It's official: President Bush on Wednesday signed the long-debated energy bill into law.

The Energy Independence and Security Act sets a national fuel economy standard of 35 miles per gallon by 2020 -- a 40-percent increase, according to the White House -- and requires fuel producers to use at least 36 billion gallons of biofuel in 2022.

It also sets new energy-efficiency standards for appliances, requires federal buildings to use energy-efficient lighting and establishes an office to promote greener federal buildings.

The House of Representatives originally approved a more ambitious bill, which also included $21.5 billion in tax incentives for renewables and a mandate that utilities get 15 percent of their electricity from renewable sources (see House Passes Energy Bill, Will Greentech Get Anything from the Energy Bill? and Renewable Tax Credit and Portfolio Standard Could Get Cut From Energy Bill).

But that bill failed to win approval in the Senate, which passed an amended bill last week (see Senate Rejects Incentives to Pass Energy Bill and Senate Sends Energy Bill Back to Beginning). The House voted in favor of the amended bill Tuesday before sending it to President Bush.

While some greentech entrepreneurs were clearly disappointed with the outcome, others praised the new standards.

"This law is a very significant, concrete and long-overdue step forward," Union of Concerned Scientists President Kevin Knobloch said in a written statement. "No energy legislation has ever done more for America's security by saving oil and curbing global warming pollution. The fuel economy mandate will breathe new life into a faltering domestic auto industry."

The Biotechnology Industry Organization said the renewable-fuel standard could add up to an additional $170 billion for the U.S. economy in advanced technology development, biofuel production and infrastructure construction.

Even Chrysler commended the new law.

"Chrysler is committed to meeting the fuel-economy standards of the bill and doing our part to reduce greenhouse-gas emissions and our country's reliance on foreign oil," CEO Robert Nardelli said in a written statement.