Steven Chu told a Senate committee late Wednesday that some estimates put the price of FutureGen as high as $2.3b.

He said a cost of more than $2b is ``becoming a very deep issue with me because we need a portfolio of projects’’ that can demonstrate CCS including ones that FutureGen would not address. He noted there is only so much money available to the Energy Department (DOE) to help do this.

`` I'm looking at how do you bring down the cost so we can go ahead,’’ Chu said, adding that CCS technology to be utilized by FutureGen ``certainly is worth testing.’’

DOE would fund 74% of the project, which was proposed in 2003, and the balance by a non-profit consortium of private coal producers and electric power companies.

Coal-fired power plants provide about one-half of the supply of electricity used in the United States, and DOE estimates that coal accounts for approximately one-third of the total CO2 emissions in the US.

The prior Bush administration pulled out on FutureGen after investing $174m, citing cost escalation. However, Government Accountability Office, the nonpartisan research arm of Congress, this week said that decision was based on a cost overestimate.

The GAO report said that the Energy Department last year did not conduct a proper analysis and made a $500m math error when it decided to cancel the experimental plant slated near Mattoon, Illinois. The report did not estimate how much FutureGen currently might cost.

According to the report, one estimate was based on so-called "constant dollars," which reflect the buying power of dollars in 2005. The other estimate was inflation-adjusted, with dollars worth less each year because of inflation.

As a result, GAO auditors concluded the cost of FutureGen was put at $1.8 billion, up from $950 million when it should have been $1.3 billion.

Illinois' congressional delegation has urged the Obama administration to revive it, arguing it would boost economic development in the coal-rich, east-central part of that state. Mattoon was selected for the project after it beat out two proposed sites in Texas.

FutureGen’s CCS technology would comprise several components: separation of CO2 from other gases emitted by the plant; capturing it; compressing it into a fluid state to facilitate its transportation; transporting it to a storage location; injecting it into geologic formations for storage, and monitoring the storage site to verify that it remains in place.