WASHINGTON - The coal industry in Wyoming and elsewhere faces a bleak future unless ways are developed on a commercial scale to capture and store carbon dioxide in the campaign against global warming, according to a study released Wednesday.

A Wyoming mining official, however, said it would be a mistake to shun additional coal-fired electrical generation until technology is developed to sequester carbon dioxide.

The report by the Massachusetts Institute of Technology says coal, which accounts for half of the country's electricity production, will remain the fuel of choice to produce electricity in the United States because it is relatively cheap and abundant. But if carbon limits are imposed to address climate change, that could change unless the government and industry develop a program to capture and store the tens of millions of tons of carbon dioxide that now spew from coal-burning smokestacks into the atmosphere.

Carbon dioxide is the principal so-called "greenhouse" gas because as it concentrates in the atmosphere it creates a blanket-like effect that many scientists believe is warming the earth. While carbon dioxide is released in the burning of all fossil fuels, coal produces greater amounts of it because of the fuel's high carbon content.

Wyoming is the nation's largest coal-producing state, and the industry is a major piece of the state's economy.

"I recognize that the industry needs to support efforts to burn our coal more efficiently and to burn it cleaner, and we do support that effort," said Marion Loomis, executive director of the Wyoming Mining Association. However, "carbon sequestration is an unproven technology at the present time, and the nation is in need of more electricity now. It is going to take time to develop the technology to sequester the carbon and to identify the storage sites for disposal…

"The nation and the states should recognize that every coal plant is going to be cleaner than the last plant, but we can't sit on our hands until all of the carbon sequestration issues are resolved," Loomis added. "This nation needs additional power now, and that should be with the latest technology available now."

A central message of the MIT report is that carbon capture from coal burning is technically and economically possible, but that it has yet to be proven on the broad commercial scale that would be needed if limits on carbon emissions are imposed.

The Democratic-controlled Congress is considering a number of proposals that would impose a cap on greenhouse gas emissions, primarily carbon dioxide, along with various provisions aimed at reducing the economic cost.

"Coal will continue to be used to meet the world's energy needs in significant quantities," said the MIT report. With carbon capture programs more coal would likely be used in 2050 than is used today, but global carbon emissions would likely be only slightly more than today, the study said.

The MIT report said its doubtful that either China or India will impose carbon controls anytime soon, although both countries are rapidly expanding coal use in power and industrial plants.

Neither China nor India is likely to take such actions without the United States moving to curtail carbon emissions first, the study said. Eventually, carbon capture from coal burning will be crucial for both China and India if climate change is to be addressed.

And the United States will have to take the lead, the study concluded.

"If the coal industry wants to protect itself from a very bleak future … they have a great interest in seeing carbon dioxide sequestration practically demonstrated now," John Deutch, co-chairman of the MIT panel that wrote the coal report, said in an interview.

Deutch, a former CIA director under President Clinton and senior official in both the Defense and Energy departments, said the government is not moving fast enough to develop demonstration projects capable of capturing and depositing in deep geological formations as much as a million tons of carbon a year.

The report said three or four such demonstrations projects should be developed as soon as possible.

Loomis said carbon sequestration at that magnitude poses huge challenges.

"When we talk about storing carbon in underground formations, we are not talking about a million tons or 100 million tons - we are talking about billions of tons," he said. "To store anything that constitutes billions of tons is a daunting task even if we had the technology."

President Bush has said carbon capture and sequestration is a top energy priority. The government hopes to have an experimental coal burning power plant called FutureGen built by 2012 capable of capturing and storing underground a million tons of carbon a year.

But the MIT report said more is needed and that the Energy Department's budget for clean coal programs "falls far short of what is required" to ensure coal remains a primary fuel in a carbon-constrained world. The administration last month asked Congress for nearly $600 million for coal technology research for the next fiscal year, including $79 million for carbon sequestration and $108 million for the next installment in FutureGen.

The report also urged that government tax breaks, loan guarantees and other assistance be directed only at new coal plants that include carbon capture and sequestration and to programs aimed at retrofitting other plants.

Loomis said the industry supports development of such technology, but additional coal-fired plants that don't capture carbon are needed to meet the nation's growing power demand.

"It is critical that everyone understands that the demand for affordable, reliable power continues to grow," he said. "It would be tragic if we stop building plants that provide affordable and reliable power now and find ourselves with brownouts or worse."