Several days ago Toyota announced that they are developing plug-in hybrids. These are hybrids with larger battery packs. They're designed to be plugged into a socket and charged at night, then you can drive up to, perhaps, 8 or 10 miles on battery power alone before the gasoline motor kicks in. You should get many of the benefits of an electric car, but still retain the long range and ability to "fill her up" at gas stations during those extended highway trips.
Some people have already developed conversion kits to make the exsting Prius into a plug-in hybrid. It does void your warranty, unfortunately. It seems likely that these homebrew kits, plus the higher price of gasoline, spurred Toyota to give plug-ins a proper try.
As with pure electric cars, batteries are the limiting technology. Not only are they expensive, but the discharge cycle of an electric car is much more demanding on batteries, and they are prone to degrade faster than the batteries in a "conventional" hybrid.
One interesting aspect of this is that it could eventually pave the way for fully electric cars. I can imagine future models that move more and more work onto the electrical system, with improved battery technology, until it becomes practical to jettison the gasoline engine completely.
Now, speaking of electric cars. . . I was floored by the recent unveiling of the Tesla Roadster. It's going to be an expensive car and very much a toy rather than a practical, economical car -- but what a toy! You are looking at 0-60 MPH in 3.7 seconds, upwards of 250 miles driving range per charge, and top speed about 135 MPH. It appears that battery technology is just beginning to edge over the line of adequacy for electric cars. Storage technology (both batteries and supercapacitors) is being heavily researched around the world, so it's only going to get better.
I can imagine five or six years from now, electric cars becoming really practical. The benefits can be huge. These cars can get energy efficiency equivalent to 135 MPG. Mechanically they are very simple: no complex engine to repair or keep in tune, no oil changes, no filters or hoses, no spark plugs, no exhaust system. They could have a long lifespan with very little maintenance. Based on some storage technology that's in labs today, it's just possible they might achive
400-mile range, fast recharge, and much reduced battery degradation over time (or practically none, in the case of supercaps).We aren't there yet. But I'm beginning to feel optimistic, there's a light at the end of the tunnel for electric cars. It's getting close enough to think about buying one sometime before I get onto Social Security. :)