The Maryland governor said in a statement that after "careful deliberation" he decided to sign the bill, which will allow waste-to-energy plants that burn and convert garbage to energy, to sell renewable-energy credits just as solar and wind plants do.
The state currently gets 5.5 percent of its energy from renewable sources, and officials hope to boost that number to 20 percent by 2022. Mr. O'Malley said he intends to achieve the goal "through as much in-state energy generation as possible.
"This will require a diverse fuel mix including onshore and offshore wind, solar, biomass including poultry litter, and now waste-to-energy if we are to realize our 20 percent goal," he said.
While supporters have called such plants a more environmentally friendly alternative to dumping trash in landfills, opponents have argued they release pollutants, remove the incentive for recycling programs and would compete directly with cleaner renewable sources.
A slew of health and environmental groups have blasted the bill, including the Chesapeake Bay Foundation, American Lung Association and state Sierra Club chapter.
Mr. O'Malley pointed out that Maryland was not alone in making such a decision.
"Over half of the states that have a renewable energy goal classify municipal solid waste as a renewable fuel," he said. "European countries that are many decades ahead of the United States in reducing their carbon footprint and their reliance on fossil fuels make broad use of modern waste to energy facilities and employ comprehensive recycling efforts in order to land fill as little waste as possible."
The governor, whose proposal this session to establish offshore wind plants failed to get enough votes in the Democratic-controlled assembly, has championed renewable energy as a way to help the environment and attract new businesses. He said in his statement that he remains committed to the goal.
"With this decision, I also reaffirm my commitment to bringing offshore wind to Maryland," he said. "It is only through a diverse, renewable fuel mix that we will be able to reach our aggressive goals, protect our precious environment, and create the economic engine to move Maryland forward."