can homes, light stoves, and power water heaters becomes a vehicle
fuel when it is squeezed into cylinders as "compressed natural gas"
(CNG) or chilled until it forms "liquified natural gas" (lNG). Natural
gas is found underground and is mostly methane, with small amounts
of other gases and water vapor. It is formed over centuries when
animals and plants decompose while sealed off from oxygen.
emissions are 25 percent lower than gasoline, and each fill-up is
currently cheaper than gasoline.
currently in 17 states for about $2,000 and mounts on a garage wall,
allows customers to fuel their cars directly from the natural gas pipes
that heat their homes. (liquified natural gas, by contrast, is used al-
most exclusively for large industrial vehicles.) As for the safety of Phill
units, the manufacturer, FuelMaker Corp. of Toronto, says they have
safety mechanisms that will shut them down if they're not connected
properly or if the system senses a methane leak or other malfunction.
change this situation, however.)
diesel technologies close the gap between the two fuels, according to
Don Anair at the union of Concerned Scientists. Today, new ultra-low-
sulfur diesel makes it possible to bring particulate matter pollution from
diesel engines down to levels as low as natural gas engines, though older
diesel vehicles require a retrofit filter for this improvement. For the
next few years, natural gas engines still have lower emissions of nitrous
oxides than diesel vehicles, though diesels are expected to reduce that
pollutant to equally good levels by 2010.
comes to reducing emissions.
of natural gas from conventional sources in the uS, and more than a
200-year supply from advanced technologies and new discoveries.
This technique is used widely in developing countries, including India
and Costa Rica, but is still experimental on a municipal level in the uS.
other fuels--and better convenience, too. Plus, if you're looking
to be part of a long-term environmental solution that's renewable
indefinitely, CNG isn't it.
that's renewable indefinitely, natural gas isn't it.
mainly on passenger cars, trains and planes are definitely part of
our climate-changing mix as well.
pollutants, the EPA recently announced new rules that will
reduce annual nitrogen oxide emissions (a key ingredient in
smog) from diesel locomotives by 80 percent, and annual soot
emissions by 90 percent.
bad: One international round trip flight emits nearly as much
CO
used successfully in some diesel locomotives, and a greater use
of electric trains promises to reduce emissions (though they
need more renewable energy to power them). For airplanes,
most alternatives being explored for cars, i.e. biodiesel, ethanol,
and hydrogen, are thought to be out of the question due to the
cold, harsh conditions in the upper atmosphere.
Consider reducing your carbon footprint by offsetting your
travel emissions, no matter what mode of transportation
you choose. See our Real Money article, "Carbon Offsets
Demystified," at www.coopamerica.org/pubs/realmoney/ar-
ticles/carbonoffsets.cfm for more information.