A viable pathway for hydrogen as fuel • Hacker News Board

Re: A viable pathway for hydrogen as fuel

#41

Post by semi-extrinsic » Sat, Feb 17, 2018, 7:33 PM UTC

nine_k wrote: post #26

semi-extrinsic wrote: post #25

Earlier quoted context omitted.

> the best engineering solution to the remainder of the task list of transport, store, and burn the resulting carbon-free hydrogen, is to modify the hydrogen by synthesize up some carbon containing hydrocarbons If that's the case, it's equally true for H2 from renewables, no? And I don't think it's true. LPG vehicles today are common enough, and they've solved very similar transport and distribution problems.

Not really. Hydrocarbons are much easier to store and handle. Cars may not need it so much, but as a jet fuel, kerosene is much easier than hydrogen.

Easier, sure. But Tupolev built and flew 100 flights with the Tu-155, a cryogenic H2 fueled narrow-body airliner, in the 1980s. So it's very far from impossible, it's just a matter of time IMO. Currently aviation is pushing biofuels to kick the can down the road, but they can't do that forever.

Re: A viable pathway for hydrogen as fuel

#42

Post by teraflop » Sat, Feb 17, 2018, 8:58 PM UTC

monkeycantype wrote: post #14

cornholio wrote: post #7

Earlier quoted context omitted.

But wait, a "tall, rangy, blond, inveterate maker and builder whose eyes light up when he talks engineering" claims he's solved all efficiency and and storage problems with super-secret technology. Incidentally, he's also the CEO of the company and probably paying for the piece: >To date, most hydride fluids have been less energy dense than compressed hydrogen, and far short of fossil fuels. They weigh too much for t…

I'm curious about his early career in video compression. I'm thinking of a friend whose first job was working with a video compression startup whose secret algorithm was to hide ethernet cables inside the power cord.

Did your friend work for Zekko, by any chance?

https://www.bizjournals.com/sacramento/stories/1999/03/08/st...

Re: A viable pathway for hydrogen as fuel

#43

Post by Obi_Juan_Kenobi » Sat, Feb 17, 2018, 9:34 PM UTC

Animats wrote: post #34

Something is wrong with his numbers. "Johnson boasts that his electrolyzer can produce hydrogen at about three or four times the rate of electrolyzers with similar footprints, using about a third the electrical current. That represents a stepwise drop in costs. " Three or four times? Current efficiencies are 65-70% for larger plants.[1] There's a theoretical maximum here; it takes a known amount of energy to break do…

Considering the smaller footprints are less efficient, then perhaps that makes room for a 3-4 fold improvement. Whether that's true is another issue, but at least it appears somewhat consistent.

Re: A viable pathway for hydrogen as fuel

#44

Post by parametrek » Sat, Feb 17, 2018, 9:40 PM UTC

ekun wrote: post #39

sebazzz wrote: post #17

Earlier quoted context omitted.

How does that compare to using batteries? Batteries are re-usable of course, but also degrade over time and need to be replaced.

It mentions this in the article Li-ion go have a life cycle of roughly 1,000 recharges whereas these have 10,000.

Depends on the li-ion. There are chemistries out there right now that are good for 20,000 cycles like LTO. And a substantial amount of li-ion research is extending cycle life.

It doesn't matter how good hydrogen becomes. Battery tech will continue to improve faster than hydrogen tech. H2 will never catch up.

Re: A viable pathway for hydrogen as fuel

#45

Post by georgecmu » Sat, Feb 17, 2018, 9:58 PM UTC

It's a puff piece (who's his PR firm? I want to talk to them!)

Those interested in the topic should acquaint themselves with the policy context and the state-of-the-art.

[1] https://energy.gov/eere/fuelcells/doe-technical-targets-hydr...

[2] https://www.nrel.gov/docs/fy14osti/60528.pdf

The DOE goal for cost of distributed / dispensed hydrogen is $4/kgH2. Cost of centralized production is estimated at half that even with electrolysis. I find it suspicious that there aren't any specific production cost estimates cited; just vague comparisons to unspecified existing technologies.

Also, methane is a far better source of hydrogen than water (less energy required to break down the molecule for the yield of twice as much hydrogen). Steam-methane reforming (95% of industrial hydrogen production) gets you hydrogen from both methane and water, but is a huge CO2 emitter (9-10 kgCO2/kgH2).

I'm personally a big proponent of thermal decomposition of methane [3]. Theoretical energy consumption is only 1.29 kWh/kgH2. if you can use a non-emitting source of energy, there's no CO2 emission. Carbon falls out as a solid and capture and sequestration is free. If you can make a valuable carbon (e.g. graphene) along the way, then you're set and there's no way electrolysis will ever be competitive.

[3] https://www.nrel.gov/docs/fy02osti/31351.pdf

Re: A viable pathway for hydrogen as fuel

#46

Post by jessaustin » Sat, Feb 17, 2018, 10:44 PM UTC

VLM wrote: post #23

semi-extrinsic wrote: post #21

Earlier quoted context omitted.

I really don't understand why the debate on H2 is so focused on electrolysis. Even today, 95% of all hydrogen is produced not by electrolysis, but from natural gas through steam methane reforming (SMR). SMRs can be easily scaled up to meet all H2 demand, and they are easily fitted with carbon capture technology (since it's a single large emission point). Then you have zero-emission H2 in quantities as large as oil an…

The problem with nifty solutions to removing carbon from raw fuels resulting in carbon free hydrogen, is the best engineering solution to the remainder of the task list of transport, store, and burn the resulting carbon-free hydrogen, is to modify the hydrogen by synthesize up some carbon containing hydrocarbons to make some delicious hyper optimized liquid fuels, which coincidentally we have massive infrastructure t…

You can burn anhydrous ammonia in a regular ICE. If we adopt GP's hypothesis that energy is cheap, then it's also cheap to turn H2 into NH3. We already have a robust infrastructure for the manufacture, storage, and transportation of liquid anhydrous ammonia. It does present some dangers to human safety, but so does any fuel.

If cars ever run on hydrogen in significant numbers, they'll actually be running on ammonia.

Re: A viable pathway for hydrogen as fuel

#47

Post by dpark » Sat, Feb 17, 2018, 10:51 PM UTC

DesertVarnish wrote: post #35

dpark wrote: post #33

Earlier quoted context omitted.

Methanol isn’t a common additive is it? Most (all?) gasoline in the US has ethanol added.

Methanol is commonly sold as "octane booster". It's definitely around.

Is it in common use as such? Meaning 92 octane is 88 buffered with methanol? If it’s just in those little octane booster bottles, I would not consider that a “substantial additive“ in the context of the trillion dollar petroleum industry.

Re: A viable pathway for hydrogen as fuel

#48

Post by jessaustin » Sat, Feb 17, 2018, 10:55 PM UTC

DesertVarnish wrote: post #35

dpark wrote: post #33

Earlier quoted context omitted.

Methanol isn’t a common additive is it? Most (all?) gasoline in the US has ethanol added.

Methanol is commonly sold as "octane booster". It's definitely around.

Around here it is used (in solution!) as ballast in tractor tires.

Re: A viable pathway for hydrogen as fuel

#49

Post by _ph_ » Sat, Feb 17, 2018, 11:10 PM UTC

mojomark wrote: post #31

_ph_ wrote: post #3

The article names it, but then does not dive deeper into it: the hydrogen chain has huge energy losses. First, electrolysis unfortunately has not a high efficiency - I have read numbers around 70%, but then the compression of the produced hydrogen takes a lot of energy, as compressing gases heats them up. Then the hydrogen has to be transported and stored, requiring further energy. Finally, you have to use the hydrog…

Did you read the full article? It's in there - he developed a new Titanium electrode to improve the efficiency ond reduce the footprint of the electrolysis hardware and he also developed a new hydride (with a weak H2 bond to support release of H2 using waste heat) for greatly improved energy density. The specific values are in the article; maybe someone nicer than me will do more work to pull that for you.

I rechecked the article, and I could not find any specific values in there. Care to point them out to me? I could only find some hand-wavy statements about a somewhat improved electrolysis device, but no numbers about its efficiency. Nor what those "hydrides" supposed to be.

Re: A viable pathway for hydrogen as fuel

#50

Post by ncmncm » Sun, Feb 18, 2018, 5:09 AM UTC

The hydrogen fuel pathway has already been solved, and much more elegantly.

Hydrogen produced by direct, catalytic hydrolysis from sunlight, in water, is taken up by microbes in the water that absorb CO2 and excrete hydrocarbons -- oil -- that floats to the surface, and is directly usable in existing fuel tanks and engines, no further processing needed.