By Harry Keller
Editor, Science Education
Now that Elon Musk has revealed details of his Hyperloop concept for traveling between cities faster than double the speed of an airplane, it’s time to put his ideas to the test. Will they work? Should we build it?
Such a complex system has no trivial answer. We can consider two important factors, however. Will it work? Does it satisfy the demands of a new technology?
For the second question, the answer comes from considering how technology is supposed to work. When you inject technology into an existing space such as travel (or education for that matter), it should work better, result in faster results, and cost less than what it’s replacing or supplementing. Dan Goldin of NASA put it into really simple terms long ago: Better, Faster, Cheaper.
How does Elon Musk’s plan stack up? From his own blog, here are his goals for intermediate distance transportation of from a few hundred miles up to around 900 miles when compared to existing system.
- Lower cost
- More convenient
- Immune to weather
- Sustainably self-powering
- Resistant to Earthquakes (he’s in California)
- Not disruptive to those along the route
The second two items match nicely. Musk claims that a ticket on the Hyperloop from Los Angeles to San Francisco should cost about $20 one-way. The speed of 700 to 800 mph certainly counts as faster. Is it better too? That depends much on what you consider to be better. The travel pods will hold about 28 people if his design is chosen. They will not be spacious. His drawings suggest a rather cramped environment that could bother claustrophobic passengers, except that this system will be above ground and could have a view. However, the drawings don’t show windows.
A 350-mile trip might take around a half-hour, long enough to become upset with being in a small closed space with others. The potentially longest trip of 900 miles would require over an hour. All current modes of transportation, planes, trains, automobiles, and boats, have windows that passengers tend to like very much despite the view. Looking out of a window at 30,000 feet or traveling at 70 mph can be disconcerting. However, the power of the desire to see overcomes this problem for most.
To complete the evaluation, assume that claustrophobia will not be a problem. The speeds are low enough (really!) so that the turns necessary to follow California’s Interstate 5 with some adjustments will not create uncomfortable g forces. The force during a turn increases as the square of the speed. Supersonic speeds will cause serious problems for living passengers.
How will you create enough energy to move the pods at such high speeds and avoid air friction? Musk’s elegant solution has the tubes at a low pressure but not a severe vacuum. Vacuum is hard to maintain over 700 miles of round-trip tubes large enough to hold pods of people. He takes care of the inevitable problems of the air piling up in front of the pod by using it. Compressors in the front of each pod suck the air in and eject it below the pod to use the same effect that an air hockey table uses to elevate the pod on a nearly frictionless layer of air.
These compressors will run off of batteries in the pods, but the pods will not be propelled by energy from the batteries. They would be far too large and heavy for that. You can’t readily transfer energy to the pods either. So, Musk has a linear electric motor that’s sort of inverted. The powered element is below the pod in the tube. He says that only about 1% of the tube length has to have these motor elements to make up for inevitable speed loss during the trip. Very substantial linear electric motors will operate for the first minute or so to accelerate a pod to traveling speed.
As long as you have all of this tube length, Musk suggests that solar cells be placed on top of all of it. The electricity will run the entire system with plenty left over, at least in sunny California. He claims that he’ll store the energy in some form, for example compressed air. I would imagine that it would cost less to put it on the state’s electrical grid and take it back as necessary. If you can believe the estimates of energy generation, it will make money. It’s part of the reason that his tickets are supposed to cost only $20.
Will they cost so little? Driving 350 miles, even in a energy-efficient hybrid, will take eight or nine gallons of gasoline. In California today, gas is around four dollars per gallon. The trip takes around five-and-one-half hours depending on exactly where you start and end in the two cities. You spend around $35 and five or more hours, and that doesn’t count your car’s depreciation due to the extra mileage. Unless you’ll die without your own car, it makes sense to take the Hyperloop – even without the stress factor of all of that driving.
An airplane will cost around $100 each way, and you certainly won’t have your own car. Today, a train ride is around $60 each way, again without your own car. The Hyperloop would be faster than either, much faster than even the planned high-speed rail that Musk was so upset by. That train would take about 2.5 hours. If successful, the Hyperloop could not maintain such a low price because of simple economics. The demand would quickly drive the price up. Resellers might buy the low-cost tickets and resell them at prices that could even rival those of airplanes.
The amazing part of this entire analysis is the low cost to build his system: about $6 billion or so. That price must assume no corruption. However, it stands in stark contrast to high-speed rail for the same route estimated at $70 billion, ten times the Hyperloop cost with lower speeds as well as less safety.
The bottom line here is that, if it works as planned, it will make money like the mint. The operating costs, including amortization, are supposed to be around $20 per passenger. It can put 28 people on the system every 30 seconds, but Musk has assumed two-minute intervals in his analysis allowing up to 840 people per hour to make the trip. That’s around $17,000 per hour during busy times. You might take in a quarter million dollars a day at that rate. You can double the price and still not have much impact on ridership. The extra quarter million dollars will be profit. Astounding!
While luggage compartments are supposed to be at one end of each pod, they don’t show up on the diagrams. With little space (about 6’2” external height and 4’5” external width), you won’t be able to have unlimited bags. If you’re rather large, you may not fit in a single seat and would have to pay for two. Even so, the elbow room looks tight to me. You’ll be sitting shoulder-to-shoulder – literally. These figures are, of course, subject to change. Perhaps, Mr. Musk has narrower shoulders than average and hasn’t checked the average shoulder widths of travelers.
When can you ride? Due to the extreme requirements of permits for such a large project, it would take as much as seven years. Without these problems, Elon Musk suggests that he could do it in one or two years. There’s no new technology, just a different combination of existing technologies. Sounds a bit like Mars One, but with a big difference. Musk is not attempting to get rich from this scheme. He’s already there and, unlike too many of the wealthy, he doesn’t covet the next billions he could be making. He would like to change the world for the better.
In summary, this is a wonderful conception that is practical and could become reality. Some details must be worked out yet but they’re the prosaic ones that are apart from the technology. The price of a one-way ticket is very unlikely to be $20, but it could be a great value proposition even at $40 or $50. Unlike Mars One, this project will have real immediate practical implications for us all. We won’t have to await hoped-for technological advances created by the project.
Now, if Elon Musk would just take his SpaceX, Tesla Motors, and Hyperloop smarts and apply them to fixing our education system, that might have a similar impact. In the meantime –
Go for it!
Filed under: Transportation