Electric cars have been around for decades, but it hasn't been until recently that they have been controversial.

The U.S. government, as well as influential cities and states like Colorado, New York and California, have committed to increasing the number of electric cars we buy and drive. The reasons given are to reduce C02 emissions, as well as reduce the country's dependence on oil by tapping into the U.S.'s vast natural gas and coal reserves, which are the two biggest energy sources powering electric power plants.

But how do they work exactly? What's it like to own one and live with one? Are they as powerful as gas-powered cars?

What is it?

An electric vehicle is powered by a battery rather than an internal combustion engine. They have been around a long time. Most of the electric cars we have seen hit the market have been powered by a nickel-metal-hydride battery. This is battery tech that has been widely employed for digital cameras and the like. In fact, most of the rechargeable batteries you can buy at Radio Shack have been nickel-metal hydride. But more recently, the battery technology has changed to where automakers are using lithium-ion batteries. These batteries have longer range than nickel-metal-hydride batteries, and are considered to be the future of electric vehicles. Lithium ion has been used in recent years to power most laptop computers and cell-phones.

How does it work?

Between the batteries and the motor there is a device called a "controller." The controller takes power from the batteries and delivers it to the motor. The accelerator pedal is connected to a pair of variable resistors (known as "potentiometers") Those provide the signal that tells the controller how much power it is supposed to deliver. The controller can deliver zero power when the car is stopped, full power when the driver floors the accelerator pedal, or any level of power in between.

Pure electric vehicles

There are a handful of pure electric vehicles on the market today or coming in the next few months: Ford Focus Electric and Ford Transit Connect Electric; Nissan Leaf; Chevy Spark; Tesla Model S. The operate on batteries alone. The Leaf, for example, has a range of around 80-100 miles. When the battery runs out, you must stop and re-charge. For this reason, the car is really best for people who nearly always drive less than 100 miles a day and have re-chargers at home and at work.

Extended range electric vehicles

An extended range electric vehicle is one that is powered by a battery, but also has a gas motor on board. Now, don't confuse these cars with "hybrids." En extended range EV goes a certain distance on an electric charge. In the case of the Chevy Volt, for example, the car will go about 35 miles on a charge. When the battery is almost run down, the gas motor kicks in and continues to power the battery, which in turn powers the car. This motor does not recharge the battery, but rather it just keeps the battery going. Because of the gas motor, there is never any chance the driver will be stranded for lack of power. This approach eliminates "range anxiety," which is the worry on the part of a driver that their car will run out of juice with no place to re-charge.

Where do I recharge?

An EV owner can recharge anywhere there is an electric outlet. But it is advised to have access to at least a 220-volt dedicated recharger in one's garage. The cost of these chargers varies from about $1,500 to a few thousand dollars. Utility companies, though, have generous rebates on such chargers. An increasing number of companies and parking garages/structures, shopping malls, airports, universities, libraries, mass-merchandise stores, public buildings are equipped with electric chargers. There are smart-phone apps that tell you where chargers are. The ideal situation for an EV owner is to have a re-charger at home, and one available at their place of work. There are 4,400 charging stations nationwide, but that number is growing. Here is a link to find charging stations.

Does it pay?

That all depends. Here is an example of the math you need to do if you are buying one. A Chevy Volt recently leased for $189 per month, with about $2,000 down after downpayment/security deposit, fees, etc. If you are buying, the Volt's MSRP is $39,995. But there is a Federal tax credit of $7,500, knocking the price down to $32,495. California has an additional $1,500 credit on the Volt. In Colorado, the state tax credit for a 2012 model is up to $5,896. That could knock down the price to $26,599. That makes the Volt, which we would favorably compare with vehicles such as an Audi A4 or Lincoln MKZ, equivalent in price to a typically equipped Honda Accord or Ford Fusion. The extra benefit is that a Volt owner--as well as owners of all EVs and most extended-range EVs coming--can drive in high-occupancy-vehicle lanes in metropolitan areas. And time is money.

Electricity vs. gas power

Acceleration and power in an electric vehicle is much better than one would expect. These are not golf carts. The 149-horsepower electric motor in the Chevy Volt, for example, accelerates smartly right up to its 101 mph hour limit. Our 0-60 speed was 8.8 seconds on full electric power--about the same as a Chevy Sonic. We found it perfectly adequate.

Gas vs. electricity

This is a tricky comparison and will vary for people. But it can be find to sort it out.

Let's say you are a college professor at the University of Michigan in Ann Arbor, Mich, and you drive your Nissan Leaf 35 miles to campus. The cost of your fill-up (when rates are cheapest) was about $0.11 per kilowatt-hour. Charging the Leaf will cost about $2.64 to reach a full charge. That professor should be able to make a roundtrip without recharging, and the cost compares with $4.00+per gallon for gasoline right now. Two-and a half gallons of gas for a Nissan Versa would be 10.00. Add to that calculation the fact that the University of Michigan, as well as a number of companies, have free re-charging at many parking spots. So, free-recharges, as long as they last, can really benefit the early adopter of an EV.

Every buyers is going too have a different set of variables, but it is fun to calculate them.

Are EVs for everyone?

We would say No. Would it surprise you to learn that the average U.S. driver goes less than 30 miles a day in their car? That statistic would suggest that EVs would be perfectly adequate for millions of drivers. But people worry about the days they have to travel 75, 100, 125 or 150 miles a day or more. Consider making an EV or extended-range EV the second car in a two-car household. The number of households where both drivers need cars that would out-last an EV battery are very few.

Bottom line:

Electric cars like the Nissan Leaf, and extended-range electric vehicles like the Chevy Volt represent a new way of driving. Depending on driving habits, the prevailing deal from the automaker, and the cost of gasoline, EVs and extended-range RVs can make a lot of sense. But owning one is a bit of a lifestyle choice. Owning one stress-free, and to get the most out of free charging spaces, takes a bit of planning, commitment and organization.

There are arguments and debates all the time about whether these vehicles pay the driver back based on the higher purchase price. Figuring it out for yourself, though, takes a clean sheet of paper, a sharp pencil and a calculator. Here is a link to find out about state incentives. And here is an online calculator that helps figure out your costs based on your driving habits and the car your are considering.