A recent post in Daily Kos explains  how Xcel Energy has become a big proponent of wind power.

Colorado is learning how to integrate its significant wind turbine capacity with its electrical needs. Wind is intermittent power generation, which creates a systems operation challenge. Colorado has changed from believing that more than 10% of their electrical energy from wind would be impossible to now believing that they can reliably integrate very large percentage of wind and have demonstrated this with a 60% wind energy contribution on one day.

Here is an excellent article in MIT’s Technology Review.

Wind power is booming on the open plains of eastern Colorado. Travel seven miles north of the town of Limon on Highway 71 and then head east on County Road 3p, a swath of dusty gravel running alongside new power lines: within minutes you’ll be surrounded by towering wind turbines in rows stretching for miles.

Colorado has been quietly generating wind capacity, but have been fought by one of the largest energy corporations.

Before the forecasts were developed, Xcel Energy, which supplies much of Colorado’s power, ran ads opposing a proposal that it use renewable sources for a modest 10 percent of its power. It mailed flyers to its customers claiming that such a mandate would increase electricity costs by as much as $1.5 billion over 20 years.

The breakthrough was achieved by accurate wind predictions and therefore power output of the turbines. This is critical to a Systems Operator and you can’t commit to energy production on a given day if you can’t predict, with accuracy, what the instantaneous power output will be per turbine.

Xcel Energy has completely changed their tune and has become an advocate of wind energy.

It has installed more wind power than any other U.S. utility and supports a mandate for utilities to get 30 percent of their energy from renewable sources, saying it can easily handle much more than that.

Here is a quote from an excellent study on “Cost-minimized combinations of wind power, solar power and electrochemical storage..”

We find that 90% of hours are covered most cost-effectively by a system that generates from renewables 180% the electrical energy needed by load, and 99.9% of hours are covered by generating almost 290% of need. Only 9–72 h of storage were required to cover 99.9% of hours of load over four years. So much excess generation of renewables is a new idea, but it is not problematic or inefficient, any more than it is problematic to build a thermal power plant requiring fuel input at 250% of the electrical output, as we do today.At 2008 technology costs, 30% of hours is the lowest-cost mix we evaluated. At expected 2030 technology costs, the cost-minimum is 90% of hours met entirely by renewables. And 99.9% of hours, while not the cost-minimum, is lower in cost than today’s total cost of electricity.

Over-generation is cost-effective at 2030 technology costs even when all excess is spilled.

The study looked at the mid-Atlantic region of the US. The important conclusion is that geographically distributed wind and solar combined with overcapacity can produce very high percentages of required energy on a given day, and at a cost effective point.

The case for wind today is totally compelling. It’s the only source that can be deployed in units of gigawatts, and it’s competitive with fossil fuel in $ per KWh. We are now learning how to integrate wind to 90% plus energy contribution.

The challenge for this community is to make wind and solar deployment a major strategy for the US. That means getting Congress to support this. It currently takes 7 years to permit an offshore wind farm in Federal waters. This should be completely unacceptable. We are seeing major blockage of wind power deployment from influential individuals who just don’t like the inconvenience to their “viewshed”. We now know how to site wind for maximum efficiency and minimum impact to residents. We could acheive 90% or more of our stationary electrical power from wind and solar by 2030. We just need to will to do this.