Energy Sources and Fossil Fuels

Fossil Fuels and Alternative Energy

• Most of Earth's energy comes from the Sun
• Internal energy of Earth (core) is available for geothermal power
• Tidal energy is generated from ocean currents

Non-Renewable Energy Resources: Fossil Fuels

• Have a high energy content
• Used for electricity, industry, and transportation
• Formed from ancient organic matter over millions of years
  • Coal: hard, blackish substance formed from compressed organic matter
  • Oil: thick, blackish liquid consisting of many types of hydrocarbon molecules
  • Natural Gas: gas consisting primarily of methane (CH4) and other volatile hydrocarbons

Problems with Fossil Fuels

• Depleting fossil fuel reserves
• Non-renewable energy resource (used faster than replenished)
• Known world usage of fossil fuels will peak and run out
• Need to find alternative solutions

Obtaining Fossil Fuels

• Mountaintop mining for coal
• Drilling for oil in terrestrial and oceanic habitats
• Offshore oil rigs
• Hydraulic fracturing of shale for oil and gas (fracking)

Impacts of Fossil Fuel Use

• Release of pollutants into the environment
• Burning fossil fuels increases carbon in the atmosphere, leading to:
  • Global warming
  • Ocean acidification
• Increase in habitat destruction and negative impact on biodiversity

Renewable Energy Resources

• Goal: provide energy for three types of applications:
  • Generate electricity
  • Heat air and water
  • Fuel vehicles
• Much debate in some nations over feasibility of completely switching to renewables and away from fossil fuels

Solar Energy

• Every day, the Earth receives enough solar energy to power human consumption for 25 years
• Passive Solar Energy Collection: buildings designed to maximize absorption of sunlight
• Active Solar Energy Collection: uses mechanical and electrical equipment to focus, move, or store solar energy
• Benefits:
  • Sun expected to burn for 4-5 billion years
  • Decentralized power control over energy
  • No emissions of greenhouse gases or other pollutants
• Disadvantages:
  • Upfront costs of technology are expensive
  • Need to be in an area exposed to a lot of solar energy
  • Intermittent resource

Wind Power

• Harnesses wind power from air movement using wind turbines
• Wind turbines are often erected in groups (wind farms)
• Benefits:
  • No emissions of greenhouse gases or other pollutants
  • Can get a return on final investment
  • Can be used at multiple spatial scales
  • Landowners can lease their land for wind development
• Disadvantages:
  • Expensive upfront
  • Need to be in an area with a lot of wind
  • Intermittent resource
  • Folks might not like having a wind turbine nearby
  • Birds and bats sometimes killed when they fly into the turbine

Geothermal Energy

• Harnesses thermal energy from beneath the earth's surface
• Can be harnessed directly from geysers at the surface or through wells drilled down hundreds or thousands of meters
• Geothermal power plants harness energy from naturally heated underground water and steam to generate electricity
• Benefits:
  • Reduce greenhouse gas and pollutants compared to fossil fuel combustion
  • Jobs created
• Disadvantages:
  • Geothermal power plant cannot operate indefinitely
  • Geothermal activity in the earth's crust naturally shifts over time
  • Restricted to regions where energy can be tapped from naturally heated groundwater

Ocean Energy Sources (and Freshwater)

• Harnesses energy from tides, waves, and currents
• Wave energy: harnessing the motion of the oceans' waves and converting it into electricity
• Tidal Energy: erecting dams across outlets of tidal basins to generate electricity