A cheaper, better way to make hydrogen (82% efficiency)

In the battle between the Shark and the Tiger, I would not place my bet until I figured out if the battle were taking place on land or in the ocean. Likewise FCV vs EV fuel comparisons are rather dependent on what form the starting energy takes. If we start with electricity we get an extremely different answer than if we start with natural gas. Or in other words, the efficient race winner is determined by where the starting line is established.

 

I don't have a problem at all with ICE vehicles using sustainable fuel. In fact Boeing flies the Phantom Eye on H2 and a modified Ford car engine. The two important priorities are getting any and all vehicles to sustainable fuels and NOT picking favorites politically between any technology.

 

at post #41, FL-prius-driver hit the nail on the head. what's the starting line. In your premise that BEV's are better for shorter usage, you necessarily had to discount that Teslas have time & time again already driven the length and breadth of the U.S. ... and similarly, the starting line for hydrogen cars - in order to be better for longer range, means that billions in taxpayer funding was already - and willingly coughed up by taxpayers, and that hydrogen stations were necessarily already built, and that 10's of thousands of hydrogen cars too, already got built - so that the fueling stations could theoretically turn a profit. Or, maybe I misunderstood - is 'profit' an objective of FC refuel stations anywhere? If profit is not the objective of refueling hydrogen cars - yes, you could have just a handful of cars, & unprofitable government sponsored refueling stations. In this case ... even the notion of "better" has to be defined as whether we're operating on land or the ocean.
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Medical experts will tell you that you should
As for planning, I spend less time planning supercharger stops than hotels.

Back to price, I was referring to the CA rebates. However, I couldn't find information if the price includes those or not.

Is Japan providing Toyota with rebates for all FCVs sold, or just those sold in Japan?

 

Again with the double standard - bemoaning how (cheaper to build) quick charge networks are not yet on every corner ... and yet (the ungodly more expensive) hydrogen stations are not even on many states' agendas. So as it stands - your 1st break in 3 hrs - may take a few years, as you wait to find out whether or not more taxpayer money can be wrangled away from the public.
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Besides for metal hydrides' potential to being swappable at the local supermarket, I am against hydrogen fuel cells at this point. But improving the efficiency, and thus cost, of electrolysis made hydrogen is a big deal. It decreases the likely hood that FCEVs would just switch one fossil fuel for another. It is also good news outside transportation in using electrolysis and fuel cells for storage of off peak renewable electric production.

As for the waste oxygen, more O2 bars? Actually, I wonder if it could be used to improve the efficiency of a natural gas power plant or even *gasp* coal.

 

Let me be clear on this.
I'm all for advancing the technology of H2 and FCV.
This breakthrough could be important in terms of both efficiency and/or cost reduction.
But it will probably take 5 or more years before this has any affect on commercially available H2 refueling.

AND

I am a bit skeptical of the 82% number. The article does not say exactly what this is.
If you read this article
Electrolysis of water - Wikipedia, the free encyclopedia

they say that the "standard" for measuring electrolysis efficiency is based on declaring a certain input voltage (1.48V) as 100%. And that if you heat up the water first you can achieve > 100%. Of course this makes no sense from what we want as a numerical efficiency value. Some of the chemical energy created is coming from thermal energy.

So, it is highly likely that this 82% number is NOT a measure of net energy input divided by net energy output, but rather 82% as good as this standardized metric.

Mike

 

The actual paper.
Bifunctional non-noble metal oxide nanoparticle electrocatalysts through lithium-induced conversion for overall water splitting : Nature Communications : Nature Publishing Group

 

agreed, and not just cost reduction, but overall - this could turn hydrigen into a truly clean fuel source - as opposed to just distilling hydrogen from natural gas, a non-renewable. Yes, it may take years to bring this discovery to production, but if it pans out, that's one less miracle it will take (leaving costly infrastructure, & costly cars as the last hurdles) to bring hydrogen on as an affordable clean fuel to the masses.
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Here, I think, is the key sentence from the paper (they rounded the actual 81.5% to 82%):

By improving both OER and HER activities, the galvanostatic cycling method successfully elevates the efficiency of water-splitting electrolyser at 10mAcm−2 current to 81.5% using only one material, making good preparations for the scale-up of water photolysis/electrolysis with high efficiency and low cost.​

I don't pretend to understand all the details...but it seems that they are measuring percentage efficiency in terms of the Wikipedia article I linked to before...and NOT in terms of net energy out divided by net energy in.

Just to summarize.
In a BEV you will likely get about 75% of the energy delivered at the wall socket back to the wheels. This is a 10-15% loss of the charging side and another 10-15% loss on the discharge. (Of course this assumes zero overhead, no heat, no A/C etc.)

In a FC car you have losses from electrolysis, losses for liquefying, losses for compressing, probably some hydrogen leakage in the whole production and refueling, then more losses when the stored hydrogen gets converted back to electricity in the fuel cell. Just for round numbers, about 65% on the production of hydrogen and 65% on the fuel cell gives you a net 42%. But, that number is quite high.

Do a google search on "net energy efficiency of electrolysis" and the first hit is a .doc that has these numbers:

Hydrogen Production Storage Electrical Energy efficiency
Electrolysis Near-Isothermal Compression 30%
High-Temp Electrolysis Near-Adiabatic Compression 32%
High-Temp Electrolysis Liquefaction 22.5% <== the one we need​

source: ( pubpages.unh.edu/~msbriggs/HydrogenSummary.doc )

The value used for the electrolysis efficiency isn't broken out, but even assuming 60% and even assuming the 82% is the true efficiency...that would only raise the 22.5% number to (22.5 * 82/60) about 31%. In terms of cost per mile this does not compare favorably to a BEV. More than 2x as much electrical cost at the wall. AND some cost/depreciation on the electroyzer. Note...very little cost for an electrical charging station by comparison.

Refuel time.
The FCV wins on refuel time only on long trips; otherwise the BEV wins since it can be recharged at home at night or at the work place.

Mike

 

The pun Mike referenced: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCwQFjAA&url=http%3A%2F%2Fpubpages.unh.edu%2F~msbriggs%2FHydrogenSummary.doc&ei=12aTVcDZAYmagwTE5oDQCg&usg=AFQjCNFtdIIWWBWra8JCGzimqW0uWCpW3g&bvm=bv.96952980,d.eXY

For low temperature electrolysis, it uses an efficiency of 73%. The power plant efficiency is low, 35%, but is consistent if using nuclear. The fuel cell efficiency is low at 50%. 60% is more reasonable now.
But under those assumptions, the net energy is 10.6% of the electric production fuel gets to the wheels.
If the 81.5% is comparable to the 73%, then this process might mean 12% gets to the wheels.

edit: Found some more info here, Tesla Trumps Toyota: Why Hydrogen Cars Can&#039;t Compete With Pure Electric Cars | ThinkProgress, but it is siting another source.

"The entire process of electrolysis, transportation, pumping and fuel-cell conversion would leave only about 20 to 25 percent of the original zero-carbon electricity to drive the motor. In a plug-in hybrid, the process of electricity transmission, charging an onboard battery and discharging the battery would leave 75 to 80 percent of the original electricity to drive the motor. Thus, a plug-in should be able to travel three to four times farther on a kilowatt-hour of renewable electricity than a hydrogen fuel-cell vehicle could."

Best case, the improvement reported in the OP maybe a 14% efficiency increase in the electrolysis step. As I stated earlier, improving the electrolysis efficiency is important for renewable energy storage, but it is starting to sound like this breakthrough isn't enough for renewable hydrogen for FCEVs.

 

Nice I had been using 65 mpge for the mirai, but Toyota has now given its epa estimate of 67 mpge, so we can chug through this efficiency chart and see again if it looks real.

As talked about before the chart is low on methane to electricity conversion, but for the sake of this post lets assume toyota's efficiency.

The other huge problem with this chart is it assumes all the power for hydrogen and bevs comes from natural gas, that no hydro, nuclear, geothermal, wind, etc is used. The fuel cell advocates have lately been harping on the california mandate of 30% renewable. Let's use that figure for both, 30% renewable electricity. Current hydrogen takes about 60kwh of electricity to make 1 gge of hydrogen, but 43 kwh is a lowest estimate so lets use that.

0.7 gge of hydrogen @ 67% efficiency of natural gas = 1.04 gge natural gas
0.3 gge of hydrogen @ 43 kwh to produce 1 gge /33.7kwh/gge = ..383 gge of electricity.

Currently natural gas is more efficient but using toyota's 39% figure1.04 gge nat gas x 39% +.383 gge electricity = 0.79 gge at the plug.

Compare Side-by-Side
Now using the same energy
mirai 67 mpge = 67 miles
tesla 70D 101 mpge = 80 miles
bmw i3 124 mpge = 98 miles
tesla 85d 100 mpge = 79 miles
leaf 114 mpge = 90 miles

For the gen II volt we need to decide percent electric, but this gets messy. Let's say it is
67% electric miles @102 mpge
33% gasoline miles @43 mpg

Using toyota's 84% efficient oil to gasoline and some algebra we get
gen II volt 78 miles on 0.71 gge oil, .33 gge natural gas, and 0.383 electricity (oil plus natural gas same as mirai)
gen II volt 78 miles so the mirai is 86% as efficient as the gen II volt, but substitutes more natural gas than oil, but the volt could use more renewables.

I'm not sure how you use the california 30% renewable requirement and get a bev or phev to be less efficient than a fcv. Its time to throw away that chart and its bad assumptions.
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Nasa has proven over the decades that FCV works in the hostile environment of launches, vacuum, temp extremes, and constant radiation bombardment of space. If it works in space, it sure as heck can work in the 100 + temps of Death Valley to the sub zero temps of Alaska.

Factors of production, initial government / industry investments, tax credits will also help expand FCV and hydrogen generation. This approach helped with BEV technology, it will help with FCV fuel technology.

DBCassidy

 

Sure, when cost is essentially not an issue

Mike

 

I'm still not convinced that the 81.5% is actually what you think it is.
Can you address the definition of the electrolysis metric on wikipedia vs the article?

Mike