Seen on reddit and other sources:
https://old.reddit.com/r/fresno/comments/1hxqlx7/the_more_i_try_to_save_energy_the_higher_the/
Its already 50c or more per kilowatt hour… https://www.pge.com/assets/pge/docs/account/rate-plans/residential-electric-rate-plan-pricing.pdf
On top of the “The Electric Home Rate Plan includes a $15-per-month Base Services Charge”… because people were starting to get 100% of their power from solar and it was “unfair”.
That example breaks down with electricity sources with a fuel cost. But it makes more sense as the grid moves to more energy sources without fuel.
But also, if energy supply is higher than demand on a large grid, they can decrease investments into new solar plants so they fall below the replacement rate from facilities aging out. In your example there’s only one solar farm, but in reality there’s many being built on a grid at any time.
I’d say their example is just an oversimplification to keep it understandable. Ultimately fuel based energy has a lot of the same concerns. That natural gas facility costs money to keep viable even if, hypothetically, zero fuel were being burned in some given week. The power lines need repairs, maintenance, upgrades, and expansion over the potential capacity, not actual usage. You have fixed costs alongside the marginal costs. The marginal costs certainly make sense to map directly to usage based rate, but fixed costs are significantly covered by those usage rates as well rather than bumping up the “basic charge” sort of line item on a power bill.