WASHINGTON - Business leaders who huddled with Obama administration officials on Tuesday said an infusion of more than $1 billion in federal grants for renewable energy projects is driving a surge of private investment in wind and solar operations.

But they said sustaining the boom could depend on whether Congress will require utilities to derive a share of their power from renewable sources.

The meeting with Energy Secretary Steven Chu and Treasury Secretary Timothy Geithner came as the U.S. released $550 million in stimulus dollars for renewable energy projects in West Texas, Berkeley, Calif., and other regions. Earlier this month, the federal government began distributing $503 million to wind and solar facilities.

Gabriel Alonso, CEO of Houston-based Horizon Wind Energy, said the promise of federal stimulus funding jump-starting stalled renewable projects and made the U.S. a more attractive place to invest.

"Twelve months ago, we were looking at our business plan and really thinking where can we put the $1.2 billion we wanted to invest in 2009," Alonso said. "We had the opportunities to invest in Brazil. We had the opportunities to move it to Poland, Romania and Spain. But when the program came into place, we saw that the best way to invest all this money was in the U.S."

The direct grants, which were funded by the $787 billion economic stimulus package enacted in February, mark a change in the way the federal government is subsidizing wind and solar projects. The cash awards are meant to replace a production tax credit that developers had relied on for years to finance projects but which became a less potent investment incentive when credit lines began freezing last year.

The largest award - $121.9 million - went to the Pyron Wind Farm in Roscoe. Other Texas recipients include the Bull Creek Wind operation in O'Donnell, the Barton Chapel Wind Farm in Jacksboro, and Rio Grande Valley Sugar Growers in Santa Rosa.

Executives at Tuesday's meeting urged the Obama administration to prod Congress to approve a renewable energy standard that would ensure long-term demand for wind, solar, hydro and other alternative energy.

The House passed climate change legislation in June that would require renewable power for 15 percent of utilities' supplies by 2020. That is close to the mandate for 15 percent renewable power by 2021 embedded in the broad energy bill approved by a Senate committee this year.

Martha Wyrsch, president of the wind turbine manufacturer Vestas Americas, which is building a 100-employee research and development facility in Houston, said: "There is a lot of investment going on today that might not have happened had we not had the (grant) opportunities."

But she added: "We need a renewable energy standard to be implemented here in the United States."

Chu said the Obama administration aims to send a signal to international investors that the federal government is committed to supporting renewable energy.

"This is what it's all about: How do you get the private investment sector back in the game?" he said. "It's something that will take massive investment."

Chu said it was "very important to establish a long-term sustained effort in this, instead of up-and-down signals." Investors need to know "it's not going to disappear in a couple of years."

At the same time that subsidies for renewable energy projects are flowing, the White House is moving to curb government spending on fossil fuels.

At a United Nations summit Tuesday, President Barack Obama said he would promote a plan to "phase out fossil fuel subsidies" as part of an effort to combat climate change.

Administration officials have said that eliminating the subsidies could spur more conservation efforts - thereby driving down U.S. emissions of greenhouse gases produced when fossil fuels are burned.

On Capitol Hill, some Republicans have questioned the fiscal soundness of government investment in renewable wind and solar projects that they say are only viable when propped up by federal subsidies.