A new link between the eastern and western U.S. power grids recently opened in Rapid City, S.D. The Rapid City tie will be operated by a federal agency, the Western Area Power Administration (WAPA), and is 65% owned by Bismarck, N.D.-based Basin Electric Power Cooperative. Rapid City-based Black Hills Corp. has a 35% stake.

The 200MW bi-directional tie became only the sixth link between the massive eastern North American power grid and its smaller counterpart in the western United States and Canada.

“The tie converts electricity from AC to DC and then back to AC as the phases of electricity in the two power grids are slightly out of sync,” says LaVerne Kyriss, WAPA spokeswoman.