Xcel Energy has stopped burning coal at its Bay Front power plant, ending more than a century of coal use at the Ashland site.

The utility announced Thursday that the last shovel of coal was burned Dec. 1 and going forward will use natural gas as a backup fuel for the 56-megawatt plant, whose generators can be powered by any of three boilers. 

Built in 1916 by Ashland Light & Power and the Street Railway Company, the plant was converted in 1979 and has since burned more than 6 million tons of biomass. According to Xcel it was the first in the nation to burn waste wood.