Nonrenewable Energy Resources & Patterns of Energy Use

After reading this module, you should be able to:
- Describe the use of nonrenewable energy in the world and in the United States.
- Explain why different forms of energy are best suited for certain purposes.
- Understand the primary ways that electricity is generated in the United States.

Fossil fuel: A fuel derived from biological material that became fossilized millions of years ago.
Nonrenewable energy resource: An energy source with a finite supply, primarily the fossil fuels and nuclear fuels.
Nuclear fuel: Fuel derived from radioactive materials that give off energy (e.g., Uranium).

In 2011, worldwide annual energy consumption was primarily from oil, coal and peat, and natural gas.
There is global variation in total annual energy consumption and per capita energy consumption.
The top 10 largest and smallest energy users vary significantly.
Commercial energy source: An energy source that is bought and sold.
Subsistence energy source: An energy source gathered by individuals for their own immediate needs.
Historically, wood and then coal dominated the US energy supply.
Currently, a mix of three fossil fuels (oil, coal, and natural gas) accounts for most of our energy use.
There has been a recent increase in natural gas use and a decrease in coal and oil use.

United States annual energy consumption is tracked by resource and end-use.
Consumption is categorized by fuel type and end-use sector (e.g., commercial, residential, transportation, industrial).

The best form of energy to use depends on the specific purpose for which it is needed.
Energy efficiency can be determined by calculating the energy return on energy investment (EROEI).
$EROIE = \frac{Energy\ obtained\ from\ fuel}{Energy\ invested\ to\ obtain\ fuel}$
The larger the value of EROEI, the more efficient the fuel.
During WWII, vehicles in Europe and Japan were converted to operate on gases generated from coal or wood due to gasoline shortages.

Coal exemplifies inefficiencies in energy extraction and use.
Energy is lost at each stage, from extraction, processing, and transport of the fuel to the disposal of waste products.

Nearly 30% of energy use in the United States is for transportation.
Efficiency is particularly important in the transportation sector.
Transportation relies primarily on vehicles fueled by petroleum products like gasoline and diesel.

Electricity can be generated from many different sources, including fossil fuels, wind, and water.
Electricity is a secondary energy source and energy carrier, moving and delivering energy in a convenient, usable form to end users.

All thermal power plants convert the potential energy of a fuel into electricity.
Turbine: A device with blades turned by water, wind, steam, or exhaust from combustion that turns a generator in an electricity-producing plant.
Electrical grid: A network of interconnected transmission lines that joins power plants together and links them with end users of electricity.

A coal-fired electricity generation plant converts energy from coal combustion into steam, which turns a turbine that turns a generator, producing electricity.
Steps for using coal to produce electricity:
- Burning fuel from coal transfers energy to water, which becomes steam.
- The kinetic energy within the steam is transferred to the blades of a turbine.
- As the energy in the steam turns the turbine, the shaft in the center of the turbine turns the generator.
- This mechanical motion generates electricity.

Combined cycle: A power plant that uses both exhaust gas and steam turbines to generate electricity.
Capacity: In reference to an electricity-generating plant, the maximum electrical output.
Capacity factor: The fraction of time a power plant operates in a year.

Cogeneration: The use of a fuel to generate electricity and produce heat; also known as combined heat and power.
For example, if steam is used for industrial purposes or to heat buildings, it is diverted to turn a turbine first.
This improves the efficiency to as high as 90%.