See Also the post for September 3, 2012
According to current estimates, the U.S. has about a one-hundred-year supply of natural gas. These estimates assume that we will keep using gas at the same level as today. However, gas consumption has been rising at the rate of about four percent annually over the past few years. If this rate persists we have only a forty-year supply (see Mathematical Derivation below). However, there is great uncertainty in this result.
Estimates
of supply are notoriously uncertain. We may have more or less gas
than currently thought. Also a new technology may come along to
produce new supplies (just as fracking has done). More certainly, the
U.S. will likely start exporting large quantities of natural gas to
Europe and Asia, where prices are much higher.
The
recent rise in consumption is mostly due to electric generation and
this rise is likely to be sustained. Another source will be increased
use of methane (natural gas) feed stock replacing oil in chemical
processes. There also may be some increase in natural gas as fuel for
vehicles, currently a very minor application. Countering these trends
will be the lower need for heating as winters become warmer due to
climate change.
In
sum, there are too many uncertainties in estimates of how long our
supply of natural gas will last. My inclination is to believe that a
century is a gross overestimate.
Data
Sources EIA Table “Natural
Gas Consumption by End Use” and NaturalGas.org “Resources”
Mathematical
Derivation
Let
total reserves be S and current year's usage be c; with no increase
there is a 100-year supply of natural gas and S/c = 100. Let
consumption rise by r percent per year.. The fist year we use c, the
second year we use c(1+ r), the third year we use c(1+ r)2,
etc. So we need the sum of the series:
c[1
+ (1+ r) + (1+ r)2 + . . .]
which
is:
S
=c [(1 + r)n -1]/[(1+ r) -1].
where
n is the number of years that the reserves will last. Rearranging and
solving for n gives 40 years for r = 0.04.
