Exxon CEO doubts Obama's alternative energy goal

WASHINGTON (Reuters) - Exxon Mobil CEO Rex Tillerson said on Thursday it would be difficult to meet President-elect Barack Obama's goal to significantly boost U.S. alternative energy production.

In a speech at George Mason University in Fairfax, Virginia, Obama said he wanted the United States to double its output of alternative energy sources during the next three years as part of his plan to revive the American economy.

"I think that's going to be very challenging to do," Tillerson told reporters following a speech at the Woodrow Wilson Center in Washington.

He said the United States will not be able to double biofuels output during that period and there was not enough manufacturing capacity to build the wind turbines needed to meet Obama's goal.

"I'm not wanting to be critical of his aspirational goal. Aspirational goals are good because they challenge us all to go out and find the right answer," Tillerson said of Obama's plan.

But he added: "Let's be realistic about timeframes. Let's not fool ourselves."

Despite calls for more alternative energy use, he said, "for the foreseeable future" the world will rely on oil and natural gas for 60 percent of its energy needs.

Renewable energy sources, which include solar, wind, hydroelectric, geothermal, biofuels and other biomass, accounted for 7 percent of U.S. energy supplies in 2007, according to the Energy Department.

Tillerson said the slowdown in the global economy would be temporary and then strong energy demand from emerging nations will return.

He also said that even with the weak economy, Exxon remained committed to investing in projects to meet future energy demand.

He said the company was sticking with its $125 billion capital spending budget planned for the next five years, despite the steep drop in oil prices and the global economic slowdown. Any changes to the capital spending budget will be announced in March at a meeting with analysts, he said.

Separately, Tillerson reiterated that it would be better for Congress to pass climate change legislation that levies a carbon tax to curb greenhouse gas emissions, instead of imposing a complicated cap-and-trade system that allows businesses to buy and sell pollution permits to spew emissions.

Tackling climate change is a top priority for the incoming Obama administration and the Democratic-majority Congress.

Tillerson said a carbon tax, which could be tacked on to fuel supplies and electricity consumption, was the most efficient way to reflect the cost of carbon.

By comparison, a cap-and-trade system is difficult to verify, requires new government regulators and "a Wall Street of emissions brokers," he said.

(Reporting by Tom Doggett; Editing by Walter Bagley)