How can the Bitcoin system realistically survive without electricity?
Good old pencil and paper + carrier pigeons.
This is not realistic:
https://bitcointalk.org/index.php?topic=801196.0Now, let me turn that question around: How can you survive without electricity? If the world loses electricity, you wouldn't be worried about bitcoin, you'd be worried about survival.
Of course not, electricity is a fundamental part of my life. But you were the one that suggested that electricity is not needed for Bitcoin to work.