Hydrogen and FCEVs discussion thread

[SageBrush]

What is the efficiency of electricity to hydrogen conversion?
I'm assuming that's where this is going.

There are actually multiple inefficiencies

1. Electricity to H2: About 70% conserved
2. Compression of H2: About 7% lost IIRC
3. Transport of H2: Who knows
4. Fuel Cell: About 65% used IIRC

So 0.7*0.93*0.65 = 42% of source electricity makes it to the motor ... if we ignore the transport to filling station problem, and the cost of filling stations. There is also the pesky problem of the cost of the fuel cell and its reliability.

A couple decades ago when Li-X cost over $1000 a kWh, H2 looked like it might be a fossil replacement. Today it is just silly. A methanol fuel cell might have some future life if the world agains decides to turn agriculture into fuel. It might yet happen for those applications that do better with a liquid, energy dense fuel.

[GRA]

A little over two years ago I spoke with a friend about his experience with H2 forklift refueling and I posted about what he told me. I concluded with the following:

It looks like there are real applications in the forklift industry (inside a freezer, for instance), but it seems to me that there is lots of room in that market for Li-ion batteries that has not yet been addressed.

It seems I was not alone in that assessment. A CA company named Flux Power was founded to address the space in the forklift market which is not well addressed by lead-acid batteries. It seems they are experiencing triple-digit YOY growth on their first-generation Li-ion battery offerings.

It will be interesting to see if their success continues. Given that both H2 and Li-ion each only have a small portion of the forklift market and both offer benefits over lead-acid batteries, I expect both technologies will continue to grow rapidly in this space for the next few years. But they will soon be competing for the same customers. I suspect each will have clear benefits over the other depending on the customer situation. Here are a few thoughts about what will weigh heavily in customers' decisions:

Benefits of H2 fuel cells in forklifts:
- Faster refueling: 3 minutes per shift versus 1 hour per shift (could be significant for two- or three-shift operations)
- No loss of power as fuel is used like is experienced with batteries (Li-ion is better than lead-acid, but H2 wins here)
- Available in 48V version for forklifts (both are available in 36V versions)

Benefits of Li-ion batteries in forklifts:
- Cheaper refueling infrastructure (In fact, these batteries are compatible with existing lead-acid recharging equipment)
- Cheaper fuel: In most cases, MUCH cheaper fuel.
- Likely higher reliability (H2 systems are simply much more complicated)
- Available in 24V versions for hand trucks (perhaps Plug Power has a similar offering?)
- Wider operating temperature range (both on the low and high ends, though I suspect you would not want to operation Li-ion batteries on the high end of the range given)

Specifications which are comparable:
- Runtime with a single refueling (using 75% DOD for the Li-ion batteries and 40% efficiency on the fuel cells gives about the same electrical energy output for similar-size products)

Characteristics which I cannot compare:
- Unit cost (though only the Li-ion battery says they provide lower lifetime costs than lead-acid batteries)
- Unit lifetime (Li-ion batteries are specified for 2000 cycles at 80% DOD and 3000 cycles at 70% DOD)

For reference, here are datasheets for the products which I am comparing:
- Datasheet for the Plug Power GenDrive 1000
- Datasheet for the Flux Power X-Series Li-ion Forklift Batteries

I'm in general agreement with the above advantages and advantages, and having used gas, diesel, propane and battery forklifts (and pallet jacks), I'd say that for multi-shift operations FCEVs win hands-down - you just don't have the down time to charge, especially when the shifts overlap and both of them are using the same equipment.

As to refueling infrastructure, that depends. I've used propane forks that refueled either from a large tank with a pump, or else by swapping of portable tanks on the forklift. The former is probably cheaper over the long term, but the only on-site infrastructure the latter method requires is a rack to hold the tanks; if you've ever swapped tanks at a supermarket, think a big version of that, with the tanks stored horizontally so they can easily be slid off the rack). Assuming H2 tanks can be swapped like propane can, the on-site costs are essentially zero.

Re efficiency, current fuel cells are apparently about 60% efficient. As for maintenance, sealed no-maintenance batteries should have the advantage here (flooded lead-acid were a pain, getting all sorts of gunk on their terminals, using hygrometers etc.), depending on the details of the fuel cell (does it need to be pressurized). The fuel cell's components can apparently be refurbished, while battery packs that aren't very new will quickly pull new cells down to the level of the old cells. From what I've read, fuel cell stack lifetimes are currently considerably longer than batteries.

I suspect at the moment it depends on your operating requirements as to which is cheaper, and there's not as yet any universal "best" answer for now.

[SageBrush]

What is the efficiency of electricity to hydrogen conversion?
I'm assuming that's where this is going.

There are actually multiple inefficiencies

1. Electricity to H2: About 70% conserved
2. Compression of H2: About 7% lost IIRC
3. Transport of H2: Who knows
4. Fuel Cell: About 65% used IIRC

So 0.7*0.93*0.65 = 42% of source electricity makes it to the motor ... if we ignore the transport to filling station problem, and the cost of filling stations. There is also the pesky problem of the cost of the fuel cell and its reliability.

A couple decades ago when Li-X cost over $1000 a kWh, H2 looked like it might be a fossil replacement. Today it is just silly. A methanol fuel cell might have some future life if the world again decides to turn agriculture into fuel. It might yet happen for those applications that do better with a liquid, energy dense fuel. Maybe ... but I doubt it. There is so much money and R&D occurring in battery technology that high density batteries seem all but inevitable, on the order of 5x what we have now.

[RegGuheert]

I'm in general agreement with the above advantages and advantages, and having used gas, diesel, propane and battery forklifts (and pallet jacks), I'd say that for multi-shift operations FCEVs win hands-down - you just don't have the down time to charge, especially when the shifts overlap and both of them are using the same equipment.

I agree in the case where shifts overlap into the break times. Otherwise, it seems that a one-hour quick charge could be accomplished during two 30-minute breaks each shift.

The drawback to charging only during breaks is that it creates very high peak electricity usage, which can drive costs up significantly. The question is whether it can drive costs up to H2 fuel cell cost levels

Assuming H2 tanks can be swapped like propane can, the on-site costs are essentially zero.

That assumption is almost certainly wrong. If you can support it with some reference, feel free. Plug Power ONLY discusses refueling, NOT swapping.

No, H2 fuel cells for forklifts are refueled using specialized refueling equipment. As I learned from my discussion with a friend, this equipment is extremely expensive. In that case, a four-station filling system for Plug Power fuel cells cost $3.5M. This is a huge drawback for fuel cells, which will limit their use to larger sites.

Re efficiency, current fuel cells are apparently about 60% efficient.

You may be right here, but that would only be true in the very latest units from Plug Power, which only recently started shipping:

Plug Power says it has created a new, more efficient fuel cell for its fork lift customers that the company says will reduce the need for refueling.

"This new GenDrive model stores more fuel on-board than earlier models, increasing run-time by 56 percent and reducing a customer's overall fueling time by more than 30 percent," the company said in a statement. "The first customer orders for these GenDrive units are scheduled to ship at the beginning of the third quarter of 2018."

I've read elsewhere that they increased the capacity of the storage tanks by about 10%, so that means the efficiency of the fuel cell must have increased by about 42%. Plug Power "plugs" this as reducing the number of refuelings from three per day to only two. This is an interesting claim, as it implies that there is value in saving those extra three minutes each day. In fact, Plug Power claims those three minutes have extremely high value:

"For a typical customer with more than 90 Class 2 vehicles, this translates to a projected productivity savings in excess of $400,000 over five years," Plug Power said.

I seriously doubt any company can translate that time savings into anywhere near that big of a dollar savings. I also doubt the third refueling is a big deal to any company which operates three shifts.

But it *does* indicate that Plug Power likely has a runtime benefit over Flux Power, at least for the time being. In the long run, Li-ion batteries will win out over fuel cells in terms of runtime. How do I know this? Simple: if we agree that fuel cells are 60% efficient today, then they can only ever realize a 38% efficiency boost before they reach their theoretical limit of 83%. OTOH, Li-ion batteries are a long way from reaching theoretical capacities. Many are expecting that solid-electrolyte Li-based batteries are capable of 1000 Wh/kg or even more. Since solid-electrolyte lithium batteries will have lower efficiency than their Li-ion counterparts, there will be a real tradeoff between capacity and efficiency. In any case, it should not be long before Li-ion batteries are capable of providing two full shifts of energy before needing a recharge, which will meet the needs of all but the most demanding warehouses.

The fuel cell's components can apparently be refurbished, while battery packs that aren't very new will quickly pull new cells down to the level of the old cells. From what I've read, fuel cell stack lifetimes are currently considerably longer than batteries.

While all of that may be true, there is a lot more to fuel cells than just the life of the stack. We know that Plug Power has had some problems with the reliability of their units. Perhaps that is why they have recently redesigned their units for better servicability:

These new units are designed with Plug Power’s proven ProGen hydrogen fuel cell engine technology which delivers increased efficiency and higher reliability. The new units include several significant enhancements such as larger fuel tanks for increased runtime (approximately 10%) and wireless communication capabilities for operations data and effective fleet management. With a new design that is focused on ease of service for both field technicians and customers, Plug Power also improved the product serviceability, reducing the time and effort required to work on the units.

It will be interesting to see how these new units stand up when compared with Li-ion batteries.

I suspect at the moment it depends on your operating requirements as to which is cheaper, and there's not as yet any universal "best" answer for now.

As I stated above:

I suspect each will have clear benefits over the other depending on the customer situation.

Overall, it seems that fossil fuels now have a home in high-demand materials handling applications.

[Oilpan4]

Last time I looked it up 70% is about double the electricity to hydrogen conversion efficiency anyone had been able to demonstrate.
50% was though to be achievable.
Is there actual living breathing proof of water electrolysis exceeding 50% anywhere?

I think methanol, natural gas, lithium batteries look way better than hydrogen.

For forklifts I saw one charging the other day on a pretty good size charger. It was running 262 amps at 44 volts.
All a company would have to do is have about 10% to 20% of the forklifts be spares for a 24hr operation like where I work and that would be a tiny fraction of the price of going to a fancy hydrogen system.

[WetEV]

Last time I looked it up 70% is about double the electricity to hydrogen conversion efficiency anyone had been able to demonstrate.

https://en.wikipedia.org/wiki/Hydrogen_production

50% was though to be achievable.

Round turn 50%. electric power + Water => hydrogen => compressed for storage => fuel cell => water + electric power

Hydrogen is a battery. A way of storing energy. Advantage is that the tank can be very large compared with the electrolysis and fuel cells. Disadvantage is poor efficiency and relative high cost.

Probably makes sense for seasonal storage of renewable energy.

Probably doesn't make sense for forklifts, cars, laptops and phones.

Might make sense for aircraft. Or hydrogen => methanol or similar liquid. Even lower efficiency, but liquids are easier to handle.

[Oilpan4]

Wikipedia still showing high temperature, high pressure electrolysis might be able to reach 50% efficiency.
So unchanged since 2006.

[GRA]

I'm in general agreement with the above advantages and advantages, and having used gas, diesel, propane and battery forklifts (and pallet jacks), I'd say that for multi-shift operations FCEVs win hands-down - you just don't have the down time to charge, especially when the shifts overlap and both of them are using the same equipment.

I agree in the case where shifts overlap into the break times. Otherwise, it seems that a one-hour quick charge could be accomplished during two 30-minute breaks each shift.

The drawback to charging only during breaks is that it creates very high peak electricity usage, which can drive costs up significantly. The question is whether it can drive costs up to H2 fuel cell cost levels.

When I was working as a (union) dockworker, there were two 15 minute coffee breaks and one 1/2 hour lunch per shift. The last coffee break overlapped with the next shift, and they used the equipment then and often from that point on. The other issue with BEVs is that you have to have charging stations in a fixed area of the dock and it must be kept clear, which means that part of the dock isn't available for freight to be staged. The forklifts also must be returned to that area for charging, but as that would normally be close to the break room they often get driven there in any case, so that's usually not a big deal. Pallet jacks are another matter.

Assuming H2 tanks can be swapped like propane can, the on-site costs are essentially zero.

That assumption is almost certainly wrong. If you can support it with some reference, feel free.

I can't , but I have no knowledge of what might prevent them doing so. Propane tanks are also under pressure, the gas is extremely cold when vented so you wear gloves when swapping tanks etc. Maybe there's some particular reason that this wouldn't be feasible with H2, but I don't know what that might be. If there isn't, then there's nothing that would prevent tank swapping, with the industrial gas provider simply putting full tanks in the storage racks and taking the empties away to be refilled, or filling them on site instead as the case may be. Otherwise, you fill using a big on-site storage tank and a compressor.

Plug Power ONLY discusses refueling, NOT swapping.

No, H2 fuel cells for forklifts are refueled using specialized refueling equipment. As I learned from my discussion with a friend, this equipment is extremely expensive. In that case, a four-station filling system for Plug Power fuel cells cost $3.5M. This is a huge drawback for fuel cells, which will limit their use to larger sites.

Sure, but prices will come down with economies of scale (in production and deployment along with technical improvements, just as they have with batteries.

Re efficiency, current fuel cells are apparently about 60% efficient.

You may be right here, but that would only be true in the very latest units from Plug Power, which only recently started shipping:

Plug Power says it has created a new, more efficient fuel cell for its fork lift customers that the company says will reduce the need for refueling.

"This new GenDrive model stores more fuel on-board than earlier models, increasing run-time by 56 percent and reducing a customer's overall fueling time by more than 30 percent," the company said in a statement. "The first customer orders for these GenDrive units are scheduled to ship at the beginning of the third quarter of 2018."

I've read elsewhere that they increased the capacity of the storage tanks by about 10%, so that means the efficiency of the fuel cell must have increased by about 42%. Plug Power "plugs" this as reducing the number of refuelings from three per day to only two. This is an interesting claim, as it implies that there is value in saving those extra three minutes each day. In fact, Plug Power claims those three minutes have extremely high value:

"For a typical customer with more than 90 Class 2 vehicles, this translates to a projected productivity savings in excess of $400,000 over five years," Plug Power said.

I seriously doubt any company can translate that time savings into anywhere near that big of a dollar savings. I also doubt the third refueling is a big deal to any company which operates three shifts.

Depends. The propane forklifts I used to drive would typically last one shift, plus or minus an hour or two depending on how they were being used. But three minutes is pretty much the minimum time, and they can easily take a lot longer. If (as often happens), the fork is driven until empty (the gauges were not very accurate), then another fork is needed to push it out to the fueling site, taking two people and two forks off-line at the same time. IME some people do this deliberately to provide some extra break time, and aren't in any hurry to complete fueling. I've long felt that they should provide an emergency supply that would require some sort of "get out of your seat" activation, as well as rules that penalize people for playing this game.

With tank swapping, that will normally take longer depending on where you are when you run out, as you have to find a hand truck, bring it back, unscrew the fuel feed line, remove the tank, wheel it out to the storage rack (always outside), get a new tank, and reverse the above. 5 minutes minimum, 10 minutes is pretty common, but you're only taking one person/forklift out of action.

But it *does* indicate that Plug Power likely has a runtime benefit over Flux Power, at least for the time being. In the long run, Li-ion batteries will win out over fuel cells in terms of runtime. How do I know this? Simple: if we agree that fuel cells are 60% efficient today, then they can only ever realize a 38% efficiency boost before they reach their theoretical limit of 83%. OTOH, Li-ion batteries are a long way from reaching theoretical capacities. Many are expecting that solid-electrolyte Li-based batteries are capable of 1000 Wh/kg or even more. Since solid-electrolyte lithium batteries will have lower efficiency than their Li-ion counterparts, there will be a real tradeoff between capacity and efficiency. In any case, it should not be long before Li-ion batteries are capable of providing two full shifts of energy before needing a recharge, which will meet the needs of all but the most demanding warehouses.

With the caveats noted above re dock space etc., I agree.

The fuel cell's components can apparently be refurbished, while battery packs that aren't very new will quickly pull new cells down to the level of the old cells. From what I've read, fuel cell stack lifetimes are currently considerably longer than batteries.

While all of that may be true, there is a lot more to fuel cells than just the life of the stack. We know that Plug Power has had some problems with the reliability of their units. Perhaps that is why they have recently redesigned their units for better servicability:

These new units are designed with Plug Power’s proven ProGen hydrogen fuel cell engine technology which delivers increased efficiency and higher reliability. The new units include several significant enhancements such as larger fuel tanks for increased runtime (approximately 10%) and wireless communication capabilities for operations data and effective fleet management. With a new design that is focused on ease of service for both field technicians and customers, Plug Power also improved the product serviceability, reducing the time and effort required to work on the units.

It will be interesting to see how these new units stand up when compared with Li-ion batteries.

Yes, both techs are improving, and both are still suffering from teething problems. I forget where it was, but one city pulled their (BYD?) BEV busses offline because they were failing to meet their performance and maintenance metrics. Competition will solve those problems.

I suspect at the moment it depends on your operating requirements as to which is cheaper, and there's not as yet any universal "best" answer for now.

As I stated above:

I suspect each will have clear benefits over the other depending on the customer situation.

Overall, it seems that fossil fuels now have a home in high-demand materials handling applications.

I expect it will be at least five and maybe ten years before one or the other tech reaches the stage of virtually universal choice which fossil fueled MHE have held for the past century.

[RegGuheert]

Probably doesn't make sense for forklifts,...

Except that it does in some cases. Sure, some of Plug Power's customers are "greenwashing" or virtue signaling using OPM, but there are applications where H2 fuel cells are the best solution. Here's an excellent example from five years ago:

“We move 40% more volume during a 9-hour shift with fuel cells than we did with batteries,” said Phil DeMedici. “And our drivers are happier because they can do their jobs efficiently and comfortably.”

“I would never go back to batteries,” said David Saoud. “The case for fuel cells in freezer warehouses is too strong."

Fuel cells in warehouses solve real business problems. That's the main reason Plug Power has already sold over 20,000 fuel cells to power material handling equipment.

[RegGuheert]

I expect it will be at least five and maybe ten years before one or the other tech reaches the stage of virtually universal choice which fossil fueled MHE have held for the past century.

Do you have any evidence that Plug Power Fuel Cells are not powered by fossil fuels? My friend told me the hydrogen he provided for that purpose was steam reformed from natural gas.

Of course some of the energy for electric forklifts comes from fossil fuels, as well.