Posted on April 7th, 2008 1 comment
For the first time in history, Boeing demonstrated a manned, hydrogen fuel cell powered aircraft. I had written about a Sonex electric aircraft I saw at Oshkosh last year, albeit as a static display model that used 250 lbs of batteries. It would only operate for about 18 minutes at full power, or just a small fraction of the time you’d expect from a gasoline powered aircraft.
In this case, the flight was at a speed of 55 kts, at an altitude of 3300 feet for 20 minutes in a converted motor glider, so the range/capacity is likely to be on par with the Sonex. Boeing does not anticipate that hydrogen fuel cells will be able to provide primary power for a commercial aircraft.
I think that the outcome of these recent demonstrations show that the future of air travel will continue to depend on liquid hydrocarbon fuels. Short of a miraculous discovery, when fossil fuels are exhausted hydrocarbon fuels will need to come from biomass feedstocks. After a rash of articles inspired by a recent Science article critical of biofuels, even Time Magazine has jumped on the dogpile, parroting the statements that biofuels are a scam and an environmentally damaging approach to generating energy.
In the future, the sun and wind will likely provide enough energy to heat our homes and provide us with electricity. Those energy sources may even power a commuters vehicle a few dozen miles a day. But to move something like a ship, a truck, a train, or a plane, it appears we’ll be dependent on liquid hydrocarbon fuels for some time. This might not be the case if the energy density of battery technology would approach that of hydrocarbon fuels per kg., but thus far it’s still several orders of magnitude away. Even with the thermal to mechanical energy inefficiency of the internal combustion engine which averages around 30%, energy density is still the primary advantage of conventional fuels over batteries.
Perhaps the best chance to please everyone would be to use wind and solar power to pull carbon dioxide out of the atmosphere, combine it with hydrogen, and synthesize clean burning hydrocarbon fuels. I suspect that no sooner than a method became practical, there’d be another dogpile forming, no doubt protecting existing interests by decrying the evils of robbing CO2 from the atmosphere.
Renewable energy certainly has a lot of controversy and drama associated with it. You wouldn’t expect that from a field that should be primarily technical and scientific, but when anything has the potential to affect economics, politics, and the environment, technical arguments seem to hold little sway.