What if the ship loses electricity?

If the main electrical power source is lost, we have plans for a contingency and we move to using the emergency generators.  These are typically located on the upper decks and they have their own fuel supply and are completely independent. The generators can provide emergency lighting, fire detection systems, operate elevators and even provide power to re-start the engines, if necessary.  They can also power communication channels - radio, telefax, email, so the ship can continue to communicate with shoreside.