I agree the energy usage are the same for SuperSwappers and SuperChargers. But you can't support 2 million cars via either 100 SuperChargers or 100 SuperSwappers. The scale is way-way off.
2 million cars charging 15 times per year == 30 million charges. Let's say 40% is during the week, and 60% during weekend (Elon thinks it's much more that that in the weekend), but let's just say 30% during Friday and 30% during Sunday.
That means on Sunday there will be 30% of 30million / 52 weeks / 100 locations == 1730 swaps/charges per location on Sundays. Let's ignore where you're going to get 70 MWh of power from for a second and just look at car throughput:
The largest layout I've heard of is 10 chargers at 1 location. That means over a 12 hour period, every car can park/connect/charge/disconnect/leave only for a 4 minute cycle. That's not enough. You need 5 times that capacity just for absolute minimum usage. Even that further assumes a perfectly even distribution of all cars over the 100 locations, with perfectly spaced arrival times.
Similarly, with a swapper, it would need to do it's thing in 24 seconds - which includes car arrival and departure time, payment time etc. And again, assumes perfectly even distribution, with perfectly evenly spaced arrival times.
100 locations for either Supercharging or SuperSwapping is off by 2 orders of magnitude.
Next, why would Tesla charge $4b dollars for access to a network, but then only spend $30m to build a vastly undersized network?
Next-to-last, Tesla committed to 200 locations already, so why are we even talking about 100?
Lastly, Elon told us already he wants to make the system solar positive by itself, which is doable with 12'000 locations (keep in mind this is worldwide), at a cost of $3.6b from $4b of revenue. There's no problem with the SuperCharger financials with a 166 vehicles per SuperCharger location ratio.
So now if you want to go and say, take some of these 12k 10-charger SuperCharger locations and change them to SuperSwappers instead, then sure, go ahead (and figure out where you're going to put the Solar Panels if you take those SuperCharger parking spots away). But 100 locations, whether it has 100 swappers or 1000 chargers, simply cannot service 2 million vehicles.
Why are you arbitrarily limiting the number of charging stalls at a location? Grid issues aside, 30 or 40 parking spaces is not a radically high number. You only get multi-acre parking lots when you have to support 10's of millions of cars.
I don't see how it makes much difference at all whether you spread this out or group it together. The only justification I can see is the grid issues. But those issues are always mitigated if you have sufficient storage on site. Instead of having to have grid capacity to support peak loads, you just need enough to support average loads for a peak season (or year with enough storage).
I've argued that the CapEx for SuperChargers or SuperSwappers is virtually identical in terms of potential throughput. We both seem to agree that the CES requirements are the same.
However, I'd also argue that both CES and Swapping lend themselves very well to centralization, while SuperCharging is more agnostic until you look a couple of decades ahead.
A quickie calculation shows that my house, which is a two story, 3,000sq ft structure can store almost 1,000 batteries if you use the attic, and assume your racks give 8 inches of space for the 4 inch battery. That's 85mWh of storage in my house. Attach a swapper to my house and the one next door and its 2,000 batteries and a high swap throughput, heavy duty CES facility. Make it 4 houses to give yourself plenty of room to move batteries around.
That's what it looks like in 2025. Right now it's just the swapper and a mostly empty house that won't fill up with batteries for a while. That's a scalable solution. If you don't agree that it can support 2 million cars once you scale up to 4 full houses, then fine, call it 500,000 cars. If the completed swap station is $1.5m, and the batteries are $20,000,000, that works out to $300 for the swapper, and $4,000 for the batteries per car.
But again, we expect to make some money doing CES, and additional money doing swaps. Using your 15 swaps per year assumption, and my $20/swap fee, that works out to $150m/year in revenue just from swaps. So charging the CapEx to the cars is not the way to look at this. Ideally the network is profitable as a business instead of being a charge on the car.
In contrast, the SuperChargers require the same CES and grid capacity, more land area, less maintence and maybe less CapEx. And their only revenue source is the CES business.
