Many ship types experience a wide variation in propulsion power demand during normal operating conditions. These variable load demands are coupled with small percentages of operating time when full propulsion power is required. Therefore an integrated electric plant providing both ship service and propulsion power can be very effective in reducing operating costs. Variable operating profiles in conjunction with stable ship service load demands commonly occur in such diverse ship types as oceanographic research vessels, cruise ships, icebreakers, product oil tankers, automobile ferries, and combatant ships with multiple warfare roles.