WASHINGTON, Nov 17 (Reuters) - The top U.S. environmental regulator will propose early next year twice-delayed rules on greenhouse gas emissions from power plants, she told the energyNOW television show. "I can't tell you what the regulations say right now, but what we are planning to do is release them early next calendar year," Lisa Jackson, the Environmental Protection Agency administrator, told the program in a segment seen by Reuters that is to be broadcast over the weekend. The EPA in June delayed the proposed rules on power plants, which are the largest source of U.S. greenhouse gas emissions, saying it needed more time after talking with businesses, states and green groups. It delayed them again in September. Republicans in the House of Representatives have waged a war on EPA clean-air regulations, saying such rules will kill jobs and add costs to businesses suffering in a battered economy. In September, President Barack Obama directed the EPA to delay a major rule on smog-forming pollutants until 2013, forcing Jackson to embrace a George W. Bush-era smog rule she previously described as legally indefensible. The move led some environmentalists and health groups to worry the administration would subject other clean-air rules to long delays. But earlier this month, the EPA sent the planned rules on carbon emissions from new power plants to the White House's Office of Management and Budget for review, a process that can take about 90 days. The rules could force big coal-burning utilities, including Southern Co and American Electric Power , to use more natural gas, which is lower in carbon emissions, or to invest more in wind and solar power. Jackson has said the agency's coming slate of clean-air rules can add jobs in technology to deal with smokestack emissions. Lobbyists for utilities, however, say there is no affordable technology yet that can be bolted on to power plants to cut greenhouse gases. A process to bury carbon dioxide emissions underground, known as carbon capture and sequestration or CCS, has been suggested as a way to help utilities cut emissions in coming years. But Jackson, whose agency looked at CCS as it developed the rules, said the technology has a long way to go. "It can be years, maybe a decade or more, until we have the technology available at commercial scale," she said. Cheaper options exist to cut emissions, she said. "It would be shortsighted, or you would have to have blinders on, not to look at the fact that there are other game-changers out there like our nation's supply of natural gas that are going to be important as people look at where they want to make investment decisions," she said. Lobbyists for the power industry say energy markets, not the EPA, should push utilities toward natural gas, adding that the chemical industry is also eyeing new natural gas supplies, which could eventually push up prices for the fuel.