Yeah, we have these shyster bastards where I live, too. The entire thing is a scam. Think about it: The power lines are owned by the utility company. The generation facilities (at least where I live) are also owned by the same utility company. All of them. There are no third party options, there are no power stations that are independent entities. How then, in any possible way, could any middleman somehow make it "cheaper" to buy power from the vendor you're already buying it from and sell it back to you?
No points for guessing that they can't. All these guys do is get billed on your behalf from your same old power company, then charge you their own added bullshit fees on top of that. They haven't saved anyone in my region a single nickel, ever.
Now the tactic they use is admitting that you might pay slightly more, but they'll switch you to "more green" energy sources to prey on people's environmental sensitivity. Isn't that worth paying a little more for? Too bad this claim is bullshit, too -- There is a very low percentage of renewable energy generation in our region (which yes, is something that needs to change) but what little of it exists is already integrated into the regular power grid and is... you guessed it, owned and operated by the same utility company that already owns the lines and power plants!