The motor of an electric vehicle, when it’s running, will on average use
something like 10 kW, with an efficiency of 90–95%. Some of the lost power,
the other 5–10%, will be dissipated as heat in the motor. Perhaps electric
cars that are going to be used in cold places can be carefully designed so
that this motor-generated heat, which might amount to 250 or 500 W, can
be piped from the motor into the car. That much power would provide
some significant windscreen demisting or body-warming.
Some lithium-ion batteries are unsafe when short-circuited or overheated,
but the battery industry is now producing safer batteries such as
lithium phosphate. There’s a fun safety video at www.valence.com.
World lithium reserves are estimated to be 9.5 million tons in ore deposits
(p175). A lithium-ion battery is 3% lithium. If we assume each
vehicle has a 200 kg battery, then we need 6 kg of lithium per vehicle. So
the estimated reserves in ore deposits are enough to make the batteries for
1.6 billion vehicles. That’s more than the number of cars in the world today
(roughly 1 billion) – but not much more, so the amount of lithium may be
a concern, especially when we take into account the competing ambitions
of the nuclear fusion posse (Chapter 24) to guzzle lithium in their reactors.
There’s many thousands times more lithium in sea water, so perhaps the
oceans will provide a useful backup. However, lithium specialist R. Keith
Evans says “concerns regarding lithium availability for hybrid or electric
vehicle batteries or other foreseeable applications are unfounded.” And
anyway, other lithium-free battery technologies such as zinc-air recharge-
ables are being developed [www.revolttechnology.com]. I think the elec-
tric car is a goer!
The superjumbo A380 is said by Airbus to be “a highly fuel-efficient air-
craft.” In fact, it burns just 12% less fuel per passenger than a 747.
Boeing has announced similar breakthroughs: their new 747–8 Inter-
continental, trumpeted for its planet-saving properties, is (according to
Boeing’s advertisements) only 15% more fuel-efficient than a 747–400.
This slender rate of progress (contrasted with cars, where changes in
technology deliver two-fold or even ten-fold improvements in efficiency)
is explained in Technical Chapter C. Planes are up against a fundamental
limit imposed by the laws of physics. Any plane, whatever its size, has to
expend an energy of about 0.4 kWh per ton-km on keeping up and keeping