I was happy to see an article attempting to help readers understand hybrids and plug-in hybrids in the widely read magazine Condé Nast Traveler last week. These vehicles have the potential to dramatically reduce petroleum consumption, but of course the only way they'll catch on is if people know about them.

I wasn't as happy after I read the article.

No, today's hybrids cannot drive 30 miles on electricity alone. They're designed to go only a couple of miles before the gasoline engine kicks on.

No, we do not need a new kind of battery to make plug-in hybrids work. Kits exist today for converting conventional hybrids into plug-in hybrids (it can be done in about two hours). The major automakers have higher standards for plug-in batteries, but GM engineers say that they already have the batteries they need. The challenge now is incorporating them into big battery packs. But that's been done before with other batteries, and GM engineers say that they'll have the new packs ready for testing this year. By 2010, GM aims to have the packs in production vehicles. (See "Electric Cars 2.0.")

And no, plug-in hybrids won't cause blackouts. There's plenty of excess electricity capacity at night, when most people will be plugging them in. Indeed, eventually plug-in hybrids could be used to prevent blackouts. (See "How Plug-in Hybrids Will Save the Grid.")

But here's the biggest problem with the article. It defines a plug-in hybrid as "a hybrid you have to recharge just like an electric car." This is exactly wrong, and it is just what automakers are concerned that people will think. One reason people haven't adopted electric cars is because their limited range and long charging times make long trips difficult. (One electric-car champion boasted to me that he takes road trips all the time in his electric car. But he has to hunt down RV parks and take two-hour breaks along the way for recharging.) The whole point of a plug-in hybrid is to get around this problem.

Plugging in a plug-in hybrid is strictly optional. If you plug it in to recharge the battery, you can drive to work and back using electricity alone, which will save you money and reduce carbon emissions. (See "Plug-in Hybrids Get Green Grades.") You can also make the first miles of a road trip using electricity alone. But if you prefer not to plug it in, or if an outlet isn't handy, the car simply runs on gasoline. Indeed, a plug-in hybrid can get much better range than a conventional gasoline car because it uses gasoline more efficiently. GM's Volt plug-in is to have a 600-mile range using gasoline, with 40 miles more if you happen to plug it in.

A new study shows that when consumers understand what plug-in hybrids are, they want them. The vehicles, which have large onboard batteries, can be recharged overnight by plugging them in, storing enough electricity to power daily commutes. For longer distances, a gasoline engine kicks in, assisting the electric motor and recharging the battery. The major automakers do not yet offer plug-in hybrids, but several are developing them. For those consumers who can't wait, a handful of companies offer conversion kits for conventional hybrids.

Of the more than 3,000 consumers asked if they would consider buying a "grid-connected hybrid," the term used for plug-in hybrids in the survey, only 24 percent said that they would, according to the survey by Synovate Motoresearch. But when they were told what such a car could do, that figure nearly tripled, to 64 percent. That's well above the percentage of people who would consider buying an ordinary hybrid, like the Toyota Prius, which doesn't have extended battery-powered range. Scott Miller, the CEO of Synovate Motoresearch, presented the survey's results this week at the Advanced Automotive Battery Conference in Long Beach, CA.

The results suggest that consumers like the idea of the plug-in hybrid--but that so far, car companies are doing a lousy job of getting the word out. That's not the case with flex-fuel vehicles, though. These cars, which can burn either gasoline or a mixture of 85 percent ethanol, scored high on the desirability charts--that is, until consumers were told more about them. Flex-fuel vehicles have been the subject of heavy promotion by automakers. But the marketing campaigns have fallen short of providing all the details: consumers thought that flex-fuel improved fuel economy, Miller said. Actually, the opposite is true. Ethanol contains much less energy than gasoline does, so miles per gallon will be significantly lower, as will range on a tank of gas. When consumers were told this, the percentage of people who would consider buying the cars dropped from 52 to 33 percent.

It remains to be seen if the desirability of plug-ins is enough to overcome their steep price tag. They could cost thousands of dollars more than a conventional hybrid, which already comes at a premium. Still, consumers are willing to shell out thousands of dollars more for SUVs than for minivans because of their perceived advantages. So if the word gets out and the cars get built, plug-ins might just be the next big thing.