* Romney plan would maintain mandate, but details scant
* Mandate signed into law by George W. Bush
* Obama has been supportive of ethanol
WASHINGTON, Aug 23 (Reuters) - Republican presidential candidate Mitt Romney released an energy plan on Thursday that supports Washington's ethanol quota, a mandate several U.S. governors want to suspend as the worst drought in over 50 years sends corn prices to record levels.
Governors from North Carolina, Arkansas, Georgia and New Mexico, where large numbers of livestock are reared, have petitioned the Obama administration to waive the mandate which they say raises prices for corn, an important animal feed.
The grain is also the main stock for making U.S. ethanol.
The five-year old Renewable Fuels Standard, or RFS, signed into law by then-President George W. Bush, requires more than 13 billion gallons of grain-based ethanol to be blended into gasoline this year and more in coming years.
Romney's energy plan would "support increased market penetration and competition among energy sources by maintaining the RFS and eliminating regulatory barriers" to diversify the power grid, the fuel system and vehicle fleets. The plan did not detail how Romney, a former Massachusetts governor, would support the ethanol mandate.
President Barack Obama, a Democrat, has also been a strong supporter of ethanol, which provides jobs in Iowa and other swing states that will be central in the Nov. 6 presidential election.
The ethanol industry applauded Romney's plan. "By working to remove barriers to market access for renewable fuels, as Governor Romney suggests, America can help spur an economic recovery while securing our energy future," said Bob Dineen, the CEO of the Renewable Fuels Association.
The Environmental Protection Agency is considering the waiver requests from the governors but is not likely to rule on it before the November election.
In 2008 the agency rejected a similar waiver requested by Texas Governor Rick Perry. In the rejection, the EPA said future petitions would have to show that the mandate was responsible for severe economic harm and did not simply contribute to it.