Electrical Energy Distribution Grid Notes

Electrical Energy Distribution Grid

• The electrical energy distribution grid, also known as the power grid, is the system that provides most of the electrical energy we use (excluding batteries).
• Plugging devices into wall outlets at home utilizes electrical energy from this grid.

Electrical Energy Generation

• Most electrical energy distributed by the grid is produced in electrical generating stations.
• These stations employ generators, which are large machines that convert mechanical energy into electrical energy.
• Generators use magnets and a wire coil to produce electricity.
• The energy in wind or flowing water can be converted into electrical energy.
• The movement of wind or water rotates a turbine, which is connected to the generator.
• As the turbine spins, the coils of wire in the generator produce electrical energy.

Hydro-Electrical Generating Stations

• Hydro-electrical generating stations utilize fast-moving water to turn turbine blades.
• Ontario has over 180 hydro stations that use waterfalls, rivers, and reservoirs behind dams to generate electricity.
• Hydro-electric generation is a renewable energy source.

Pros of Hydro-Electric Generation

• Renewable resource
• Does not pollute air or water

Cons of Hydro-Electric Generation

• Artificially creates large volumes of falling water via dams.
• Dams change the ecology of the watershed, disrupting normal water flow.
• Disrupts fish migration.
• Construction of dams requires significant resources (concrete, steel, etc.).
• Dam breakage can result in significant damage to surroundings.

Tidal Energy

• Tidal energy is generated by the moving ocean waters during high tide.
• Generating stations operate when the tide comes in and goes out, for about 5 hours, and are off for 7 hours each day.
• The Annapolis station, located in the Bay of Fundy, utilizes the highest tides in the world.

Pros of Tidal Energy

• Source of renewable energy
• Produces no pollution

Cons of Tidal Energy

• Stations can only be built near coastlines with significant tides

Thermal Generation

• Thermal generation involves heating water to produce steam.
• The steam is used to rotate a turbine to generate electricity.
• Common methods to produce steam include using radioactive materials or burning fossil fuels.
• Fossil fuels include coal, oil, and natural gas.
• Fossil fuels take millions of years to form from decaying organisms from the Carboniferous period (approximately 360 to 300 million years ago).

Pros of Thermal Generation from Fossil Fuels

• Produces large amounts of energy
• Coal is cheap
• Natural gas burns more cleanly than coal

Cons of Thermal Generation from Fossil Fuels

• Burning fuels releases $CO_2$ into the atmosphere, contributing to the Greenhouse Effect.
• Extraction and refining of fossil fuels create pollution and destroy natural habitats.
• Burning coal produces smoke, $SO<em>2$, $NO</em>2$, and ash, which pollute the air and result in smog and acid rain.
• Burning oil contributes to air pollution.
• Oil spills can be devastating to wildlife.
• Natural gas is extremely limited; about half has already been used.

Nuclear Generation

• Long "feeder rods" are filled with radioactive uranium.
• The rods are placed inside a nuclear reactor.
• When a neutron collides with uranium, nuclear fission occurs, releasing a large amount of energy used to generate steam.
• Uranium is a non-renewable energy source.

Pros of Nuclear Generation

• Does not directly generate air pollution
• Does not contribute to acid precipitation

Cons of Nuclear Generation

• Produces thermal pollution because the water used to produce steam is returned to the environment at high temperatures, affecting aquatic ecosystems.
• Mining of uranium results in pollution and habitat loss.
• Produces radioactive waste with serious environmental and health consequences.
• Expensive to build nuclear power plants.
• Accidents can cause extensive damage.

Fukushima Daiichi Nuclear Power Plant Disaster

• Following the earthquake and tsunami off the coast of Japan on March 11, 2011, the Fukushima Daiichi nuclear power plant was damaged.
• The structural integrity of the building was compromised, with failures in the reactor cooling systems.
• The power plant could no longer cool down the nuclear reactions and entered a state of "meltdown."

Alternative Ways to Make Steam

• Three alternative methods to make steam are:
  1. Biofuel Generation: Burning plant or animal matter
  2. Geothermal Generation: Using thermal energy deep in the Earth’s crust
  3. Using sunlight to heat water
• Biomass is any form of plant or animal matter along with decaying natural materials (e.g., biodegradable wastes) excluding fossil fuels.
• Biofuel is biomass used to produce steam.
  1. Biomass can be burned to heat water.
  2. Methane gas released from decaying matter can be collected and burned as fuel.

Pros of Biofuel Generation

• Renewable resource
• Does not pollute air or water

Cons of Biofuel Generation

• May not produce enough energy to meet demands
• Growing crops for fuel reduces land available for food

Geothermal Generation

• Uses thermal energy from deep in the Earth’s crust to heat liquid to produce steam.
• There are currently no geothermal generating stations in Ontario.
• Geothermal energy is renewable because thermal energy is always available in the Earth’s crust.

Pros of Geothermal Generation

• Renewable resource
• Does not pollute air or water
• Does not contribute to climate change

Cons of Geothermal Generation

• Generating stations can only be built where ground temperature is high enough to make steam

Wind Turbines

• Wind turbines can be used to generate electricity.
• As the wind blows, the blades of the turbines turn, which are connected to a generator.

Pros of Wind Energy

• Wind is a renewable resource
• Does not directly generate air pollution
• Does not contribute to acid precipitation
• Wind turbines are cheap and easy to install
• "Wind farms" can be built closer to urban areas than other generating plants.

Cons of Wind Energy

• Power generation may not be steady due to changing winds
• Wind turbines are noisy and annoying
• May cause adverse side effects/health issues (e.g., headaches)
• Many people consider them to be eyesores.

Solar Energy

• Using photovoltaic cells, electrical energy can be produced without a turbine or generator.
• Solar cells use light from the sun to produce energy.
• Sunlight shining on the cell creates a flow of electrons.
• This is a renewable source of energy.

Pros of Solar Energy

• Renewable resource
• Does not pollute air or water directly
• They can operate independently of a power grid

Cons of Solar Energy

• The production and disposal of photovoltaic cells creates pollution
• Solar cells are only about 30% efficient
• Solar cells are very expensive
• Solar cells require prolonged sun exposure to produce electricity