CoalSwarm began in 2007 as an informal effort by journalists and activists to document over 150 proposed coal plants in the United States. In order to provide a collaborative platform for its research, the group established the CoalSwarm portal on SourceWatch, a wiki developed by the Center for Media and Democracy. In 2008 CoalSwarm expanded its research to include international coal topics. In 2013, CoalSwarm began publishing CoalWire, a weekly global news digest. In 2014, CoalSwarm released the Global Coal Plant Tracker.