Given what Xcel Energy CEO Dick Kelly has been saying recently, it comes as no shock that his company is considering boosting the size of a planned "clean-coal" plant for Colorado from 350 to 600 megawatts. After all, a few months ago Kelly boasted to a reporter that he had a "grand scheme to make this company the leader in clean power and clean energy" so it never had to build another traditional coal-fired plant with its troublesome emissions.

Such a pronouncement sounds wonderful, of course, but what about this clean-coal technology? Is it really ready to lead us to the promised land? Glad you asked. On the one hand, Xcel's aggressive stance toward clean coal only recognizes a reality that is sometimes missed by those entranced with the potential for renewable energy: No matter how fast the production of wind and solar energy expands in the next few decades, utilities won't be able to serve projected demand without tapping other sources. If they're going to minimize pollution, their two major options are nuclear or a technology such as the "integrated gasification combined cycle" process used in clean-coal projects. Don't forget that the Colorado Energy Forum last fall estimated the state's demand for electricity would leap by half over the next 20 years alone.

Coal is plentiful in the United States, it's produced domestically, it's relatively cheap, its price does not fluctuate wildly, and it provides reliable "base-load" energy. Meanwhile, clean-coal plants pollute far less than conventional coal facilities, even those with the very best emissions controls.

So what's not to like? Well, clean-coal plants are more expensive than conventional plants by at least 15 or 20 percent. They require fairly large federal subsidies before utilities - Xcel included - will invest in them. None exist at Colorado's altitude. Finally, the ultimate hope for clean-coal plants - the capture of their carbon dioxide for storage underground - has yet to be mastered anywhere.

Environmentalists are fond of pushing subsidies for renewable energy sources such as solar in the hope that their wider use will hasten innovation, lower costs and thus speed their commercial viability. We suppose a similar process is at play in Xcel's clean-coal project: If it succeeds, the experience will be a boon to other utilities interested in alternatives to traditional coal plants.

We're deeply skeptical of the wisdom of such subsidies no matter what the technology. But with nuclear seemingly off the table in Colorado and the state's political culture no longer hospitable to traditional coal plants, it would be foolish to march into the future hoping that wind and solar will suffice.

Wish Xcel luck with its clean-coal plans - after all, you're going to pay for them. And come 2030, they may be all that stands between you and an occasional blackout.