SALEM, Ore. -- After a vigorous debate, the Oregon Senators passed a bill Tuesday that would require the state's largest utilities to eventually draw 25 percent of their power from renewable sources such as wind, waves, sunlight and manure.

A centerpiece of Gov. Ted Kulongoski's effort to reduce global warming, supporters argued the bill also would help insulate Oregonians from volatile fossil fuel prices.

The measure passed despite opposition from Republicans who said it might result in higher costs for consumers by forcing new technologies into the market before they are cost competitive.

"This bill is one of the strongest actions this body can take to do our share to curb global warming and protect and our increasingly fragile planet," said Sen. Ben Westlund, D-Bend. "It helps brand us as the environmentally clean state that we are ... this has huge implications not only for today but for our future."

The bill would require Oregon's major utilities to obtain 5 percent of their power from renewable resources by 2011, increasing by increments to 25 percent by 2025.

But most Senate Republicans said the bill unfairly moves the cost and risk of developing new renewable energy sources from private businesses to residential and industrial electricity consumers.

"This is a huge shift of a burden to two groups of people that we need desperately," said Sen. Larry George of Sherwood. "One is our businesses, and two are the most vulnerable citizens who can't afford to pay higher rates."

The bill allows utilities to recover the cost of investing in new generating sources, such as wind farms, through increases to customers but includes a provision that could release them from the mandate if their costs increase by more than 4 percent of their revenue in one year.

Sen. Ted Ferrioli, R-John Day, said the bill was "part of somebody's political agenda, and it has got a lot of energy behind it, a lot of heat behind it, and a lot of political power behind it. But it isn't good public policy."

Ferrioli and other Republicans said they supported a renewable energy standard for the state but argued a renewable mandate should include electricity generated from hydroelectric dams. Although the legislation allows electricity generated from new "low-impact" dams to count toward the standard, existing hydroelectric generation is not included under the bill.

Oregon gets about 40 percent of its electricity from hydroelectric dams, according to the state's Department of Energy.

Supporters said the measure would kick-start new technologies and techniques and help make Oregon a leader in the rapidly emerging clean energy, low-carbon economy, as it continues to race with other states for swiftly flowing investment capital.

"There are unique situations when the government does create a market, knowing that the market will outpace government," said Sen. Jason Atkinson, R-Grants Pass, one of two Republicans to support the bill. The other was Sen. Bruce Starr, R-Hillsboro.

"Quite honestly this bill will not be able to keep pace with the investments and the technologies that come in after this bill is passed," Atkinson said.

Atkinson said the bill was critical to keeping Oregon competitive for investment capital, particularly as markets for clean energy technologies in neighboring Washington accelerate.

"There is a giant sucking sound of investment capital leaving this state and going north," Atkinson said.