There's also the values of geographic distribution: * on site transmission cost is $0 for power used * the effect of a man-made or natural disaster in one loc

There's also the values of geographic distribution: * on site transmission cost is $0 for power used * the effect of a man-made or natural disaster in one location is contained: throwing a breaker for maintenance at the Arizona border doesn't shutdown power across an entire region: https://en.wikipedia.org/wiki/2011_Southwest_blackout https://en.wikipedia.org/wiki/2011_Southwest_blackout.