American television audiences are likely noticing a battle being waged during commercial breaks as millions of dollars are being spent on advertising to promote or denigrate a mysterious-sounding buzzword: clean coal technology.

On his 120-acre farm in Minnesota, Richard Peterson harvests crops of corn, soybeans and, since 2005, wind. His turbine is just one of 67, all housed on adjoining farmland, that make up a wind farm capable of generating 100 megawatts…