What is a wind turbine and how does it work?

A wind energy system – made up of wind turbines – transforms the kinetic energy of the wind into electrical energy that can be harnessed for practical use.

There are two basic designs of wind turbines: vertical axis (or “egg beater” style) and horizontal axis (propeller style) machines. Horizontal-axis turbines are most common today.

Turbine systems include:

• A rotor – or blades – which convert the wind’s energy into rotational energy
• A nacelle (enclosure) containing a drive train, a generator, and usually a gearbox
• A tower to support the rotor and drive train
• Electronic equipment such as controls, electric cables, ground support equipment, and interconnection equipment

Wind turbine towers are mostly tubular and made of steel; the blades are made of fiberglass-reinforced polyester or wood-epoxy.

Wind turbines vary in size. The chart below shows a variety of turbine sizes and the amount of electricity they are each capable of generating:

How much electricity can one wind turbine generate?

The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW, 1,000 watts), megawatt (MW, 1 million watts), and gigawatt (GW, 1 billion watts) are usually used to describe the capacity of generating units like wind turbines or other power plants.

The output of a wind turbine depends on the turbine's size and the wind's speed through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 3 megawatts (MW).

What may seem like a small difference in wind speed can mean a large difference in available energy and in electricity produced, leading to a large difference in the cost of the electricity generated.

How does wind energy contribute to our electricity needs?

U.S. wind power plants already serve more than 4.5 million average households with 12 million people. Wind power is capable of providing 20 percent of the country’s energy by 2030.

Wind energy contributes to our energy security. It’s an inexhaustible, domestic resource, and it helps reduce our dependence on imports of natural gas, oil and other fuels that often come from unstable countries like Nigeria and Russia.

What are America’s current sources of electricity?

Coal, the most polluting fuel and the largest source of the leading greenhouse gas, carbon dioxide (CO2), is currently used to generate more than half of all the electricity generated in the United States. Other sources of electricity include natural gas, oil, nuclear, and hydropower.

Does wind power offer real environmental benefits?

Absolutely. Wind requires no mining, drilling, or transportation of fuel, and does not generate radioactive or other hazardous or polluting waste. Wind power offsets other, more polluting sources of energy. This is important because electricity generation is the largest industrial source of air pollution in the U.S. When wind power projects generate electricity, fuel at other power plants is not consumed.

How does wind power benefit the economy?

Wind power supplies affordable, inexhaustible energy to the economy. It also provides jobs and other sources of income. Best of all, wind powers the economy without causing pollution, generating hazardous waste, or depleting natural resources. Wind has no “hidden costs.” Finally, wind energy depends on a free fuel source – the wind – so it is relatively immune to inflation.

Can wind energy help with rising natural gas prices?

Yes, wind can help with rising natural gas prices. When a wind farm generates electricity in the U.S., the fuel it is most likely to displace is natural gas. Ample wind plants could be built within four years to eliminate the entire gas shortage, which is estimated at 3-4 billion cubic feet of gas per day.