Republicans will take their first shot at derailing a top Democratic priority — climate change legislation — by offering as many as 200 amendments when the House Energy and Commerce Committee begins marking up its bill this afternoon.

The markup, which could stretch over several days, probably provides House Republicans with their best opportunity for offering changes to a bill that will likely see limited amendments on the floor.

“Our folks are united against cap-and-trade,— Energy and Commerce member Fred Upton (R-Mich.) said of the carbon control policy being pushed by Democrats.

Last week, Democrats agreed among themselves on a plan setting national standards for renewable energy and electricity use. Moreover, the plan would limit carbon emissions through a cap-and-trade system that would auction off or give away credits for emitting greenhouse gases like carbon dioxide.

Ranking member Joe Barton (R-Texas) will offer an alternative plan that would still set carbon emission standards for new coal and natural gas plants but grandfather in all existing plants. Current plants would receive accelerated depreciation on technology that they install to improve their efficiency.

Barton — a longtime ally of the oil industry and skeptic of the scientific basis of global warming — believes the Democratic bill does not provide companies enough time to develop technologies that could limit carbon emissions. He said the plans for limiting carbon should be held off on until at least 2015.

Barton and Upton said they will oppose any bill that calls for cap-and-trade, saying they believe such a system would send energy prices soaring. Upton said he doubts there are 60 votes in the Senate needed to advance a bill with cap-and-trade provisions.

But another group of Republicans wrote a letter to Speaker Nancy Pelosi (D-Calif.) and Minority Leader John Boehner (R-Ohio) calling for a more conciliatory approach and outlining provisions that must be in the bill to win their support. The group includes Energy and Commerce member Mary Bono Mack (Calif.) and Reps. Vernon Ehlers (Mich.), Mark Kirk (Ill.), MikeCastle (Del.), John McHugh (N.Y.) and Ileana Ros-Lehtinen (Fla.).

The current legislation “fails to reflect the current economic challenges which all Americans face and fails to include major opportunities for achieving energy independence,— the GOP lawmakers wrote. They want the final bill to call for the safe use of coal and nuclear energy, require compliance by other industrial nations and keep energy costs in check.

Despite the coming onslaught of GOP amendments, Energy and Commerce Chairman Henry Waxman (D-Calif.) said he expects the committee to pass the bill before lawmakers leave at the end of the week for the Memorial Day recess.

The agreement among committee Democrats — worked out after two weeks of arduous negotiations — addressed concerns raised by some Members from coal- and oil-producing states by giving carbon emitters more pollution credits and phasing in the new standards at a slower rate.

The lead negotiator for the moderate Democrats, Rep. Rick Boucher (Va.), who hails from a coal-rich part of Virginia, said he would vote for the bill in committee this week and is urging his colleagues to follow suit.

But Boucher has “remaining concerns— that he intends to address as the legislation moves to the floor. Pelosi said she wants the bill passed before lawmakers leave for August recess.

Already, Waxman has given in on some concerns raised by moderate Democrats about rising energy prices by agreeing to offer free pollution credits to some utility companies. Waxman said he made the concession “primarily to protect the rate payer.—

This afternoon’s session of the markup is unlikely to get beyond opening statements from the 59-member panel.