While wind power is the fastest-growing source of new energy in the U.S., it still faces many challenges towards future development. One of the toughest challenges today is carrying this energy from remote windy plains and deserts to highly populated cities.

High voltage lines that carry renewable energy from one point to another means crossing not only through hundreds of farm fields and backyards but also through multiple states with different regulatory requirements.

What is further complicating the transmission puzzle is that the nation’s electric grid was designed primarily to serve particular states and regions, not necessarily to move electricity from one part of the U.S. to an entirely different area.

The permitting of these transmission lines that cross state boundaries is an extremely difficult and time-consuming process. Regulators in a single state can effectively veto a multi-state transmission line by refusing to grant the permits needed if they feel that their state would not receive an adequate share of the benefits or will lead to increased rates.

Wind power currently generates 4.5% of the nation’s electricity, but that number is expected to more than double to 10% by 2020, stated in a report obtained by USA Today that will be released Thursday by the U.S. Department of Energy.