[P]urchasers of green energy will find that wind energy produced in Pennsylvania is much more expensive than wind produced in, say, Montana. This mainly has to do with the location of wind resources. Montana has more areas with a higher sustained four wind than Pennsylvania. Also, since Montana is less densely populated, there are fewer troubles in siting the windfarms. The drawback, obviously, is that Montana is very far away, and electricity grids lose power over long distances. However, some researchers in Europe claim to have found a solution: DC current.