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Honda produces a natural-gas-powered Civic. What
exactly comes out of the vehicle’s tailpipe, and how harmful to the
environment is the extraction and refinement of natural gas? Which is
greener, a hybrid or a car powered by natural gas?
Honda’s natural-gas Civic GX, which debuted in
2006 in California but is now becoming available in other parts of the
country, just may be the cleanest mainstream car on the road — or at
least the American Council for an Energy-Efficient Economy thinks so. The
nonprofit group publishes an annual Green Book listing the greenest (and meanest) cars of the year,
and it put the Civic GX at the top of its 2007 list of environmentally
friendly cars, edging out Toyota’s hybrid Prius. Although neither car is a slouch when it comes to
fuel economy and reduced emissions, the natural-gas-fueled Civic scored
slightly better than the Prius on both counts in ACEEE’s battery of
tests. It also scored better in terms of the pollution generated in the
manufacturing processes. Natural gas is the cleanest-burning of all fossil
fuels. According to the U.S. Department of Energy, the burning of natural
gas emits 117,000 pounds per billion (ppb) BTUs of carbon dioxide, compared
with gasoline’s 164,000. Its 92 ppb of nitrogen oxide emissions are
considerably lower than gasoline’s 448, and its mere 1 ppb of sulfur
dioxide emissions is dwarfed by gasoline’s 1,122. Natural gas also
emits just 7 ppb of particulates, compared with 84 for gasoline, and it
emits no mercury whatsoever against the trace amounts emitted by
gasoline-burning engines. Natural-gas combustion does generate slightly
more carbon monoxide than gasoline, at 40 ppb versus 33, but the difference
is negligible. The big tradeoff for Civic GX owners is the
car’s limited 220-mile range between fuelings. The gasoline-powered
Civic can go 350 miles on a tank; the Prius, even with just an 11-gallon
tank, can go considerably farther, operating at as much as 55 miles per
gallon in highway driving. Although a few dozen natural-gas refueling
stations have popped up around the United States, they are few and far
between. For those who need to make longer trips but still value a greener
ride, a hybrid may be the best bet, because it will produce only marginally
worse emissions while taking advantage of the ubiquity of gas stations out
on the road. Those who already use natural gas for home heating
can pay $5,000 to have a car-fueling system installed in the garage or
driveway. Although that cost may seem high, owners can save about $1 per
gallon over gasoline and can also get a federal $1,000 tax rebate. (Also,
as with the Prius, the purchase of the Civic GX itself qualifies for a
federal tax break of $2,000, plus as much as another $2,000 in state and
local incentives where applicable.) Some Honda dealers lease home systems
for $34 to $79 a month. Honda pegs the fuel cost at 3.75 cents per mile,
compared with 8.8 cents per mile for the gasoline-powered Civic. Regarding the extraction and distribution of natural
gas, the fuel is often sourced along with or near oil reserves and involves
similarly invasive drilling methods. Accidents do happen from time to time,
and, though natural gas does not spill like oil and cause ground- and
sea-level ecosystem disturbances, it rises into the atmosphere, where it
contributes directly to global warming.
For more information:
Database for State Incentives for Renewables and Efficiency,
www.dsireusa.org; ACEEE’s Green Book, www.greenercars.com; Honda Civic GX,
automobiles.honda.com/civic-gx.
Send questions to Earth Talk, care of E/The Environmental Magazine,
P.O. Box 5098, Westport, CT 06881 or e-mail earthtalk@emagazine.com.
This article appears in Aug 2-8, 2007.
