I think the report of SNL energy is incorrect.
The EIA’s numbers, citing the most recent data indicate that coal remains the biggest...
http://www.eia.gov/totalenergy/data/monthly/pdf/sec7_5.pdf
That won’t stop AP from printing propaganda.
You are looking at the previous report. The data out for April 2015 shows:
457,305 Thousand Megawatthours = coal
92,516 Thousand Megawatthours = natural gas
http://eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_1_01
Sorry, grabbed the wrong field make that:
88,835 coal
92,516 nat gas