"... has noted that a considerable percentage of the energy recovered from
these alternative sources is expended in their processing--two barrels out of
every three in the case of tar sands and a similarly low net energy recovery
for heavy oil".
two letters and an article on oil (all peer review and short)-
July 1, 2005 Science Magazine
When Will the Oil Run Out?
In his Policy Forum "Oil: Never cry wolf--why the petroleum age is far from
over" (21 May 2004, p. 1114), L. Maugeri has done considerable double-counting
to reassure us that "the world is not running out of oil." He cites various
upward revisions in historical estimates of oil reserves and resources,
culminating in the 2000 U.S. Geological Survey estimate of 3021 billion barrels
of ultimately recoverable resources, from which he draws the conclusion that
"overall, the world retains more than 3 trillion barrels of recoverable oil
Unfortunately, that 3021 figure includes the oil that has already been
consumed. It consists of "undiscovered conventional oil" (732 billion barrels),
"reserve growth" (688 billion barrels), "reserves remaining" (891 billion
barrels), and "cumulative production" (710 billion barrels) (1). Deduct the 710
billion barrels already consumed, and the remaining oil totals 2311 billion
barrels, a figure closer to other estimates.
Maugeri ignores the fact that the discovery of reserves lowers the estimate for
undiscovered oil; it does not necessarily raise the total figure for ultimate
recoverable oil resources.
He also calculates a "life index" of 40 years for known reserves, using current
consumption figures. Using the 891 billion barrels (reserves remaining) figure
would reduce that number to 32 years, but there are flaws in that calculation.
Making projections based on current consumption is meaningless if consumption
is rising (which it is). With a projected annual growth worldwide of 1.9% from
2001 to 2025 (2), the 32 years' supply would decline to about 26 years.
I believe we should draw very different conclusions from the present estimates.
First, although the experts may quibble over their differences, they are in
broad agreement: All the estimates I have seen agree within a factor of about
two as to how much oil remains. The policy implications are not much different,
wherever you may stand in that range. Oil resources are running down, and the
supply is inelastic.
Second, we should be preparing now for a difficult transition. Europe and
Japan, poor in oil resources, have gone much farther in making adjustments in
energy use than the United States. Furthermore, they have stable or declining
populations and similar requirements for energy and have chosen to limit
demand, particularly by imposing high taxes on gasoline.
The United States is putting itself in the worst possible position for the
energy transition by encouraging unchecked population growth (mostly driven by
immigration) and doing very little to encourage energy efficiency.
In his Policy Forum "Oil: Never cry wolf--why the petroleum age is far from
over" (21 May 2004, p. 1114), L. Maugeri claims that new discoveries of oil and
other hydrocarbons will stave off oil scarcity for many generations to come. As
the physicist Albert Bartlett (1) demonstrated nearly three decades ago, "When
we are dealing with exponential growth we do not need to have an accurate
estimate of the size of [the] resource in order to make a reliable estimate of
how long the resource will last." Assume, he said, that the entire volume of
Earth is oil (6.81 1021 barrels). At the then prevailing growth rate in oil
consumption of 7.04%/year, "this earth full of oil [would] last only 342
years!" Now, with China and other rapidly industrializing nations dramatically
increasing their energy consumption, there seems little hope that exponential
growth of hydrocarbon consumption will level off soon (2).
Of course, Earth is not made entirely of petroleum--far from it. Moreover, the
alternative hydrocarbon sources that Maugeri mentions, Canadian tar sands and
Venezuelan and Russian heavy oil, are no substitute for cheap oil. The
petroleum geologist Walter Youngquist has noted that a considerable percentage
of the energy recovered from these alternative sources is expended in their
processing--two barrels out of every three in the case of tar sands and a
similarly low net energy recovery for heavy oil (3). The same statement can be
made about oil shale and biofuels. Ethanol from corn or sugar cane sometimes
yields a net energy loss. The energy losses in producing and packaging hydrogen
for the hydrogen economy will be considerable. Hydrogen is not a primary fuel,
and its fundamental properties limit its ultimate utility. Nuclear power has a
continuing role to play in generating electricity, but unlike oil, it is not a
chemical feedstock, there are intractable safety concerns, and cheap oil and
other hydrocarbons still mine and process the nuclear fuel and build the
nuclear plants (4, 5).
By referring to the legitimate concerns about oil scarcity as "hysteria" and
"crying wolf," Maugeri deflects us from the only course that can save
industrial civilization from the consequences of its overconsumption of energy.
We need to begin a crash program to develop and implement energy-saving
technologies in construction, manufacturing, transportation, and agriculture
while the world still has enough oil wealth left to pay for the job. And at the
same time, we have to speedily change a
self-destructive mindset that glorifies waste and unnecessary consumption.
The road from old to new energy sources can be bumpy, but the transitions have
gone pretty smoothly in the past. After millennia of dependence on wood,
society added coal and gravitydriven water to the energy mix. Industrialization
took off. Oil arrived, and transportation by land and air soared, with hardly a
worry about where the next log or lump of coal was coming from, or what the
explosive growth in energy production might be doing to the world.
Times have changed. The price of oil has been climbing, and ice is melting
around both poles as the mercury in the global thermometer rises. Whether the
next big energy transition will be as smooth as past ones will depend in large
part on three sets of questions: When will world oil production peak? How
sensitive is Earth's climate to the carbon dioxide we are pouring into the
atmosphere by burning fossil fuels? And will alternative energy sources be
available at reasonable costs? The answers rest on science and technology, but
how society responds will be firmly in the realm of politics.
There is little disagreement that the world will soon be running short of oil.
The debate is over how soon. Global demand for oil has been rising at 1% or 2%
each year, and we are now sucking almost 1000 barrels of oil from the ground
every second. Pessimists--mostly former oil company geologists--expect oil
production to peak very soon. They point to American geologist M. King
Hubbert's successful 1956 prediction of the 1970 peak in U.S. production. Using
the same method involving records of past production and discoveries, they
predict a world oil peak by the end of the decade. Optimists--mostly resource
economists--argue that oil production depends more on economics and politics
than on how much happens to be in the ground. Technological innovation will
intervene, and production will continue to rise, they say. Even so, midcentury
is about as far as anyone is willing to push the peak. That's still "soon"
considering that the United States, for one, will need to begin replacing oil's
40% contribution to its energy consumption by then. And as concerns about
climate change intensify, the transition to nonfossil fuels could become even
more urgent (see p. 100).
If oil supplies do peak soon or climate concerns prompt a major shift away from
fossil fuels, plenty of alternative energy supplies are waiting in the wings.
The sun bathes Earth's surface with 86,000 trillion watts, or terawatts, of
energy at all times, about 6600 times the amount used by all humans on the
planet each year. Wind, biomass, and nuclear power are also plentiful. And
there is no shortage of opportunities for using energy more efficiently.
Of course, alternative energy sources have their issues. Nuclear fission
supporters have never found a noncontroversial solution for disposing of
long-lived radioactive wastes, and concerns over liability and capital costs
are scaring utility companies off. Renewable energy sources are diffuse, making
it difficult and expensive to corral enough power from them at cheap prices. So
far, wind is leading the way with a global installed capacity of more than 40
billion watts, or gigawatts, providing electricity for about 4.5 cents per
That sounds good, but the scale of renewable energy is still very small when
compared to fossil fuel use. In the United States, renewables account for just
6% of overall energy production. And, with global energy demand expected to
grow from approximately 13 terawatts a year now to somewhere between 30 and 60
terawatts by the middle of this century, use of renewables will have to expand
enormously to displace current sources and have a significant impact on the
world's future energy needs.
What needs to happen for that to take place? Using energy more efficiently is
likely to be the sine qua non of energy planning--not least to buy time for
efficiency improvements in alternative energy. The cost of solar electric power
modules has already dropped two orders of magnitude over the last 30 years. And
most experts figure the price needs to drop 100-fold again before solar energy
systems will be widely adopted. Advances in nanotechnology may help by
providing novel semiconductor systems to boost the efficiency of solar energy
collectors and perhaps produce chemical fuels directly from sunlight, CO2, and
But whether these will come in time to avoid an energy crunch depends in part on how high a priority we give energy research and development. And it will require a global political consensus on what the science is telling us.
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