There's just one problem with an electric car—the battery. The rest is easy. Much simpler than a gasoline car. But a 300-mile battery is nowhere in sight. They're still struggling to make a reasonable 10-mile battery. But by 2015, they hope to have a 40-mile battery. I would say 20 miles would be a reasonable bet by then.

Here's the good news. Even a 20-mile battery would cover half of all driving. Only 20 Miles?? So that's why a hybrid is crucial. The car must have a regular engine to keep the batter charged on long trips. More good news. When the engine is charging the battery it can be way more efficient because it runs at the perfect speed.

The net result is a plug-in hybrid that's cheap to run on short trips, and energy efficient on average. more

But what about CO2 emissions? When you plug-in, the electricity you get comes mainly from coal. Electric cars will help with global warming very little—until we clean up electricity. More wind turbines will help, and Google is working on solar-thermal. But what we will probably need for a few decades is coal with carbon capture. The technology is close, but it will be a bit expensive. To do the job, this country needs a real energy policy. Bush has been spending 10 cents per person per year on clean coal—he said it was to be a $2 billion FutureGen project, but that's been canceled. You can read the new zFacts book on energy energy policy here: Carbonomics: How to Fix the Climate and Charge it to OPEC.