Washington (Platts)--9Oct2009/557 am EDT/957 GMT

Existing technologies, at relatively low cost, could effectively reduce most mercury emissions from coal-fired generation, the Government Accountability Office said Thursday in a report to the US Senate Environment and Public Works Committee.

Sorbent injection systems can be used to reduce between 80% and 90% of mercury emissions, the GAO found in tests that the Department of Energy conducted at 14 coal-fired plants. Similar reductions can be made across the country, as most coal-fired power plants used the tested coal and boiler configurations, said John Stephenson, GAO's Director of Natural Resources and Environment.

The GAO report found that the average cost to buy and install boilers that use sorbent injection systems alone is about $3.6 million, while the costs of operating such technologies, mostly from the use sorbent, range from $76,500 to $2.4 million.

By comparison, the average cost to buy and install a wet scrubber to control sulfur dioxide is $86.4 million for each boiler, the report said.

In one state, for example, installing sorbent injection systems in two plants cost about $4.4 million and $4.5 million, respectively, and with a rate increase of 6 to 10 cents/month for customers of the plants, Stephenson said.

The Environmental Protection Agency is working to establish maximum achievable control technology standards for hazardous air pollutants and plans to set a MACT floor according to an average of the best-performing 12% of selected units. In a July 2 Federal Register notice, the agency proposed having have coal-fired power plants submit data over six months to update its current data from 1999.

If EPA bases its MACT standard on more current data, which does not take into account reductions that have taken place in recent years, the average emissions reductions of the best-performing coal-fired plants will be greater, said Stephenson, resulting "a more stringent mercury emission standard than was last proposed in 2004."

"More significant mercury emissions reductions are actually being achieved by the current best performers than was the case in 1999 when such information was last collected and similar results can likely be achieved by most plants across the country at relatively low cost," Stephenson said.

On the basis of EPA's 1999 data, GAO estimated that about a fourth of the industry achieved mercury reductions of 90% or more with the aid of other pollution control devices.

--Mu Li, mu_li@platts.com