The tussle pits power companies against American Indians, fishermen and environmentalists who want dams removed because they have blocked endangered salmon from migrating, threatened Indian livelihoods and devastated commercial fishing off the Oregon and California coasts.

One river, the Klamath, runs 250 miles from southwest Oregon to the California coast, connecting two states where power and water supply have long been controversial issues. Both California Gov. Arnold Schwarzenegger and Gov. Theodore R. Kulongoski of Oregon are pushing clean-fuel sources. Last year, California passed a law requiring a 25 percent reduction in carbon dioxide emissions by 2020. Oregon is also promoting renewable energy use.

Removing the four Klamath dams should be an option, they say, but neither has taken a firm position. Earlier this year, Schwarzenegger proposed spending about $4 billion to build two dams on the San Joaquin River for water storage, an idea environmentalists have opposed.

PacifiCorp, which operates the Klamath dams, had its federal license expire last year, and the government has said it must build fish ladders over the four dams to get a new one, which could cost $300 million and reduce the power the dams generate, potentially making removal a less costly choice.

The company has said whatever is spent to restore salmon, and whether the solution is fish ladders or dam removal, its customers will bear the cost, and the carbon