electrons are pretty much interchangeable. I suppose that all the megawatt-hours (MWh) of energy generated by renewable resources can be exported to adjacent and other nearby states on the grid, leaving the energy that stays within Wyoming "pure."
I mean, it's just accounting. For every MWh of renewable-sourced energy that enters the grid, that much is sent out of state. The actual electrons don't care.
I think that's some Great Plains grid they're on. I'll have to look this up later.
Per Google:
Wide area synchronous grid
Western Interconnection
The Western Interconnection is a wide area synchronous grid and one of the two major alternating current (AC) power grids in the continental U.S. power transmission grid. The other major wide area synchronous grid is the Eastern Interconnection. The three minor interconnections are the Québec Interconnection, the Texas Interconnection, and the Alaska Interconnection.
All of the electric utilities in the Western Interconnection are electrically tied together during normal system conditions and operate at a synchronized frequency of 60 Hz. The Western Interconnection stretches from Western Canada south to Baja California in Mexico, reaching eastward over the Rockies to the Great Plains.