Reliable backup power is critical to nuclear power plants (NPPs). Many original nuclear power plant site designs did not sufficiently plan for changing requirements or modifications. There is a critical need to update outdated facilities and improve reliability of the backup power system. An IET publication printed a story written by a Caterpillar subject matter expert. The article discusses the various levels of emergency power sources at NPPs, their functions, technical requirements, and safety classifications that affect the design and implementation of emergency backup power installations. Cat® modular power solutions can shorten project duration, reduce investment cost, and project risk.