Greener Jet Engine Could Reduce Aviation’s Carbon Footprint
One of the biggest names in aviation has developed a jet engine that is more efficient, less polluting and cheaper to use than almost everything else in the sky, and it could revolutionize an industry facing skyrocketing fuel prices and mounting pressure to clean up its act.
Pratt & Whitney has spent the better part of two decades developing the geared turbofan engine that burns 12 to 15 percent less fuel than other jet engines and cuts carbon dioxide emissions by 1,500 tons per plane per year. It's being called one of the most exciting developments commercial aviation has seen in years, and it was a hot topic at the Eco-Aviation Conference, where the aviation industry spent two days charting the course to a greener future.
"It's technology like that geared turbofan that's going to drive fuel efficiency forward for this industry in the short and medium term," says Earnest Arvi of the Arvi Group. "Alternative fuels show great potential, but they're decades away."
Pratt & Whitney was just one of the heavy hitters at the conference, an unprecedented gathering that underscored the severity of the issues the industry faces. With airline passenger growth rates and aircraft emissions expected to double by 2020 and 2030, respectively, the pressure is on to address those problems quickly. The conference saw a lot of talk -- and a little green-washing -- about developing alternative fuels to replace jet fuel, easing airport pollution, and building greener aircraft to replace the industry's aging fleet. Nearly 1,000 planes flown by domestic carriers will be more than a quarter of a century old by 2015, and Boeing officials have said that more than 10,400 new planes will be needed in the coming decades and making them as green as possible will go a long way toward reducing commercial aviation's carbon footprint.
That's why Pratt & Whitney has so much to brag about with its geared turbofan, which significantly advances jet-engine technology. Current jet engines have fans that suck air into the combustion chamber, where it is compressed, mixed with fuel, and ignited. Then it's blown through a turbine, generating thrust. It works, but it's inefficient because the fan is connected to the engine and turns at the same speed as the turbine. Fans work best at low speed, while turbines work best at high speed.
Pratt & Whitney solved that problem with a gearbox that lets the fan and turbine spin independently. The fan is larger and it spins at one-third the speed of the turbine, creating a quieter, more powerful engine the company says requires less fuel, emits less C02 and costs 30 percent less to maintain. Pratt & Whitney has been torture-testing the engines, and its engineers have simulated more than 40,000 takeoffs and landings.
The company's VP of Technology and Environment, Alan Epstein, says the engine will not only cut CO2 emissions, but will also reduce nitrogen-oxide emissions, noise and -- ultimately -- ownership costs. "For the next generation of single-aisle aircraft, there's no question that engine performance will be key," he says. "Both economically and environmentally, this engine will deliver significant benefits."
The industry seems to agree and is lining up behind the engine, which Pratt & Whitney expects to have in regular service by 2013. It's already slated for jets currently being developed by Mitsubishi and Bombardier.
Pratt & Whitney isn't the only firm developing greener aircraft. Airbus is dabbling in alternative fuels and researching ways of recycling more than 6,000 planes slated for retirement during the next 20 years. Boeing is dabbling with hydrogen fuel cells and investing in algal fuels while pushing lighter planes like its 787 Dreamliner. Boeing says composite materials make up nearly 50 percent of the plane, which can carry as many as 330 people, making it far lighter than other planes its size. It is 20 percent more fuel-efficient and produces 20 percent fewer emissions than similarly sized aircraft, company officials say. Boeing is betting composite construction will bring huge improvements in fuel economy and emissions to commercial aviation.
Further gains could come from improving the nation's outdated air traffic control system, something nearly everyone at the conference said must happen. The current system is based on radar technology that dates to World War II, and plans to replace it with a satellite system known as NextGen are at a standstill while FAA reauthorization is stalled in Congress. But the industry has several other ideas, from allowing flights through military airspace to widespread adoption of a quieter, more efficient landing technique called continuous descent approach. Industry experts say adopting such steps could significantly reduce fuel consumptions and delays. The International Air Traffic Association says cutting just one minute from every commercial flight would save more than 1.9 million tons of fuel and 6.3 million tons of CO2 annually.
The air travel industry has taken a lot of heat for being slow to address its environmental impact, and some say parts of the eco-conference were just slick PR. But even some critics say the fact the industry is discussing environmental stewardship shows it's finally getting serious about the issue -- if only because doing so is in its best interest. "Climate change could mean fewer coastal vacation destinations, inaccessible airports and a general economic malaise that cuts travel spending," says Liz Barratt-Brown of the Natural Resources Defense Council. "Looked at in that context, you could argue that the aviation sector has the most to lose from global warming."
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