Couldn't big airplanes be made to fly on electricity?

Dear EarthTalk: Can airplanes be run on cleaner fuels or be electric powered? Are there changes afoot in the airline business to find cleaner fuels?

Reema Islam

Dhaka, Bangladesh

Given air travel’s huge contribution to our collective carbon footprint — flying accounts for about 3 percent of carbon emissions worldwide by some estimates — and the fact that basic passenger and cargo jet designs haven’t changed significantly in decades, the world is certainly ready for greener forms of flying.

But since air travel emissions were not regulated under the Kyoto Protocol, the international agreement signed in 1997 that set binding targets for reducing greenhouse gas emissions, the friendly skies aren’t much greener than they were a few decades ago. And most national governments have been reluctant to impose new environmental restrictions on the already ailing airline industry.

Nonetheless, some airlines and airplane manufacturers are taking steps to improve their eco-footprints. Southwest and Continental have implemented fuel-efficiency improvements, waste reduction programs and increased recycling, and are investing in newer, more fuel-efficient airplanes. Another airline on the cutting edge of green is Virgin Atlantic, which made news in early 2008 when it became the first major carrier to test the use of biofuels (liquid fuels derived from plant matter) on passenger jet flights. Now Air New Zealand, Continental, Japan Airlines (JAL), JetBlue and Lufthansa are also testing biofuels.

Even airplane maker Boeing is getting in on the act by developing a carbon-neutral jet fuel made from algae. Boeing’s newest commercial jet, the much vaunted 787 Dreamliner (now in final testing before late 2010 delivery to several airlines), is 20 percent more fuel efficient than its predecessors thanks to more efficient engines, aerodynamic improvements and the widespread use of lighter composite materials to reduce weight. Airbus is also incorporating more lightweight composite materials into its new planes.

On the extreme end of the innovation spectrum are zero-emission airplanes that make use of little or no fuel. The French company, Lisa, is building a prototype small plane, dubbed the Hy-Bird, that uses solar power (via photovoltaic cells on the elongated wingspan) and hydrogen-powered fuel cells to fly with zero emissions — and nearly no engine noise. The company claims the Hy-Bird is the first 100-percent eco-friendly plane, and is readying a round-the-world flight punctuated by 30 event-filled stopovers.

Even more unusual is the proposed fuel-free plane dreamed up by Mississippi-based Hunt Aviation. The company is working on a prototype small plane that harnesses the natural forces of buoyancy (thanks to helium-filled pontoons) for lift-offs and gravity for landings — along with an on-board wind turbine and battery to power everything in between — to achieve flight without any fuel whatsoever.

Don’t look for these futuristic planes on airport runways anytime soon. It will likely be decades before this technology filters its way up to the big leagues. Until then, take a train or bus instead. If you must fly, compensate for your flight’s emissions by buying a “carbon offset†from TerraPass or CarbonFund.org, which will use the money to fund alternative energy and other greenhouse-gas reduction projects.

CONTACTS: Lisa Airplanes, lisa-airplanes.com; Hunt Aviation, fuellessflight.com; TerraPass, terrapass.com; CarbonFund.org, carbonfund.org.

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