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Don't be fooled by electric-vehicle myths, part two
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Updated: Sep. 5, 2010 | 11:22 p.m.
In my Aug. 6 column, I noted that the rollout of electric cars by the automotive industry has led to a lot of uncertainty among potential consumers.
That column focused on common questions and myths about electric car performance such as range, refueling time, horsepower, speed and acceleration. This week, I want to step back and focus on larger infrastructure questions about the impact of the electric car on the NV Energy electricity grid system and the environment.
Q: Are gasoline-burning internal combustion engines more efficient than battery-powered electric motors?
A: The power density of gasoline is about five times greater than the best storage battery at this time, but an electric car gains ground when you compare overall efficiency from its fuel storage area to the wheels of the car.
Internal combustion engines are inefficient in utilizing the power density of gasoline because they only generate about 25 to 30 percent of the potential horsepower available from the gasoline tank to the wheels of a vehicle.
Electric motors and electronic drive trains can generate 80 to 90 percent of the potential horsepower from the electrical energy stored in the vehicle's battery pack to the wheels of an EV.
Q: How can consumers calculate the cost-per-mile to operate gas-burning cars versus electric cars?
A: To compare the two competing fuels and drive train technologies in economic terms, use dollars to calculate refueling costs.
For example, the Nissan Leaf battery-powered electric car will drive approximately four miles on one kilowatt-hour of electricity that costs 11.8 cents from NV Energy. That's about 3 cents per mile.
A similar gasoline-powered vehicle such as a Honda Civic Si with a combined city/highway rating of 24 miles per gallon costs around 10 cents per mile when you start with gasoline priced today at about $3 per gallon and remove 58 cents worth of taxes.
What happens if the price of gasoline starts to rise back up to 2008 levels, when a gallon of regular gas at local service stations spiked above $4 nationwide?
Q: EV battery packs eventually have to be replaced. Won't this add to the refueling cost of electric cars in the long term?
A: The manufacturer's warranty for the battery packs of the Chevrolet Volt and other emerging electric-powered cars are being announced at eight years or 100,000 miles, whichever comes first.
Even then, lithium-ion battery cell technologies age much slower than lead-acid battery cells after repeated use. An eight-year-old lithium-ion battery pack may still retain 80 percent of its original capacity if properly maintained, which means that the electric-only range of a Chevrolet Volt would drop from about 40 miles to 32 miles before the hybrid gasoline engine needed to begin recharging the battery pack.
Automotive manufacturers anticipate that battery pack replacement costs will decline by that time and the life cycle of battery packs for electric cars will continue to improve to eventually exceed a life span of 10 years.
Q: Will charging EVs call for extra electricity to be generated, thus requiring burning more fossil fuels?
A: Charging up an electric car at night does not necessarily have to consume extra power from the grid or require the burning of more fossil fuels.
Between 10 p.m. and 6 a.m., excess energy may be wasted on the grid network because it has nowhere to go other than to continue traveling around the grid transmission line infrastructure, gradually becoming dissipated in the form of heat.
During 2009, NV Energy initiated a special electric vehicle Time of Use program that allows EV owners a discount on their monthly electricity consumption rates when recharging during late night hours.
Studies by the National Renewable Energy Laboratory in Colorado have shown that displacing internal combustion engines with electric cars will reduce overall nitrogen oxide emissions, even if the electricity used is generated from a coal-fired "smokestack."
Stan Hanel has worked in the electronics industry for more than 30 years and is a long-time member of the Electric Auto Association and the Las Vegas Electric Vehicle Association. Hanel writes and edits for EAA's "Current Events" and LVEVA's "Watts Happening" newsletters. Contact him at stanhanel@aol.com.
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It's interesting to note that even at todays prices gasoline is at least three times expensive as electricity. Even if electric cars do require extra electricity to be generated (and the article makes a good point that it won't be as much more as some people like to pretend), at these prices we CAN afford to produce that extra energy using renewables (even solar starts becoming affordable). Add to that the likelihood that oil prices will start rising again and that renewables keep getting cheaper and it seems obvious that electric vehicles + renewables are the future.
Bob.. I agree, Nevada, Utah, and Arizona has a lot of room for wind power. My main focus is cutting oil dependency, lets get the single occupant gasoline commuter car off the road first and use a renewable energy fuel to replace it. Major city's have rush hours and pollution, the rush hour is caused by commuters trying to get to work and if we replace most of those vehicles with electric we will cut oil dependency and pollution. If you want to cut rush hour traffic get company's to stager employee start times like my company did.
Richard..
The wind doesn't shut down at night either. In fact it often blows harder. (And that's American wind. ;o)
Charging EVs at night is likely to lower your daytime electricity costs. If there is a market for nighttime wind-produced electricity that will make it financially attractive to build more wind farms. Peak hour rates plus a solid nighttime market make the bottom line stronger.
Bringing more wind farms on line will drop power costs as is now being seen in Spain and Texas.
I like the way you compared the two fuels, the coal fire electric power plants don't shut down at night so you might as well charge the electric car when electric demand is low. I also like the fact that coal is energy from American. The electric car looks like it will do everything I need if for in town and I will use the wifes car when we go out of town.
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