There can be too much of a good thing even in renewable power. Imagine that you run a wind farm with 50 wind turbines churning away above gusty hills and valleys. Suddenly a message from the grid operator who buys your electricity flashes on a screen in your control center. Her wires are transmitting power at capacity, demand is dropping, and she wants you to reduce output. This is what industry calls “curtailment.”
You start manually shutting down your turbines to meet her request and avoid a penalty. But wind and demand often fluctuate unpredictably and you end up turning off too many turbines to comply and lose revenue. “It’s like driving on a road where you can’t see the hills and valleys and the speed limit is constantly changing and you don’t know when it’s going to go up and down,” says William Noto, software innovation leader for renewables at GE Power and Water. “You end up taking your foot off the gas too much,” Noto says.
That’s why GE engineers developed “cruise control for wind turbines.” It’s called WindCONTROL and belongs to GE’s Industrial Internet arsenal. The software system automatically monitors power requests from the grid and allows wind farm operators to smoothly reduce output across their machines. “When the wind is howling and the turbines are all running at rated power, making, say, 1,600 kilowatts each, if you reduce power manually you can only do it in increments of 1,600 kilowatts,” Noto says. But WindCONTROL smoothly lowers the amount each turbine generates and keeps the whole farm spinning. The system, which runs on the wind farm’s servers, helps keep power production at the allowed maximum, improves wind farm efficiency, and cuts back on wear and tear caused by “cycling,” or frequent switching of the turbines on and off.
The system can also add power when it’s needed. When one turbine “trips” and stops generating power, WindCONTROL will command the others to incrementally pitch in so that the total output remains constant, which is what grid operators want.
First Wind, a Boston-based independent wind company that owns and operates 264 turbines at eight sites across the U.S., will install WindCONTROL on 95 GE wind turbines at two Maine wind farms. “The effect of the curtailment on wind turbines has been an area of concern for us,” says E.J. Martin, vice president of operations at First Wind. “The application of GE’s WindCONTROL technology to our wind turbines in Maine will help the units maximize energy capture while mitigating the strain on our units as we regulate power production.”
GE is already servicing First Wind’s fleet of GE turbines and the wind company is using other Industrial Internet products to make its farms more efficient. The New York Times reported last November that sensors were measuring temperature, wind speeds, location and pitch of the blades, and sending the data to GE software for analysis to improve performance. The Times reported that upgrades on 123 turbines on two wind farms had delivered a 3 percent increase in energy output, or $1.2 million in additional annual revenue.