The Colorado Public Utilities Commission made the right move by launching an inquiry into why 300,000 Front Range residents lost power for as long as four hours on a frigid morning last month. A key question is whether the region’s electrical system is too fragile.
On Feb. 18, Xcel Energy triggered unprecedented wintertime rolling blackouts. “It’s an incredible hassle when you have negative temperatures to not only not have power but not be able to operate your furnace,” PUC chairman Greg Sopkin noted during Wednesday’s hearing.
Since Xcel’s explanations suggest the trouble went beyond its sown ystem, parallel inquiries by the PUC and a regional oversight body, the Western Electricity Coordinating Council (WEEC), are appropriate and necessary.
Modern electrical grids are both broadly based and interdependent, so a problem in one state can cascade across entire regions. In August 2003, trouble in an Ohio power system caused electrical failures as far away as Canada and New York.
On Feb. 18, the WEEC warned that Xcel was in danger of triggering a similar mess, so Xcel cut power to thousands of Colorado customers. Xcel insists that decision prevented outages elsewhere across the western United States.
A regional electrical system is like a big tub of water, with many spigots (power plants) continuously replenishing the supply and numerous drains (public utilities) always drawing on it. Ideally, the level in the tub (the electrical supply) remains roughly the same. The spigots can be turned up only so much, though, so if one utility starts draining more than its share, the supply drops for everyone in the system. Instead of blackouts affecting just one utility, the problems spread.
On Feb. 18, Colorado’s cold spell doubled the normal demand on the region’s natural gas supplies, for both home heating and electrical generation. (Xcel gets about half of its electricity from natural gas-fired plants.) What very little additional natural gas could be purchased in the region couldn’t be moved quickly because pipeline pressures had dropped.
Meanwhile, the cold caused mechanical woes in 18 generating units at a dozen power plants. Xcel owns five of those units, but independent power producers run 13.
When Xcel tried to get juice from other sources, it risked draining the regional system.
The independent power suppliers clearly are part of the puzzle, but the PUC lacks authority over them. So the WEEC is right to be asking questions, too.
