The Hyperloop hyperbole

I discussed the hyperloop proposal sometime ago and I thought I would be worth updating on its progress. On the one hand, they have managed to build a test track and run some tests. However, the critics argue they’ve barely got started and still haven’t tackled any of the major technical challenges yet.

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Figure 1: The first Hyperloop test track [Credit: Hyperloop one]

A structural engineer for example has pointed to a host of challenges hyperloop would face in terms of building the system, protecting it from seismic events, countering the effect of thermal expansion and dealing with NVH issues. The high speeds proposed would mean the system would have to achieve some extremely high manufacturing tolerances, which might not be possible on such a large scale. Certainly if it was possible, it would likely be very expensive. Economic experts with experience of civil infrastructure projects estimate it would cost at least ten times as much as Musk has proposed, perhaps as much as $100 billion, much more expensive than the CHSR project, yet with only 10% of the capacity.

And those NVH issues will make for a very uncomfortable ride. One physicist has suggesting it will be a barf inducing ride (Hyperpuke?). Another points to the enormous technical challenges of maintaining a partial vacuum over a 600 km vacuum chamber, particularly given the needs for thermal expansion joints. And heat represents a particular problem for hyperloop. Aside from the issues of thermal expansion, the compression of air inside the tube, all of that high voltage electrical equipment and even the body of occupants will conspire to create a major cooling problem.

Now while there are solutions to all of these issues, the problem is the complexity of making it all work, while maintaining the sort of tight engineering tolerances needed to do so is going to be a significant challenge, which its likely to take a long time to develop and likely to be very expensive. So when supporters of Hyperloop talk about successful tests being a “kitty hawk” moment, they need to remember how long it took to go from Kitty hawk to reliable long distance air travel.

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Figure 2: Hyperloop’s “Kitty hawk moment”….so only 30-40 years to go then….

And then there’s the thorny issue of safety. Phil Mason (aka Thunderf00t) discusses a number of the engineering challenges faced by hyperloop, but also raises concerns, particularly about the consequences if the tube were to be breached. In such an event, a catastrophic implosion across a section of the tube is likely and the shock-wave released by this down the tube would likely destroy any capsules for a considerable distance in both directions (hence why I suspect the media will be calling it the deathcoaster after the inevitable accident).

Similarly, any stray nut or bolt could destroy a capsule, in much the same way a stray piece of metal on a runway destroyed a Concorde on takeoff. Its worth remembering that the most dangerous section of a flight for a plane is during take off and landing, because the aircraft is travelling at speed in close proximity to the ground and the pilots have no time to do anything should the encounter a major problem. Some of the most deadly aircraft accidents have occurred either on the runway, or just shortly after take off. And being in a pressurised cylinder travelling in a partial vacuum raises some safety concerns as well. Not only of asphyxiation if the capsule the de-pressurizes, but the damage that might do to the hyperloop system itself.

Again, while these issues are solvable (up to a point!), the expensive of maintaining a 600 km long partial vacuum chamber at aircraft level standards is going to be horrendously expensive. My take on this is to ask what is the rather obvious question I don’t think those behind it have asked – what specific advantage does hyperloop offer? And is it worth the enormous expense, time and effort needed to achieve this?

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Figure 3: The concept of a Vac-train is not a new idea, its been promoted from time to time in the past [Credit: Economist, 2013]

Its supporters claim it will be faster than aircraft. However, given the engineering challenges I mentioned earlier, I would argue that’s far from proven. And the best way of solving those challenges would be to lower the operating speed down to more reasonable levels. Given the dangers mentioned earlier, its unlikely hyperloop can be operated more cheaply, particularly given that with aircraft we only have to maintain a plane and the runways, while with hyperloop we need to develop build and maintain one of the largest machines ever built.

You’d still need to go through some sort of security check in and the current proposal for hyperloop, from LA to San Francisco, won’t actually go city centre to city centre, but from the outskirts of both, so any time gained will be thrown away on a bus crawling into town (obviously city centre to city centre would be even more expensive and raise all sorts of planning issues, given the safety issues mentioned earlier).

And besides aircraft can theoretically go faster, Concorde remember went at about Mach 2. Aircraft manufacturers have tried to revive supersonic travel, coming up with new aircraft designs that fly supersonic but with a reduced sonic boom, or fly at high subsonic speeds. However, such projects tend to falter because the feedback they get from the airlines is that there simply isn’t a huge market for such aircraft. Yes there are some people who’d pay more to get from London to New York an hour or two quicker. But the majority of travellers would prefer to just bring a good book and save some cash.

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Figure 4: One of a number of proposals for new supersonic passenger planes under development [Credit Boom, 2016]

So aircraft could theoretically match hyperloop for speed. The only difference is that aircraft manufacturers reckon that the few billion in costs to achieve that wouldn’t be economically viable given the likely small size of any market for such a service. Hyperloop is based on the premise that this market (for something a bit faster than conventional planes) is sufficiently big to justify expenditure in the order of a hundred billion or so. And that hyperloop can deliver on the levels of speed advertised. Neither is likely to be true.

Of course the major down side of planes is that there’s only so many people you can squeeze on them at any one time. Although that said, there are single class versions of the A380 and 747 which can seat over 500 people. But generally, there’s only so many people you can realistically move by aircraft without seeing a rapid escalation in costs. This is where trains gain an advantage. While trains come with large fixed infrastructure costs and high maintenance costs for the track and signal infrastructure, once those have been met, the costs of running trains on it is relatively small. So they are a great way to move lots of people aroundd. And as noted earlier, hyperloop will cost significantly more and yet still only be able to support a fraction of the capacity of the CHSR system.

Trains can also make multiple stops, so that makes them much more useful for joined up journey’s. Hyperloop’s all well and good if you live in LA or the Bay area, but what if you live somewhere between the two and you’re destination is somewhere else between the two cities or further afield. For many journeys trains are better. Trains also bring economic benefits to the towns along their routes. Someone living in Milton Keynes can conceivably live there and afford a three bedroom house, yet commute into work in London. A small business who can’t effort the extortionate rents of the city centre, can base themselves out of a commuter belt town, yet still be able to get in and out of the city. This brings much needed business and tax revenue to communities along the route of a train line, which serves to counter the negative impact of having a train line in your back yard.

Hyperloop by contrast will offer no such benefits. Indeed, given the time county sheriff’s will need to devote resources to protecting it from terrorist attacks, it will likely cost communities along its route money. And given the performance issues I mentioned earlier, hyperloop will not have a lot of leeway to alter its route in order to limit planning objections (as it can’t climb slopes as steeply as a train can, nor undertake tight turns). So the likelihood is its going to be even harder to hammer through hyperloop proposals in the face of local opposition than it is to get a High speed railway line built. And ultimately that’s going to have a significant financial cost.

Would tunnelling solve some of these problems? Possibly, but it would greatly increase the expense. And it depends what we are tunnelling through. Some types of rock are porous and water leaking into the tunnel would become a problem, particularly if you are trying to maintain a partial vacuum (remember anything pumped out of the tunnel, including the air extraction to maintain a partial vacuum, must also now be pumped all the way up to the surface). Others types of rock are very difficult to drill through. Its difficult to seismically isolate a sealed tube buried underground, so it might not work in earthquake zones. Drilling tunnels underground is also going to have an impact on those living above the tunnel. And inevitably some will object and demand compensation.

Another disadvantage of planes is the high energy consumption. Hyperloop might be able to offer lower rates of energy consumption, but its difficult to say, given the thorny question of how much energy we expend making sure that air tight seal is maintained. And, as I discussed in a prior article, there are various ways the airline industry can be cleaned up. It is going to be far more technically feasible to convert aircraft to run on hydrogen or biofuels than it is to develop an entire new transportation system and built all of the infrastructure to support it. And of course, trains are generally the most energy efficient means of transport.

All in all one is forced to the conclusion that hyperloop seems to come with all the disadvantages of train travel along with all the disadvantages of air travel, plus a whole pile of other excess baggage, which does suggest it might not be a terribly viable idea. However for me what really gets my spidey senses tingling is the lack of any response to such criticisms from the designers of hyperloop. Now granted, if you went back in time and asked Wilbur Wright how he would deal with the issues of aircraft safety, he’d likely say well I’ll just let go of the controls, slide off the wing and do a tuck and roll the 4 ft to the ground. So its a bit premature to be talking about the nitty gritty. But equally, that means its a little early to be making inflated predictions as to hyperloops level of performance or costs.

But where hyperloop really jumps the shark for me, is in relation to how they plan to initially use the system for cargo delivery. I mean have these guys even done the most basic market research? You do know that freight is a highly competitive business with very tight margins?

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Figure 5: Average freight revenue per ton-mile [Credit: National Transportation Statistics, 2009]

But I can order something on Amazon and have it delivered by hyperloop in under an hours its supporters say. Ya, if you’re willing to pay a small fortune for hyperloop delivery and if you live directly opposite the terminus at one end and the seller lives at the other end. Otherwise its going to have to go on a truck either end, which isn’t necessarily going to take a direct route. Likely it will take a circular route with multiple stops….so why not just sent it by truck all the way, save money and get it delivered to your door the next day. Indeed this is the whole reason why trucks are so cheap, they are flexible and can make multiple stops along a route. And aircraft can match hyperloop for speed (as discussed) but probably at a much lower cost.

Air freight is made cheaper these days by using the room in cargo holds on passenger flights for air freight. Its so competitive and cheap these days that some UK supermarkets will fly freshly picked groceries from Spain to the UK so costumers can have freshly picked fruit and veg….well until brexit happens anyway. But its difficult to see how hyperloop can compete with either. And of course for bulk cargo delivery, you can’t beat ships or trains. Its precisely why most of the major industrial areas of the world are built near waterways, ports or they are connected to them by railway lines.

So all in all, hyperloop does not live up to the hype. It doesn’t help that its achieved something of a cult following, particularly from libertarians, as they see a relationship between it and a key plot line in an Ayn Rand book. As with other technologies this is leading to a significant overselling of the proposal by those with an irrational and emotional attachment to it.

There is some potential merits to hyperloop no doubt, but at this early stage to even consider it as a realistic alternative to existing transport options is just silly. Certainly thought there is a need to resist the “grass is greener” syndrome associated with it, as there’s always a tendency to see new ideas as better than existing ones, simply because we don’t know what the real problems with the new proposal are.

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About daryan12

Engineer, expertise: Energy, Sustainablity, Computer Aided Engineering, Renewables technology
This entry was posted in aviation, cars, energy, environment, future, space, sustainability, technology, transport and tagged , , , , , , , . Bookmark the permalink.

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