Steam — Steam power first appeared in the late 1700s and was commonly used for driving mills in the 1800s.  By the late 1800s, steam engines were the popular source for power.  Despite its strength in supplying power, steam was largely inefficient. 

Electric — Electric powered machines first appeared in the U.S. around 1900.  Power was conveniently transmitted from remote generators to motors directly attached to mills.

Electric power remains the choice for operations today.