By a wide margin, the U.S. Congress approved the first increase in automobile fuel economy in 32 years on Tuesday, and President George W. Bush has signalled he will accept the mandates on the auto industry.

The energy bill, boosting mileage by 40 per cent to 35 miles per gallon _ about 6.7 litres per 100 kilometres _ passed the House of Representatives 314-100 and now goes to the White House following the Senate's approval last week.

In a dramatic shift to spur increased demand for non-fossil fuels, the bill also requires a six-fold increase in ethanol use to 36 billion gallons (136 billion litres) a year by 2022, a boon to farmers. And it requires new energy efficiency standards for an array of appliances, lighting and commercial and government buildings.

``This is a choice between yesterday and tomorrow'' on energy policy, declared Democratic House Speaker Nancy Pelosi of California, who was closely involved in crafting the legislation. ``It's groundbreaking in what it will do.''

While some Republican legislators criticized the bill for failing to address the need for more domestic oil and natural gas production, 95 Republican members joined Democrats in support of the bill.

``This legislation is a historic turning point in energy policy,'' said Majority Leader Steny Hoyer of Maryland, because it will cut demand for foreign oil and promote non-fossil fuels that will cut greenhouse gases linked to global warming.

It increases energy efficiency ``from light bulbs to light trucks,'' said Democratic Representative John Dingell of Michigan, a longtime protector of the auto industry who was key to a compromise on vehicle efficiency increases.

Many Republicans denounced the Democratic-crafted bill for failing to push for more domestic production of fossil fuels and for mandates some Republican legislators warned will not be possible.

Democrats disagreed. The legislation takes measured and concrete steps that are achievable, said Dingell.

The Senate passed the bill last week after discarding billions of dollars in higher taxes on oil companies and a solar and wind power mandate that opponents said would raise electric rates in the U.S. Southeast. President George W. Bush and Senate Republicans opposed those measures.

The centrepiece of the bill remained the requirement for automakers to increase their industrywide vehicle fuel efficiency by 40 per cent to an industry average of 35 mpg by 2020, compared with today's 25 mpg (9.4 litres per 100 kilometres) when including passenger cars as well as SUVs and small trucks.

Congress has not changed the auto mileage requirement since it was first enacted in 1975.

Democrats said the fuel economy requirements eventually _ when the fleet of gas-miser vehicles are widely on the road _ will save motorists US$700 to $1,000 a year in fuel costs. They maintain the overall bill, including more ethanol use and various efficiency requirements and incentives, will reduce U.S. oil demand by four million barrels a day by 2030, more than twice the daily imports from the volatile Persian Gulf.

The automakers have repeatedly fought an increase in the federal fuel standard, known as CAFE, maintaining it would limit the range of vehicles consumers will have available in showrooms and threaten auto industry jobs.

Bush has also argued against an arbitrary, numerical increase in the fuel efficiency requirement, preferring instead legislation to streamline the federal requirements and market incentives to get rid of gas guzzling vehicles.

But the automakers have accepted the political shift toward a tougher requirement. After the Senate approved the legislation last week, the White House immediately said Bush would sign it once it reaches his desk.

The bill requires a massive increase in the production of ethanol for motor fuels, outlining a rampup of ethanol use from the roughly 22.7 billion litres this year to 136 billion litres by 2022.

After 2015, the emphasis would be on expanded use of cellulosic ethanol, made from such feedstock as switchgrass and wood chips, with two thirds of the ethanol from such non-corn sources.

However, commercially viable production of cellulosic ethanol has yet to be proven and some Republicans have argued that the new requirements could be impossible to meet and may raise corn prices and food supplies.

The bill requires improved efficiency standards for lighting, commercial and government buildings, and appliances such as refrigerators, dishwashers and freezers. It also tells the Energy Department to issue efficiency standards more quickly.

Democrats failed to get through a broad tax package that they had designed to pay for incentives aimed at spurring the development of wind, solar and alternative fuels such as cellulosic ethanol, as well as energy efficiency and conservation programs.