Quick Facts

Wind Power

  • Two types of wind machines are commonly used today, the horizontal-axis with blades like airplane propellers and the vertical-axis, which looks like an eggbeater.
  • About 95% of all wind machines are horizontal-axis. A typical horizontal wind machine stands as tall as a 20-story building and has three blades that span 200 feet across.
  • The largest wind machines in the world have blades longer than a football field! Wind machines stand tall and wide to capture more wind.
  • Vertical-axis wind machines make up just five% of the wind machines used today. The typical vertical wind machine stands 100 feet tall and 50 feet wide.
  • Wind plants also need a lot of land. One wind machine needs about two acres of land to call its own. A wind power plant takes up hundreds of acres. On the plus side, farmers can grow crops or graze cattle around the machines once they have been installed.
  • An average wind speed of 14 mph is needed to convert wind energy into electricity economically. The average wind speed in the U.S. is 10 mph.
  • Scientists use an instrument called an anemometer to measure how fast the wind is blowing. An anemometer looks like a modern-style weather vane. It has three spokes with cups that spin on a revolving wheel when the wind blows. It is hooked up to a meter that tells the wind speed. A weather vane shows the direction of the wind, not the speed.
  • Wind machines convert 30-40% of the wind's kinetic energy into electricity. A coal-fired power plant converts about 30-35% of the chemical energy in coal into usable electricity.
  • One wind machine can produce 1.5 to 4.0 million kilowatt-hours (kWh) of electricity a year. That is enough electricity for 150-400 homes per year.
  • In this country, wind machines produce 10 billion kWh of energy a year.
  • Wind energy provides about 0.1% of the nation's electricity.


  • Coal is used to generate more than half of all electricity produced in the United States. It's also used as a basic energy source in many industries, including, steel, cement and paper.
  • The use of western coals (from Wyoming, Montana, Colorado, and Utah) can result in up to 85% lower sulfur dioxide emissions than the use of many types of higher sulfur eastern coal.
  • Almost 91% of the coal used in the United States is used to generate electricity. The amount of electricity generated from coal is about 51% of the total amount of electricity generated in the United States.
  • Coal plants typically have a 75% capacity rating since they can run day or night, during any season of the year.

Energy Use in the United States

  • 37% Industrial
  • 27% Transportation
  • 16% Commercial
  • 20% Residential

Acid Rain

  • Scientists have found different ways to reduce the amount of sulfur dioxide released from coal-burning power plants.
  • One option is to use coal that contains less sulfur.
  • Another option is to wash the coal to remove some of the sulfur.
  • The power plant can also install equipment called scrubbers, which remove the sulfur dioxide from gases leaving the smokestack.
  • Human activities are the main cause of acid rainLink opens in new window - close new window to return to this page..
  • Power plants release the majority of sulfur dioxide and much of the nitrogen oxides when they burn fossil fuels, such as coal, to produce electricity.
  • The exhaust from cars, trucks, and buses releases nitrogen oxides and sulfur dioxide into the air. These pollutants cause acid rain.

Acid Rain

  • Pure water has a pH of 7.0. Normal rain is slightly acidic because carbon dioxide dissolves into it, so it has a pH of about 5.5. As of the year 2000, the most acidic rainLink opens in new window - close new window to return to this page. falling in the US has a pH of about 4.3.

Air Pollution

  • State environmental agencies take samples of the air at more than 1,000 places in the United States to see if the air is dirty or clean.
  • Pollutants are what make the air dirty and cause pollution. Five pollutants are used by the EPA to determine the Air Quality Index (AQI)Link opens in new window - close new window to return to this page.. Two of the pollutants, Ozone and Particulate Matter, make up most of the air pollution in this country.
  • Particulate matter is mostly dust and soot so small that it floats in the air.

Energy Efficiency

  • Your refrigerator uses the most electricity of all the appliances in your home.
  • A refrigerator produced in 1990 uses twice the amount of electricity needed to operate an ENERGY STAR® model.
  • About 35% of all electricity is used to run homes.
  • 90% of the energy used for washing clothes is for heating the water.
  • 60% to 80% of the power used by the dishwasher is consumed just to heat the water.
  • Compact Fluorescent Light bulbs (CFLs) use 66% less energy than a standard incandescent bulb and last up to 10 times longer. This means that over the life of one CFL, a consumer can avoid replacing up to nine incandescent bulbs!
  • Where does your home use energy?
  • 60% - Air conditioning/heat
  • 16% - Water heater
  • 12% - Refrigerator
  • 7% - Lights
  • 5% - Computers, TV, etc.

What Becomes of Fuel?

  • The 500 million automobiles on earth burn an average of 2 gallons of fuel a day.
  • Each gallon of fuel releases 20 pounds of carbon dioxide into the air.
  • Approximately 5 million tons of oil produced in the world each year ends up in the ocean.
  • Publication: Mercury in Your Community and the Environment (By Wisconsin Department of Natural Resources)
  • For more information visit Planet PalsLink opens in new window - close new window to return to this page.


  • Mercury is the only metal that is liquid at room temperature.
  • Mercury easily evaporates in the air.
Last Updated: 10/17/2014