- safety margins (keep, to not harm the customer)

- employee benefits (keep, to not harm the employee, e.g. retirement)

- profit margins for stockholders (you could probably get rid of this)

In the days before electricity deregulation, power companies had rates regulated to achieve a fixed return on investment. This tended to result in overbuilding. Not huge overbuilding, but about 10% - 20%. The quest for "efficiency" wiped out some of that safety margin.