Be Careful What You Wish For

When it comes to so-called “green” automotive technology, the phrases, “be careful what you wish for” and “too good to be true”, both come to mind.  Electric vehicle technology has apparently matured to such a level that Motor Trend magazine has selected the Chevrolet Volt as its 2011 Car of the Year, calling it a “game changer”, “astonishing” and an engineering breakthrough.  It’s an electric vehicle that takes 10 hours to fully charge at 110 volts and 4 hours with the 220 volt kit, and shifts to a small gasoline engine for extended range if you run out of charge.   But if you’re a typical commuter, you may never need to use gas!

The Volt is truly an engineering marvel, delivering fuel efficiencies on the order of 70- to 100 miles per gallon, depending on your driving habits.  But there’s a price for this efficiency.  A decently equipped Volt will run you about $41,000.  Even with the $7,500 Federal tax rebate being offered to Volt buyers, this is still a lot of money to pay when you could buy an equivalent vehicle for around $20,000 or less.

As with most leading edge technologies, what’s expensive at first gradually becomes more affordable as the technology matures, production volumes increase and more competition is involved.  It’s certainly conceivable that, within a few years, the so-called “plug-in hybrid” technology of the Chevy Volt will be offered by many car manufacturers.  As the price comes down, the demand for these cars could grow to the point where every household might own at least one electric vehicle.

Would our electric power infrastructure be able to handle a world in which most vehicles are powered by electricity?  I did a bit of research to find out more about the implications of a greater demand on the grid due to electric vehicles.  What I discovered suggests that we may not have completely thought through these implications.

According to the US Energy Information Administration, the average annual electricity consumption per US household is about 10,656 Kilowatt-hours (KW-Hr).  This unit of energy (the KW-hr) is important because it allows us to compare the energy content of electricity with that of gasoline.  A gallon of gasoline contains the equivalent of 33.7 KW-Hr of energy.  So, if you drive an average of 15,000 miles per year in a car that averages 25 miles per gallon, you will have consumed 600 gallons of gas, which is equivalent to 20,220 KW-Hr of energy – almost twice as much as your entire electricity usage for the entire year!

What would happen if you replaced two cars with two Chevy Volts?  First of all, you’d spend a lot less money on gasoline; about $4,000 less per year at current gas prices.  But you’d also be transferring much of your transportation energy requirements from gasoline to the electric power grid.  Fortunately, Motor Trend tested their Chevy Volt over a 299 mile course to determine how much electricity and how much gas it would use.  It used 58.6 KW-Hr of electrical energy and 2.36 gallons of gas.  Knowing these numbers allows us to calculate about how much of an increase in electrical demand a Volt would place annually on our household usage.  Two Volts would add 5,879.6 KW-Hr of demand annually, which is a 55 percent increase, so you would see your electric bill go up just as your gasoline bills would go down.

But what would be the potential effect on the entire electrical grid if every household’s electricity demand increased 55 percent?  Energy Information Administration data tell us that residential electricity usage accounts for about 40 percent of total demand.  For the state of Virginia, this translates to an overall increase in demand of about 26 percent.  This does not bode well, given that Virginia is a net importer of electricity (we import 36% of our electric power).

Two electric vehicles in every garage will not solve our energy and carbon footprint problems.  At best it will simply shift much of the energy burden from gasoline to coal or nuclear.  Until a major energy technology breakthrough occurs, we must summon the political will to expand our current electric power generation capacity in advance of the inevitable increase in demand.