January 26, 2012

Students in Sheri Matthew's and Kevin Warren's grade 7 science class today heard about the challenges of wind power from a GE official who has overseen the installation of thousands of electricity-generating wind mills/ turbines all over the world.

Harvey Williams, project operations manager for GE's Renewable Energy division in Schenectady, talked to the students about how electricity is generated - volts, amps and watts - and how that translates to creating an energy that can power turbines and other generating equipment.

He said that generating electricity is changing with alternative energies like wind and solar energy.

"Most of our turbines are concentrated in the (US) midwest and west on farms because the land is flat out there and the wind is constant," said Williams, who has worked for GE for 16 years. "They are a very efficient use of land. It doesn't take up much land, has a small footprint and the farmers love them because they receive royalty fees (for using their land). Everybody wins."

The 1.5 megawatt turbines - the most popular ones installed by GE - produce 1.5 million watts of energy - enough power for 500 houses, 1,200 hair dryers, 25,000 100-watt light bulbs or 652,000 Game Boys. "That is why your fathers tell you not to use those hair dryers all the time...they use a lot of energy," he quipped.

The 1.5 megawatt turbine costs about $2 million each and takes two days to install, he said. GE has installed more than 16,000 of them worldwide. They require a wind speed of at least 7-8 miles per hour and can handle wind speeds up to 62 miles per hour. The blades are 126 feet long and the entire windmill stands 388 feet high.

GE also produces larger turbines that generate 2.5 megawatts of power each.

Williams also shows a cross-section of a blade, which is made of balsa wood, controlled by a computer-driven controller box that shifts the blades to take the most advantage of the wind's speed and current at the time as well as protects it from high winds.

He explained the importance of aerodynamics in turning the blade as well as lifting an airplane. "By turning the blade (with the controller box), you can increase the lift and the speed of the blade," he said, explaining how that would then generate more electricity.

 One student asked what happens when there is a problem with a wind turbine. He said he is aware of only three out of 16,000+ GE turbines in which the blades turned too quickly, burning out the controller unit and sharing the unit apart.

"A lot of things have to go wrong for a turbine to go into what we call 'destructive overspeed,'" said Williams. "It doesn't happen much but, yes, it can happen."

He told students about installing wind turbines in the city of Kodiak on Kodiak Island in Alaska. He said the only means of generating power there was expensive diesel fuel. There is no electric connection with the mainland. GE was hired by the local government to install three turbines that provides up to 60 percent of the island's needs today. Delivering and installing the turbines on the island was difficult, he said, because of its location and mountainous terrain.

Here are photos of Harvey Williams' presentation. Click on each photo to enlarge it: