U.S. Congress begins drive for climate change bill

*U.S. House panel kicks off debate on climate change bill

*EPA says bill could bring 9 percent energy cost increase

*Democrats, Republicans disagree on jobs impact

By Richard Cowan

WASHINGTON, April 21 (Reuters) - The U.S. Congress on Tuesday began work on a bill that would fundamentally change the way American factories and power plants use and supply energy as part of the Obama administration's drive to cut harmful greenhouse gas emissions.

"The time for delay, denial and inaction has come to an end," declared Democratic Representative Edward Markey in opening the House Energy and Commerce Committee's effort to produce a climate bill by the end of May.

President Barack Obama and his fellow Democrats who control both houses of Congress have made combating climate change a priority, worrying Republicans and some other opponents who fear skyrocketing energy and compliance costs.

Over the next five weeks the committee will debate and fine-tune a Democratic draft bill that would drastically reduce the amount of carbon dioxide and other industrial emissions that scientists say contribute to climate problems.

At the bill's core is a "cap and trade" plan to reduce carbon emissions -- lowering them by 20 percent by 2020, 42 percent by 2030 and 83 percent by 2050, with 2005 as a base year.