Published on October 1st, 2017 | by Matthew Klippenstein


Hyperloops Are To HSR As Hydrogen-Fuel-Cell Cars Are To Battery-Electric Cars (#CleantechTalk 34)

October 1st, 2017 by  

Hyperloops, high-speed trains, battery-electric cars, and hydrogen-fuel-cell cars — how do they relate?

You can listen to this episode and subscribe to Cleantech Talk on iTunes or Soundcloud. You can also listen via the embedded player below or download this episode. Jump into the show notes below for more goodies.

BNEF’s Epic!™ Deck

Michael Liebreich’s slidedeck for the recent BNEF Summit was, to use Zachary’s words, epic. I love his presentations too, and not just because the first girl I asked to marry me was a Liebreich. (No relation to Michael. She said no. I was 5. 😃 )

It had the feel of a victory lap, a “look how far we’ve come” tone to it, which makes me think Liebreich will retire from BNEF soon. (Jigar Shah previously speculated on The Energy Gang podcast that Liebreich would run for mayor of London, for which the next election is in 2020, and Zachary got the scoop years ago on why he might consider a mayoral run for a previous election.)

The slide on the progress of battery electric vehicles versus fuel cell vehicles got a lot of attention, and deservedly so.

The challenge is that in the US, the sum total of hybrid + electric vehicle market share has been steady for a few years, which means that we’ve mainly been cannibalizing hybrid buyers. (Consider this chart from the PIRA Energy Group, via this article, showing that hybrid sales have dropped off about as much as plug-in electric vehicles have risen.)

We need to reach the other 97% of new car buyers, and that $7,500 federal tax credit won’t last forever. For a 50 kWh vehicle, that works out to a $150/kWh discount on the battery. Put differently, the effective cost of the base Tesla Model 3, battery will be about $150/kWh higher after the tax credit expires. All of which means that we need to continue ferociously squeezing costs out.

A more diverse product lineup (trucks, please!) will help broaden the market, and it’s good that all OEMs are releasing plug-in vehicles while only Toyota pushed hard on hybrids, but there’s still the worry that a lot of people won’t buy a car unless they can refuel it in a few minutes, even if battery-electric vehicles are superior in every other dimension. Kind of like how, when Texans cleared grocery shelves in the wake of Hurricane Harvey, they left the tofu untouched, even though tofu is indisputably better than “not eating” in every dimension except possibly taste.

To that end, Mercedes’ limited-run fuel-cell plug-in electric vehicle might offer a path forward. And if you’re driving your first 25 miles per day on electricity, you’d be refilling your hydrogen so infrequently you wouldn’t need many hydrogen pumps per town.

Before you jump into the comments, none of this takes away from the fact that fuel cells are perhaps one-third as efficient as battery-electric vehicles, which are themselves far less efficient than bicycles, which are themselves less efficient than velomobiles. It’s just that efficiency isn’t a consideration for most new vehicle buyers. The F-150 gets an EPA combined rating of 19 mpg, one-third as good as the 52 mpg of the Prius (and the Hyundai Ioniq is even better at 55 mpg), but the F-150 dwarfs them in sales.

I’ll also note that Mark Z. Jacobson (of 100% Wind Water Solar fame) is also bullish on fuel cells for larger transport applications. His 139-country WWS roadmap assumes that 7% (!) of the electricity produced in the world in 2050 goes towards hydrogen production through electrolysis for use in transport applications (see page 3). (For context, Japan and Germany, when combined, use about 7% of the world’s current electricity.) 

Yes, Hyperloops Are To High Speed Rail …

… as fuel cell vehicles are to EVs.

So, the jump-off point to all this is India’s decision to start building a high-speed rail network, which is awesome — think of all the jet fuel it will avoid burning in the coming decades, as it passes China as the world’s most populous country. And if there’s an extensive high-speed rail network there like there is in their geopolitical rival, that works in favour of battery-electric vehicles — if families take train trips instead of road trips, car buyers might not worry about having that 150th or 200th mile of range in their vehicle.

As for hyperloops and fuel cells, the parallels are uncanny. Compared to the mature, proven, been-around-for-decades [high-speed rail / lithium-ion battery] technology, [hyperloops / fuel cell vehicles] are immature platforms. While fuel cell automobiles haven’t been built at truly commercial scale, a hyperloop hasn’t been built, period.

Back in university, a classmate of mine had a “space pen.” Normal pens don’t work upside down or in zero-G because the ink won’t flow without gravity, but the space pen used a tiny cylinder of compressed CO2 to push the ink out, required a specially-formulated ink, and cost something like $100. For that same hundred dollars, you can probably buy a thousand pencils, which will also work in zero gravity.

Hyperloops and fuel cells are the “space pen” in this analogy, while high-speed rail and battery-electric vehicles are the pencils. Fuel cell vehicles might never amount to much of the passenger car market, but their advantages over batteries in productivity sectors like forklifts (advantages which will widen as production volumes increase and costs come down) are significant. In contrast, it’s hard to see where hyperloops have a competitive edge yet.

If hyperloops won’t work everywhere, they might not ever reach the scale where costs can really come down. We might call this the Airbus A380 syndrome, after the ill-fated plane which was so big only a handful of airports could even handle it. The fate of the Concorde showed that going faster isn’t enough to guarantee success, either. And the projected hyperloop costs are eye-popping. Just as plug-in electric vehicles have entrenched themselves nearly everywhere, high-speed rail has entrenched itself everywhere except North America. And any advances Elon makes in tunnelling technology could be equally applied to an underground high-speed rail line.

By far, though, the biggest hurdle for hyperloops is safety. That’s because the universe isn’t ruled by Newton’s Laws or Einstein’s Laws, it’s ruled by Murphy’s Law. Anything that can go wrong, will go wrong — it always has and always will.

If there’s an accident or emergency on a high-speed rail line, there are a lot of ways to get out safely: there are doors on each side of each passenger car, at the front and back. Worst-case scenario, you might climb down a ladder (if on an elevated train platform) or go up some stairs (if underground) to get medical assistance.

But a hyperloop will be different. First off, you’re basically in a vacuum tube. If you’re in a pod halfway between stations — and, again, Murphy’s Law tells us this will happen, and probably sooner than anyone expects — you’ll need to open the doors to get out. But opening doors into the air pressure equivalent of 150,000 ft altitude isn’t safe. Before you did so everyone on board would need to be wearing an oxygen mask, which means adding a compressed air tank on board. That adds complexity and cost — high-speed rail doesn’t need those things!

If the tube has been re-pressurized, there’s another challenge: how do you get out? The hyperloop “alpha” white paper says that the inner diameter of the passenger tube will be 2.23 m (page 26) while the maximum width of the pod will be 1.35 m (page 15). That means if the stranded pod is stuck in the middle of the tube, there will be (2.23-1.35)/2 = 0.44 m = 44 cm of clearance on either side of the pod at its widest point.

My shoulders are more than 44 cm wide, but I’m not quite 30 cm at my fattest point, so I could slide past the pod in profile. But if I’m in a stranded pod with one of my young children, I’ll probably have to carry them out, which means I’ll need more than 44 cm to do that. Or at least that would be the case if the tube was a rectangular shape. The alpha document conceives of a circular tube with a 7’4” inner diameter, which means that at the edges (where exiting passengers will be) there won’t be much height at all. People would have to crawl away like cave explorers. That’s a non-starter. It won’t pass regulatory scrutiny in any country.

This problem could be solved by making the tube a lot bigger (it’s hard to imagine making the pod smaller, it’s only envisioned as being 3’8” high) but that will add a lot of cost, since the area of the tube (and steel and tunnelling, if necessary) will increase with the square of the diameter. And once the tunnel equals the size of a train tunnel, why not go with the train?

Regulators would need there to be emergency exits for people to crawl towards. But from Figure 4, we see that the passengers are stuck between an enormous compressor fan and a massive battery bank. You could design the battery bank with a crawlspace to allow people to get out the back, but what if that’s blocked or there’s a fire? How would passengers get past the compressor fan, which is designed to be almost as big as the tube itself? There would need to be still more safety and emergency power systems, which will add still more cost and complexity, and periodically need inspected.

Having gotten safely out of the pod, we’d need to be able to get out. That doesn’t just mean emergency lighting — hundreds of miles (!) of emergency lights lining the insides of the tube — it also means regular entry and exit points. That means probably thousands of seal assemblies, which will dramatically increase the cost of each segment of tube. Each seal will be a possible source of leaks (remember Murphy’s Law) which will eat at the system’s operating efficiency.

It’s true that the hyperloop alpha white paper is just an alpha paper, and that any commercial designs will necessarily undergo testing and regulatory review. But why wait?

Above-ground high-speed rail systems — like battery-electric vehicles — have already established themselves in the marketplace, and it’s great to see India joining the club. Hyperloops and fuel cell vehicles will probably emerge in their own due time, and find markets / niches where they can flourish. That’s a wonderful thing, but we shouldn’t let the perceived-to-be-perfect options of tomorrow slow our progress on the plenty-good-enough-thank-you solutions of today!

… now to check on those comments. Where did I put that asbestos underwear…?

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About the Author

Matthew Klippenstein is a renewable energy consultant in Vancouver, Canada. He has chronicled the Canadian electric car market for since 2013, and has provided commentary (in English and French) for print, television, radio, web and podcast media. An early guest on "The Energy Transition Show", his work has also been discussed on "The Energy Gang". An occasional contributor to CleanTechnica, he co-hosts our own CleanTech Talk with Nicolas Zart.

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