General Electric’s wind energy division is trying to find a “Goldilocks” turbine design, one that’s not too big and not too small.
Like other wind manufacturers, GE is benefiting from booming demand for wind turbines in Europe and in the U.S., even with the possibility of a renewable-energy tax credit lapsing later this year.
Still, the rapid expansion is being throttled by high prices of steel and other commodities, making wind power more expensive.
So instead of making bigger and bigger machines, manufacturers are trying to squeeze more energy from conventionally sized wind turbines.
That will be done by using alternative materials, better electronics, and shaping turbine blades to better capture the wind, said Stephane Renou, who manages research and development for General Electric’s wind technology platform.
“The optimal point is changing…and going bigger is not the answer,” Renou said. “Turbines in the two or three megawatt zone are the most efficient and the best cost per kilowatt.”
A 2 megawatt or 3 megawatt wind turbine is still large. The tower on a 2.5 megawatt machine can stand nearly 330 feet high.
But making 5 megawatt or 6 megawatt turbines, as some off-shore turbine makers are doing, also means more raw materials, notably steel, which drives up the cost. The logistics of delivering and assembling these massive components can add to costs as well.
To get more power from the same footprint, GE is looking at a variety of technologies, said Renou, who oversees development at four GE wind research centers around the world.
“I see a lot more technology going into each of the components, especially the blades,” he said. “The blades will look more funky and twisted to get better performance.”
By adding more carbon composite to turbine blades, GE can add 16 feet to their length, which translates into a significant boost of energy.
Although it’s four times more expensive than fiberglass, carbon also gives blades more flexibility, allowing them to operate at higher wind speeds.
GE is also working on electronics controls to optimize performance and sound level of entire wind farms, Renou said.