Electric vehicles (EVs) are becoming more and more popular because they can be conveniently refueled with plug-in charging stations that recharge their batteries with electricity. They pay for themselves over time through dramatic fuel savings, especially when powered by solar energy.

As global demand for transportation keeps growing and political unrest in oil-rich nations like Libya continues to rise, we will continue to see the price of gasoline creep higher and higher. Automotive manufacturers have already been instructed to make vehicles more fuel efficient, which is good, but it only offers a partial solution to an issue that has persisted for many years. And drilling for more oil will not bring any long term resolutions either.

Electric Vehicles (EVs) like the Nissan Leaf and Chevy Volt are becoming more and more popular because of their high MPG ratings, their convenient ability to be plugged-in and recharged, and the frustrating and unpredictably wild increases in the price of a gallon of gasoline. The cost of "filling up your tank" for $30 dollars or more is decreased to under $5 dollars though charging your vehicle's batteries with electrical energy. But even though EVs emit very low emissions (some are even emission free), when you plug-in your EV you charge it with power generated at a traditional coal plant, a source that spits out lots of harmful and toxic byproducts into the air. There has got to be a better option, right?

What about solar-powered cars?

Just like a solar energy system atop a home or business can provide power for light bulbs, appliances, and other devices needing electricity, so too can an automobile be powered by solar energy. Solar panels (also called photovoltaics) absorb energy in sunlight form. This energy from the sun is then converted into traditional electricity which can then be used to provide power to anything, even an automobile! And while EVs like the Leaf and Volt are not the first of their kind (Toyota introduced an electric Rav-4 in 1997 that was later discontinued), they are surely an innovative step in the right direction.

Do EVs really make financial sense?

The price of a brand new EV is surprisingly affordable. The suggested retail price for a 2011 Chevy Volt is just over $40,000 dollars while a new Nissan Leaf is a little more affordable at $35,200 dollars. A federal tax credit will reduce these prices by $7,500 dollars bringing their effective costs to $32,500 and $27,700 dollars, respectively. Certain states also offer tax credits for purchasing an EV, like in Georgia where a $5,000 dollar tax credit is available and further decreases the cost of a new Nissan Leaf to $22,700 dollars (the MSRP on a 2011 Honda Accord Sedan LX is $22,180 according to Edmunds.com). And just like with any other new product, innovation combined with competition and increasing demand for more affordable substitutes will help lower these costs of electric vehicles even further in years to come.

How much does it cost to charge an EV?

Using a standard single-phase charging station to recharge a Nissan Leaf it takes 30kWh (charge time 6-8 hours) to recharge a fully depleted EV battery back up to 100 miles worth of driving range. That means to recharge at home it would cost approximately $3.60 at an average cost of 12 cents per kWh. But this cost really varies depending on the vehicle and electricity rates. Overall, an energy bill will be lowered by driving with electricity. EVs are so efficient that the cost per mile driven is significantly less than with a gasoline-powered car. For instance, an automobile that averages 25 mile per gallon would cost $13 dollars to drive 100 miles (using a conservative cost of $3.25 per gallon x 4 gallons of gasoline). In comparison, a 2011 Nissan Leaf will travel 100 miles on 30kWh worth of electricity. At $0.12/kWh, this is $3.60 (as previously stated). There are also public locations EV owners may go to recharge that advertise anywhere from $3.50 to $5 dollars per full charge. But most drivers charge every trip, rarely needing to fully recharge a battery, so this cost is probably a little lower.

Using solar photovoltaics (PV) at your home or business makes even more sense with a plug-in EV. The investment in solar panels pays off faster when the solar power is not only replacing grid electricity but replacing much more expensive gasoline. EVs typically can travel 3-4 miles (or more) per kWh of electricity. If you drive 12,000 miles per year, you will need 3,000-4,000 kWh. Depending on where you live, you will need a 1.5kW-3kW PV system to generate that much power using about 150-300 square feet of space on your roof. And utility credits for the daytime solar power that you sell back to your power company can offset the cost of charging the car at night.