Electricity and Energy Sources: A Comprehensive Overview

Electricity and Fossil Fuels

• Fossil fuels include coal, oil, and natural gas.

• Energy conversions occur when fossil fuels are burned to heat water, creating steam (water vapor). This steam spins turbines, converting chemical energy into thermal energy, then mechanical energy, and finally electrical energy.

Renewable vs. Nonrenewable Energy

• Fossil fuels are nonrenewable energy sources.

• Advantages of fossil fuels:

  • They are relatively cheap.

  • Infrastructure for using them already exists in many places.

  • They employ a large number of people.

• Disadvantages of fossil fuels:

  • They pollute the environment by adding greenhouse gases like $NO<em>2$, $SO</em>2$, and $CO_2$.

  • These gases mix with water to create acid precipitation, which makes water more acidic, slowing plant growth and reducing food for aquatic and terrestrial animals.

  • Habitat destruction occurs due to mining.

  • Fossil fuel use consumes large amounts of fresh water, a limited resource.

  • Coal-fired plants release toxic mercury (Hg), a neurotoxin poisonous to all living things.

  • Accidents can occur during extraction and transportation.

Nuclear Energy

• Nuclear energy is produced during nuclear fission.

• It is considered a low-carbon energy source.

• Nuclear fission boils water to create steam, which spins turbines to generate electricity.

• Advantages:

  • Provides a reliable energy supply.

• Disadvantages:

  • High construction costs.

  • Potential for accidents (e.g., Chernobyl).

  • Generates radioactive waste.

Hydro-electric Energy

• Hydro-electric energy is a renewable resource that uses the free fall of water from reservoirs to spin turbines.

• Advantages:

  • Reduces reliance on fossil fuels.

• Disadvantages:

  • High initial construction costs.

  • Can contaminate water.

  • Reservoirs disrupt fish migration.

  • Methane release from reservoirs.

Wind Energy

• Wind energy is a renewable resource where wind turns the blades of turbines, which powers a generator to make electricity.

• Advantages:

  • Free and clean, no greenhouse gas emissions.

  • Predictable meaning can store excess energy.

• Disadvantages:

  • Can be noisy.

  • Turbines can be threat to birds.

  • Transmission lines are needed to connect turbines to homes.

Solar Energy

• Solar energy is a renewable resource that uses photovoltaic cells.

• Solar panels capture sunlight and convert it into electricity.

• Advantages:

  • Can be placed independently.

  • Reduces air pollution compared to burning fossil fuels.

• Disadvantages:

  • Manufacturing of solar panels can cause some pollution.

  • Solar panels are not very efficient at converting sunlight to energy (around 30%).

  • Panels may replace habitats when being built.

  • Costly.

Biomass Energy

• Biomass uses organic matter, including wood, plant oils and animal manure , and waste to burn for fuel make electricity.

• Partially renewable as long as the waste is renewable.

• Advantages:

  • Some forms reduce waste.

• Disadvantages:

  • Can cause air pollution, adding $NO<em>2$, $SO</em>2$, and $CO_2$ to the air.

  • Can lead to deforestation and higher food prices.

Calculations in Electricity

• Key quantities and units:

  • Voltage (V) in Volts (V)

  • Current (I) in Amperes (A)

  • Resistance (R) in Ohms (Ω)

  • Energy (E) in Joules (J)

  • Power (P) in Watts (W)

  • Time (t) in Seconds (s)

• Ohm's Law and Power Formulas:

  • $V = I \cdot R$

  • $P = \frac{E}{t}$

• Rearranging formulae:

  • $I = \frac{V}{R}$

  • $R = \frac{V}{I}$

  • $E = P \cdot t$

  • $t = \frac{E}{P}$

Efficiency Calculations

• Efficiency is calculated as:

  • $\text{Efficiency} = \frac{E<em>{\text{out}}}{E</em>{\text{in}}} \times 100\%$

  • $E<em>{\text{out}}= \frac{E</em>{\text{in}} \cdot \text{Efficiency}}{100\%}$

Electricity Prices in Canada (2023)

• The average residential cost of electricity in Canada is $0.179 per kWh, including fixed and variable costs, based on an average monthly consumption of 1,000 kWh.

• Electricity costs vary across provinces and territories.

  • Examples: QC (10.2), MB (11.4), BC (13.9), NB (14.1), SK (25.8), AB (18.3), NT (35.4), NU (41.0)

• Territories have higher rates than provinces due to:

  • Colder climates, requiring more energy for heating.

  • Lower population density and remote communities, limiting the viability of lower-cost energy infrastructure.

  • Reliance on expensive and carbon-intensive energy sources like diesel and fuel oil.

Energy in Northern Territories

• Nunavut relies almost entirely on diesel-fired power generation facilities and fuel oil for heating, importing fuel in bulk during the summer.

• The Northwest Territories generate over half their power and heat from diesel and fuel oil, with roughly one-third from hydroelectric resources.

• Yukon's electricity is mostly from regional hydro resources, with diesel and natural gas-fired generators used as backup and in remote communities.

• Growing interest in less carbon-intensive energy sources:

  • NT has over 20 megawatts of installed wood-pellet biomass capacity.

  • Inuvik, NT fuels a gas-fired power plant with liquefied natural gas (LNG) trucked in from British Columbia.

  • Yukon Energy's Whitehorse LNG facility provides a cleaner alternative to diesel generators.

  • Solar projects have been introduced in both NT and NU.

Electricity Review

• A short circuit is a low-resistance path that can cause excessive current flow, leading to overheating and potential fires.

• Safety devices to prevent electrical fires include fuses and GFCIs (Ground Fault Circuit Interrupters).

• Fuses vs. circuit breakers:

  • Fuses are one-time use devices that melt and break the circuit when excessive current flows.

  • Circuit breakers can be reset and reused.

• An EnerGuide label helps consumers compare the energy efficiency of appliances to save money at home.

• TOU (Time-of-Use) pricing varies electricity rates based on the time of day, allowing consumers to save money by using electricity during off-peak hours.

• To make bulbs appear as bright as possible in a circuit with two batteries, a switch, and three light bulbs, build a parallel circuit.

• The part of an electrical circuit that transforms electrical energy into another form of usable energy is the load (e.g., a light bulb).

• The electrostatic series is a useful resource for engineers to determine the charge transfer when two materials are rubbed together, allowing them to control static electricity.

• If a light bulb uses 100 J of electrical energy to produce 40 J of light energy, the remaining 60 J is converted to heat.

• The relationship between voltage drop and the number of loads in a series circuit: More loads result in a greater voltage drop across each load, reducing the voltage available to each.

• Insulators vs. conductors:

  • Conductors have low resistance and allow electricity to flow easily (e.g., metals).

  • Insulators have high resistance and prevent electricity flow (e.g., rubber).

• To charge rods negatively by friction:

  • Use rabbit fur to charge an ebonite rod negatively.

• Static electricity involves stationary charges, while current electricity involves moving charges.

• Electroscope can be negatively charged by conduction by bringing a negatively charged object into contact with the electroscope.

• Conduction vs. induction:

  • Conduction involves direct contact for charge transfer.

  • Induction involves charge redistribution without direct contact.

• The law of electric charges states that like charges repel and opposite charges attract.

• The electrostatic series helps determine the polarity of charge when two materials are rubbed together.

• Grounding is connecting an electrical circuit to the earth, providing a safe path for fault current to prevent electrical shock.

• If a cat rubs against a student's rubber boot and the boot repels an ebonite rod charged with rabbit fur, the boot is negatively charged, and the ebonite rod is also negatively charged.

Electricity Sources and Energy Conversion

• Classifying electricity sources by energy conversion:

  • Thermal generation: Uses steam to spin a turbine (e.g., nuclear, fossil fuels).

  • Mechanical generation: Uses movement to spin a turbine (e.g., hydro, wind).

  • Light energy to electrical energy: No turbine spins (e.g., photovoltaic cells).

• Circuit diagram with a 3-cell battery:

  • Show a light bulb in parallel with a motor and a voltmeter to measure potential difference.

Circuit Analysis

• In a circuit with multiple bulbs and switches, analyze what happens under different conditions:

  • If bulb 1 is unscrewed and switch A is open: No current flows past that point and no bulbs light up.

  • If bulb 3 is unscrewed and switch B is open: No current flows past that point and no bulbs light up.

  • If bulb 4 is unscrewed and all switches are closed: Current will still flow since it's a parallel circuit and the other bulbs light up.

• Canada still relies heavily on non-renewable resources due to the availability, existing infrastructure, and economic factors.

• Ammeter vs. voltmeter:

  • An ammeter is connected in series to measure current.

  • A voltmeter is connected in parallel to measure potential difference.

Static vs Current Electricity

• Static electricity involves stationary charges, while current electricity involves moving charges.

Miscellaneous

• Explaining how to negatively charge an electroscope by conduction, using pictures in the explanation, is imperative.

• Generator works by moving a conductor through a magnetic field, which induces a flow of electrons.

• Lightning is caused by the buildup of static electricity in clouds, resulting in a discharge when the potential difference becomes too great.

• Energy usage calculations:

  • $\text{Cost to use a device} = \text{Power} \times \text{time} \times \text{cost rate}$