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In this section, you will:
In this section, you will:
Learn about technologies that convert other forms of energy into electric energy
Learn about different sources of energy available for the production of electricity
Examine different technologies used to generate electricity
Construct a model that converts the energy of flowing water into electric energy
Examine light intensity and how solar cells produce energy
Vocabulary
Vocabulary
Photovoltaic cells (PV) - wafers made of the element silicon that is covered with thin layers of metals.
Power Grid - an electricity distribution network.
We saw in the previous section that electricity is made in a generator. These generators consist of a magnet and a coil of wire. As the wire coil is moved through the magnetic field, it induces an electric current. For larger generating stations,thermal or kinetic energy is what turns the turbines , which turns the generator.
Solar power generation works in a slightly different way. It is the photovoltaic solar cells that turn solar energy into electric energy. Photovoltaic cells are wafers made of the element silicon that is covered with thin layers of metals. When the solar energy strikes these layers, a stream of electrons (electricity) is created.
Power Grid
Power Grid
Getting the electricity from the generating stations (renewable and non-renewable energy sources) to the consumer requires more than simply hooking up the wires from the stations to the house.
Step 1: Electricity is produced at the powerplant
Step 2: Electric Power Transmission is the bulk movement of electrical energy from the generating site to electrical substations
Step 3: Electricity arrives at electrical substations. Substations transform voltage from high to low, or the reverse. It needs to be high enough to travel long distances. As we learned in the previous section, there is loss of energy as it transfers to other forms of energy.
Step 4: Electric Power Distribution - Leaving the substations, the electricity travels along the powerlines to the distribution station (located close to the final destination of the electricity) where the electricity voltage is downgraded to a medium voltage through transformers.
Step 5: Electricity arrives at its destination.
There has become a concern around electromagnetic corona and how it may have biological and psychological effects on humans. Because of this concern, power companies are looking at ways to put power lines through highly populated areas where electromagnetic fields might negatively affect residences.
Most people falsely believe that only power generated by fossil fuels can impact the environment. However, there are risks associated with some renewable energy sources as well. Hydro-electric power is created by the force of energy generated from the flow of water. To help regulate the amount of energy created, hydro dams adjust the amount of water by opening and closing water supplies which inadvertently impede the migration of fish and wildlife and by changing the floodplains. Proactive approaches to avoiding this challenge are:
Regular water testing
Fish ladders
Examination of fertilization of farmland.
Generating Electric Energy in Canada
Why are there so many ways to generate electricity in Canada? Why are some used in certain locations?
Wea re going to be doing some investigating on Callysto HUB
STEP 2
Click on "curriculum-notebooks"
STEP 3
Select "Science" Folder
STEP 4
Select "CanadianElectricityGeneration" Folder
Communicating scientific data in an easy to understand language is an important aspect of sharing information with the public. One way to do this is through the use of graphs. There are many types of graphs but understanding when to use each graph is a practiced skill.
You will be putting this to practice today. Using data that has been pulled from Energy Sources and Distribution site created by Natural Resources Canada. To manipulate the data so that it is visually easy to read and understand, we are going to work through the Canadian Electricity Generation Jupiter Notebook on Callysto
Making Hydro-electric Energy
Making Hydro-electric Energy
Much of the power produced in Canada is through hydroelectric power plants. The falling water generates kinetic energy, which produces the electricity. Hydroelectric energy requires controlled water flow. To do this, dams are built. There are many types of dams. The type depends on the land around and how much water flow is being controlled. The purpose for building a dam depends on the location and what the intended purpose is for.
Reasons for building dams:
Reasons for building dams:
Irrigation
Flood control
Water supply
Hydropower generation
Water storage
Recreation
Control of debris
Navigation flow
Types of Dams
Types of Dams
There are different classifications based on multiple factors:
Hydraulic
Function
Material construction
structure
Arch dams
made of concrete
prevents flooding while directing water towards the sides creating energy to supply generators.
Embankment dams
made of rock and soil
Prevents leakage of poisonous sludge from industrial ponds
Buttress dams
Made of concrete
Provides electricity to a large customer base
Gravity dams
Reinforced concrete structures used to create reservoirs that can be used for recreational purposes.
Benefits and Drawbacks to Using Dams
Benefits and Drawbacks to Using Dams
Benefits
Provides large amounts of relatively cheap power
Generators operate without creating pollution
Flowing water is reliable and inexpensive
Maintenance and operating costs are relatively low and stable.
Small hydroelectric dams are relatively flexible, inexpensive and quick to install.
Dams used for hydroelectric generation can also be used for flood control and to provide water for irrigation.
Reservoirs could provide recreational sites.
Drawbacks
Large dams are expensive to build and take years to construct
Appropriate sites can be scarce depending on landscape.
Land and water ecosystems upstream and downstream of the dam are disrupted or destroyed.
Transmission lines are usually needed to move electricity from the dam location to places where people can use it.
Reservoirs may flood human settlements, forests, agricultural land, as well as change the ecology of the area.
Reservoirs can eventually fill with sediment and no longer store water or produce electricity unless they are dredged.
People living in the area are displaced.
Coal-fired Thermo-electric Generation
Coal-fired Thermo-electric Generation
Coal-fired generation has been one form of electric generation that has been in the media a lot because of the negative impact it has on the environment.
When coal is burned, the oxygen in the air combines with the carbon to produce carbon dioxide. One molecule of carbon dioxide is 3.67 times heavier than a molecule of carbon. This is why 1 lb of carbon emits 2.07 pounds of CO2.
Coal is cheap and plentiful in Alberta, which makes it an easy option for generating electricity.
As we found on our Callysto research, there are only four provinces that continue to use coal generation.
The process of producing coal generated electricity
The process of producing coal generated electricity
Science Connect 2, page 104
Process
Process
A. Pulverized coal is blown into the combustion chamber of the furnace. When it is broken into such small pieces, the burning is more rapid and efficient.
B. In the furnace, thermal energy from burning coal converts water to steam.
C. High pressure steam flows through the pipes and onto the fan blades of the turbine.The turbine spins with kinetic energy.
D. The spinning turbine turns the generator. The generator converts the kinetic energy into electric energy.
E. The steam leaves the turbine and enters a cooling chamber. Steam is condensed to water in this chamber and returned to the furnace.
F. Electricity is distributed to consumers by transmission lines.
Nuclear Energy
Nuclear Energy
Nuclear fission is the splitting apart of heavy atoms to create energy. Most nuclear generating plants use uranium atoms that release large amounts of energy in the form of heat and radiation. The thermal energy is used to create steam that turns the turbines.
A. Uranium fuel rods are inserted into the reactor core. Nuclear fission begins.
B. Fission reactions produce a tremendous amount of thermal energy. The energy is carried away from the reactor by a coolant.
C. Coolant is taken to a tank where the thermal energy converts water into steam.
D. High pressure steam flows through pipes and is directed through the blades of the turbine. The blades move and make the shaft spin.
E. The spinning turbine turns the generator. The generator converts the mechanical energy into electric energy.
F. Transmission lines take electric energy to consumers.
Check Your Understanding
Check Your Understanding
List four steps as the energy in coal is converted to electricity in a thermoelectric generating station.
What is a turbine?
What does a thermo-electric plant have in common with a thermonuclear power plant?
Why does only 90% of the electric energy leaving a power plant reach the consumer?
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