That’s one takeaway from a new ranking of power plants released by Environment America. The list comes ahead of next week’s expected carbon pollution limits on new plants, to be proposed by the U.S. Environmental Protection Agency.

There are over 6,000 power plants in the United States, but a majority of the carbon pollution comes from only a handful of the plants. According to Environment America, “about 30 percent of all power-sector carbon dioxide emissions in 2011 came from the 50 dirtiest power plants; about half came from the 100 dirtiest plants; and about 90 percent came from the 500 dirtiest plants.”

Other findings include:

  • Texas, Ohio and Florida lead the nation for most carbon pollution from power plants.
  • The top five most polluting power plants are Georgia Power Co’s Plant Scherer, Alabama Power Co’s James H Miller Jr. Plant, Luminant’s Martin Lake in Texas, Ameren’s Labadie in Missouri, and NRG Energy’s W A Parish in Texas.
  • America’s power plants are its single largest source of carbon pollution - responsible for 40 percent of emissions nationwide.

Power plants are the largest source of global warming pollution in the United States, responsible for 41 percent of the nation’s production of carbon dioxide pollution, the leading greenhouse gas driving global warming.

The Obama Administration has set a timeline for proposing limits on carbon carbon pollution for existing power plants by June 2014, with rules being finalized by the following June.