Nonrenewable Energy Notes

Nonrenewable Energy

Fossil Fuels

• Include coal, oil, and natural gas.

• Formed over millennia from the remains of organisms without the presence of oxygen.

• Different conditions for the remains of the organisms result in the different types of fossil fuels.

Coal

• Formed from plant remains subjected to high heat and pressure over millions of years.

• Provides over $1/4$ of the world’s energy.

• Advantages:

  • Cheap.

  • Needs little processing.

  • Easy to transport.

  • Most abundant fossil fuel on Earth.

How Coal is Obtained

Strip Mining

• Overlaying rock and soil are removed to access coal.

• Safer for miners.

Subsurface Mining

• Underground shafts are dug to access coal under Earth’s Surface.

• Better for the environment.

Oil

• Dark, liquid fossil fuel made up mostly of hydrocarbons.

• Formed from the remains of ancient marine organisms and found in underground deposits.

• Uses:

  • Fuel for cars, trucks, planes, and ships.

  • Used in chemical compounds (petrochemicals).

  • Plastics.

• Also known as petroleum.

Drilling and Refining Oil

• After crude oil is extracted from the ground, it is separated into different fuels in a refinery.

Primary Extraction

• Oil flows out of the well because it is already under pressure.

Secondary Extraction

• Increased pressure or injections are needed to remove the rest of the oil.

Natural Gas

• Primarily methane gas with small amounts of other gasses mixed in.

• Often found above oil or coal deposits.

• Much less polluting than coal or oil and releases more energy when combusted.

• Used for heating, appliances (stoves and dryers), and making electricity.

Fossil Fuel Supply

• Consumption is still rising.

• New fossil fuels are not formed on a human timescale.

• New oil sources are expensive, energy-intensive, and can be hazardous to obtain:

  • Oil Sands

  • Oil Shale

  • Methane Hydrates

• Coal sources are still relatively abundant, but not infinite.

• Some studies suggest that nearly half of Earth’s oil has been extracted and that U.S. coal supplies may last just 130 years.

Pollution, Climate Change, and Public Health

• Burning fossil fuels releases $CO_2$ which contributes to global climate change.

• When coal and oil burn, $SO_2$ and nitrogen oxide are released, contributing to smog and acid deposition/precipitation.

• Oil spills, equipment ruptures and malfunctions, and oil in runoff pollute waterways, oceans, and costal areas.

• Coal fired power plants release mercury (40% of US mercury emissions), which harms human health.

• Crude oil contains trace amounts of lead and arsenic.

Damage Caused by Extracting Fuels

Mining

• Humans risk lives and respiratory health.

• Ecosystems are damaged by habitat destruction, extensive erosion, acid drainage, and heavy metal contamination downslope of the mines.

Oil and Gas Extraction

• Roads and structures have to be built to support drilling operations.

• Break up habitat and harm ecosystems.

• The long term consequences of accidents can be uncertain or unpredictable.

Dependence on Foreign Sources

• Fossil fuels are not evenly distributed across the world.

• Some countries must import fuel sources.

• Nations that import fuel may be vulnerable to changes in prices.

• Nations can import less fuel by developing domestic oil sources and renewable energy sources.

Energy Conservation

• The practice of reducing energy use to make fossil fuel last and to prevent environmental damage.

Transportation

• Gas-efficient cars and higher gas prices could help conserve energy in the U.S.

Personal Choices

• Individuals can save energy by:

  • Turning off lights.

  • Taking public transportation.

  • Transportation accounts for $2/3$ of all U.S. oil consumption

  • Buying energy efficient appliances.

Nuclear Fission

• Splits an atomic nucleus into two smaller nuclei.

• Releases neutrons and large amounts of energy. If enough unstable nuclei are present, a nuclear chain reaction can occur.

• About 20% of electricity produce(d) in U.S.

Generating Energy Using Nuclear Energy

1. In the reactor vessel, uranium undergoes nuclear fission, producing heat.

2. The heat changes water into steam.

3. The steam turns a turbine that generates electricity.

4. Water from the cooling tower cools steam in the condenser, changing the steam to liquid water. The water returns to the reactor.

Benefits and Costs of Nuclear Power

Benefits

• No air pollution

• Requires little uranium fuel and little mining

• Under normal conditions, nuclear power plants are safer for workers than coal-burning power plants

Costs

• Expensive to build and maintain

• Catastrophic accidents are possible

• Nuclear waste must be stored for thousands of years

Nuclear Waste

• Waste is currently held at power plants as a stopgap, but a long-term storage location is needed.

• Long-term storage sites must be distant from population centers, protected from sabotage, have a deep-water table, and be geologically stable.

• Yucca Mountain, Nevada, was chosen by the U.S. government in the 1980s, and a storage site was constructed there. But, as of 2010, the Yucca Mountain project is no longer under development.

Nuclear Fusion

• Joining two atomic nuclei to form one nucleus.

• Releases much more energy than fission.

• Currently impractical because very high temperatures are needed, but scientists continue exploring fusion for our future energy needs