The additional insurance is needed for the larger tier 2 systems just in case your solar PV system malfunctions, causes damage to our equipment and/or hurts one of our linemen.
That's the answer, the rest is distraction. This says a few things:
1. 10-20MW systems can cause $700k ($1m - typical $300k HO coverage) more damage to utility equipment than a 9.9MW system can
2. The damage that a 20MW system can cause is an equal risk to the utility as the damage that a 100MW system can cause
3. NEC 2017 and UL 1741 compliant inverters are expected to fail hot and cause damage or lineman exposure rather than failing cold, rather than shutting down, for some reason they continue to produce
4. Given PTO, we, the utility, confirm that we can handle this load, but your 20MWs really scare us and we need you to pinky-swear that you, the homeowner, will protect us
5. As a utility, we seek extra protection from you covering the possibility that your system energizes a circuit a lineman is working on, but none of our linemen are trained to check for current initially and often, and our linemen never work with active circuits
6. We're happy to let a little bit of our revenue go, up to 10MW worth, but you people who want no power bill are really the problem we're solving here
We'll be stuck with this rule for a while, but I may as well let PSC know how I feel.
Any other thoughts I can add?
What do you think about requiring $500k HO liability for 10-25MW?