Well, no electricity, and no internet connection would kill BTC for sure! You wouldn't be able to make any transactions without these.
Other issue can be all the countries in the world ban BTC, but this will not restrict it's circulation, as no internet connection do!
I also agree with you, bitcoin will die if electricity and internet network around the world also die. besides that there is also another problem that is the state forbids bitcoin, but this way will not kill bitcoin, it will only affect the price of bitcoin to be down.
bitcoin is not that easy to die because if the electricity and internet network are dead then man will fix the problem quickly.