LOS ANGELES — Southern California is gambling its future power needs on its constant sunshine, wind and the ability of engineers to effectively harness those and other alternative energy sources.

Officials in Anaheim, Burbank, Glendale, Pasadena and Riverside notified the South Jordan-based Intermountain Power Agency this week that they would not be renewing their contracts for cheap, coal-fired power.

Those contracts expire in 2027. That leaves the cities two decades to secure the alternative energy sources they'll need — from wind farms to desert solar power.

"It's a huge change," said Mayor Todd Campbell of Burbank. The Los Angeles Department of Water and Power had already given notice to the Utah-based power agency.

The five California cities collectively purchase 75 percent of the electricity currently generated by IPA.

Reed Searle, general manager of Intermountain Power Agency Inc., said the decision by the California cities to not renew their contracts does not cause any significant concern.

"There certainly is enough sunshine and wind," Searle said. "The problem is land mass. To replace our coal facilities, for example, with solar it would take up more acres than the state of Utah has available. It can make a substantial impact, but you can't replace coal."

Searle went on to say that the decision puts more pressure on IPA to find new ways to reduce carbon emissions.

"We believe that technology will come along," Searle said. "The technology is probably there. It's a matter of cost."

The power agency is starting expansion to its plant near Delta, adding a 950-megawatt third generating unit, expected to be completed in 2012. Rocky Mountain Power, based in Salt Lake City, will be entitled to 37 percent of the third unit's power. Utah Associated Municipal Power Systems is claiming 51 percent and the Southern Nevada Water Authority is taking 11 percent.

The third unit will come equipped with a new device to remove most of the nitrogen oxide emissions.

"That device had never even been conceived of by the scientists when we built our last plant," Searle said. "Our new unit is likely to be one of the first to have that on it."

The moves by California could put the region in the forefront nationally of the commercial use of alternative energy in coming years, but researching and building the infrastructure to replace coal-fired power will be a costly, risky business.

"All of these technologies are still in their infancy," said Phyllis Currie, general manager of Pasadena Water & Power. "We're still looking at the fact that right now, the Intermountain plant is 65 percent of our energy."