Key Concepts in Energy Resources and Consumption

Energy Definition

  • Energy: ability to do work; measured in Joules (J).
  • Power: rate of doing work; measured in Watts (W), where 1 W = 1 J/s.

Laws of Thermodynamics

  • 1st Law: Energy can neither be created nor destroyed, only converted.
  • 2nd Law: Energy conversion results in less useful forms; e.g., only 20% of gasoline's energy is converted for engine use.

Energy Units

  • Kilowatt-hour (kWh): unit of energy; 1 kWh = 1000 Watt-hours = 3.6 MJ.
  • British Thermal Unit (BTU): energy to raise 1 lb of water by 1°F; 1 W = 3.4 BTU/hr.
  • Horsepower (HP): 1 HP = 746 W = 2540 BTU/hr.

Forms of Energy

  • Mechanical: Potential (stored) and kinetic (motion).
  • Thermal: Heat due to atomic vibration.
  • Chemical: Energy stored in atomic bonds.
  • Electrical: Movement of electrons.
  • Nuclear: Energy in atomic nuclei.
  • Electromagnetic: Energy traveling in waves (e.g., light).

Renewable vs Non-renewable Energy

Renewable Energy
  • Sources: sunlight, wind, water movement, geothermal heat.
  • Sustainable, replenished rapidly.
Non-renewable Energy
  • Sources: fossil fuels (coal, oil, natural gas).
  • Limited supply, formed over billions of years, e.g., fossil fuels make up 87% of US energy consumption.

Fossil Fuels

  • Coal: formed from decomposed organic matter; major energy source.
  • Oil: produced under high pressure, essential for many chemical products.
  • Natural Gas: mainly methane (CH4), seen as transitional fuel with lower emissions.

Coal

  • Types: Lignite, bituminous (high sulfur), and anthracite (highest heat content).
  • Produces about 25% of world energy; environmental regulations in place (e.g., Clean Air Act).

Oil & Natural Gas

  • Heavy reliance on imports; issues with spills and pollution; infrastructure for transport exists.

Nuclear Energy

  • Pros: high energy output, low emissions during operation.
  • Cons: waste handling, meltdown risks, high construction costs.

Renewable Energy Sources

  1. Biogas: methane from anaerobic decomposition; reduces fossil fuel reliance.
  2. Biomass: recently living material used for energy; mitigates waste but can pollute if not managed.
  3. Biofuels: produced from biomass; renewable, but raises food prices.
  4. Geothermal: heat from Earth; reliable but site-specific.
  5. Hydroelectric: generated from water flow; impacts ecosystems and can be costly.
  6. Solar: energy from the sun; growing but limited by land and efficiency issues.
  7. Wind: efficient, low emissions but requires stable wind conditions.

Future Renewable Sources

  • Hydrogen Fuel Cells: produce water and heat with low emissions; storage and production challenges.
  • Nuclear Fusion: potential for low waste, no emissions, currently experimental.
  • Tidal and Wave Energy: harnessing movements in water; currently limited.

Energy Conservation

  • Energy efficiency programs like ENERGY STAR; reduce phantom loads, improve appliances.

Smart Grids

  • Automated electrical systems improving efficiency and reliability of energy distribution.

Transportation and Energy Use

  • Increasing reliance on petroleum; need for alternative fuels; CAFE standards aim to improve vehicle fuel efficiency.