Hybrid cars have been with us for a while now, and with EV adoption happening slower than expected, they are likely to be part of the landscape for a good while longer. But why should the technology be limited to the ground? Turns out, the airline industry is also actively looking for ways to get higher fuel efficiency and reduce greenhouse gas emissions, and the same basic idea behind a Prius could well be the way to do it. On Tuesday, GE Aerospace successfully tested a megawatt-class hybrid-electric plane engine, paving the way for a first flight test. If all goes according to plan, this one technology could solve a bunch of aviation industry woes in one fell swoop.
GE Aerospace is doing all this in cooperation with no less than NASA, as part of the aeronautical (not just space!) agency’s Electrified Powertrain Flight Demonstration (EPFD) project. For NASA, the goal is to help with the science and engineering of next-generation commercial aircraft that will be 25-30% more fuel efficient. Since EPFD focuses on smaller commercial planes to start, GE’s new hybrid system was hooked up to one of its reliable old turboprop engines, the CT7. As for the test itself, it “simulated various flight phases such as taxi, takeoff, climb, and cruise,” but the big step is that the engine ran off of electric power alone for a bit.
Weaning off of jet fuel
Reducing emissions is good for the Earth: NASA says that aviation is responsible for 2-3% of the whole world’s greenhouse gases. But just in case the green you care about is more monetary in nature, how does saving money on fuel sound to you? Jet fuel accounts for around 20-25% of an airline’s operating costs, so a sizeable reduction there is a windfall for them. With prices marching upwards as a consequence of the war in Iran, the idea of a hybrid system is only going to get more appealing.
So, good for the Earth and good for the bottom line, but don’t forget about your ears. Electrified plane engines would be quieter, too. Beyond the obvious benefits to passengers and anybody living under a landing path, noise actually had big implications for the aviation industry. Flight paths are partly determined by a city’s noise pollution rules, which is why a big focus for newer aircraft is noise reduction. If the plane is quieter, it can fly more direct routes over cities without breaking the limit. If these new hybrid designs can take off and land on electric alone, whole new routes open up.
The path of least resistance
But first, a hybrid engine has to get in the air. GE Aerospace says that it will retrofit a Saab 340B with hybrid CT7 engines for testing “later this decade.” In the meantime, rivals like Pratt & Whitney are also working on their own hybrid designs, and NASA’s goal is to get electrified propulsion into commercial operation by 2035. The main barrier, as it’s always been, is how to keep the weight of all those batteries down. That’s why the start here is with smaller, regional turboprop planes, not bigger jet planes.
It’s worth pointing out that this hybrid approach has the advantage of being compatible with existing airframes. They might need a retrofit for the batteries and new electric system, but something like a Saab 340B or a De Havilland Dash 7 could be converted. By contrast, another new frontier of aviation, going fully electric, requires producing entirely new aircraft. That introduces a whole host of new questions, like how capable, safe, and reliable they are. Simpler just to use a pre-existing plane.
That possibility is much closer now that GE Aerospace’s CT7 test went well. There’s obviously a long way to go between now and NASA’s 2035 goal. But if it happens, this could be a revolution in the business of flying, one of the biggest in decades.
