Why
40 is the Chevy Volt's Magic Number
Wednesday, September 17, 2008
GM's
top execs flank the Volt at GM's Centennial Celebration
40 miles of electricity. Sounds pretty arbitrary, right?
Wrong.
Yesterday, I wrote Volt
EV Range: Is 40 enough? Would 80 be better? Should GM
increase the Volt's EV range as battery technology
develops?
Well, let's first analyze the American driver and the
future of the American driver. Around 80 percent of
American commutes are 40 miles or less. And, as people
continue their migration back into cities, these commutes
are plagued by traffic, congestion and sub-20 mile per
hour speeds - conditions that bring out the worst in
today's conventional vehicles.
These horrible conditions, however, bring out the very
best in hybrid
cars and they will also bring out the best in
plug-ins, such as the Chevy
Volt, thanks to regenerative braking.
Thus, for the average commuter slugging through their 40
miles or less of daily congestion, the Volt will require
no petroleum, just 80 cents, or less, worth of
electricity, depending on when you charge. That's right.
80 cents is the high end.
That's cheap, right? So why not try to add more batteries
and get the Volt's EV range up to 100 miles, which
probably covers 90 percent of daily commutes?
Why? Diminishing returns.
That extra 10 percent of EV range has high costs. In fact,
it would be far cheaper to just use gasoline, or some
cellulosic ethanol, for this small percent of driving.
Plus, that other 10 percent of driving, when you are
traveling hundreds of miles, you don't have to carry
around all that extra battery weight. And, you'll never
suffer from range anxiety.
Even more interesting, as battery technology develops, GM
would prefer to use those advancements to make the Volt
cheaper, rather than adding range that might not make
financial sense. Hence, 40 miles isn't the goal for the
first Volt, but the next generation of Volts as well.
Certainly, if driving patterns indicate that 30 or 50
would be better standards, then GM would make adjustments.
Today, however, the data seems to demonstrate that 40 is
the magic number.
But will the Volt really achieve 40 miles of
electricity?
I asked Tony Posawatz, Volt vehicle line director, about
some research coming out of a Argonne National Laboratory
Conference on batteries that questioned
the Volt's 40 miles of electric range, claiming that
aggressive driving and AC use could push Volt EV range
well under 20 miles.
Tony first told me that Argonne would eventually test GM's
Volt batteries, but they are not yet testing GM's final
product.
Then, I asked Tony about the Volt's 40 miles of electric
range if drivers were aggressive or used lots of AC and
what researchers at Argonne stated.
"Well, one of the things that we're gonna do, is we
will take these vehicles now, our next level of vehicles,
with real batteries and run them through those tests and
there will be some degradation.
They are not incorrect in the assumption there will be
some degradation because we use the standards that we
have. Right now our target, and we feel confident, is 40
miles for the city cycle and 40 miles ....highway cycle.
Those are the two cycles that exist today.
Will people drive these vehicles harder, and will the
mileage in EV range be subject to your behaviour? Yes.
It's premature to make any initial assessments as to how
much, or what, until we test the vehicles. That's
something for a future date......There is some variation
around that.
If you are an abusive driver, temperature conditions, or
if you feel like you need to go full comfort, that's that
way with any vehicle."
I concluded my interview by asking if sub-20 miles of EV
range was a possibility.
"Don't know. We don't know right now."
So, yes there will be variability, and the way you drive
and the conditions you drive in will affect EV range, just
as they affect hybrid vehicle fuel economy.
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