Is there any way to start the quiz from same question, and with same amount of remaining time.In case of any power failures or for any other reason, session breaks. Student should be able to resume the assessment where it was left. In any version of moodle.
How do you plan to tell if the student really lost power or simply turned their computer off and said that they had a power failure?
Do you know of any system that can tell if a student lost power on their end? I guess you could ask the student to submit proof from their power company that they lost power. Also, you might have to verify that they also lost cell phone power because some student could be taking the quiz from their phone.
If it were me, I would just give the student one more attempt, if I really believed that they really lost power. This is easy to do in Moodle.