I'm betting 79 cents a month on a greener future.

My local electrical utility,

Con Edison

(ED) - Get Report

, offers a way to switch from standard electricity, sourced from a toxic mixture of coal, oil, natural gas and nuclear power, to

green energy, theoretically drawn from a cleaner mixture of wind and waterpower.

The environmentalist and penny pincher in me caused me to sign up two years ago.

It cost a little more per kilowatt-hour than the electricity I used previously, partly offset by a break on the

taxes added to my bill, but in my small New York apartment the difference seemed negligible. It seemed like a way to help move us away from our dependence on finite foreign oil and dirty, dangerous coal.

Besides, I figured that the way

oil prices have been climbing, it can't be long before my green juice would cost less than the brown stuff.

"But it hasn't happened yet, has it?" Sam Swanson, director of the

Renewable Energy Technology Analysis Project at Pace Law School in New York, asked rhetorically when I related my cunning plan to him.

No, it hasn't.

According to

ConEd Solutions, which sells the green power, electricity from wind and hydroelectric sources costs 1 cent more per kilowatt-hour than the regular stuff, and it is 2.5 cents more if you want your power to be all-wind, which has the least environmental impact, according to the

EPA.

Finding out why I'm still paying more was no easy task. I had to talk with customer service people, spokespeople and a ConEd Solutions executive, then supplement that with a tutorial from Swanson, before I could make sense of how green electricity works for ConEd Solutions and for

other utilities around the country.

Wind-farm owners such as

Airtricity and

Enel North America sell their wind-generated electricity directly into public power grids. Just about all of what's generated in New York already goes into the grid for use around the state and in New England, according to Peter Blum, manager of renewable energy services at ConEd Solutions.

But separately, the wind-farm owners also sell

renewable energy certificates, or RECs, which are the on-paper rights to the environmental benefits of that wind energy. Utilities such as mine buy these RECs for their green-energy programs, but other organizations and even individuals can also buy them to offset the carbon footprints they create, say by owning a fleet of trucks or flying a private jet.

Once energy goes into a public grid, no utility can direct specific electrons to specific homes. But they can buy these RECs on behalf of customers like me so that we both get credit, on paper, for being greener.

Beyond that, Swanson says, the RECs are how wind-farm owners make their real profits. They're the incentive for building wind farms and at least part of the

capital used to build new capacity. As additional wind farms are built in New York, the amount of local electricity coming from dirtier sources can ratchet down. And the more people who sign up for green energy, the sooner more wind turbines can be built. "It does make a difference," Blum says.

As for my electric bill, Blum explained that my green power costs more, and most likely always will, because ConEd Solutions is buying my power from the grid along with everyone else's, for the same price. On top of that, it's also buying those RECs on my behalf.

Austin Energy in Texas has managed to buy long-term contracts that feed wind-generated electricity directly into the city's power supply, and it passes the savings along to its GreenChoice customers in the form of a flat rate that stays the same even if the prices of electricity sourced by other means go up.

They can do that in Austin because in flat, open Texas, companies can build their wind farms relatively close to the cities, Blum explains. In other regions, the windiest open spaces might be hours from the population centers.

But all isn't lost.

ConEd Solutions gives me the option of fixing my rates for a year at a time, at least. Had I stuck with ConEd proper, my rate would fluctuate from month to month based on wholesale prices and demand. Translating that to actual usage, this past August my Green Power bill was $71.86, and the customer service folks at ConEd Solutions told me that it would have been $71.07, or 79 cents less, had I stuck with regular electricity.

It's a small price to pay.

Eileen P. Gunn writes about the business of life and is the author of "Your Career Is An Extreme Sport." You can learn more about her at

her Web site.