WASHINGTON (AP) - The House tackled a broad energy bill Wednesday that would open an Arctic wildlife refuge to oil drilling and provide tens of billions of dollars in tax breaks for energy industries.

The Bush administration touted the legislation as key to meeting the country's future energy demands and called it a balance between needed energy development and energy conservation.

Democrats said it was too heavily tilted toward helping energy companies, with more than $33.5 billion in tax benefits over the next decade. They said $8 of every $10 would go to coal, oil, nuclear and other energy industries.

The revenue drain could force Congress to dip into Medicare or Social Security trust funds, Democrats charged, although the bill's GOP supporters disagreed.

Debate on the 510-page bill, the first broad overhaul of federal energy policy in a decade, was expected to extend into the late evening with hotly contested showdowns over drilling in Alaska's Arctic National Wildlife Refuge and a proposal to boost fuel economy requirements for popular sport utility vehicles.

"This bill is a giant step forward in securing America's energy future," declared Rep. Billy Tauzin, R-La., chairman of one of eight House committees that had a hand in crafting the legislation.

The House action, coming only days before Congress is scheduled to begin its summer recess, marked the first legislative response to President Bush's energy blueprint unveiled in May and to the growing concern in Congress about the nation's energy future - concerns elevated by the widely fluctuating gasoline prices and the electricity shortages that have plagued California and much of the West this year.

The bill was broadly endorsed by the White House.

It is "focused on increased conservation, promoting technology, expanding the use of renewables and increasing efficiency, increasing energy exploration and promoting a clean environment," said White House press secretary Ari Fleischer.

But critics charged that the bill, despite its numerous provisions, contains little that is expected to provide immediate relief or result in significant energy savings.

"This moves America backward," insisted Minority Leader Dick Gephardt, D-Mo., "It provides little short-term relief for consumers hit by high prices" and is "tilted to the energy lobby." He argued that 80 percent of the tax breaks "go to oil, gas, coal, nuclear and other big energy special interests."

Among the bill's major provisions were:

- About $27 billion in tax breaks over 10 years for energy development including incentives for coal, gas and oil and nuclear energy development.

- Nearly $6 billion in conservation incentives including tax breaks for buying solar panels, fuel-efficient hybrid gas-electric cars, and energy efficient appliances and homes.

- Increasing federal research into clean coal technologies.

- A boost in federal spending to help low-income families pay heating and cooling bills, and make energy efficiency improvements.

- A requirement that automakers make modest reductions in SUV fuel use.

Democrats charged that the tax incentives - substantially broader than what Bush had proposed in his energy plan - would dig into the budget surplus and lead to a raid of the Medicare and Social Security trust funds.

The White House acknowledged that the tax incentives would reduce the budget surplus by at least $30 billion and cautioned lawmakers the administration would oppose anything that might jeopardize income tax relief.

"What we're talking about is a budgetary train wreck," declared Rep. Charles Rangel, D-N.Y.

"They're about to build their oil rigs on top of the Medicare and Social Security trust funds," added Rep. Edward Markey, D-Mass., during floor debate.

On of the most contentious issues involved fuel economy of sport utility vehicles, which are now subject to less stringent requirements than automobiles.

Markey and Rep. Sherwood Boehlert, R-N.Y., planned to propose requiring that SUVs and minivans, which account for nearly half of the vehicles sold, be subject to a fleet average of 27.5 miles per gallon, the same as cars, by 2007.

The debate over the Arctic refuge unleashed intense lobbying in the weeks leading up to Wednesday's vote.

An unusual alliance of House GOP leaders and several labor unions - led by the Teamsters - put pressure on wavering Republican moderates and on undecided Democrats to support drilling, which they claims would result in thousands of jobs.