Every president since Richard Nixon has vowed to reduce the United States’
dependence on foreign oil. None has succeeded. Imports—and thus America’s
vulnerability to disruptions—have increased to where now they supply
two-thirds of consumption. As former Secretary of State George Schultz asked:
“How many more times must we be hit on the head by a two-by-four before we
do something decisive about this acute problem?”

Our aim should not be total independence from foreign sources of petroleum.
That is neither practical nor necessary in a world of interdependent economies.
Instead, the objective should be developing a sufficient degree of resilience
against disruptions in imports. Think of resilience as the ability to absorb a
significant disruption, bigger than what could be managed by drawing down
the strategic oil reserve.

Our resilience can be strengthened by increasing diversity in the sources of our
energy. Commercial, industrial, and home users of oil can already use other
sources of energy. By contrast, transportation is totally dependent on
petroleum. This is the root cause of our vulnerability.

Our goal should be to increase the diversity of energy sources in
transportation. The best alternative to oil? Electricity. The means? Convert
petroleum-driven miles to electric ones.

Electric miles do not necessarily mean relying on all-electric cars, which would
require building an extensive and expensive infrastructure. They can be
achieved by so-called plug-in electric vehicles (PEVs). (Since many plug-in cars
are modified hybrid automobiles, they are sometimes called PHEVs.) PEVs
have both a gasoline-fueled engine and an electric motor. They first rely on the
electricity stored onboard in a battery. When the battery is depleted, the vehicle
continues to run on petroleum. The battery then can be charged when the
vehicle is not in service.

The amount of gasoline a PEV consumes is dependent on the number of miles
it is driven between the times when it is recharged. Let us explain this by
simplifying the picture a bit. If the electric-only range is, say, 40 miles, and the
number of miles driven between charges is less than 40, the vehicle uses no gas
at all, so it’s not possible to calculate the miles per gallon. If the number of
miles driven is greater than the electric range, the gas mileage starts out very
high and then declines with the additional miles until the mileage approaches
what an ordinary gasoline-powered vehicle would provide. Consequently, the
fuel performance of the vehicle is defined by a curve (exhibit). The 40-mile
mark was chosen because it is a good range to shoot for. More than 80
percent of the cars on US roads are driven less than that distance daily.

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