Unit E: Electrical Applications
Chapter 11: Electrical Energy
11.3: Renewable Energy Sources
pg. 428
Key Concepts:
1. Electrical energy is generated using a variety of
technologies.
2. Electrical energy is generated using both renewable and
non-renewable sources.
3. Electrical energy production has an effect on the
environment and society.
Renewable Sources
Renewable Energy Source: an energy source that can be
replaced in relatively short period of time.
Hydro-electric Generation
The use of falling water is used to turn a turbine and
generator to generate electricity. Many hydro-electric
generating stations use water stored behind dams to turn the
turbine. The dams control the water flow and direct water
over the turbine. There are 180 hydro-electric generating
plants in Ontario.
Table 1: Advantages and Disadvantages of Hydro-electric Generation
Advantages
- does not release pollution into the air or water
Disadvantages - disrupts the natural water flow pattern
- can restrict fish movement unless fish ladders are built.
- Large land areas behind a dam are flooded, resulting in habitat loss.
- Generating stations are expensive to build.
- Difficult to find suitable locations for generating stations.
Wind Generation
Wind has been used to move sailboats and windmills to
pump water on farms. Wind can be harnessed to turn
turbines, large blades, which are connected to generators,
which produces electricity.
Table 2: Advantages and Disadvantages of Wind Generation
Advantages
- Wind is free and does not need to be transported
- Building and maintaining wind farms is less expensive than
generating stations that use fossil fuels or uranium.
- Wind turbines can be built anywhere winds are reliable and relatively
strong.
Disadvantages - Turbines may change scenic views.
- Large land areas are needed for wind farms.
- Noise pollution for people living nearby.
- Wind turbines may disrupt the paths of migrating birds and bats.
Photovoltaic Generation
Photovoltaic Cell: a device that converts light directly into
electrical energy.
Producing electricity without turbines and a generator can
be done photovoltaic cells. The sun supplies an abundant
amount of energy to Earth. A photovoltaic cell or solar cell,
is capable of converting sunlight energy into electrical
energy. Charged particles are excited by sunlight energy,
photon, causing them to move and create electrical current.
Table 3: Advantages and Disadvantages of Photovoltaic Generation
Advantage
- Free and readily available
- Can be installed anywhere that receives enough sunlight
- Does not create air or water pollution
Disadvantage - Currently expensive and inefficient
- Can only work during the day, but small systems can use batteries to
store electricity for nighttime use.
Thermal Generation Using Biomass
The use of Biomass, or biofuel, is used to produce thermal
energy. Water is heated to create steam, which is used to
turn a turbine and generator to produce electricity.
Biomass is any form of bacterial, plant, or animal matter, or
and gas given off from decaying matter from farms, sewage
treatment plants, and landfills.
Table 4: Advantages and Disadvantages of Using Biomass
Advantages
- Always renewable – trees and crops can be replaced; plant and animal
waste is produced continuously; gases are continuously produced by
decay.
Disadvantages - Burning biomass produces greenhouse gases.
- Using crops as fuel results in lower food production.
Geothermal Generation
In areas where there is volcanic activity, there is a great
deal of heat trapped underground. Pipes are drilled deep
into the ground to access this source of heat. Hot
geothermal gases are piped to generating stations to turn
the turbines, which turn the generator to produce electricity.
Geothermal energy can also be used to heating and cooling
homes.
Table 5: Advantages and Disadvantages of Using Geothermal Generation
Advantage
- Geothermal energy is always present deep in Earth’s crust.
- Geothermal fluids can be continuously pumped back underground to be
reheated and reused.
- does not produce pollution or greenhouse gases.
Disadvantage - Suitable geothermal areas are rare; very few are near populated areas.
- Generating stations are difficult and expensive to build.
What Does the Future Hold?
26% of electrical energy is produced from burning coal and
natural gas. 52% comes from nuclear power plants,
meaning that 78% production comes from non-renewable
sources.
How do we meet the growing needs of electricity? Can we
change the way we use electrical energy? Are there new
ways to generate electrical energy and still be friendly to
the environment?
Figure 6: This circle graph shows how Ontario’s electrical energy was generated in 2007.
Check Your Learning:
Questions 1 – 5, pg. 431
Wrap Up:
- Sources used to generate electrical energy can be
renewable.
- Renewable sources used to generate electricity include
hydro-electric, wind, solar, biomass, and geothermal energy.
- Producing energy using renewable sources has advantages
and disadvantages for society and for the environment.
11.3: Renewable Energy Sources
pg. 428
Table 1: Advantages and Disadvantages of Hydro-electric Generation
Advantages
- does not release pollution into the air or water
Disadvantages - disrupts the natural water flow pattern
- can restrict fish movement unless fish ladders are built.
- Large land areas behind a dam are flooded, resulting in habitat loss.
- Generating stations are expensive to build.
- Difficult to find suitable locations for generating stations.
Table 2: Advantages and Disadvantages of Wind Generation
Advantages
- Wind is free and does not need to be transported
- Building and maintaining wind farms is less expensive than
generating stations that use fossil fuels or uranium.
- Wind turbines can be built anywhere winds are reliable and relatively
strong.
Disadvantages - Turbines may change scenic views.
- Large land areas are needed for wind farms.
- Noise pollution for people living nearby.
- Wind turbines may disrupt the paths of migrating birds and bats.
Table 3: Advantages and Disadvantages of Photovoltaic Generation
Advantage
- Free and readily available
- Can be installed anywhere that receives enough sunlight
- Does not create air or water pollution
Disadvantage - Currently expensive and inefficient
- Can only work during the day, but small systems can use batteries to
store electricity for nighttime use.
Table 4: Advantages and Disadvantages of Using Biomass
Advantages
- Always renewable – trees and crops can be replaced; plant and animal
waste is produced continuously; gases are continuously produced by
decay.
Disadvantages - Burning biomass produces greenhouse gases.
- Using crops as fuel results in lower food production.
Table 5: Advantages and Disadvantages of Using Geothermal Generation
Advantage
- Geothermal energy is always present deep in Earth’s crust.
- Geothermal fluids can be continuously pumped back underground to be
reheated and reused.
- does not produce pollution or greenhouse gases.
Disadvantage - Suitable geothermal areas are rare; very few are near populated areas.
- Generating stations are difficult and expensive to build.