Hydrogen vs. Battery

[dpeilow]

This document (originating from Shell) has some interesting numbers on the energy use of a station electrolysing hydrogen on site: http://www.phaedrus-project.eu/userdata/file/Public deliverables/PH-D1.1-Report on fuelling system requirements and targets for capex and opex.pdf

However, I cannot get my head around why the 200kg per day system uses more energy per kg of hydrogen than the demonstration 5kg per day system. Can anyone work it out?


EDIT possible answer here: https://www.sciencedirect.com/science/article/pii/S0360319917339435#bib34

Efficiency and environmental impact
Six of the ten interviewees indicated that improvements in efficiency are possible but not prioritised for two reasons. First, relatively low electricity cost and non-continuous operation in the given case study mean that operating costs are small, so that reduction of capital costs has priority. Second, efficiencies are maximised at low current density, but to reduce capital costs, however, research is focussed on increasing current density. Experts also highlight that system efficiency alone is not the most important factor, but rather the efficiency including hydrogen purification and pressurisation for its final application

 

[JeffK]

why the 200kg per day system uses more energy per kg of hydrogen than the demonstration 5kg per day system.

Compression?

 

[mspohr]

This document (originating from Shell) has some interesting numbers on the energy use of a station electrolysing hydrogen on site: http://www.phaedrus-project.eu/userdata/file/Public deliverables/PH-D1.1-Report on fuelling system requirements and targets for capex and opex.pdf

However, I cannot get my head around why the 200kg per day system uses more energy per kg of hydrogen than the demonstration 5kg per day system. Can anyone work it out?


EDIT possible answer here: https://www.sciencedirect.com/science/article/pii/S0360319917339435#bib34

This seems to describe a hypothetical new system which might achieve better efficiency. A key part is electrochemical compression but I have no idea how that works and it's not in the paper.
"The major objective is to develop and validate a new concept for 70 MPa hydrogen refuelling retail
stations by showing the applicability of electrochemical hydrogen compression technology in combination
with a PEM electrolyser, storage units and dispensing system. The use of electrochemical hydrogen
compression technology is a step change in both the efficiency and cost of ownership of an integrated
hydrogen refuelling system. The applicability will be demonstrated in a fuelling system producing 5 kg
hydrogen per day, while a design is made for a fuelling system capable of producing 200 kg hydrogen per
day. Safety aspects, efficiency and economic viability of the system’s components will be analysed and
validated as well.
"

 

[Saghost]

This seems to describe a hypothetical new system which might achieve better efficiency. A key part is electrochemical compression but I have no idea how that works and it's not in the paper.
"The major objective is to develop and validate a new concept for 70 MPa hydrogen refuelling retail
stations by showing the applicability of electrochemical hydrogen compression technology in combination
with a PEM electrolyser, storage units and dispensing system. The use of electrochemical hydrogen
compression technology is a step change in both the efficiency and cost of ownership of an integrated
hydrogen refuelling system. The applicability will be demonstrated in a fuelling system producing 5 kg
hydrogen per day, while a design is made for a fuelling system capable of producing 200 kg hydrogen per
day. Safety aspects, efficiency and economic viability of the system’s components will be analysed and
validated as well.
"

Interesting. It's apparently something like an ion engine, using electric charge to push the protons into high compression, then returning the electrons:

Electrochemical hydrogen compressor - Wikipedia

 

[mspohr]

Interesting. It's apparently something like an ion engine, using electric charge to push the protons into high compression, then returning the electrons:

Electrochemical hydrogen compressor - Wikipedia

Interesting. Theoretically very efficient. Of course, the problem is that when using the hydrogen, all of that compression energy is lost when expanding the hydrogen. It looks like simple mechanical compression or liquefaction of H2 is 90% efficient so that is not the main problem with H2 vehicles. It's the fuel cell which is only 50% efficient and electrolysis which is 75% efficient (50% x 75% = 38%). These factors pale in comparison to a battery which is 85% efficient.
The paper is old (2013) and projected a pilot in 2015... haven't heard about any progress.

 

[dpeilow]

It works a bit like an electrolyser in that hydrogen is forced through a membrane with the build-up on one side creating the pressure. There are a couple of EU funded projects going on to scale up and demonstrate a larger station using this technology.

As in the quote above, it seems that there is a trade-off between current density (which in turn drives the size or number of electrolysers you have and hence capex) vs. the efficiency of the electrolyser. In the small pilot plants they optimise for efficiency, as the capex isn't that high anyway. For the next round of demo plants (200 kg / day etc) they are optimising for capex as it is already in the millions. Therefore they are not so bothered about their opex as the cost of electricity is proportionally less compared to what they have to amortise from the plant cost. Efficiency is getting sacrificed. It's the opposite of what you would expect to happen.

I have assumed that this will happen going forward and incorporated it into my calculations for the presentation I have posted here before. I have also updated it to included 2017-18 UK grid emissions (lower than before) and the Hyundai Kona as the main EV comparison as the Bolt never went on sale here. Feedback welcome as always.

Dropbox - Hydrogen Presentation Short.pdf

 

[dpeilow]

I quite often hear people say stuff like, "ok maybe it doesn't work for cars and trucks but really big stuff like ships could be powered by hydrogen". So I decided to look at the case of a hydrogen-powered tanker bringing hydrogen to the UK from the Middle East. Kawasaki Heavy Industries is proposing to build a ship that can take 160,000 m^3 of liquid hydrogen from Austrailia to Japan. It is based on their qualified natural gas ships that carry a similar amount.

However it appears that loading a container ship with ISO containers full of the stuff actually carries more.

A 40ft ISO tank can take 41.6 m^3 volume and weighs 19t gross with 3t of LH2 in it: Gardner Cryogenics

The Emma Maersk is a large container ship that Maersk says has 11,000 TFE (twenty foot equivalent) capacity. They work this out by assuming each container weighs 14t on aveage, giving total capacity of 154,000 tonnes. They also use 30 MW when cruising.

Some sources say it will actually carry 15,000 TFE based just on number of containers, so 7,500 40ft containers.

7,500 containers gives 22,500 tonnes of hydrogen. That's double the specialised ship the Japanese are proposing. If you look at the format of those specialised gas tankers, they have large spherical tanks which waste a lot of volume in the ship. Is the ISO container route actually better? Am I missing something here?

 

[cwerdna]

Not sure if this is the right thread for this...

I recently heard an NPR story on FCEVs in Japan via their app.

I found it via Japan Is Betting Big On The Future Of Hydrogen Cars but the text there doesn't match up completely w/what's in the under 4 minute audio clip (e.g. example is a mention of an H2 station that says they get a max of 15 customers a day).

Only about 11,000 fuel cell vehicles are on the road worldwide. Nearly half of them are in California, which has stringent vehicle emission regulations and tax credits that incentivize electric and fuel cell vehicles.

 

[JohnSnowNW]

Not sure if this is the right thread for this...

I recently heard an NPR story on FCEVs in Japan via their app.

I found it via Japan Is Betting Big On The Future Of Hydrogen Cars but the text there doesn't match up completely w/what's in the under 4 minute audio clip (e.g. example is a mention of an H2 station that says they get a max of 15 customers a day).

Japan and California are great examples of why FCEVs can't compete in the market place. Japan also has great incentives for the purchase of FCEVs, along with 3x the number of H2 stations as CA, but less FCEVs on the road. On top of that, FCEVs, in Japan, (at least as of 2017) had been primarily purchased by Govt. and fleets...which skews actual public interest. You would also think the fact that Japan is basically 100% drivable with current infrastructure would incentivize FCEV purchases, yet more people in the US are willing to own a vehicle that is essentially drivable in <10% of the country.

In the instance of CA, automakers are essentially paying consumers to drive them...which is ridiculous on its face, and obviously untenable.

Anyway, I would say that Japan's bet is more of a bluff...and one that's going to cost Japan and California a great deal of money.

 

[Saghost]

Japan and California are great examples of why FCEVs can't compete in the market place. Japan also has great incentives for the purchase of FCEVs, along with 3x the number of H2 stations as CA, but less FCEVs on the road. On top of that, FCEVs, in Japan, (at least as of 2017) had been primarily purchased by Govt. and fleets...which skews actual public interest. You would also think the fact that Japan is basically 100% drivable with current infrastructure would incentivize FCEV purchases, yet more people in the US are willing to own a vehicle that is essentially drivable in <10% of the country.

In the instance of CA, automakers are essentially paying consumers to drive them...which is ridiculous on its face, and obviously untenable.

Anyway, I would say that Japan's bet is more of a bluff...and one that's going to cost Japan and California a great deal of money.

It'll be interesting to see how FCEVs develop in California over the next few years. The CARB rules that gave them a big advantage over EVs for legacy manufacturers changed last year. Will we continue to see more FCEV models and production for CA, or will they die out now that they've lost the CARB credit edge?

 

[mblakele]

Anecdotal, but in CA I see about 50 Teslas for every Mirai. I tend to think the success of the Model 3 is closing the door on FCEV.

 

[BluestarE3]

It'll be interesting to see how FCEVs develop in California over the next few years. The CARB rules that gave them a big advantage over EVs for legacy manufacturers changed last year. Will we continue to see more FCEV models and production for CA, or will they die out now that they've lost the CARB credit edge?

Even under the old rules that heavily favored them, FCEV adoption in CA has been mediocre at best. Even here in Tesla, i3, Bolt/Volt, Prius country where people are more amenable to alternative fuel vehicles, I've seen fewer than a handful of Mirais over the years.

 

[mblakele]

This pdf seems to have the latest data available, plus projections for growth.

https://www.arb.ca.gov/msprog/zevprog/ab8/ab8_report_2018_print.pdf

 

[ohmman]

Anecdotal, but in CA I see about 50 Teslas for every Mirai. I tend to think the success of the Model 3 is closing the door on FCEV.

I see one Mirai in my area repeatedly, but hundreds of Teslas, and lots of Bolts. So up north of you, we're significantly more skewed towards BEVs.

 

[miimura]

I see Mirai regularly, like every day or two. However, I cannot even count all the Teslas, Bolts, and Leafs I see every day.
One interesting thing I saw was a row of Mirai at the Sunnyvale Toyota used car lot. While I can imagine someone leasing a new one that comes with fuel allowance, I cannot imagine buying one used where you are responsible for all the maintenance and fueling costs.

 

[jerry33]

I see Mirai regularly, like every day or two. However, I cannot even count all the Teslas, Bolts, and Leafs I see every day.
One interesting thing I saw was a row of Mirai at the Sunnyvale Toyota used car lot. While I can imagine someone leasing a new one that comes with fuel allowance, I cannot imagine buying one used where you are responsible for all the maintenance and fueling costs.

Plus they have an expiration date. Don't drive after ...

 

[brucet999]

Plus they have an expiration date. Don't drive after ...

Explain, please? For those of us who don't know much about hydrogen vehicles. Are the pressurized fuel tanks short-lived?

 

[jerry33]

Explain, please? For those of us who don't know much about hydrogen vehicles. Are the pressurized fuel tanks short-lived?

Yes. The problem is the same as with steam. Less than railroad type maintenance (when railroads used steam and maintenance was perfectly done (at least four nines) means a ticking time bomb. There is actually a do not drive after label on them. No idea how much a replacement system costs to allow continued driving. There are other issues as well, such as the pressure burn off shoots a flame straight up for a few feet.

 

[jelloslug]

Explain, please? For those of us who don't know much about hydrogen vehicles. Are the pressurized fuel tanks short-lived?

It's for any component that comes in direct contact with the hydrogen. Hydrogen causes a phenomenon called hydrogen embrittlement. The hydrogen itself impregnates the metals used in the system and weakens the materials. This can lead to cracks and failures in the high pressure systems in the cars, fueling stations, storage, and any other systems that come into contact with the hydrogen.

 

[RubberToe]

Plus they have an expiration date. Don't drive after ...

@jerry33 I thought you were joking when I read this, but per your follow ups below it seems you aren't joking.

Can you provide a link or a photo of a Mirai expiration date on any component? I have been following fuel cell car development pretty closely and am surprised I never heard of this before.

RT