A 1915 paper presented to the American Society of Mechanical Engineers comparing the cost and practicality of generating electric power in a private mill plant against buying it from a central station, applied to textile mills. It uses cost curves for plant size, load factor and fixed charges, and examines the use of exhaust steam for heating, slashing and dyeing, with a worsted mill dye house case study and a cotton mill heating table. It also covers water power, reliability, and census figures on purchased power in the textile industries. The paper is followed by a discussion by other engineers and a reply from the author.