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Comment by SigmundA | Hacker News Reader

Not the biggest Elon fan but I do believe he is right about Hydrogen [1].

Hydrogen is not sitting around somewhere to be pumped out of the ground it must be split from something else like water which is very energy intensive.

It is very low density and must be highly compressed / liquefied, much more energy.

Even liquefied has very low energy density per volume.

It is very difficult to store and transport safely in the highly compressed or liquified form.

Might as well just charge a battery with the energy rather than creating hydrogen.

1. https://www.youtube.com/watch?v=yFPnT-DCBVs

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The other elephant in the room with hydrogen is the fact that using current production methods, it's a fossil fuel.

Direct solar separation will be a game changer when/if that becomes a thing at scale, but right now almost all hydrogen produced for industry is made by steam reforming natural gas, which releases just as much CO2 as burning it. More, if you account for the extra steps in the process and the energy required to perform them.

I wouldn't consider that a decision criteria since it's also true for battery tech.

(Most Teslas are powered by fossil fuels today via the grid, not renewables. 80% of US energy is still non-renewable and non-nuclear.)

Is that what OP meant by fossil fuel? Fixing the source of electricity is (probably) a lot easier than fixing the source of hydrogen itself.

If by “energy” you meant “electricity” (which is the only thing that makes sense given context), that is incorrect. The US electrical grid is about 40% clean (half being renewable and the other nuclear). Coal is 19% and falling. The rest natural gas.

But even on natural gas, Teslas are more efficient than conventional cars. This is NOT true for hydrogen. Making electrolytic hydrogen from existing grid energy is not better than a good hybrid in terms of overall efficiency.

The “but electric cars still use the grid which has a lot of fossil fuel production” argument is actually compounded for hydrogen cars as they require over twice the electricity input to achieve the same distance traveled as battery electric.

Several companies have demonstrated generating copious amounts of hydrogen from algae - much more efficient than converting sunlight to electricity than performing electrolysis. I've seen even more alternate ways of generating hydrogen over the last 20 years - lots of thought around production; without demand it isn't worth pursuing/refining the processes to do so.

Production can be distributed - no need to ship fuel or electricity over vast distances either.

Charging batteries isn't without loss either.

Most importantly, vehicle refueling speed is on par with liquid chemical energy (i.e. gas or diesel) which is the single biggest problem with batteries. And we haven't had EVs long enough to where people are needing to replace battery packs in volume. That's going to be fun when that day inevitably starts to roll around.

I used to be a big hydrogen skeptic - but the more I have looked at it, the more I think we could deploy infrastructure for hydrogen faster than battery tech can improve. There aren't many combinations left to try, or to try to make practical for high volume production and that would be safe enough for universal adoption that will produce any significant gains. Maybe with liquid electrolytes - but those introduce new complexity/safety issues. I'm a huge fan of "liquid batteries" for stationary storage capacity - think Tesla powerwall but on an industrial neighborhood/town scale.

Even with a 100% energy efficiency to create hydrogen you use a huge amount of energy to compress it.

Can that energy be utilised?

With the price of solar so much cheaper than anything else, solar will almost certainly be overbuilt times of solar output exceeding overall demand. This will probably lead to negative energy spot prices at specific times during the day. People will want to figure out a way how to use this energy. Maybe it will be pumped hydro, batteries, compressed air, or hydrogen. Maybe it'll even lead to colocation with aluminum smelting or something like that.

The point is something needs to be figured out how to handle the increasingly excess energy supply. Each technology has a different set of tradeoffs. Hydrogen is a potential but if it has any chance of succeeding, the technology has to be built now and quickly. Once a specific solution has momentum, it will be difficult to overcome. Large scale batteries seem to have the lead for now but the weight efficiency has always been an issue. I imagine at least one of the more weight efficient solutions will gain some reasonable % of market share.

Elon and Tesla have bet the entire farm on batteries. Something tells me he is not the most unbiased source here.

passenger vehicles are a TOTALLY different ballgame than commercial long haul trucking. Even the early Tesla models could beat top of the line sports cars in some performance measures. The thing is the people who buy class 7 & 8 trucks work off an excel spreadsheet. They don't give a shit if the truck can accelerate way faster than a Cummins diesel or that the driver has a way better HUD or user experience than in a Freightliner cab. They certainly don't care very much that the truck is more environmentally friendly. Maybe they'll pay 10% more all else equal but that's not what Tesla or anyone else is able to provide.

They only care about $/mile and unless there is some massive technical breakthrough, batteries ain't beating diesel any time in the near future on that measure.

Notice the Tesla Semi has been delayed for three years now?

So where are the hydrogen semis?

$/mile hydrogen is far behind diesels and batteries at this point.

Hydrogen is more feasible than battery for long haul as the technology stands now. A lot of big names in commercial trucking have made huge investments in it.

But it's still not there yet and likely requires some giant gov't subsidies or some tech breakthrough. No amount of $ makes batteries work for long haul at current tech or anything we see in the near future.

This is not true. Batteries are MUCH cheaper to operate and we have capability to make 500 mile battery electric semis:

https://selenianboondocks.com/2017/11/tesla-semi-part-1/

The same place as all the battery semis: they don't exist yet. That is the whole point of this research thing that actual truck companies are doing.

> Elon and Tesla have bet the entire farm on batteries. Something tells me he is not the most unbiased source here.

I completely agree with you on this. Elon is not a credible source of arguments against Hydrogen trucks.

However, I'm having a hard time finding credible arguments for them, at least given low prices for diesel fuel in the US. What is the energy usage per mile for a hydrogen truck?

Elon and Tesla invested in batteries because of their opinions on hydrogen. Its not like they realize this now.

15 years ago Tesla could have bet on hydrogen, and they didn't.

> They only care about $/mile

Every analysis so far shows that hydrogen is more expensive then electricity by far.

Lets go threw it:

- Infrastructure for hydrogen is far more expensive

- Price per energy is more expensive for hydrogen

- The truck is more complex to design and build

- Hydrogen power trains are harder to maintain

> Notice the Tesla Semi has been delayed for three years now?

Because one Semi uses the same amount of batteries as 4 cars and 4 cars make more profits. This is really not that hard to understand.

If I need to side with someone here, I'm more inclined to side with the two companies that have a long history in making trucks vs. the person whose company has yet to made the truck they debuted in 2017.

There are no hydrogen trucks on the road either, time will tell which one is viable. Physics tells me which one will be more likely no need for a argumentum ab auctoritate.

Since when has listening to an authority on a topic been a bad thing? Daimler and Volvo are the two biggest truck companies in the world. I imagine they have a pretty good grasp on the market and on the engineering.

Volvo also has real electric trucks on the road and working today. So if anybody knows the pros and cons of electric trucks, its probably Volvo.

That argument doesn't always work. GM had the EV1 "on the road and working" in 1996. Then they decided that electric cars could never work. Then Tesla happened.

Volvo has not decided that electric or hydrogen is not viable yet.

There was good reason for GMs decision, the battery tech and costs in early 2000s were not simply viable for mass market adoption at that time. They were not interested in niche product.

Battery cost per kwh had reduced orders of magnitude now. It is still not price competitive with gasoline bases vechiles but is close , in another five years it will be cheaper than gasoline vehicles.

The equations have fundamentally changed in 20 years.

Volvo or any large maker has no need to be first in the market , they just need to have good enough product when adoption kicks in, their network, brand and service will be enough to compete.

While they will invest, they don't need to bet the farm in a make or break product that startups will need to do.

> Since when has listening to an authority on a topic been a bad thing?

It isn't a bad thing, but a reasoned argument is always preferable to an appeal to authority. This is especially true when there is scant evidence of actual authority.

Not true.

They had a pilot program (limited to Scandinavia) some years ago. I think they decided to pivot from personal vehicles to trucks due to the lack of charging stations (all government funding was allocated for EV chargers back then, so thanks a lot Elon).

Shell also invested heavily in hydrogen production for trucks at their oil refineries in Scandinavia a year back or so.

I've heard one of Elon's other sidegigs deals with a buttload of hydrogen per launch...

SpaceX does not use hydrogen in its rocket engines.

https://en.wikipedia.org/wiki/SpaceX_rocket_engines

No, but they’ll have to make a bunch of hydrogen for synthesizing that methane eventually. (Won’t make sense to do that until we mostly phase out fossil fuels from the grid.)

I agree with him that hydrogen won't be a viable solution for cars in general. However for owners of large fleets of trucks traveling fixed routes I can see it working in many cases.

I think we should invest way more in trains. They are basically long electric trucks that don't have to bring their batteries with them. All its advantages, with the disadvantage of being on a REALLY fixed route. We should only do last mile with other means of transport

Likely not realistic. Rail in the US, speaking modernly, tends to wind up being an expensive boondoggle even on fairly short routes.

The US has one of the best freight rail networks in the world. It is far from a boondoggle. There is potential to further expand it, and reduce carbon emissions through electrifying tracks.

Passenger rail is a whole separate problem.

How much of that is legacy routes where the cost of securing rights of way, dealing with NIMBYs, etc, is long since sunk? It hasn't gotten any easier.

There are medians in the middle of every freeway in the United States just begging for train tracks.

eHighway[0] anyone?

[0]: https://www.dw.com/en/germany-tests-first-ehighway-autobahn/...

+1. Want energy-efficient, electric-based transportation? Electric trains between major routes, they could even be autonomous, or at least don't need a meat engineer on cockpit. Electric small trucks to carry from hubs to final destinations.

Need more monorails it worked out well for Ogdenville

What stands out in this is that basically: if you want to make synthetic fuel for higher energy-density than batteries, synthetic propane or methane look better.

If you're going for a synthetic hydrocarbon, you might as well go for one which is liquid at normal operating temperatures, which makes logistics a lot easier.

So are liquid hydrocarbons as easy to synthesise as gas ones? (I genuinely have no idea, just wondering)

No. Methane is the easiest hydrocarbon fuel to synthesize, although the CO2 capture requires some energy. The others require increasing amounts of CO2 for the same fuel energy and also have higher energy losses in synthesis and combustion.

Ammonia has no CO2 requirement but the hydrogen to ammonia energy conversion process (Haber process) is slightly less efficient than that for methane (Sabatier).

From methane you can relatively easily produce methanol, which also has a relatively low ratio of carbon atoms vs others. Sure, not as energy dense as, say, kerosene, but an easy to handle liquid.

That’s true, but that means losses.

I don't know why you're getting downvoted, your points are surely valid.

They will not be carrying the hydrogen in a compressed form. Most solutions are to carry the water and split the hydrogen and oxygen on demand. This reduces risk of explosion.

That makes no sense, it's takes much more power to split hydrogen from water than you get out of it. Where does the power come from to split the water?

https://www.cummins.com/fuel-cells

https://www.youtube.com/watch?v=ECNO_FFk7Hw

https://www.youtube.com/watch?v=fP_1Fe6sET4

Uses hydrogen (H2) not water (H2O), again H2 has to be split from O with energy somehow.

I edited and added some videos on HHO systems. It's a demonstration of splitting the H2O on the move rather than carrying a gigantic tank of liquid hydrogen.

You're describing an 'infinite energy' device. The Cummins link does not support your claim, no credible firm or engineer will claim to be able to do this.

The maximum amount of energy you can get out of combining hydrogen and oxygen is exactly the minimum energy required to split water into it's components.

its components.

This is physically impossible perpetual motion.

Do you have any links I can read about solutions like this? My understanding is that producing hydrogen through electrolysis takes more energy than it produces. How would you power this in mobile applications?

https://timecube.2enp.com/

If you somehow have access (on a vehicle? On the move, even?) to the _massive_ amount of energy required to split water into Hydrogen and Oxygen, just skip the hydrogen fuel cell and use the energy to move the vehicle.

There are more ways than electricity to split water: https://www.wired.com/2011/05/bio-engineering-algae-to-make-...

How efficient are algae at making hydrogen vs a solar cell splitting water with electrolysis?

How efficient is that vs just charging a battery with the solar cell?

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