Would someone please fill me in on why we use propane and not natural
gas? I read the Wikipedia article at
and I still don't understand the difference. I do know that propane
appliances such as ranges require adjustment to or different burners
for each. Why not eliminate this problem and just use LNG only? In
terms of household heating the only difference then would be that in
one case you have a pipe coming in from the utility and in the other
you have a big tank in the back/front yard and a tanker comes and
fills you up from time to time. Or for your barbeque you go to the
home center and instead of propane you get a tank or a refill of LNG.
Natural gas is mostly methane. It's attractive as a fuel because it's
plentiful, but it's also very difficult to turn into a liquid. Any fuel
that you transport in tanks wants to be a liquid because you can store
many times as much fuel in a given volume tank as a liquid than as a
Let's back up a bit:
Butane is easy to handle because the amount of pressure needed to keep
it liquid at room temperature can be provided by a plastic container
(e.g. cheap butane lighter) or a very thin aluminum can. Thus, you
can carry a lot of fuel in a small, light tank. But it's relatively
Propane requires considerably higher pressure to be liquid at room
temperature, so it has to be stored in heavier steel tanks that can
withstand the pressure. But it *is* liquid in there, so again you can
have quite a bit of fuel inside one small tank.
Methane cannot be practically compressed into a liquid at room
temperature. You can make it liquid by making it very cold; that's how
LNG (liquid natural gas) is produced. But it's got to stay cold to stay
liquid, just like liquid oxygen or nitrogen. It's practical to ship
very large volumes of it in specially-insulated tanks in ships, but it's
not practical to keep that cold in a tank on your car or barbecue.
So when you see a car or bus powered by compressed natural gas (CNG), it
tends to have very large tanks to hold a relatively small amount of gas,
since there is no liquid in the tanks. Propane will power a car for
much longer with a smaller tank. So CNG isn't very popular as a vehicle
It isn't practical for house heating or stove or barbecue either. If a
trunk brought you liquid natural gas, you'd need cryogenic storage
(which is expensive) and you would continually lose some fuel to boil
off. If a truck brought you compressed natural gas, you'd need large
tanks, and you'd have to wait for a compressor to re-pressurize them
Natural gas *is* practical if it can be brought to you in gas form at
normal temperature by pipeline. It's just not practical to store or
distribute in a tank except on an enormous scale.
Perhaps where you live, everyone has the ability to hook up to a
natural gas utility. There are large areas of the country where
that's not the case.
On Feb 15, 11:24 pm, snipped-for-privacy@Somewhere.edu wrote:
If natural gas were to become available in my area, I would kicking,
pushing and punching my way to the front of the line. I pay $90.00 a
year to rent my 450-litre tank and with each fill-up, I'm charged a
$6.00 delivery fee and an additional $4.00 hazardous material handling
fee. The cost per litre, as of my last delivery, was $1.05 and if my
math is correct, that works out to be $4.00 per U.S. gallon (then add
tax). If I had access to natural gas, my total, overall cost would be
roughly one-third that.
OK, I now need to spit.
On 16 Feb 2007 07:10:34 -0800, email@example.com wrote:
True, but re-read the post. Aside from Dave, everyone is missing the OP's
one question. Why not deliver LNG instead of propane? LNG is being used is
some applications, like cars, but it is not as universal as propane, now
will it ever be as pointed out in a detailed and interesting post by Dave
I'm not absolutely sure about this, but I thought you had to cool
natural gas to minus 160 Celsius in order to transport it as a liquid,
then obviously reheat it again to revert it back to its original
gaseous state. The dollar and energy cost to do this in terms of
local delivery and long-term on-site storage I expect would be
Were you thinking of "compressed" natural gas or CNG, as opposed to
"liquid" natural gas (LNG)?
CNG requires a much larger volume of storage and very high pressures
-- I believe something in the range of 3000 to 4000 pounds per sq.
inch. It might work OK for vehicles where on-board storage
requirements are relatively modest, but for higher volume residential
applications, it isn't likely to work all that well.
Thanks for the links. Assuming CNG is the way to go (because I'm
still not sure how long we can cost-effectively store LNG at those
very low temperatures), do you have a sense of the size tank required
to supply an average home?
For argument's sake, we might assume a "typical" residence uses about
100 therms of natural gas per month during the winter season (e.g.,
space heating, domestic hot water, cooking, dryer), and that
deliveries are scheduled about once a month (it might be closer to
every three weeks but throwing in an extra week as a margin of safety
in the event of weather delays, etc.).
As a point of reference, I believe one U.S. gallon of propane contains
a little over 91,000 BTUs, so 100 therms is roughly equal to 110
gallons or just about an entire 120 gallon/450 litre tank. I'm
guessing a 120 gallon tank is about two-and-a-half in diameter and
maybe five or so feet high.
I'm not exactly sure how they compare in terms of volumetric energy
density, but my hunch is that CNG would come in much lower than liquid
propane; perhaps as little as 1/10th? (That's purely a guess; I
really don't know).
In any event, I'm thinking the high cost and large size of the on-site
storage tanks (as well as those of the delivery trucks) would make CNG
a very expensive alternative to propane. Plus, at 3,000 or 4,000 PSI,
I'm not sure I'd want to be standing next to one if it should suddenly
spring a leak!
I would imagine that a large portion of the cost of propane is in the
costs of storing and transporting it, rather than the actual cost of the
fuel as it is produced. Figure these expenses in along with the much
more expensive storage tanks of CNG, and CNG delivered would probably be
even more expensive than propane. Larry
The retail price of propane, as is the case with any other commodity,
is determined entirely by supply and demand. The costs of
production, transportation, storage, etc. are borne by those who
touch it before you get it home.
nat gas is there,without having to call a truck to bring it. and
having had propane in my early days,it was way more expensive than nat
gas.... it cracks me up when i see the commercials about how great and
cheap propane and heating oil is...lucas
There are several downfalls to Propane
1. The BTU content for Propane is lower than NG and Oil
2. It is dangerous
3. Requires refills by propane truck (similar to oil delivery)
Except for a swimming pool heater you will never see propane used where Nat
is available (i could not back up never)
Ed, believe it or not Oil was cheaper to heat with this year than NG. I
don't think you can compae the two in price. One year ones higher and the
next year the other is. I think it is genuinely a wash in the long run
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