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Floating Anodes and Cathodes

image credit: NWPB.ORG

In this post we review nautical electric vehicles. When I started writing this paper, I assumed that there would be some volume of fuel-cell nautical EVs, and also some battery-electric nautical EVs. I started with the latter, and found a large volume of these (hereafter BNEVs) already in service. When I got to fuel cell versions, I basically came up empty. Thus below will cover BNEVs, followed by a short section where we review possible reasons why I was wrong about hydrogen/fuel-cell ships.

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John Benson's picture

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Nathan Wilson's picture
Nathan Wilson on Jan 11, 2020 5:56 pm GMT

Ammonia powered ships may eventually be the maritime technology for zero carbon long haul shipping.  Batteries may catch on for short routes as your article points out, but hydrogen is worse than ammonia in almost every way!

Liquid ammonia has triple the energy density of 5000 psi gaseous hydrogen (without the need for high pressure storage vessels).  It even beats the density of liquid hydrogen, without the inconvenience of cryogenic temperatures.

Best of all, good efficiency (around 50%) can be achieved with specially made (in-expensive) internal combustion engines, so while certain fuel cells can be used, they are not required.

New Research Shows Benefits of Ammonia as Marine Fuel

Ammonia-fueled ships: entering the design phase 

Matt Chester's picture
Matt Chester on Jan 10, 2020 12:59 pm GMT

Thanks for this additional viewpoint, Nathan-- can you comment on why liquid ammonia doesn't seem to have the fervor behind it that development of hydrogen does? What are the drawbacks (perceived or real) that are holding it back?

Nathan Wilson's picture
Nathan Wilson on Jan 11, 2020 7:56 pm GMT

Hydrogen fervor?  Fossil fuel is still absolutely dominant in the transportation industry.  The vast majority of hydrogen and ammonia today are made from fossil fuel, hence they cost more than fossil fuel.  That's the main barrier to adoption.  The hydrogen projects that exist today are mainly public relations stunts and political messaging.  Hydrogen is more familiar to the public than ammonia (how much of the public knows that ammonia is NH3, and basically burns to form only water and air, and because of its popularity as a fertilizer is one of the most common industrial chemicals?).  Thus hydrogen has more PR value.  

However, as we evolve our electric grids to use more clean and sustainable energy, there will be more and more hours per year of excess (near-zero priced) clean electricity production.  That excess electricity can be used to make hydrogen or ammonia that could compete in price with gasoline and diesel (which are a few times more valuable than fossil gas).

Of course the fossil fuel companies want to make hydrogen and ammonia from fossil fuel with CC&S.  And advanced nuclear technology with >700C output temperatures may eventually produce affordable hydrogen and ammonia (using the Hybrid Sulfur process).  But these will likely require a big price on carbon emissions to be economical.

We've got a decade or two before large amounts of clean hydrogen and ammonia are available, but we should still start developing the market demand for these clean fuels now.  The excess clean electricity needed to make them will never be more than a quarter of the whole electricity market, so we should not believe the hype that hydrogen in the future will be as big a market as gasoline.  Our hydrogen and ammonia plans should focus on niche area where batteries and direct electrification are ill-suited, e.g.: long haul shipping, long haul trucking, perhaps even aviation (each of these favors ammonia over hydrogen BTW).

Matt Chester's picture
Matt Chester on Jan 13, 2020 3:25 pm GMT

Our hydrogen and ammonia plans should focus on niche area where batteries and direct electrification are ill-suited, e.g.: long haul shipping, long haul trucking, perhaps even aviation (each of these favors ammonia over hydrogen BTW).

This I completely agree with. There are multiple pathways towards decarbonizing the grid, and the debate seems mostly about picking out the optimal one. But these applications you point out have no immediate decarbonization pathway without a great advance in these types of fuels. 

John Benson's picture
John Benson on Jan 10, 2020 9:13 pm GMT

Thanks for the response, Nathan:

I came across some articles on using ammonia as a fuel a year or two ago, and spent some time researching it. I finally decided it didn't have a launch pad.

To explain: I learned my lesson earlier with another development that was supposed to be the wave of the future. The problem was it was competing against another similar (renewable) technology that was already very inexpensive, was still rapidly declining in price, increasing capabilities  and was very reliable. Furthermore there were no launch pads - that is, medium-sized niche applications that the new technology could address better than the existing technology and thus develop sales volume to fund additional development.

I looked at the first link in your response, and anything I said in this article about hydrogen and fuel cells applies to ammonia and solid oxide fuel cells (SOFC). They both still need a launch pad. I will grant you ammonia may be a better fuel (with SOFC, not all fuel cell technologies can use ammonia directly).

I would guess that aviation might be the launch pad for both of these technologies a decade or two from now. for more information on this see the paper (Flying Cathodes and Anodes Everywhere) linked in the introduction of this paper (and below). On the other hand, my former employer (Siemens) has produced combustion turbines that burn hydrogen - not too sure about ammonia.



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