[maxerickson]

Sure, it's complex. Take your example. The Hoover dam sells power into California. So installing solar panels in Boulder City is not that different than installing them in Los Angeles (there would be some extra grid losses in LA). If the Hoover Dam had the capacity to supply the entire southwest it would matter, but it doesn't have that capacity.

There's also the question of whether buying Chinese solar panels makes China more or less likely to convert to solar itself.