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The Electric Vehicle
In a bid to lower air pollution in big cities,
much emphasis has been placed on the electric car. The notion
of driving a clean, quiet and light vehicle appeals to many
city dwellers. Being able to charge the car at home for only
a dollar a day and escape heavy fuel taxes (at least for the
time being) makes the electric car even more attractive.
The battery is still the main challenge in the
development of the electric car. Distance traveled between
recharge, charge time and the limited cycle count of the battery
continue to pose major concerns. Unless the cycle life of
the battery can be increased significantly, the cost per mile
will be substantially higher than that of a fuel-powered vehicle.
The added expense is the need to replace the battery after
a given number of recharges. This could offset any advantage
of lower energy costs or the absence of fuel taxes. Disposing
the spent batteries also adds to the expenditure.
Another challenge associated with the electric
vehicle is the high power demand that would be placed on the
electric grid if too many cars were charged at a certain time.
Each recharge consumes between 15 to 20kW of power, an amount
that is almost as much as the daily power requirement of a
smaller household. By adding one electric car per family,
the amount of electric power a residence requires would almost
double. Delayed charging could ease this problem by only drawing
power during the night when the consumption is low.
A rapid shift to the electric car could create
shortages of electric power. With the move to reduce the generation
of electricity due environmental concerns, electricity would
need to be imported at high costs. This would make the electric
car less attractive.
If the electricity was generated with renewable
energy such as hydroelectric generators and windmills, the
electric vehicle would truly clear the air in big cities.
The generation of electricity by means of nuclear power or
fossil fuels simply shifts the pollution problem elsewhere.
However, a central source of pollution is easier to contain
than many polluting objects in a metropolitan area.
A hybrid car is an alternative to vehicles running
solely on battery power. Here, a small combustion engine works
in unison with an electric motor. During acceleration, both
the electric and combustion engines are engaged. Because of
superior torque, the electric motor takes precedence during
acceleration. Once cruising, the combustion engine maintains
the speed and keeps the batteries charged. Hybrid cars achieve
fuel savings of 30 percent or better compared to the
combustion engine alone.
A hybrid car is less strenuous on a battery than
a conventional electric car because the battery is not being
deeply discharged during regular use. A deep discharge only
occurs on a long mountain climb where the small combustion
engine could not sustain the load and would need assistance
from the electric motor and its battery bank. Driving habits
would, to a large extent, determine the service life of the
battery. A light foot on the pedal will help the pocket book
also with the hybrid car.
Another alternative to powering cars is the fuel
cell. Although much cleaner running than the combustion engine,
the fuel cell must solve a number of critical problems before
the product can be offered to the consumer as an economical
alternative. The major challenge is cost reduction. If fossil
fuel remains as low-priced is it is today, many drivers owning
high-powered cars, SUVs and trucks would be reluctant to switch
to a new technology. Concerns over pollution only persuade
a limited number of drivers to switch to a cleaner-running
vehicle. With the slow and gradual progress in the fuel cell,
it will be some time before this technology renders the combustion
engine obsolete.
Europe is talking about the three-liter motor,
an internal combustion engine running on gasoline or diesel
fuel. Remarkably, ‘three’ does not denote the engine displacement
but stands for liters of fuel consumed per 100 km traveled.
There is talk about the one-liter engine also. Major car manufacturers
are divided on the fuel that will power our cars in the future.
Within one large auto manufacturer in Europe, opinions regarding
the fuel cell and an economical three-liter engine are divided
fifty-fifty.
Strengthening the Weakest Link
The speed at which mobility can advance hinges
much on the battery. So important is this portable energy
that engineers design handheld devices around the battery,
rather than the other way around. With each incremental improvement
of the battery, the doors swing open for new products and
applications. It is the virtue of the battery that provides
us the freedom to move around and stay in touch. The better
the battery, the greater the freedom we can enjoy.
 The
longer runtime of newer portable devices is not only credited
to higher energy-dense batteries. Much improvement has been
made in reducing the power consumption of portable equipment.
These advancements are, however, counteracted with the demand
for more features and faster processing time. In mobile computing,
for example, high speed CPUs, large screens and wireless interface
are a prerequisite. These features eat up the reserve energy
that the more efficient circuits save and the improved battery
provides. The result is similar runtime to an older system,
but with increased performance. It is predicted that the improvements
in battery technology will keep par with better performance.
Wide-band mobile phones, dubbed G3 for third
generation, are being offered as replacements for the digital
voice phone. There is public demand for Internet access in
a tiny handset that connects to the world by the push of a
few buttons, twenty-four hours a day. But these devices require
many times the power compared to voice only when operating
on wideband. Higher capacity batteries are needed, preferably
without added size and weight. In fact, the success of the
G3 system could hinge on the future performance of the
battery. G3 technology may be ready but the battery lags behind.
The battery has not leap-frogged at the same
speed as microelectronics. Only 5 to 10 percent
gains in capacity per year have been achieved during the last
decades and the ultimate miracle battery is still nowhere
in sight. As long as the battery is based on an electro-chemical
process, limitations of power density and life expectancy
must be taken into account.
The battery remains the ‘weak link’ for the foreseeable
future. A radical turn will be needed to satisfy the unquenchable
thirst for mobile power. What people want is an inexhaustible
pool of energy in a small package. It is anyone’s guess whether
the electro-chemical battery of the future, the fuel cell
or some groundbreaking new energy storage device will fulfill
this dream.
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