The world’s largest coal company and one of the nation’s top fossil-fueled power companies are among the leading donors so far this year to Newt Gingrich’s political advocacy group, which has been fighting climate legislation on Capitol Hill with a “Stop the Energy Tax” phone-in campaign to Senate offices.

Peabody Energy, the St. Louis-based coal giant, gave $250,000 to American Solutions for Winning the Future in February, putting it atop the Gingrich-led group’s big contributors for the first half of 2009, according to the nonprofit’s newly filed report at the Internal Revenue Service. Peabody also gave American Solutions the same amount in 2008. The firm’s chief executive, Greg Boyce, has publicly expressed doubts about global warming, so it is not entirely surprising that Peabody would support an issues advocacy group that is going all-out against the climate bill.

More surprising, perhaps, is the $100,000 donation in May from American Electric Power, of Columbus, Ohio. Though the company is either the largest or second-largest source of carbon dioxide emissions in the U.S. power industry, AEP has voiced support for the climate bill passed by the House. Although the company would like further changes in the bill on greenhouse gas targets and timetables, company spokesman Pat Hemlepp confirms AEP supports climate legislation, and says the company is not in step with Gingrich on the issue.

“AEP gives funds to a variety of organizations that have views on issues that for the most part align with our company’s views on the issues,” said Hemlepp. “That doesn’t mean that all the organizations’ views align with ours.”

In particular, he said AEP strongly agrees with American Solutions’ advocacy on development of more domestic energy resources. “Some of their positions on climate we don’t necessarily agree with, but they are also involved in health care and economic issues and since some of their positions align with ours we thought it was a good place to put some money,” Hemlepp said.

AEP Chief Executive Mike Morris himself had been a leader in the utility industry in talking about the greenhouse gas problem as a member of the Pew Center’s Business Environmental Leadership Council. AEP was a founding member of the first U.S. voluntary greenhouse gas emissions reductions system, the Chicago Climate Exchange (CCX); and it exceeded the targets it set under that program to reduce its carbon emissions, mostly through energy efficiency measures.

AEP had not joined the business-environmental coalition most active in lobbying for the legislation, the U.S. Climate Action Partnership, although the company released a statement earlier this year saying it was “in basic accord with most of the principles of USCAP today.”

Gingrich, on the other hand, has been a vocal opponent of what he calls the “cap-and-trade energy tax,” railing against it in frequent appearances on Fox News and recently at a news conference at the National Press Club. American Solutions also ran TV ads against the climate bill the week that it closely passed the House.

In addition, American Solutions has boasted on its web site that phone calls to House member offices ran “as much as 19-to-1” against the bill, and has urged its supporters to call offices at the Senate, slated to take up the bill in September.

Numerous conservative groups and TV commentators have joined in urging phone calls to Capitol Hill. Joe Romm, a former Clinton administration energy official who writes the Climate Progress blog for the Center for American Progress, reports that Senate offices are receiving hundreds of calls daily against the climate bill.

Altogether, American Solutions took in $8.1 million in contributions in the first half of 2009, about 45 percent, or $3.7 million, from donations of less than $200 (meaning the donors’ names did not have to be reported under IRS rules). But three of the six largest donations came from companies that would be directly affected by climate legislation.

Vince Haley, vice president for research and policy at American Solutions, says the contributions from the fossil fuel industry haven’t dictated the agenda for the organization, but “it has certainly attracted people who agree” with the group.

“We’re happy to take money from any organization that agrees with our positions,” he said. “And what you see is a dynamic where the more vocal we are, and more effective we are, the more support we get.”

Haley says with the Senate vote coming up, “I’m sure American Solutions will be quite engaged in working to stop the energy tax.”

As a 527 nonprofit issues advocacy group that does not campaign for or against candidates, American Solutions is not subject to federal campaign finance law or its prohibitions on accepting donations directly from corporations. But it is required to regularly report contributions and expenditures to the IRS. American Solutions — which gained notoriety for its “Drill Here, Drill Now” campaign last year, was the third largest 527 group in the 2008 election cycle, taking it $22.7 million, according to the Center for Responsive Politics. Although the group calls itself nonpartisan and even “tri-partisan,” many of large donors last year were big GOP contributors, as the Center for Public Integrity detailed in a special report.

Gingrich himself had said one of the reasons that he chose not to embark on a presidential run in 2008 was to devote time to American Solutions; but he has raised his profile this year, and in interviews has left the door open to a future run for high office.

David Donald and Tuan Le contributed to this post.