On a 57-40 vote, supporters of the bill failed by three votes to cut off debate on the legislation. They needed 60 votes under the Senate's rules to close debate on the bill, which supporters said would increase and diversify energy production and provide farmers an economic boost by expanding use of corn-based ethanol.
The House passed the legislation earlier this week.
"This will not be the last vote on this bill," said Majority Leader Bill Frist, R-Tenn. "We're going to keep voting until we pass it and get it to the president."
A growing number of Democrats, along with several Republicans, had argued that the bill – crafted largely in closed-door Republican negotiations with the House – was too expensive and amounted to a collection of subsidies to special interests.
Six Republicans joined Democrats in opposing the bill.
Frist, who was obligated to change his vote and cast it with the majority so the measure can be brought up again, vowed not to abandon the legislation. But he could not say when it would be back for another try.
Democratic leader Tom Daschle of South Dakota, who voted for ending debate, called the defeat "unfortunate." He said Senate energy negotiators "were undercut by manipulation by the House Republican leadership" that pressed for measures in the bill that many senators could not accept.
Approval of an energy bill has been a top priority for President Bush, who repeatedly called on Congress to finish the legislation this year.
As opponents to the bill appeared to gain strength, Vice President Dick Cheney began calling GOP senators urging them not to abandon the president on the issue. Energy Secretary Spencer Abraham, a former senator from Michigan, was dispatched to Capitol Hill in the hours before the voting.
But Sen. John McCain, R-Ariz., one of the six GOP senators strongly opposed to the legislation, said the bill has "glaring examples of industry favors." He called it a "Thanksgiving turkey" stuffed with goodies for special interests.
Another Republican. Sen. Judd Gregg of New Hampshire, objected to the bill's price tag — an estimated $31 billion over 10 years — arguing that the measure exceeds the congressional budget ceiling.
Sen. Charles Schumer, D-N.Y., said there were some good things in the bill, but he strongly opposed provisions to mandate use of corn-based ethanol in gasoline nationwide and the bill's handling of MTBE, a gasoline additive contaminating water supplies.
Many Democrats, with five Republicans from New England, vowed to block the bill because it would shield makers of MTBE from product liability lawsuits and give the companies $2 billion over eight years to help them shift away from making the additive as it is phased out.
A provision to double the use of ethanol in gasoline, an economic boon to the Farm Belt states, drew opposition from senators on the East and West coasts.
"This mandate (to use ethanol) is essentially a hidden gas tax," argued Sen. Dianne Feinstein, D-Calif., who said she feared imposing the additive is increasing pump prices in California and causing more smog. About 70 percent of California's gas contains ethanol as the state eliminates MTBE because of water contamination concerns.
But the ethanol issue also is viewed as critical if the bill passes the Senate, bringing in broad support among Democrats and Republicans from farm states.
"This could mean at least a billion dollars in additional income for farmers and for our rural economy," said Daschle.
Others were bothered by the cost.
Sen. John Kyl, R-Ariz., said he found it curious that the Senate approved $15 billion in tax breaks, the House gave $17 billion, but the compromise worked out in the final bill would provide $23.6 billion. "Guess who lost — the taxpayer," he said.
The bill contains hundreds of items sought by energy lobbyists, including tax breaks for oil, gas, coal and nuclear industries, plus tax credits for renewable energy and conservation.
Among its major provisions: