When GE engineers decided to build a better power plant a few years ago, they looked up at the sky. In the 1950s, aviation legend Gerhard Neumann built the first GE supersonic jet engine by using a system of compressor blades called “variable vanes” that could turn and alter the flow of air coming inside the engine during flight. “It changed everything,” says former GE aviation engineer Jim Johnson.
Today, nearly every jet engine uses Neumann’s technology and so does GE’s new “flexible” power plant. It dramatically cuts emissions and saves utilities fuel and money by allowing them to quickly change output and generate electricity only when customers need it. “Typically, efficiency drops off quickly and emissions go up as you reduce output,” says Eric Gerbhardt, vice president for thermal engineering at GE Power & Water. “Now we can come down to as low as 14 percent of maximum output and still remain emissions compliant. That’s something customers have been asking for.”
Jet Son: GE’s new “flexible” power plant is using some of the same GE technology that allowed Chuck Yeager to fly at twice the speed of sound.
Here’s why. An electricity socket is like a shower head in your bathroom. When you take a shower in the morning, you expect the same strong water pressure. When utilities tap renewable electricity from wind farms and solar plants, they can keep the same power “pressure” flowing to your home and cut the amount of power they generate by burning gas and other fuels. The problem is that ordinary power stations are rigid and can’t respond to power gyrations caused by renewables dependent on the wind and the sun. The new GE plant, called FlexEfficiency 60, however, can ramp up power as fast as 100 megawatts per minute, twice as fast as the industry standard.
Advanced combustion technology, also developed for jet engines, keeps emissions like nitrogen oxides and carbon monoxide in check. The technology is using blades made from single-crystals of nickel-based superalloys to manage extremely high temperatures and reduce emissions in the combustion chamber. “The whole blade is grown from a single metal kernel,” Gerbhardt says. Other blades are hollow and peppered with tiny holes, like miniature strainers. The ducts and holes channel cooler air to keep the temperature around the blades just right and prevent the blades from melting. “It’s a very precise science how every hole is positioned,” Gerbhardt says. “We shine infrared light on the blades on our test stand in Greenville and pick out the hot and cool spots,” he says. “We feed that data back to our design team.”
All this innovation and research means that new plant can stay as efficient as 61 percent even at low electricity output. According to the New York Times, the U.S. Department of Energy had compared such efficiency to running a four minute mile. Gerbhardt said that before the GE “flexible” plant came along, utilities would idle their plants overnight when demand drops and restart them in the morning. This is inefficient. “Now they can run it at a very low load for several hours and turn it back on when power is needed.”