http://www.dsireusa.org/incentives/i...ive_Code=WY01R says Wyoming has Net Metering. This says it applies to electric coops and has Net Excess Generation "Credited to customer's next bill at retail rate; excess reconciled annually at seasonal avoided-cost rate". To me, that looks like you get full retail credit for your energy production. The avoided cost comes into play probably once a year where you might get cash back.
In Kansas, I don't get any cash back, but I do get full retail credit for what I generate and dump onto the grid, which can carry over from month to month until the end of the year. I activated a 5 kW system on July 31. Since then, it's generated just over 2,000 kWh of electricity. Of that, over 1,100 kWh was excess and dumped onto the grid. Over the same several months, I later pulled about 800 kWh back off the grid. The PV system is large enough that my meter runs backwards during the day, anytime that the air conditioner is not running. I'll build up excess credit, which will expire at the end of the year, and then start building up a credit for the cooling season next summer. I'll probably pay for some electricity towards the end of the summer, but it should make me close to zero net electricity usage.
One could possibly come up with a system that worked off-grid, but when you have the grid available, just connect the PV system to it.