Montana Earth Science Picture of the Week

Wind Generators near Judith Gap
Photo Courtesy of Geoff Smith, Science Teacher at Judith Gap

January of 2006 marked the completion of Montana's first major wind power project. Located between Judith Gap and Harlowton (between Billings and Great Falls), the project includes 90 wind- powered generators, each capable of producing enough electricity for 300 to 400 homes. The generators are owned by a Chicago based company called Invenergy, which sells the electricity to Northwestern Energy. Each generator stands about 260 feet tall in order to tap the stronger winds found farther from the surface.

Why here? . . .
According to an Invenergy spokesman the winds in January of 2006 averaged 42.6 miles per hour. But these strong, steady winds weren't the only factor that made this site appealing. The site is also close to a major transmission line that runs between Great Falls and Billings; two population centers that represent a significant demand for power.

How to make electricity . . .
A wind-powered generator works like a fan in reverse. Instead of using electricity to move air like fans do, wind generators use mving air (wind) to generate electricity. Here's how it works. . . . To make (generate) electricity, you need three things: a magnet, a wire, and motion. If you take a magnet and move it in close proximity to a wire, this causes an electrical current to flow within the wire. Within a generator, wires and magnets are organized so that a current will be produced in the wires if motion is provided. Generators can be designed to utilize all sorts of motion ranging from the peddling motion of a bicycle to the motion of water through the bottom of a dam. At coal-fired plants, coal is burned to heat water. As the water changes to steam it shoots through a turbine, providing the motion. With wind generators, the wind turns propeller-shaped turbines to generate electricity.

CLICK HERE to watch a short wind generator demonstration (less than 2 minutes).

Pros and cons . . .
Over half of the electricity used in Montana comes from coal-fired generators, primarily those located at Colstrip in the southeastern part of the state. Dams are the other primary source. A big advantage of wind-generated power (and hydro-power) is that there are no emissions. Coal-fired plants emit carbon dioxide (a major greenhouse gas) as well as sulfur dioxide and mercury. One problem associated with wind generators is that power companies, such as Northwestern, have to buy power from other sources to keep the power flowing when the wind isn't blowing. The short-term nature of these additional sources of electricity cause them to be more expensive.

Windfall for county . . .
Another plus for the area is the revenue (income) that the project will provide for Wheatland County. The county expects to get over $750,000 in "impact money" over the next three years to offset the impact of construction. Projects such as this have an "impact" on schools, roads, water and water systems, fire departments, etc. Impact dollars help counties pay for these services. Also, the wind generators will continue to generate tax dollars for the county and state for years to come.

Photo By Geoff Smith

Term: barotrauma (*see hot link below)


*Do wind generators harm bats?
Montana Earth Science Pictures
Wind generator demonstration for teachers

By Rod Benson
Earth Science Teacher at Helena High School

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