Re: Hydrogen? Seriously?
"There no longer really seems to be the need for hydrogen any more for transport. Battery electric works in nearly all standard use cases and already has a national supply to every home (almost), road, street."
Not anywhere close.
The range is abysmal when the temperature drops below -10.
As a result, any significant trip requires multiple recharges, whereas the typical petroleum powered vehicle can manage 800 to 1000 km. on a tank, and refuels in five minutes, not the approximate hour required to fully charge a battery.
That means many many more vehicles will require charging on the road.
How many? A lane of vehicles traveling 120 kph will see each vehicle going 120,000 m/h. In heavy (weekend, rush hour, holiday) traffic, if each vehicle occupies, with buffer, an average of 60m, that's 2,000 vehicles/h/lane.
If service centres are 100 km apart, and a premium vehicle with a large battery can go 160 km between charges, then it must charge every 100 km. Shorter ranged vehicles will also have to charge that often, if their range is good enough to count on reaching the next recharging plaza.
Speed of recharging depends, in part, on the percent of full charge. The last ~25% must be charged at a lower rate to prevent battery damage. Thus a premium vehicle might reach 70% in 30 minutes, while a smaller battery may take 60 minutes to charge.
For an approximate number, let's take 45 minutes. Thus each vehicle must, on the average, charge for 45 minutes every 100 km (50 minutes of driving time). Charging cannot begin until there is a free charging station, so it is likely to take longer.
Two lanes in each direction would produce 4,000 cars going each way in an hour. A charging plaza serving one side of the highway would thus need approximately 3,000 high speed charge points. Charge points seem to range between 75 and 150+ kw. Let's call it 125 kw/point. The charging facility will need a little more than 125x3000 = 375,000 kw = 375 Mw to service traffic in one direction.
Remembering that traffic is two ways, one needs approximately 1 charging plaza for every 50 km of road... at least 8 for a road between two cities 500 km apart. Each plaza needs about 3/8 the output of a large nuclear reactor... so that length of road will need 3 nuclear reactors to power charging.
Note that 8 plazas assumes the traffic terminates in the two cities. Through traffic will have to recharge at the second city, requiring the equivalent of another charging facility if 50% of the traffic is not terminating or originating in one of the cities.
Delivering approximately 3,000 MW along 500 km of road will require a fair bit of transmission infrastructure as well.
The numbers of cars and their separation is hand-waved. The last time I was on a major intercity highway on a normal non-holiday Sunday we were doing 140, and the average separation was something less than 60 metres, in both directions. It would not be unlikely that the above numbers are 35% low for the numbers of cars, so you might actually need 4 reactors to drive recharging, or you may have to scale up your reactors.
I have also not taken into account that fact that for 100 km or more in each direction near a big city, it is likely the roads will be 6 or 8 lanes, not 4. That would be difficult because charging needs will depend on the distance from point of origin or termination to the nominal starting point... not easy to estimate.