Comments on: The Coming Hydrogen Economy

By: daedalus2u

daedalus2u — Fri, 02 Sep 2011 02:24:33 +0000

I read some more about NH3BH3 and I am confident it will never be used to store H2 to power fuel cells for vehicles.

NH3BH3 does have a very high hydrogen density. It is also unstable so that H2 can be released spontaneously via an exothermic reaction. That reaction gets fast (and self-accelerating) at ~120 C. There are two ways to get H2, decomposition and hydrolysis. Hydrolysis yields a bit more H2, but requires H2O and is more exothermic, meaning that there is more energy lost in the cycle of storing and liberating H2. The spontaneous liberation of H2 depends on the levels of impurities and the temperature.

Neither of the two reactions are reversible, such that the material can be recycled via simply using H2, it requires more complicated chemistry with more energy losses. Boron is pretty toxic, and some of the boron-hydrogen intermediates in the regeneration of NH3BH3 are very toxic. Some of them are also pyrophoric. I think the combination of toxic, pyrophoric, unstable, requirement for offsite regeneration and high energy losses during regeneration will make this technology approach not feasible. It would require a large infrastructure to make, store, transport, deliver, recover the byproducts, return them to the central location to reprocess them.

Electric vehicles with batteries are considerably more efficient than H2 vehicles due to the losses in H2 generation, storage and use in fuel cells.

By: ncbill

ncbill — Fri, 02 Sep 2011 00:50:18 +0000

Vehicle fuel cells (PEM fuel cells) are unfortunately burdened with the requirement that they can only use hydrogen.

However, some types of stationary fuel cells can use common gaseous or liquid fuels directly, and are already being tested (e.g. the “Bloom Box”)

By: tmac57

tmac57 — Thu, 01 Sep 2011 15:28:30 +0000

Concept for a new magazine:

‘Popular Science in Perspective’

What do you think Steve?

By: Steven Novella

Steven Novella — Thu, 01 Sep 2011 13:08:21 +0000

Daedalus does raise another feature of such technology I did not raise above – the cost and the materials, which includes disposal. It would be nice if our batteries and fuel cells were not made of rare and expensive materials, or toxic materials that will clog our landfills.

So yet another feature to consider.

It’s not easy to come up with a technology that meets all the requirements to a reasonable degree, and any one feature can be a deal killer.

By: daedalus2u

daedalus2u — Thu, 01 Sep 2011 03:11:42 +0000

I misread the abstract. The paper Dr Novella reported on is about the anhydrous release of H2 from NH3BH3, the paper I cited is about the catalytic hydrolysis of NH3BH3 + 2H2O –> NH4BO2 + 3H2.

I will read it more carefully.

By: daedalus2u

daedalus2u — Thu, 01 Sep 2011 00:16:33 +0000

You could mail it to me via my corporate email through my company, nitroceutic.com

There is an email address for me there there.

The real problem with hydrogen is that is is so dangerous, it has such a low ignition energy and it is such a small molecule that it leaks through any elastomer. It is nothing like any other gas. Air is trivial to seal compared to H2. So is natural gas. All connections would have to be metal-metal seals.

You wouldn’t be able to take H2 fueled vehicles into below ground garages, into tunnels, or into garages attached to houses. It would be too dangerous.

By: nybgrus

nybgrus — Wed, 31 Aug 2011 22:58:43 +0000

I had a roommate in college once who was from New Zealand doing an exchange program for his PhD work on fuel cells. He was very much of the same opinion – it is a bad middleman to use hydrogen for fuel cells of cars. One other esoteric consideration was hydrogen escape. Lets say we do have some perfectly green way to make electricity (say, great solar tech or something) and we hydrolyze water like crazy to be an energy storage medium and power the world with it. There would inevitably be leaks, accidents, and loss no matter how good the process was. The reason hydrogen is so rare to find on earth is because it is so light it readily escapes our atmosphere. So imagine a century or two of the world being powered through hydrogen via our water supply on earth and a (small) fraction of that escaping into space via hydrogen, never to return to the water cycle. We would literally be evaporating our planet. Although, it may end up being a way to combat rising water from global warming

Just a random thought.

@d2u: I have institional access to the full article. I am not sure what the ethics/legality would be, or how exactly we would accomplish it, but I can in theory get you the full article if you really want to read it. Perhaps save it as a PDF and email it to you via your blogspot?

LMK

By: neilgraham

neilgraham — Wed, 31 Aug 2011 22:30:54 +0000

I really appreciate this article. The one thing that keeps me interested in this blog – and, to a large degree the SGU – is the honesty of the presenter demonstrated by his willingness to critique ‘science’ as well as expose psuedo-science. The scientific method at work!

By: robm

robm — Wed, 31 Aug 2011 19:10:54 +0000

While I’m a big fan of fuel cell technology, right now hydrogen cars seem as feasible as flying cars. Besides storing the hydrogen, the fuel cells that are practical for use in cars are very expensive, and there is currently no proven method of creating large quantities of H2 that doesn’t create a lot of CO2 in the processes. Hydrogen or electric cars will only make sense if electricity production is green.

By: PharmD28

PharmD28 — Wed, 31 Aug 2011 18:58:32 +0000

Hell, at this point I would fall over backwards if I could buy a diesel minivan – probably would get like 30mpg avg. At least I have my diesel wagon though

Have you all done much previous discussion on this site about electric cars, hybrids, and such? Gonna check it out when I get some time.