Bitcoin is the most widely distributed network in the world, running on several different distributions of software that are based on multiple implementations of the core process, which runs on many different configurations of hardware, powered by every source of power humans have access to, in probably every country on earth. Using bitcoin for transactional or wealth preservation purposes requires minimal electricity that could be provided by anything from a portable solar panel to a hand crank generator.
We, as humans, will be living in caves and eating eachother before the bitcoin network fails.