Renewables rising: Xcel ups ante on wind and solar.

• Author: Peterson, Eric

A SEA CHANGE in electrical generation is underway in Colorado.

Xcel Energy has received approval to add 170 megawatts of solar, 450 megawatts of wind and 317 megawatts of natural gas generation, while phasing out a coal plant in Denver earlier than originally planned.

It all adds up to a major shift in the company's resource portfolio for electricity in Colorado.

The Colorado Public Utilities Commission (PUC) approved the plan last December. PUC Chairman Joshua Epel called the approval "an historic moment" for its impact on carbon emissions and a sign of price parity between renewables and fossil fuels. The decision is effective through 2018.

But the move isn't just about going green. Gabriel Romero, Xcel spokesperson, says the plan was driven by economics first and foremost.

"We can get wind and solar for a comparable price as coal and gas," says Romero. "That's a good business decision."

Perhaps surprisingly, this decision has nothing to do with the Colorado state mandate that 30 percent of electricity come from renewable resources by 2020. Xcel expects to hit that target several years in advance.

"We're already compliant; we're going to hit the mandate," Romero says. "Any decision we make with renewable energy moving forward is a business decision."

The utility supplier is working on power purchase agreements for the more than 600 megawatts of solar and wind energy covered by the plan with energy producers and project developers. The new capacity will come online in "about a year," Romero projects.

"We're able to bring wind into our system because we have a pretty broad system," says Romero. "We're able to handle that new load. We have no problem bringing in 500 megawatts of wind, but smaller utilities aren't able to do it."

Because of the unpredictable nature of wind and solar, additional gas-based generation is critical, says Romero. "When you bring in renewable energy, you're going to have to be able to turn up and down your generation plants," he explains. "That only works with gas. That doesn't work with coal. It all works in coordination with everything else. All of that coordination makes it come in costcompetitively, and that includes solar. That's unheard of up to this point."

Because throttling down a coal plant in response to wind speeds...