"All Biofuels Contain Health Risks As Does Diesel"
20 Apr, 2007 01:32 pm
A report published this week on the safety of Ethanol suggests that in fact this popular potential replacement for oil has some drawbacks. Marc Jacobson, lead author of the report, answers Scitizen's questions.
It may increase ozone relative to gasoline in Los Angeles, the northeast, and most of the U.S. but decrease it slightly in the southeast, causing an overall population-weighted increase and increase in resulting mortality and health problems. It may increase death rates by about an addition 200 / year in the U.S., compared with death rates due to gasoline of 10,000/year.
What other biofuels that are on the forefront of alternative energy movement may
contain health risks?
All biofuels contain health risks as do diesel and gasoline and other combustion fuels. The key is to eliminate combustion in favor of battery-electric and hydrogen fuel cell vehicles,
where the electricity for batteries comes from renewable wind, solar, hydro, geothermal, tidal, wave power and the hydrogen is produced by electrolysis from the same renewables. Batteries are more efficient than hydrogen, which is more efficient than gasoline, but hydrogen has uses for long-distance travel and heavier loads.
You advocate the use of other forms of renewable energies such as solar, wind, and fuel cells for automobiles. Do you think these forms of energy are capable of meeting our energy needs?
Yes. In theory, we can power the entire U.S. onroad vehicle fleet with 70,000-120,000 5 MW wind turbines operating in 7.5-8.5 m/s annual winds. This would take 1/30th the land than powering the fleet with corn ethanol. The U.S produced 300,000 airplanes in 7 years leading up to and through WWII, so, this is a feasible goal in a short time frame with the right commitment. Such a conversion would eliminate 10,000 air pollution deaths and 25.8% of U.S. CO2 emissions (those due to onroad vehicles, compared with not eliminating and deaths and causing virtually no change in U.S. CO2 with corn ethanol.
For example, the following study by Dr. M. DeLucchi
shows, in tables 3 and 8, a 2.4 percent carbon-equivalent fuel-cycle benefit of U.S.
corn-ethanol-E90 versus gasoline (compared with a 17% disbenefit in China, a 10% disbenefit inIndia, and a 6% benefit in Chile). Multiplying this by 26% gives about a 0.5% difference between corn ethanol and gasoline, and this would require 10-20% of the U.S. to be converted to corn for ethanol.
Interview by Christopher Le Coq
Mark Jacobson is an associate professor in the Civil and Environmental Engineering Department at Stanford University in California, USA.
Marx Z. Jacobson, Environ. Sci. Technol., 2007, April 18