By Robert Bryce
Monday, March 11, 2013
Among the Mount Everest of inanities ever uttered on the
subject of energy, the blue-ribbon winner must be this: “the tyranny of oil.”
Both Barack Obama and Robert F. Kennedy Jr. have used the
line. Obama claimed it for his own back in 2007 when he declared his run for
the White House. Standing on the steps of the Old State Capitol in Springfield,
Ill., Obama said, “Let’s be the generation that finally frees America from the
tyranny of oil.”
In a speech at Sandhills Community College in North
Carolina earlier this month, Kennedy, a high-profile opponent of the Keystone
XL pipeline (he was arrested at the White House during a recent protest), said
that “we need to free ourselves from the tyranny of oil.”
Let’s be clear here: I’m no Kennedy. And I don’t have the
political savvy or oratorical skills of Obama. Both of them went to Harvard. I
didn’t. But the claim that a super-high-energy-density substance that can be
deployed for myriad purposes — from pumping well water in Kenya to emergency
generation of electricity in Lower Manhattan — is somehow bad or even
tyrannical is ludicrous. And for two leading political figures in America to
use such a phrase, “tyranny of oil,” demonstrates once again just how polluted
our energy discourse has become.
The wealth and power that are achieved through the
finding and burning of hydrocarbons are enormous. That much is indisputable.
And of the hydrocarbons — coal, oil, and natural gas — oil is the unchallenged
king. No other substance this side of uranium comes close to oil with respect
to energy density — the amount of energy, measured in joules or BTUs, that can
be contained in a given volume or mass. Moreover, the products that can be
produced from petroleum are relatively cheap, easily transported, usually
stable at standard temperature and pressure, and essential for everything from
making shoelaces to fueling jumbo jets.
Demonstrating the wondrous qualities of oil requires only
a simple bit of math and a look at one of the most famous airplanes in aviation
history: the Boeing 737. To make the math easy, let’s use metric units. And
let’s focus on weight, as that factor is critical in aerospace. The gravimetric
energy density of jet fuel is high: about 43 million joules per kilogram.
(Low-enriched uranium, by the way, is 3.9 trillion joules per kilogram.)
A fully fueled 737-700 holds about 26,000 liters of jet
fuel, weighing about 22,000 kilograms, containing about 902 billion joules (902
gigajoules) of energy. The maximum takeoff weight for the 737-700 is about
78,000 kilograms, and so jet fuel may account for as much as 28 percent of the
plane’s weight as it leaves the runway.
Obama and Kennedy are big fans of electric cars. If we
wanted to end the tyranny of oil onboard the 737, how many lithium-ion
batteries would we need? That’s a pertinent question, as Boeing’s decision to
use lithium-ion batteries to power auxiliary systems in its new 787 Dreamliner
has led to onboard fires. The 787 has been grounded as the company tries to
solve the problem.
Lithium-ion batteries have higher energy density than
most other batteries, holding about 150 watt-hours — 540,000 joules — of energy
per kilogram. Recall that jet fuel contains about 43 million joules per
kilogram, or nearly 80 times as much energy. Therefore, if Boeing tried to
replace jet fuel with batteries in the 737-700, it would need about 1.7 million
kilograms of lithium-ion batteries. Put another way, to fuel a jetliner like
the 737-700 with batteries would require a battery pack that weighs about 22
times as much as the airplane itself.
Prefer to use a “green” fuel like firewood? With an
energy density of about 16 million joules per kilogram, that same 737-700 would
require about 56,000 kilograms of wood to be stowed onboard. With that much
kindling, you can be assured there won’t be room in the overhead bin for your
carry-on.
The only “tyranny” at work in our energy and power
systems is that of simple math and grade-school physics. Obama and Kennedy may
not like oil, and their allies may particularly hate Exxon, Chevron, and
Keystone XL, but here’s the reality: If oil didn’t exist, we would have to
invent it. It’s a miracle substance.
Rather than condemn the fuel that makes modern life
possible, our political leaders should be figuring out how we can make that
miracle energy form more available to more people at lower cost.
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