Xcel Energy cut the size of the Crown Ridge II wind farm in South Dakota by one-third because of a growing problem on the Midwest's electricity grid: too much traffic.
As more renewable energy is linked to the grid, transmission capacity is being strained. New projects are facing increasing costs — and longer waits — in connecting to the grid. Some, like Crown Ridge II, get downsized; others get canceled altogether.
"The grid is full today," said Michael Lamb, Minneapolis-based Xcel's senior vice president for transmission.
More transmission, from big cross-country power lines to localized interconnections, is needed, particularly if aggressive government climate change goals are to be met, say clean energy analysts and power industry executives.
"It is a bit of a Field of Dreams concept," Lamb said of new transmission and new renewable projects. "If you build it, they will come online."
But it will be difficult.