulation in organisms).
So, instead of building...
The school can buy hydroelectric power from power plants located in Ontario (such as the one located at Niagara Falls). This idea can be implemented right away since the plants are already built. Since only the structure and building process of the power plants produce environmental issues, using the same plant for multiple purposes does not increase the negative environmental impacts.