generator

Most cities use a combination of backup generators and elevated storage to account for potential emergencies.

Tesla created a multi-phase AC generator system that first proved it could work at the Ames Hydroelectric Power Plant in Colorado.

Inside here in the bit you can't access, there's a microwave generator called a magnetron.

And if the entire British national power grid fails, which has never happened, but if it does, the barrier has three separate diesel generators, any one of which could operate the entire thing.