just think of the following.
if you are producing airbags for cars your company will go bankrupt quite quick if 5 out of 100 do not open when needed. you would need a much smaller rate of faults (or find a source of money to pay the compensation). on the other hand, if you produce something cheap and will not need to compensate unsatisfied customers and it is cheaper to produce more faults than why not?
same as with the power. you need to multiply the cost of each fault in $$$ by the probabilities and ask the economist in the team what can the company tolerate. just be careful he doesn't multiply everything by his personal bonus instead of company profit to determine policy. that was and perhaps is the common practice in mortgage banking. hahahah
hope i was clear.
ron