Future of Hydrogen Fuel Cells to Power Your Sailboat

[friz]

Originally Posted by Dooglas

If anyone thought that hydrogen fuel cells are a green solution, you need to think about how the hydrogen fuel is produced. The commonest way to produce hydrogen is a process involving heat and fossil fuels. No green benefit there. The alternative is producing hydrogen by electrolosis which requires a substantial amount of electricity. This is actually quite energy inefficient as you have to first produce the electricity, use it to produce hydrogen, then use hydrogen to produce electricity in fuel cells.

Party pooper! Another inconvenient truth. Actually, thanks for a dose of reality.

[zstine]

Originally Posted by Dooglas

If anyone thought that hydrogen fuel cells are a green solution, you need to think about how the hydrogen fuel is produced. The commonest way to produce hydrogen is a process involving heat and fossil fuels. No green benefit there. The alternative is producing hydrogen by electrolosis which requires a substantial amount of electricity. This is actually quite energy inefficient as you have to first produce the electricity, use it to produce hydrogen, then use hydrogen to produce electricity in fuel cells.

The Solar Planet boat makes Hydrogen on-board from Solar power and electrolysis. Hydrogen storage much lighter weight than storage in Li batteries... so that seems like fairly green Hydrogen to me.

[AKA-None]

And remember that it takes less energy if you go slower

[Dooglas]

Originally Posted by zstine

The Solar Planet boat makes Hydrogen on-board from Solar power and electrolysis. Hydrogen storage much lighter weight than storage in Li batteries... so that seems like fairly green Hydrogen to me.

Except that the equipment to conduct hydrogen electrolosis and hydrogen storage is complex, expensive, and adds weight. I am not convinced this gains anything over solar panels and Li batteries - when the wind doesn't blow. Remember, we are talking sailboats here .

[Adelie]

Originally Posted by zstine

One of those Solar powered boats, planet solar I think, uses power from the solar panels to make hydrogen on board for energy storage b/c it is much much lighter than Lithuim batteries. while maybe not energy dense, sometimes light weight is more important than small size. the hydrogen is then converted to electric with a fuel cell, though it would be interesting if solar to hydrogen then ICE engine is viable as an ICE engine would save $ over fuel cells.... In any case, with green/solar powered boats hitting the market, I wouldn't be surprised to see hydrogen in some production boats in the next decade.

Hydrogen itself is lighter than lithium per kW but with hydrogen you have to have a pressure container which decreases the effective advantage to about 4. Including the weight of electrolysis equipment and the compressors the advantage drops further to 2 or less. At that point the relative electrical efficiency comes into play and you start having to look at how much weight is involved in the extra solar panels, wiring, controllers and structure to support all that. I would say LFP is even or better than Fuel cells for net specific energy.

Planet solar was built a while ago and the choice for fuel cells was probably made based on a price basis, LFP was pretty expensive.

[danstanford]

The place fuel cells will proliferate in my view is as a battery for storage of power at sites producing more power than needed at certain times of day. Imagine a wind farm making power like mad at night and having no need for it and no way to store the power.
As the materials and technology evolve it seems to be a perfect fuel source for electric boats. The new medium sized cell being made is exactly what I envisioned when I first got my electric boat for those longer trips to add range or at least comfort that you had it if you needed it.

[Adelie]

Electrolyzing hydrogen has a 20% efficiency loss. Let’s say that drops to 15%. A big if but let’s assume.
And there’s another 10% loss pressurizing it for storage.

Fuel cells are 60% efficient. Let’s say that climbs to 85%.

So we lose 15% making the hydrogen, 10% compressing it and another 20% turning it back into electricity. That’s 55% of our original energy. (Actually the math doesn’t quite work that way but close enough).

Pumped hydro is already providing 75-87% efficiency right now.
Various molten salt battery technologies are already in the 75-85% efficiency range.
For Grid storage hydrogen is not the answer.

As a portable fuel it has potential in specific uses such as long range aircraft. Well see if that pans out, ammonia seems like a better portable fuel to me.

In addition to efficiency problems safety issues are much larger with hydrogen.
Hydrogen has too may drawbacks to become a primary fuel source except for specific niche uses.

[upstateny]

Originally Posted by Adelie

So we lose 15% making the hydrogen, 10% compressing it and another 20% turning it back into electricity. That’s 55% of our original energy. (Actually the math doesn’t quite work that way but close enough). .

Thanks for all the replies and math. This is kind of what I thought since H2 fuel cells have not taken off.

Amelie your post showing 55% of original energy hit me. In another forum folks posted the cost of their electricity. California and New England were posting electric cost north of 25¢ per kWh. Many other locations in USA were 12¢ per kWh. I recently paid 12.3¢ but average 15¢ here in upstate NY. My question is does that mean California and New England will/does not embrace electric cars due to double the cost of electricity? I wonder, just maybe the efficiency is not that important given the popularity of electric cars in California.

[Adelie]

Amelie was a great movie, I highly recommend it.
Adelie is a type of penguin. They are what my boat is named for.

Electric prices in San Diego are about to go up, I used the new numbers below.
Electricity costs
CA - $0.33/kWh
NY - $0.12/kWh
MN - $0.1135/kWh
TX - $0.066/kWh

Right now in San Diego I'm paying $4.50/gal for regular gas
In NY average price is $3.08/gal.
In MN average price it $3.00/gal
In TX average price it $2.80/gal

I looked up battery capacity and range for various electric cars,
and EPA MPG for various comparable vehicles.

I included the I3 REX which has a range extending engine in it which increases vehicle weight and decreases electric only range. This is the vehicle I will probably buy when my current vehicle is no longer reliable enough for work. Probably in about 2yr or so.

The attached graphic shows FUEL cost per mile for each vehicle in each locale. This is not the total vehicle cost per mile, only the fuel cost. When I need to replace my car I will do that analysis.

In San Diego I can get an EV rate plan where I can charge my car at $0.09/kwh at night. It has impacts on the rate during the day so if I get an electric car I will do that analysis then too.

Regardless, the least efficient EV on the list is pretty much even with most efficient gas vehicle on a price per mile basis and only in southern California, everywhere else there is a 2:1 or better cost per mile advantage for EVs.

[Adelie]

Oops, forgot to factor in charge efficiency. With batteries you have to account for energy in vs energy out. For Lion, that's about 93%.

Other than the I3 REX in SoCal, everywhere else there is significant cost advantage for an EV.
In SoCal if you go onto a Time Of Use electric rate plan, cost could be significantly reduced. The tradeoff is paying more for your household electricity used at peak times. I'll do that analysis when I get ready to buy.

[Na Mara]

Pure hydrogen has an impractically low energy density even in very compressed form, which is why pure hydrogen fuel cells haven’t taken off. What you need is a chemical carrier for the hydrogen that can achieve higher densities. Methanol is one such, as market by EFOY, but it has some issues, the main one being that the main way of producing methanol is steam reforming natural gas. So current available methanol is a fossil fuel. However, it has comparable energy density to combusted diesel (about a third). The other is that it requires exotic catalysts in the cell. Further, methanol is pretty toxic if it leaks out.

My understanding is that the commercial shipping sector is mainly focused on ammonia as a hydrogen carrier. Under commercially viable pressures it is a liquid at room temperature. That enables similar energy densities to methanol and ease of handling and portage with the bonus that it immediately evaporates off if it leaks. It’s also broadly nontoxic. But the biggest advantage is that it doesn’t require expensive catalysts

If commercial shipping goes the ammonia route, it won’t be long until it trickles down to yachties as well.

[Dooglas]

Originally Posted by Na Mara

If commercial shipping goes the ammonia route, it won’t be long until it trickles down to yachties as well.

The energy math works, but an ammonia leak inside a boat hull would seem like a non-trivial problem. In the presence of moisture (such as high relative humidity), liquefied anhydrous ammonia gas forms vapors that are heavier than air.

[Adelie]

I believe developments with ammonia in shipping have it being used in ICE engines with a little hydrogen for spice (needed for proper ignition if I recall).

Work is progressing on an ammonia fuel cell. We'll see about that.

Ultimately ammonia has a decent energy density and specific energy which is why I believe it will ultimately become the dominant fuel except in uses where cost is less important than energy density and specific energy. Those uses being aircraft and spacecraft.

In those cases I can see liquid hydrogen or synthetic hydrocarbons becoming the dominant fuels. In case you are wondering, gasoline/petrol & diesel can both be made from thin air (water and CO2) using the Fischer-Tropsch process, given enough energy to use.

[Adelie]

Originally Posted by Dooglas

The energy math works, but an ammonia leak inside a boat hull would seem like a non-trivial problem. In the presence of moisture (such as high relative humidity), liquefied anhydrous ammonia gas forms vapors that are heavier than air.

Ammonia storage and use will need to be in a compartment that vents overboard, like propane.

[upstateny]

Originally Posted by Adelie

Amelie was a great movie, I highly recommend it.
Adelie is a type of penguin.

I looked up battery capacity and range for various electric cars,
and EPA MPG for various comparable vehicles.

I included the I3 REX which has a range extending engine in it which increases vehicle weight and decreases electric only range. This is the vehicle I will probably buy when my current vehicle is no longer reliable enough for work. Probably in about 2yr or so.

Adelie, sorry for the name change. Darn iPad spell checking correction. Seriously thanks for all the info.

Talking about cars. Toyota is all in hydrogen and is fighting all electric battery cars. Toyota is betting that H2 cost will drop by more than half by 2025. Check out Motor Trend test drive for their Mirai all hydrogen fuel cell car driven in California of course.

https://www.motortrend.com/news/2021-toyota-mirai-hydrogen-fuel-cell-sedan-key-takeaways/


NY Times article " Toyota Led on Clean Cars. Now Critics Say It Works to Delay Them."