The Senate isn’t likely to differ significantly from the House in the way it allocates pollution allowances as part of global warming legislation, according to a key chairman

“I doubt it’ll be major. There’ll be some,” Senate Finance Chairman Max Baucus , D-Mont., said Tuesday, when asked about changes to the allocation formula.

Majority Leader Harry Reid , D-Nev., has given Senate committees a Sept. 28 deadline to complete their sections of the climate change legislation. “We’ll mark up our bill probably sometime mid, end of September,” Baucus said.

Four other committees also have a piece of the complex legislation.

The House bill, which passed in June, would impose a cap on emissions of greenhouse gases and set up a market-based program for businesses to buy and sell emission allowances. Heavy polluters could buy extra allowances; those with few emissions could sell their excess permits.

One of the most contentious issues was how to distribute the emission allowances initially.

President Obama originally favored selling the allowances at an auction and distributing the revenue to the public. The House bill, however, would distribute most of the allowances for free, to be divided among energy consumers, states and various industries.

At a hearing Tuesday before the Finance Committee, several witnesses criticized the House bill. Dallas Burtrow, a senior fellow at Resources for the Future, said there is “great uncertainty” on electricity customers will be compensated for the higher costs associated with a carbon cap. Under the bill, local utilities would receive free allowances and be required to pass their value on to consumers.

But the bill leaves the details up to state regulators, Burtrow said. “State public utility commissions will play the determining role in how households are affected, not Congress, and this will be done in 50 different ways.”

Nathaniel Keohane, director of economic and policy analysis at the Environmental Defense Fund, urged the Senate to ensure that rebates from electric companies go directly to consumers in some form. “It doesn’t have to be a utility bill, it could be a check,” he said.