WASHINGTON -- Moving to heal divisions in a fractious Democratic caucus, House Speaker Nancy Pelosi is solidifying support for legislation that would put her party's stamp on U.S. energy policy.

The California Democrat agreed in recent days to soften proposals of concern to energy-state Democrats, who feared the original package went too far in weakening existing incentives for oil and gas exploration. At the same time, Ms. Pelosi, moving to avoid a confrontation with House Energy and Commerce Committee Chairman John Dingell, the Michigan Democrat and auto-industry champion, is deferring action on the issue of raising vehicle-fuel-economy standards.

The speaker still risks some defections among conservative Democrats who have lodged complaints over a $16 billion tax package that takes away tax benefits from the oil and gas industry. She was working yesterday to address their concerns. The combined efforts were part of a strategy designed to minimize divisions among Democrats ahead of the August recess, and they reflected a calculation that party leaders will be able to piece together a stronger package when companion House and Senate bills are melded into compromise legislation this fall.

The House and Senate bills share the goal of improving energy efficiency while weaning the nation off of its dependence on fossil fuels. With gasoline prices high and voter concerns growing about the nation's energy security, especially about the country's reliance on oil produced in the Middle East, the energy bill has become a defining issue for Democrats.

The Senate bill, which drew bipartisan support in June, is more aggressive in addressing those concerns. The measure would expand the availability of cleaner-burning biofuels, such as corn-based ethanol, more than tripling the amount of those products in the nation's fuel supply. The Senate bill would also raise fuel-economy standards for cars and light trucks to 35 miles per gallon by 2020, a more than 30% increase above current law.

As the House readies to take up its version of the bill, perhaps as soon as today, Ms. Pelosi is focused on ensuring the measure includes one priority left out of the Senate package: a mandate that coal-burning electric utilities use greater amounts of renewable energy, such as solar and wind power. The mandate is strongly opposed by the United Mine Workers of America and the major electricity producers.

Tom Kuhn, head of the Edison Electric Institute Association, a group of shareholder-owned electric companies, contends the proposal would lead to higher bills for consumers and cause compliance difficulties for some utilities, especially in the Southeast, where wind and solar power aren't in wide use. "There's a better way to do this," said Mr. Kuhn, who favors letting the states set such standards.

An amendment requiring utilities to produce 15% of their electricity from renewable energy sources appears to be gaining momentum. With fuel-economy standards off the table for now, the utility mandate may be the best opportunity House members have this week to vote green.

"Inaction is no longer an option," said Democratic Rep. Diana DeGette of Colorado.

Rep. Rahm Emanuel of Illinois, the fourth-ranking House Democrat, suggested the House and Senate measures could easily be combined after House approval of a renewable-energy mandate. "Everybody's bringing significant change to the table," said Mr. Emanuel, looking ahead to negotiations. "This is coming together."