Did you read any of it? From your own link cost per mile for battery electric bus is $1.61 and $2.52 for fuel cell electric bus.

Which is definitely not a six-fold difference.

If you include current credits, the gap widens to $0.53 to $2.20.

AKA we are subsidizing BEBs way more.

Miles between Chargeable Road Calls (miles between breakdowns) 59,549 for the BEB and 6,299 for the FCEB.

You’re cherrypicking one particular period. The final numbers, reported later in the study is 7,015 for the FCEB and 6,465 for the BEB.

That’s all consistent with what other jurisdiction find when they compare the two, with some variability due to local fuel and electricity costs.

Wrong. Even if you go by the study in question, you’ll find that fuel cost per mile was nearly equal, with both the FBEB and BEB having a cost per mile of ~$1 going by MPDGE of 8.6 and 17.2 respectively. This is listed in the data in Appendix A-6. The final numbers are misleading because the BEB got more subsidies.

This ignores two additional problems. Namely, the BEBs did far fewer miles, requiring more buses to do the same number of routes. And the other is that you need to deal with battery replacements costs, which is far more than fuel cell replacement costs. This means that BEBs will be more expensive overall, as explained here: https://h2fcp.org/sites/default/files/07-24-2020-Foothill-ZEB-Update-to-Board.pdf

If you have “excess” generation, you ramp down or shut off sources, depending on technology. Use that time for maintenance, or simply let it sit idle as it’s less wear on the equipment.

That is only true of fossil fuel based systems. It is completely not possible with renewable energy. Honestly, I’m not sure how you came to this conclusion, because it is totally backwards. You must be able to convert curtailed energy production into something, or else it gets lost. Hence why hydrogen can be cheaper than available electricity.