You may know the Toyota Prius is good on gas.  Well how about if it used none?  "This particular vehicle you can operate in total electric mode up to 40 miles," says Claude Masters, who's in charge of buying vehicles for FPL.  He says for short commutes at average speeds it runs on electric.  If you're going further and faster it gives a boost, too. "We can extend that range well out to more than 100 miles per gallon...get up in the 120-125 mile per gallon range."

Wednesday, FPL unveiled four new plug-ins for use in Sarasota County.  They picked up the bill for the amount to convert the cars; about $11,000 each, says Spokesperson Sharon Bennett.  "This is the first county we have done it with.  It signifies a special partnership we have in helping Sarasota become even more green."

County leaders like Commissioner Jon Thaxton say it gives the county a chance to save some money while promoting the technology.  "It is going to save taxpayers money, but more importantly in order to get these cars on the market there has to be a demand for them.  People need to see that they are reliable.  They need to see that they are cheap and safe to operate."

So the hybrids may save some money on fuel.  How much does it cost to plug it in?  Masters says the cost to get the power is about 1/3 the cost of fuel.  "You are spending 50 to 60 cents to recharge the battery that will drive this car by itself for 40 miles."

And there's the environmental cost.  Some may argue the power coming from the plant is doing just as much harm.  Recent studies show that's not the case.  "It will ultimately reduce the carbon footprint of the vehicle for every miles traveled greatly," says Thaxton.

The plug-ins may get greener as they get older because the power grid is getting cleaner.  Since most cars will be charged at night, there might not be more demand for power plants.  "You are actually charging these vehicles under a condition that we call 'off peak'.  It helps us bolster our off peak load," says Masters.  Perhaps the best technology readily available.  "We feel like it's a good interim technology to whatever the next step is."

Last year Sarasota County spent $13.7 million on gas and electricity.  County leaders have pledged to cut consumption by 20% in the next three years.

FPL itself is going green.  The company says it has doubled the size of its hybrid vehicle fleet every year for the last three.  The fleet currently stands at more than 200 vehicles.