How about severe penalties for breaching your SLAs? Can't deliver power? Give customers $X per minute of downtime.
Now let's see you assess your risk when it comes to installing heaters and insulation.
Now let's see you assess your risk when it comes to installing heaters and insulation.
Then when one of these rare events happens, and now thousands of people are owed tons of money, either insurance pays out, or the government bails out the power company, or the power company goes bankrupt (or is forced to make cuts in other areas). In none of these outcomes has the SLA achieved its goal of ensuring that consumers have more-reliable access to power. Some of them may be richer for their suffering, but some of them are also dead.