The Zero Emissions Struggle
Hybrid cars are not a panacea. Even though they represent
a significant improvement over conventional vehicles in fuel efficiency
and emissions, because they use a combustion engine they still
produce some carbon dioxide, carbon monoxide, and smog related
pollutants. If automobile use increases in the future, perhaps
from population increases or expanding urbanization for instance,
then even a complete replacement of conventional cars with hybrids
might not reduce overall emissions. Although hybrid cars represent
a viable transition step towards reducing vehicle emissions, they
are far from the ultimate solution. That is, scientists now are
seeking to find ways to eliminate automotive emissions completely
through the zero emissions vehicle (ZEV). At present the only
well established ZEV in use is the electric car, which is still
too impractical for widespread applications. See the "Fuel Cells
and the Hydrogen Economy" link above for details on fuel cells,
another type of potential ZEV.
Sources:
http://www.ucsusa.org/clean_vehicles/advanced_vehicles/page.cfm?pageID=204|
http://www.ucsusa.org/clean_vehicles/advanced_vehicles/page.cfm?pageID=206
|
