Let's say you want to do something about our energy challenges and buy green electric power. Lots of utilities say they're happy to help, and some claim that, for an extra fee each month, they will stream green power straight into your home from things like wind and solar and geothermal. But "energyNOW!"'s Dan Goldstein discovered there are still a lot of gray areas when it comes to going green, in this week's "energyNOW!" Spotlight.

[GOLDSTEIN] Talk about green -- the University of California, Santa Cruz, is one of the most beautiful and greenest campuses in the U.S. Students like Chelsea McDaniel and Cameron Fields wanted to keep it that way by purchasing so-called green power to run the school, but something didn't add up.

[FIELDS] We weren't buying green power. I don't know if we originally thought we were purchasing green power, but we weren't getting green power.

[GOLDSTEIN] Trying to help them get that green power to campus was environmental studies professor Daniel Press. So what happened here at UC Santa Cruz?

[PRESS] So, in 2006, the UC Santa Cruz students wanted to do something about climate change and renewable energy, so they voted to tax themselves with new registration fees -- $9 a year -- to buy these renewable energy certificates.

[GOLDSTEIN] So what's a renewable energy certificate, anyway? A REC, as it's known in the industry, is essentially a promise green energy has been created somewhere on your behalf when you buy green power. At UCSC, students spent hundreds of thousands of dollars to buy RECs. At first, Press and the students liked the idea. But then...

[PRESS] I read the fine print. Now if somebody says, "Green power is really these renewable energy certificates," then I say, "I don't want to have anything to do with it."

[GOLDSTEIN] That's because the green power the students paid for may never have actually made it to campus, since we can't tell the electrons where to go. And because there aren't enough transmission lines, the utility that signs you up for green power often can't deliver it to you.

The national utility grid is a lot like this swimming pool, and when you buy green power, it goes in here. But at the other end of the energy pool, your cup may be clear. So utilities have to promise their green power customers they've bought renewable electricity from someplace else. Mike Smith of Constellation Energy tells me how they work.

[SMITH] You can't draw a string between a particular generation facility and a particular customer. The renewable energy credit allows us to create that link between a facility and a customer -- again, if it's done properly.

[GOLDSTEIN] But it's not always marketed properly. Some, like this one, say, for just $6 a month extra, you'll get 100% of your electricity from renewables. Not possible.

But it's not just utilities making this claim. Check this out -- here's an organic market in Bowie, Maryland, calling itself 100% wind-powered because it bought renewable energy certificates. But it's getting the same energy mix as everyone else.

Does a consumer understand that? Because when there's a sign outside your door that says, "100% wind power," do they think that there's actually a wind turbine on your roof?

[SCOTT NASH, MOM'S ORGANIC MARKET OWNER] Sometimes, sometimes -- yeah, our customers are incredibly savvy and educated, ours in particular. I think that some don't, and they say, "Where's your wind turbine? What happens when the wind stops blowing?” You know, "Do the lights go down?” But in general, I'm not so sure people -- I think they just assume that it's happening. And they don't really inquire. And we will tell them, you know, how it happens if they ask.

[GOLDSTEIN] Mike Zannakis, the Director of Green Power for Sacramento Municipal Utility District in California, said no businesses should claim they're supplying 100% wind energy unless they actually are.

When you say -- or a consumer sees this and says, "I'm going to get green energy," can you really make that promise?

[ZANNAKIS] No, it's the fact that it goes on the grid. They're supporting the program. They're supporting the fact that there's more renewables on the grid in Sacramento, helping the environment.

[GOLDSTEIN] So they're not really getting a stream of green electrons.

[ZANNAKIS] No, no, not at all.

[CHARLES SEGERMAN, FOUNDER, CLEAN CURRENTS] You're talking about questioning a mechanism that's established with the EPA and also with the United States Green Building Council.

[GOLDSTEIN] Charles Segerman is Director of Clean Currents in Rockville, Maryland, the broker that sells green power to MOM's Organic Market. He says, even if the buyer isn't getting green power directly, somebody is.

[SEGERMAN] Because they're buying that wind power, there's a coal plant that didn't generate the same amount of their power.

[GOLDSTEIN] But Daniel Press doesn't buy it. Last year, he wrote this op ed for the San Jose Mercury News calling RECs and environmental attributes, in effect, a feel-good green scam.

[PRESS] So, for a cent or half a cent, you could buy this REC. Well, nobody knows what "environmental attributes" means. Nobody can get their heads around that, because it's really kind of phony.

[GOLDSTEIN] Do you know where the money went?

[McDANIEL] Well, I think that was one of the really big issues, was that we say, "Oh, who knows where the money is going? Is it going to some wind farm in Texas?” Or, you know, we were basically providing funding for someone else to use green energy.

[GOLDSTEIN] Tracking those RECs is Jennifer Martin's job at Green-E in San Francisco. She says funding somebody else's green energy is exactly the way the system is designed to work.

[MARTIN] Right now, more than half the states require utilities to deliver a certain portion of their power from renewables. And all those states pretty much rely on RECs to verify that the utilities actually bought the renewable energy.

[GOLDSTEIN] But right now, no government agency watches over the sale of RECs, which can be traded state to state, and, some fear, double-counted. That's the main issue for Michael Wara, environmental law professor at Stanford University.

[WARA] I think, right now, there's very little government oversight over the kind of RECs that a consumer would buy in their green power. And there have been various pushes to increase the level of oversight, and a lot of industry resistance, I think, to creating it.

[GOLDSTEIN] UCSC decided RECs didn't live up to their claim, so last spring, students voted to toss them. Now they're taking that money and putting them into solar panels, ones they can actually see.

[SUITERS] And Dan Goldstein is back now from the West Coast, joining us in studio. And, Dan, let's begin with what consumers need to know when they want to buy green power.

[GOLDSTEIN] Well, Tyler, it's like anything else. You need to read the fine print. The utility wants to sell you a product, and you, as the consumer, just have to ask yourself, "What am I getting for what I'm signing up for?” Am I getting these RECs? Or, actually, can the utility actually sell me that green power?

[SUITERS] Another point here, Dan, is that all utilities really aren't the same when it comes to the way they handle their advertising, right?

[GOLDSTEIN] That's right, and some of them actually are getting it right. For example, you've got utilities that say, "When you sign up for this, you're supporting green power somewhere else.” And they actually are getting that claim in their marketing brochure, so consumers actually can read that, and they can actually see how it really is.

[SUITERS] Going forward, the government now is starting to take a little bit of a closer look at what's going on here?

[GOLDSTEIN] Right, and the Federal Trade Commission, which monitors marketing claims of companies, and they're looking at green claims very carefully now -- They're going to start looking at utilities and seeing their marketing claims and, really, are consumers getting what they're buying? And they're going to have new language out next year.

[SUITERS] And we'll keep an eye out for that. All right, Dan. Thank you so much.