It’s hard to say what sounds better: 100 miles-per-gallon, $1 a gallon fuel, or a car you only have to fill up once a month.

All that is the promise of a new type of car, and this one isn't a far off pipe dream, it’s something you should be able to buy in just 2 years. And it runs on fuel made in the USA.

The long yellow extension cord isn’t the only thing that makes the Toyota Prius Bob Breeze, and his co-workers, drive special. The Austin Energy Company's fleet cars have the one feature everybody wants.

“Definitely, you will get better than 100 miles per gallon,” said Breeze.

That’s more than double a regular Prius.

Like any Prius it starts out silently, running off the battery. But where a regular Prius has to fire up its gas engine after a mile or so, to recharge the battery, the plug-in hybrid can run without gas for up to 30 miles. It has a bigger, custom made battery pack, charged by relatively cheap electricity from a regular wall socket.

“With a plug in hybrid you're paying less than a dollar a gallon equivalent for the energy you're using,” said Breeze.

That means an average Texan could drive to work and back using hardly any gas.

And this plug-in technology isn't just limited to small cars like a Prius. It can work on a pickup truck, an SUV, in Austin they've even got a school bus that’s a plug-in hybrid.

These hybrids are still experimental, but the head of Austin's city owned electric company believes they are the answer to America's addiction to imported oil because they run on power that's all home grown: electricity, coal, gas, nuclear, even wind.

“Whatever you can convert into electricity, in the electric grid, can be used for the transportation sector. That’s the kind of diversity we need, instead of placing everything 100 percent on petroleum,” said Roger Duncan, General Manager at Austin Energy.

Austin started a plug-in partners program that got Dallas, and 50 other cities, to join thousands of individuals and promise to buy plug-in hybrids if the big car companies will make them.

General Motors answered the call with the Volt concept car. It seats 4, goes 100 miles and hour, and runs 40 miles before the gas engine kicks in. Target date: 2010, with a price under $40,000.

A plug-in Saturn VUE, and Prius, are expected at the same time, with Ford not far behind.

And since the hybrids would mainly charge at night, when the demand on power plants is the lowest, state regulators say the system can handle it.

“You could put millions of these vehicles onto the electric grid before we would have to build a new power plant,” said Jones.

Marguerite Jones has been driving the plug-ins for 3 years now, and every time the price of gas goes up, she gets more anxious for the chance to buy her own “I’d spend less than a dollar a day. Probably less than 50 cents,” said Jones.

Even at an estimated $3,000 more, it may be the cheapest way to energy independence.

E-mail greaves@wfaa.com