Electric semis for true long haul will never be viable unless there is a major breakthrough in battery tech. 300 gallons of diesel fuel has so much more energy than even the best batteries could pack into a reasonable size and weight.
So, lets throw some numbers around:
- Range: 500 miles - Time to recharge 80% (+400 miles) capacity - 30 minutes - Speed Limit (Interstates): 50-75MPH - Maximum Driving Times (USDOT): - 8 hours (followed by a 30min break), - 14 hours (followed by a 10 hour break) - 60/70 hours (in any 7/8 days)
So lets assume 60MPH moving average speed (very high) - gives us over 8.3 hours of driving time.
You add in a 30min break at a megacharger and you've now got yourself another 400 miles of range, which would let you drive for 6.6 hours - at which point you'll be out of hours again.
So you park up and let the truck charge overnight.
I don't see how this is so difficult.
The range options were said by Tesla to be the range of the truck plus trailer and maximum load, at highway speeds.
The 400 mile mention is the 80% capacity of a 500 mile range pack you'd get by a 30 minute charge. Also information given during the announcement.
And that is a problem just count the average number of semis in a truck stop they’ll all have to share power.
Also many of these truck stops are in the middle of nowhere and while they have electricity they aren’t connected to anything that can provide that much power.
Say you get 100 500kWh semis in a stop that need to be charged 80% that’s 4mW if we’re taking Tesla’s 30min turn around that’s 8mW which is not an unnoticeable portion of what a power plant produces and hour.
I never mentioned 'current' infrastructure, whatever that means. We're clearly talking about Tesla Semi here, that's pretty clearly not going to fit in your ordinary Tesla supercharger stall.
As for the other 'problems' - they are all solvable. I'm sure Fleet operators and major truck stops will all be jointly cooperating to add MW charging infrastructure along the trial routes. It benefits the fleet operator, it benefits the truck stop operator.
Electrical grid operators won't have an issue with it - if you look back at previous postings on HN you'll find several examples where grid operators are struggling to find demand for the grid, given the rise in household efficiency and offshoring of major production infrastructure.
Yes it'll require some work to ensure there's not huge spikes in demand, but that's solvable too. Tesla (and others) are already implementing local battery storage at some of their superchargers. This lets them have a more consistent draw on the grid.
The ends result of this is that you end up having a huge amount of deployed battery storage at truck stops all over, able to take advantage of spikes in energy production, respond to grid shortages, and smartly manage charging of trucks.
Given it's all integrated, there's no reason a major fleet operator wouldn't sign some kind of contract allowing their fleet charging to be slowed or suspended momentarily in return for lower charging costs.
I also suspect that there will be (at least) two categories of charger - the immediate "I'm on a short break" MW charger, where you're expected to move on after getting 80% or more capacity, and then an overnight charging slot where you park up for your 10+ hour break.
- Range: 500 miles
- Time to recharge 80% (+400 miles) capacity - 30 minutes
- Speed Limit (Interstates): 50-75MPH
- Maximum Driving Times (USDOT):
-- 8 hours (followed by a 30min break),
-- 14 hours (followed by a 10 hour break)
-- 60/70 hours (in any 7/8 days)
If you have access to a fleet or don't need the same truck back, it becomes more of a baton relay than a marathon.
Idle time of EV-rig per day (30min charge every 4 hours): ~11% Idle time of Non-EV-rig per day (5min refueling every 4 hours): ~2%
Sure, for short distance trips where loading/unloading takes as long as charging the EV-rig, it doesn't make a difference, but for longer hauls, the charging pauses of EV-rigs will severely cut into utilization of the fleet.
Battery volume and weight density is not that bad when you consider the weight savings without an IC engine, transmission etc. Gasoline gallon equivalent tables ignore the vastly lower efficiency of IC engines. Costs are mostly non issue as trucks would charge daily making them break even before cars.
The actual problem is manufacturing capacity which has been ramping up but has a long way to go.
Good point about substituting the weight of the engine for batteries. Still I think you're going to be way short in total energy density.
And it's not like you can just pack the trailer with batteries either, you still need to allow for the weight of the cargo and there is a gross weight limit on 18-wheelers.
As to weight the engine weighs ~3000 lb and 300 gallons of gas weigh ~1,900 gallons. Transmission is another 700lb, include tank weight and verious odds and ends and you can get ~5 hours at highway speed. Assuming a battery swap takes 10 minutes. That's easily worth saving 50+k per year in operating expenses.
I also think that regen braking in semis would be trickier because a lot of the braking happens on the trailer wheels so you would need to fit all the trailers with regenerative braking equipment.