From an article by Sean Ryan in The Daily Reporter:

There are not enough power lines to support wind farms in Lake Michigan.

That lack of transmission lines to carry power from offshore wind farms was one issue within the Public Service Commission of Wisconsin’s Wind on the Water report released Thursday. According to the report, if Wisconsin wants to generate more than 600 megawatts from a lake wind farm, the state will need a new power line parallel to Lake Michigan’s shore.

The ability to connect to transmission lines is the No. 1 factor determining where wind farms are built, and Wisconsin could make Lake Michigan more attractive to developers if there is a new power line with capacity for offshore farms, said Mike Donahue, executive vice president of Midwest Wind Energy in Chicago. For land-based wind farms, developers must choose a location and ask transmission companies if the existing power lines can handle the extra electricity generated by the turbines.

“Your transportation infrastructure has become the critical location factor for projects,” he said, “whether they’re land or offshore.”