The grid upgrade can cost millions for a DC fast charging station.
The inverter to make the DC power can cost 100,000.
Why not skip all this and have a diesel engine coupled to a 400V DC generator, thereby skipping the inverter and grid upgrade?
I think this would be cheaper, and lower capex and operational costs. Not to mention, most streets have natural gas lines which could power the diesel engines with a cheap and clean burning fuel. Natural Gas is very cheap around 4c/kwh. A 20% efficient generator, would yield 16c/kwh.
Generally air emissions would prevent this in most developed areas. Unless you also install emissions reduction technologies, but now you’re talking more money and a full operation.
Noticed your note about natural gas, and it’s not as widely available as you’d expect. Plus I’m pretty sure the costs there have been surging as well. At least in California.