From: FairfieldLife@yahoogroups.com [mailto:fairfieldl...@yahoogroups.com] On Behalf Of bob_brigante Sent: Sunday, March 22, 2009 8:42 PM To: FairfieldLife@yahoogroups.com Subject: [FairfieldLife] Re: Electric Cars for All (Interesting New Approach)
Electric Automobiles Electric automobiles sound like a good idea. The news is full of hyperbole about the great new Tesla Roadster and plug-in hybrids. Charge your car by plugging into the wall, and drive around with zero emissions. The Toyota Prius is half-electric, and that's been a big success, right? Moreover, wall-plug power is cheap. A kilowatt-hour costs only 10 cents. At $3 per gallon, the cost of energy from gasoline is about 36¢ per kilowatt-hour. That means that recharging a car by plugging it into the wall socket is equivalent to buying gasoline at under a dollar per gallon! Alas, electric automobiles have very serious problems. The fundamental one is that batteries store very little energy, compared to gasoline. High-quality, expensive batteriesthe kind used in cell phones and portable computersstore only 1% as much energy as gasoline, pound for pound. That's a big factor. It is offset somewhat by the fact that electric energy can be used more efficiently than gasoline, so the disadvantage for batteries is actually more like a factor of 30. For the same range, you can carry 62 pounds of gasoline, or 1860 pounds of batteriesalmost a ton. Because batteries have more pounds per cubic foot than gasoline, they won't take up 30 times the spacebut only 10 times as much. That's why cars like the Tesla Roadster are possible. The cost savings are illusory. High-performance batteries are very expensive and need to be replaced after typically 700 charges. Here is a simple way to calculate the numbers. The computer battery for my laptop (on which I am writing this) stores 60 watt-hours of electric energy. It can be recharged about 700 times. That means it will deliver a total of 42,000 watt-hours, or 42 kilowatt-hours, before it has to be replaced for $130. Put those numbers together to get the battery replacement cost: $130/42 = approximately $3 per kilowatt-hour. That's 30 times more expensive than the 10¢ per kilowatt-hour to charge it. The real expense for fancy batteries is not the cost to recharge them, but the cost to replace them. The same factor will be true for the Tesla Roadster. Driving it will seem very cheap, until the time comes to get new batteries. They are by far the most expensive component of that car. Here's what the article I posted said about batteries: SA: Yeah, so let's demystify batteries for a second. As a consumable, the batteries we're getting today are roughly in the range of about $.06 to $.08 a mile. If you try and find gasoline, in the U.S. you're roughly at about $.10 to $.12 a mile. So the first thing is it's cheap. Second thing is, the batteries we're using are not lead-acid batteries. They're lithium iron phosphate. All within the 35 most common elements in nature. So they're not dangerous to the environment. Three: They're consumed for a very, very long time. These batteries will last multiple generations. 20, 25 years. The fourth element is that there's always a better battery around the corner. Now in the past, that was a negative thing. Because you were afraid to buy a car and get stuck with a car that has a battery that's an older generation. And then not be able to sell it. It was a very, very negative thing. What we've done by decoupling the car and the battery is, we took away that fear. You may buy a car with generation 1 battery today, and then three years, five years, ten years from now, you may get a different battery that's designed with backwards compatibility into your car, but gives you longer range.
