Someone asked for the relative energies of natural gas compared to
Gasoline. What I've been able to gather is :
1 cu/ft NG=1028 BTU
1 gal Gasoline=125000 BTU
C. Smith

Those are "sit and burn" BTUs.

In actuality, the efficiency of gasoline as a motor fuel is very low,
while the efficiency of natural gas is very high.  Otherwise, a NG or
propane-fueled car would have pretty much no range or power.  There are
gas-powered Crown Vics in service as police cruisers!

Gasoline must be stable as a liquid, then rapidly broken down and
vaporized before it will burn, so most of a gallon of gas provides no
power.  Natural gas must simply be heated, and a far higher percentage
burns.

Keith W

Well there is still the high BTU per cubic foot of gasoline.
The tank needed for NG is also big and heavy.

Paul Lamar
-----------------------------------
Can't resist responding to this -- too much misinformation in Keith's
response.

1.    Nominally gasoline is 'octane' C8H18, although in practice it is a
wide variety of carbon containing species, including ring structures
(aromatics) and both shorter and longer chains than octane.  The energy is
derived from converting the C to CO2 and the H to H2O.  Carbon going to
carbon-dioxide is more energy rich than hydrogen going to water.

2.    Natural gas is nominaly CH4, although in fact it contains some 2,3 and
even 4 chain carbon atoms in small quantities. Less carbon = less energy /
mole.

Almost all Natural gas vehicles use compressed storage (CNG), not cryogenic
LNG.  The range of those Crown Vics IS reduced from a normal Crown Vic
running on gasoline, the reason that they can be used is that they are FLEET
vehicles that can come back to a local site for refill. It requires a very
high pressure pump to fill them, they also have very little trunk space left
after you put in the CNG tank

The EFFICIENCY of combustion in the (properly designed and tuned) engine is
almost identical between the two fuels.  The gasoline does need to vaporize,
which cools the incoming air some, but the statement that gasoline is very
low efficiency and NG is very high is just not true.

The POWER of engines running on NG is reduced from that on gasoline, there
are large stationary engines that can be run either on diesel, or with
ignition systems on gasoline or natural gas. The NG units are derated from
the liquid fuel units.

The attraction of natural gas is not that it is more EFFICIENT, but that it
is somewhat more domestic, is less of a greenhouse producing fuel (it still
does have carbon in it).

Bill Schertz
KIS Cruiser #4045
N343BS

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