Xcel strives to use more renewable energy sources

Mike Moran
Business Times

Eight rows of parabolic mirrors concentrate sunlight to heat mineral oil that in turn heats water as part of an experimental solar and coal-powered operation at the Cameo power plant east of Grand Junction. The experiment ends this year, but Xcel Energy continues to look for ways to meet a legislative mandate to produce more electricity from renewable sources. (Business Times photo by Mike Moran)

Xcel Energy faces more stringent requirements to use alternative energy sources now that the Colorado Legislature has weighed in on the issue a second time.

State lawmakers voted earlier this year to mandate that Xcel and other large utilities produce at least 30 percent of their power from renewable energy sources by 2020.

The renewable energy effort in Colorado began in 2004, when state voters approved a measure requiring large utilities to produce 10 percent of their energy from renewable sources. Lawmakers later voted to hike the share to 20 percent and then more recently to the 30 percent level.

As part of its efforts to experiment with solar power, Xcel created the first solar-coal hybrid power plant at its Cameo Station east of Grand Junction.

The system uses solar power to heat mineral oil, which flows within tubes and in turn heats water. The water is then further heated by burning coal to turn the water into steam, which turns turbines that produce electricity.

The solar project features eight rows of large parabolic mirrors and covers more than 6 acres at the Cameo plant.

Despite discussion in the Legislature to force Xcel to continue the experiment next year, no legislation was enacted. “We’re shutting down at the end of the year,” said Fred Eggleston, area manager for Xcel.

Eggleston said the solar-coal experiment has been a good one overall. He said the company learned about such factors as what time of day the plant could generate the most power from the sun. It also learned some valuable lessons about how solar power can be impeded by nature.

“We did have more negative effects from clouds (than anticipated),” he said. “No one knew what impact the clouds would have.”

The hybrid experiment drew interest from across the globe, with visitors from as far away as Japan.

Meantime, Xcel also faces pressure to convert some of its coal-fired power plants in Colorado to natural gas. State legislators enacted legislation touted as a means to reduce pollution in Colorado air while also increasing demand for natural gas that’s extracted in the state.

Colorado Gov. Bill Ritter endorsed the legislation as part of efforts to promote what he calls a new energy economy while reducing emissions of nitrogen oxide and sulfur dioxide from coal-fired plants.

Xcel has proposed to convert its Valmont and Cherokee power plants to natural gas by 2022. The Colorado Public Utilities Commission is scheduled to review the proposal in late October and early November.

As for future requirements to produce energy from renewable sources, Xcel is playing a wait-and-see game even as the company pushes forward with current plans. “I would not try to guess what will happen,” Eggleston said.

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