In Wyoming, nearly 90 percent of electricity comes from coal. In North Dakota, 80 percent, and in Colorado, 60 percent. Even before the Obama Administration's Clean Power Plan is implemented, these power plants must make retrofits to comply with current law that requires scrubbing emissions of dangerous air pollutants like mercury. Most of the nation's coal-fired power plants are racing to comply.
How does that retrofit happen? Reid Frazier of the Allegheny Front takes us to the Homer City Generating Station in Pennsylvania to see.