I live in the bay area atmospheric river and I still get a ton of juice out of my solar panels. I definitely have down seasons and the local laws with respect to off-grid power are frustrating, but I don't regret it.

You might say, "You have not recouped the cost." This is difficult to measure; my home has power during power outages. We have them regularly around here. What is the price on having uninterrupted power in your home when no one else can deliver it? Surely quite high, by comparison, no?

I have always had very reliable electricity just from the grid. The value of additional reliability would be almost neglible for me.

Well, I'm glad things have gone your way.

Sorry I missed "We have them regularly around here." I kinda thought you were protecting against something that rarely happened for peace of mind.

How about lat 57? http://aberdeensolar.com/

I'm doing nicely out of my panels at 56N, but that's mostly subsidy. It's also extremely seasonal.

Why 42° specifically? Is it related to the current cost and efficiency?

Its a thumb rule of sort!

https://globalsolaratlas.info/

The red area in the map is the most productive part for Solar and Orange is partially good.

Solar is very geographically dependent, also high altitude is good, that is why Tibet/Colorado is in dark red. Precipitation is a problem for Solar, that is why Florida is OK but not great place for it.

Germany would disagree

The energy prices they pay would agree.

https://www.statista.com/statistics/418078/electricity-price...

https://www.statista.com/statistics/418087/electricity-price...