WASHINGTON (Reuters) - A controversial climate change bill sought by President Barack Obama advanced in the US House of Representatives on Friday, clearing the way for possible approval of a measure to control global warming. The bill cleared a procedural hurdle in a narrow vote of 217-205 when the House approved the rule for debating the Democratic-backed proposal. Democratic leaders were optimistic the bill could be approved by the House as early as Friday. House Speaker Nancy Pelosi, asked by a reporter whether she still lacked the votes for passage, replied: Quite to the contrary. The procedural vote was mostly along partisan lines but was evidence Democratic leaders had made progress toward passing the legislation. At the core of the 1,200-page bill is a cap and trade plan designed to reduce emissions of carbon dioxide and other greenhouse gases by 17 percent by 2020 and 83 percent by 2050, from 2005 levels. Earlier Friday, Pelosi, welcoming German Chancellor Angela Merkel to the Capitol, said she was hopeful the climate change bill would pass and praised German leadership on combating global warming. Today hopefully well have a celebration of American leadership taking its rightful place with German leadership on this important issue, Pelosi said. Obama adviser Valerie Jarrett told CNBC on Friday the president was on the phone trying to help win passage. Obama also met at the White House on Thursday with some undecided Democrats. Its a job creator. Its going to help save millions of dollars, billions of dollars, for our economy and we dont know right now if we have the votes, so were going to work up until the last moment, Jarrett said. With House Republicans mostly opposed and warning it would hit recession-weary consumers in their pocketbooks with higher prices for energy and other everyday goods, supporters were attempting to counter those arguments. Pelosi, Obama and others cited environmental benefits, job creation and even national security as the legislation attempts to move the country away from its dependence on foreign oil in favour of developing domestically produced alternative fuels such as wind and solar energy and possibly clean coal. The American Council for an Energy-Efficient Economy said, Savings from reduced energy use will be reinvested locally, creating a multiplier effect that will generate economic activity and jobs. Under the bill, big polluters, such as coal-fired utilities, oil refiners, steel, paper, cement and glass manufacturers and other companies would receive government permits to emit lower amounts of carbon dioxide each year. Companies that end up with more permits than they need could sell them to companies that had not managed to adequately reduce their harmful emissions. Even if Obama and his fellow Democrats manage to pull off a victory this week, the legislation faces a difficult road in the Senate, where Republicans would have an easier time using procedural hurdles to block the bill. But passage by the House this year would let Obama attend a December international conference on climate change with a major victory in hand. That conference aims to lay out a global approach to dealing with climate change over the next few decades. In her quest to find enough votes for the bill, Pelosi has allowed several changes since it was approved in late May by the Energy and Commerce Committee. Those have included new protections for agricultural interests, resulting in House Agriculture Committee Chairman Collin Peterson announcing his support a move that could also win the support of about two dozen lawmakers from farm states. Supporters of the bill received other breaks this week, including the release of a Congressional Budget Office analysis concluding the bills impact on average households would be around $170 a year in higher costs far below the $3,100 or more Republicans have been warning. Some will not be moved, however. Representative Artur Davis, a Democrat who is considering running for governor of Alabama, told Reuters he would vote against the measure. The bill has been improved, but this is the wrong time, he said, noting the hard economic times and the lack of commitment from heavy-polluting countries like China and India to significantly reduce their emissions.