Reserves at the ready to cover brief shortfall

Colorado’s largest utility claims it has more than enough power reserves to handle the state’s descent Monday into shadow.

“Xcel Energy in Colorado is not anticipating any operational issues as a result of the solar eclipse, although like everyone else we will be interested in how this rare, celestial event plays out across the country,” said spokesman Mark Stutz, echoing a message sent out by other utilities in the path of the eclipse.

The solar eclipse will greatly diminish, temporarily, the amount of electricity from solar power coming onto the grid. Although Colorado won’t go completely dark, it will mimic dusk in the state’s more populated Front Range corridor.

Solar generation accounts for 3.3 percent of what is known as “net dependable capacity” on the utility’s system in Colorado, or about 255 megawatts of the 7,576 megawatts of that capacity.

On any given day, the utility carries a “planning reserve margin” that runs 16.3 percent above its expected peak load.

And if that still isn’t enough, it has another 475 megawatts in power resources available to tap if necessary.

One thing the utility doesn’t control are the rooftop solar arrays that its customers own and use to generate power they might otherwise buy from Xcel. Stutz said even if all those customers start drawing more heavily on the grid, the utility has the capacity to serve them, just as it does when the sun fades each evening.

“At the end of the day, the eclipse should be similar to a classic, fast-moving Colorado storm, where sunlight and temperatures can change very quickly. The difference is we’ll know exactly when this will happen,” Stutz said.