In a deal worth half a billion dollars, GE (NYSE: GE) today announced it has contracted to provide four 7HA gas turbines, two D600 steam turbines and six generators to energy corporation Exelon (NYSE: EXC). The deal targets the fast growing, high-efficiency market segment and represents the first HA turbines to be sold in the US.
Exelon will take delivery of the turbines in 2016, and begin operating them by mid-2017. Each turbine will have an output of 330 MW and a net combined-cycle efficiency rating that exceeds 61 percent. Compared to F-class turbines which operate at 55-59 percent efficiency, HA turbines will save $8 million in annual fuel expenditures. The turbines also feature module constructability for shorter installation schedules. GE currently has orders for nine other HA turbines in France, Russia and Japan.
The HA turbines are the largest and most efficient in the world and build on GE’s previous H-class technology, which was launched in 2003 and has now accumulated significant operating time. Unlike the previous H-class turbines which relied on steam cooling, the new HA turbines rely on air for temperature regulation. “The air-cooled version of the turbine is just much simpler and more cost-effective,” said Victor Abate, president and CEO of power generation products at GE Power & Water. “The steam-cooled turbine was technically elegant, but it was expensive to operate. Air cooling makes the turbine cheaper to maintain because there are no steam circuits to tear down before accessing key components. That adds up to lower life cycle costs.”
HA turbines have the lowest heat rate and emissions in the world. Much of this efficiency is due to the H-class’ firing temperature. Compared to E-class turbines which fire at 2000-3000 degrees, and to F-class turbines which fire at 2300-2600 degrees, H-class turbines fire at 2600-2900 degrees. “That temperature is 400 degrees hotter than the melting point of the base metals,” said Abate. “It takes a tremendous amount of material science and computational fluid dynamics to pull this off, but it results in a more efficient system.”
The new turbines are also extremely flexible, able to operate at less than 100 percent base load in order to complement renewable or other intermittent generative models. HA turbines can transition from zero to full power in ten minutes. When combined with steam turbines in a combined-cycle plant, they can be at full power in 30 minutes.
“GE is the only company in the world that has a full-speed, full-load testing center not attached to the grid,” Abate said. “This allows us to overcome the hypotheticals and determine real-world numbers for things like parts limitations. This is really just the beginning for GE. We’re very excited about where we are and where we think we can go. Around the world, the demand for more efficient, cost-effective, dispatchable power complements the renewables business very well. We’re bullish about the future.”