* Rules slated to begin over next three years
* Rule to cut toxic emissions due by Dec. 16
* Coal burners want more time to comply with rules
WASHINGTON, Dec 1 (Reuters) - Clean air rules the U.S. government is slated to impose on power generators over the next three years will not impair the ability of the grid to deliver electricity to consumers, the Department of Energy said in a report on Thursday.
The U.S. Environmental Protection agency is slated to finalize a rule by Dec. 16 that would slash emissions of mercury and other toxic gases from coal-fired power plants, one of a slate of air pollution measures opposed by industry and Republicans in Congress.
"Our review, combined with several other studies, demonstrate that new EPA rules ... should not create resource adequacy issues," said David Sandalow, assistant secretary for international affairs at the Energy Department.
The mercury rule, known as maximum achievable control technology, or utility MACT, would mostly make power stations that burn coal to start cutting the emissions by 2015. Under the proposal companies could also ask for an extra year to begin complying.
The EPA says the clean air rules will save more money in overall U.S. healthcare bills than they will cost heavy industry, which will have to make investments in technologies to clean up smokestack emissions.
INDUSTRY DIVIDED OVER RULES
But the rules have created a division in the power sector. Companies that boast large nuclear power and natural gas capacity mostly support the rules, while companies that burn large amounts of coal have asked the EPA for more time to adapt to the rules.
Anthony Topazi, the chief operating officer Southern Co. said environmental controls would take up to six years to perfect at the company's coal-burning plants.
"We cannot simultaneously satisfy the requirements of the proposed (mercury) rule and provide reliable service to our customers from 2015 to 2017," said Topazi.
And the North American Electric Reliability Corp, which is responsible for keeping the power grid reliable, issued a report this week that said the mercury rule when combined with other EPA clean air rules could force some power plants to shut and threaten reliability in Texas and New England.
Other reports have said problems would be minimal and Gina McCarthy, an EPA assistant administrator for air, has said agency rules have not led to power reliability problems in the 40-year history of the Clean Air Act.
The DOE said that even in a stringent test case of the EPA rules, the overall ability of the power grid to deliver would be adequate. It said only a small amount of additional new generation capacity, some of which is already under development, would be needed to maintain regional planning targets for power.