Mr Barack Obama president of US a longtime believer in clean coal is launching an ambitious and expensive plan to help the energy industry lock climate changing gases from coal-fired power plants deep underground.

Mr Obema said in February at a meeting with Republican and Democratic governors, including those from coal mining states that if we can develop the technology to capture the carbon pollution released by coal, it can create jobs and provide energy well into the future. The idea, which has been around for years, is a key part of Obama's plan for building a diverse mix of power sources including more nuclear energy, oil and natural gas drilling and renewable energy while also putting the country on a path to an 80% reduction in emissions of heat-trapping gases by 2050.

On the face of it, making the nation's abundant supply of coal less polluting is alluring. Keeping coal in the energy equation preserves jobs and a way of life. However, some scientists, clean energy advocates and electricity producers are questioning Mr Obama's approach. Instead, some argue, the world should phase out coal use natural gas more efficiently and put more emphasis on renewable energy.

Critics of the administration's coal strategy said that it will be too expensive to retrofit existing plants with new technology, capture the carbon dioxide, compress it and pipe it to underground storage. More coal also would be needed to run the capture equipment. What's more, the process wouldn't reduce coals other pollution problems: smog, mercury and the toxic metals such as lead and selenium in coal ash. Continuing to rely on coal also would do nothing to end the environmental damage of mining the coal itself.

Mr Bruce Nilles the club's national coal campaign director said that coal should be phased out by 2030. As for the government's goal of getting carbon capture and storage ready for wide use by then: We're highly skeptical.

The environmental group favors an expansion of renewable energy and efficiency, including efficient uses of natural gas. Mr Nilles pointed to Cornell University's new combined heat and power plant, which is fueled by natural gas. The plant generates the majority of Cornell's electricity, and the waste heat is used for campus heating. The new plant replaces a coal fired one.

Mr James Hansen the NASA climate scientist who warned about global warming 2 decades ago said that coal should be phased out worldwide by 2030.

Mr Steven Chu energy secretary, a scientist and Nobel Prize laureate, has said that he's looked at the science of carbon capture and storage and concluded that the technology challenges are large, but could be cracked with enough effort.

Mr Chu said that wind and solar power can provide no more than 20% to 30% of US energy until better electricity storage technology is invented, something the Department of Energy is also pursuing.

Mr Heather Zichal the White House deputy assistant for energy and climate change said that Mr Obama wants to diversify the energy mix in a way that allows the country to meet its emissions reductions and energy independence goals. It also sees jobs potential. He said that "To the extent we can corner the market on developing new technology; it's an opportunity for us to create jobs in exporting this technology.

Mr Pat Hemlepp spokesman said that AEP can see that carbon constraints are coming. It's working on a system to add to existing coal plants. We have very big and low cost generating plants in the East that are still a long way from retirement.

The industry funded Electric Power Research Institute and a lobby group, the Coal Utilization Research Council, recently updated its cost estimate on the needs for new coal technology and raised the government's share from USD 10.5 billion by 2025 to USD 20 billion by 2033. The CURC said that industry's share would be higher and would be partly in the form of tax incentives.

Mr Revis James directed a study for the institute on how to reduce greenhouse gas emissions at the lowest cost. Mr James, who has a nuclear engineering and power plant background said that the study concluded that a mix of energy that included carbon capture and storage and new nuclear energy would be cheaper than doing without either and increasing natural gas use instead.

The study assumed that carbon capture and storage would be widely available and added to 20% of existing coal plants and all new ones. Plants without it eventually would have to be shut. The study also estimated that 6.5% of emissions reductions would come from gains in energy efficiency.