As the owner of the first Nissan Leaf electric car sold in Maine, it is my pleasure to give slide presentations to various groups about the history, benefits, and personal experiences of driving an electric vehicle.

After a showing of the movie Revenge of the Electric Car, I was participating in a question and answer session when someone in the audience shouted, "Your car is not zero-emission!"

Although the Leaf has no tailpipe and causes no local emissions, I had to acknowledge that my car's use of electricity indirectly contributes to smokestack emissions from power plants that burn fossil fuels.

In other words, it's a transfer of pollution to a different point in the 'carbon cycle'.

This of course begs the question: What's the point of driving an electric car from an environmental perspective if this is happening, the other benefits notwithstanding?

Chin up, my friends: All is not lost.

At this point, I'll direct you to a U.S. Department of Energy link that lets you determine your plug-in electric car's CO2 footprint.

As you know, power companies across the country produce electricity both by burning hydrocarbons and from renewable sources that vary from region to region--making electric vehicles 'greener' in certain areas of the country than in others.

Keep in mind an electric car gets cleaner as the sustainability movement grinds its way forward and individual power grids gain a higher percentage of renewables.

Not having the patience to wait for that to happen, I chose a different path: solar power.