A swirling mix of bi-partisan optimism over increased use of renewable fuel sources and reservations on how the government could afford loan guarantees for such incentives have unfolded in recent weeks in the Senate.

An amendment approved during the first few days of debate in early June created a federal mandate that would double the nation’s use of renewable fuels from 4 billion gallons in 2006 to 8 billion gallons in 2012.

Such an increase in the Renewable Fuels Standard would be a 60 percent increase over the previous level passed by Congress.

A less aggressive version of the amendment passed several weeks ago in the House of Representatives calls for 5 billion gallons.

The amendment was co-sponsored by Sen. Chuck Hegel, R-Neb., who called the measure “commonsense legislation.”

Like several other farm-state congressmen, Hegel views alternative fuels as an answer to wean the country off imported petroleum and a boon to corn, soybean and grain sorghum.

So, too, does President Bush, who, in a speech delivered recently at a energy efficiency forum, said, “I like the idea of spending money on research to make ethanol more feasible, so that someday an American president says, ‘Show me the crop report’ as opposed to, ‘How many barrels of crude oil are we importing?’”

Bob Stallman, president of the American Farm Bureau Federation, called passing a comprehensive energy bill with an 8-billion-gallon renewable fuels amendment one of AFBF’s “highest legislative priorities.”

“An 8-billion-gallon renewable fuels standard would provide substantial market growth opportunities for traditional ethanol, cellulosic ethanol technology and biodiesel, while creating new markets for America’s farmers,” Stallman said. “It would also decrease our dependence on foreign sources for oil, providing greater energy independence and economic growth.”

Initially, there proved to be challenges for senators to find common ground in passing the 778-page bill.

Also early on in the process, officials from the White House Office of Management and Budget expressed financial concerns about other incentives in the proposed bill.

OMB reported that proposed subsidies for nuclear powerplants and other alternative fuel sources in the bill could exceed the president’s 10-year, $6.7 billion cap on energy incentives.

OMB added that Bush would oppose any amendment that would force energy utilities to generate 10 percent of their power from solar, wind and other renewable sources by 2020.

Other energy issues, such as provisions for exploration of gas and oil deposits along the nation’s gulf coasts, and climate change amendments have been viewed as environmental roadblocks for the bill’s ultimate approval — which the president wants finalized and on his desk by August.

Arguably, one topic loomed above all to threaten the bill’s passage: Many senators strongly oppose a provision in the House bill that gives liability protection to producers of methyl tertiary-butyl ether (MTBE), a fuel additive that has contaminated water supplies in communities nationwide.

However, some reports have surfaced that senators have agreed to put aside the issue altogether.

At mid-June, Senate Majority Leader Bill Frist, R-Tenn., indicated that the bill was likely to pass, as did Senate Minority Leader Harry Reid, D-Nev., who said, “We’ve worked through some complicated issues… I think it would be good for the country that they see we are now legislating.”

e-mail: abell@primediabusiness.com