Unit 6 - Energy Resources and Consumption Notes

Unit 6: Energy Resources and Consumption

6.1 Renewable vs. Nonrenewable Energy Sources

  • Learning Objective: Identify differences between nonrenewable and renewable energy sources.

  • Essential Knowledge:

    • ENG-3.A.1: Nonrenewable energy sources exist in a fixed amount and are not easily replaceable.

    • ENG-3.A.2: Renewable energy sources can be replenished naturally at or near the rate of consumption.

Key Differences

  • Renewable Energy Sources: Can be replenished naturally. They can be subdivided into:

    • Depletable Renewables: Can run out if overused (e.g., Biomass - wood, charcoal, ethanol).

    • Nondepletable Renewables: Do not run out if overused (e.g., solar, wind, hydroelectric, geothermal).

  • Nonrenewable Energy Sources: Exist in fixed amounts and include:

    • Fossil Fuels: Coal, oil, natural gas are formed from ancient biomass over millions of years.

    • Nuclear Energy: Generated from uranium or other radioactive fuels.

Consumption Rates

  • The rate of use must be at or below the rate of regeneration for renewable sources to remain sustainable.

  • Fossil fuels, conversely, regenerate at a far slower rate than they are consumed and are predicted to eventually run out.

6.4 Distribution of Natural Energy Resources

  • Learning Objective: Identify where natural energy resources occur.

  • Essential Knowledge:

    • ENG-3.D.1: Global distribution of resources like coal, oil, and gas is uneven and influenced by regions' geologic history.

Key Regions and Reserves

  • Fossil Fuel Reserves:

    • Coal: U.S., Russia, China, Australia (1-150 years of reserves).

    • Natural Gas: Russia, Iran, Qatar, U.S., Saudi Arabia.

    • Oil: Venezuela, Saudi Arabia, Iran, Canada, Iraq.

Fracking & Shale Gas

  • Hydraulic Fracturing (Fracking): A method to extract natural gas from shale by cracking rocks through pressurized water, which has expanded gas supply but can lead to environmental concerns such as groundwater contamination.

Tar/Oil Sands

  • Reservoirs of bitumen deposits where crude oil can be retrieved, requiring substantial energy and water inputs. The Alberta region of Canada has the largest reserves.

Crude Oil Extraction

  • Involves drilling wells to reach deposits and pumping out oil under pressure. Bitumen from tar sands is converted into oil, but the extraction process is energy-intensive.

6.3 Fuel Types and Uses

  • Learning Objective: Identify types of fuels and their uses.

  • Essential Knowledge:

    • ENG-3.C.1 to ENG-3.C.6: Types of fuels include wood (firewood and charcoal), peat, three coal types (lignite, bituminous, anthracite), natural gas, and crude oil, each with specific uses and characteristics.

Coal and Natural Gas

  • Coal is characterized by energy density, with anthracite being the highest quality. Natural gas (mostly methane) burns cleaner than coal, with significantly lower emissions of CO₂ and pollutants.

Environmental Consequences of Energy Sources

  • Fossil Fuels: Burning leads to significant CO₂ emissions, habitat destruction, and air pollution. Coal releases more pollutants than other fossil fuels.

  • Hydraulic Fracturing: Risks include groundwater contamination, increased seismic activity, and habitat loss.

  • Nuclear Energy: While cleaner than fossil fuels, poses risks such as radioactive waste management and potential for catastrophic events (Three Mile Island, Chernobyl, Fukushima).

6.6 Nuclear Energy

  • Learning Objective: Describe the use of nuclear energy in power generation.

  • Essential Knowledge:

    • Nuclear Fission: Splitting Uranium-235 atoms to release energy, producing heat to generate steam for turbines.

Environmental Considerations

  • Low emissions but thermal pollution can occur, and long-term waste storage is a pressing issue.

6.8 Solar Energy

  • Learning Objective: Describe the use of solar energy in power generation.

  • Essential Knowledge:

    • Photovoltaic cells convert sunlight into electricity.

    • Active solar systems use mechanical devices to collect and store energy, while passive systems do not.

Benefits and Impact

  • Minimal environmental pollution; construction may disrupt habitats.

6.10 Hydrogen Fuel Cells

  • Learning Objective: Describe the use of hydrogen fuel cells in power generation.

  • Essential Knowledge:

    • Hydrogen Fuel Cells: Combine hydrogen and oxygen to produce electricity with water as a byproduct. They have low environmental impacts if hydrogen is produced sustainably.

Challenges

  • Expensive technology; obtaining pure hydrogen is energy-intensive.

6.12 Wind Energy

  • Learning Objective: Describe the use of wind energy in power generation.

  • Essential Knowledge:

    • Wind Turbines: Convert the kinetic energy of wind into electricity.

Environmental Impact

  • Clean energy source but risk to local wildlife like birds and bats.

Energy Conservation

  • Learning Objective: Describe methods for conserving energy.

  • Essential Knowledge:

    • Methods include using energy-efficient appliances, improving vehicle fuel economy, and sustainable building designs to reduce energy consumption.

Summary

  • Conservation efforts can lead to a significant reduction in energy demand and greenhouse gas emissions.