Electric Cars Make Fuel-Free Power Grid Practical
by Thomas Blakeslee, Clearlight Foundation
Internal combustion engines are inherently inefficient due to friction and pumping losses. After a century of evolution gasoline engines in cars are still typically only 21% efficient! Electric motors have no such limitations and are actually capable of 98% efficiency including electronic control losses! Why do we keep wasting our precious fuel on such an inefficient system? The answer is energy storage.
Gasoline, diesel and ethanol fuels are all amazingly compact ways deliver and store energy. Fuel has dominated our transportation sector because batteries are large, heavy and expensive compared to a simple gas tank. Classic lead-acid batteries, for example, need about 388 times as much volume to store energy as gasoline. Electric cars only need to carry about ¼ as much energy because of this efficiency advantage but that still means a lead-acid battery must be 388/4= 97 times larger than a gas tank. It's no wonder gasoline has dominated for a century. Gas tanks are cheap and gas used to be cheap, so why bother?
Lithium batteries have now evolved to a point where they are safe, quickly rechargeable and capable of outlasting a car. They still take up about ten times as much space as a gas tank, but the big remaining problem is cost. Mass production will eventually reduce cost significantly but for now the plug-in hybrid (PHEV) approach solves the problem nicely: Most cars are driven to work or on errands near home except for very occasional long road trips. By providing a gas engine and generator to extend range, a 20 or 40-mile battery capacity can efficiently handle almost all driving. The only time you buy gas is when you take a long trip.
PHEVs exist now only as Prius conversions. The 2008 bailout (energy) bill provides deductions of up to $10,000 that depend on the battery capacity. By late 2010 we will have a large selection of PHEV launches including the Chevy Volt. When the battery is exhausted, a PHEV acts just like a hybrid. The real payoff is during commutes and errands, when it is essentially a pure electric car. The Tesla roadster is the first lithium-powered pure electric car. It has 244-mile range and 0-60 time of 3.9 seconds. Fifty of these cars have been shipped to date and they have a large backlog in spite of the $109,000 price tag.
Tesla has done an excellent study...
http://www.renewableenergyworld.com/rea/news/reinsider/story?id=54046