Delmarva Power and Light Company is a regulated energy company that provides electricity and natural gas services to customers in the Delmarva Peninsula. These 1926 images document the construction of gas towers and substations at the Christiana and Brandywine power plants in the Wilmington, Delaware.

Leroy Nelson Houck (1895-1980) was an electrician with the Pennsylvania Water & Power Company. He spent a large portion of his career working in the Load Dispatcher's Office. Pennsylvania Water & Power Company was established to store, transport, and generate water power for both commercial and manufacturing purposes. The Holtwood facility outside of Lancaster, Pennsylvania, was the first power plant to have both a hydroelectric generator and a coal power generator. This small collection consists of pamphlets, photographs, and booklets related to the Pennsylvania Water & Power Co. documenting Houck's experiences as an employee there. There are manuals, booklets, and brochures about Holtwood and the Safe Harbor Dam.

The Pennsylvania Water & Power Company formed in 1910 to finish construction of the Holtwood hydroelectric facility along the lower Susquehanna River in Pennsylvania. The company achieved numerous advancements in hydroelectric and steam power development in the early twentieth century, and helped bring about the electrification of Baltimore and, later, much of the Chesapeake and eastern Pennsylvania area. The records largely consist of correspondence to and from Pennsylvania Water & Power's chief engineer and later president, John Abbet Walls, and other company heads relating to operations, customers, dam construction, and numerous subjects associated with the hydroelectric industry.