This would only work (for example) to store excess solar/wind as hydrogen then use later…like a battery. Batteries are far more efficient; so is pumped hydro. All of these have a place, each with their own advantages and disadvantages.
Mike
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Or store excess nuclear as hydrogen then later us it for gas turbines to generate electricity.
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Yes. But I’m not sure that there is any hope for much excess nuclear. Who is for more nuclear?
Mike
Often nuclear plants sell their excess power at night at zero or negative prices. With more renewables and batteries on the grid making cheap electricity, nuclear is forced to sell below cost. Some nuclear plants have already experimented with making hydrogen.
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The Captain
Not too long ago natural gas fueled diesel trucks were a Fool favorite? Why did they fall by the wayside? Lack of refueling infrastructure. The hydrogen refueling infrastructure is much more complex and costly. Rickety as it might be, the electric grid already is pretty good and getting better with the adoption of storage to replace peaker plants and virtual power plants (VPP).
The Captain
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Re: steel and cement.
Steel uses hydrogen to burn off (actually reduce) the oxygen in iron ore. Traditionally that is done with coke in a blast furnace and produces carbon oxides as a by-product. Hydrogen produces steam.
In cement hydrogen is a heat source. But electric heaters should be possible. No need to make hydrogen from the electricity.
As to “cost of hydrogen” cost of electricity from solar or wind is a fuzzy number. No fuel to purchase. It’s almost all cost of finances. Operating and maintenance costs should be trivial.
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Re: natural gas fueled diesel trucks.
California has banned diesel trucks serving its ports. That forces electric trucks and gives hydrogen fuel cell trucks an opportunity.
Operating experience should reveal what works best. And more regs may follow.
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You’ve mentioned “basic physics” a few times, but I’m not sure I understand what you’re referring to. Could you elaborate what you mean by that?
As to why, the reason would be if they have to switch away from ICE and the hydrogen is a better choice than a BEV. It’s a given that the fuel cost will be higher for a FCEV semi tractor; but if the BEV semi tractor has a higher capital cost and a longer down time for refueling, then which one is more advantageous will depend on the overall cost - not just the fuel cost.
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There are a few basic steps that you must do to produce H2 from (green or any) electricity:
- electrolysis
- compression
- liquefaction
- electricity production from hydrogen in the fuel cell
Each step involves losses and notably the first and last steps generate waste heat that is part of the chemical reaction. Without some exoctic (expensive) equipment and process you are just not going to modify this nor be able to capture the relatively mild waste heat for any useful purpose.
Typical efficiencies might be:
- electrolysis: 60-65%
- compression: 90%
- liquefaction: 90%
- electricity production from hydrogen in the fuel cell: 60-65%
Multiply them all out and you get about 30% - 35% for a good process with well maintained equipment, enough regular usage to run optimally, no losses/leakage during fueling and in the car and a warmed up fuel cell (yes they must be warmed up).
Compare to EV charging at ~90% efficiency and some losses prior to spinning the motors.
All the research in the last 25 years hasn’t done much more than nibble at these efficiency numbers. Perhaps the research has or could make the equipment itself less costly or require less maintenance…but it isn’t changing the achieved efficiency values by much because they aren’t changing the chemical reactions.
Agreed. So show me the prices of the currently or soon to be available BEV semi trucks and compare to the fuel cell semi trucks or even buses that have been around for more than a decade
Research starting point
Mike
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But is that really relevant? At the end of the day, the factors driving the economics and the adoption decision are cost and utility, not efficiency. We frequently engage in activities that bleed energy in order to get the energy into a more economically useful form or location. A rechargeable AAA battery is a trivial example - we have fewer electrons coming out of the battery than we put in, but the electrons are more useful for us that way in many applications. So we do it.
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I have been reading that electrolysis and fuel cell efficiencies are increasing. Research is ongoing to get those up to 80%.
If you are only recovering a third of the energy you put in and your competitor is recovering 90% it is very difficult to have competitive costs.
Try telling that to the manager of a fleet of semi trucks.
Mike
Aren’t these sort of like the 600 mile EV batteries that can charge in 10 minutes? Lab experiments that don’t scale or can’t be manufactured economically.
Ironically the cost of H2 in CA for Murai drivers has been going up. And it is only 1/3rd green, by state law, for subsidized fuel.
I’d like to see a strong market for H2. But for most uses (especially cars and light trucks) the economics and physics just don’t work out. Maybe in a couple of more decades. But we have tens of thousands of DC fast chargers all over the country (maybe 95% of every major highway). To get H2 to all those places economically would be a huge cost. And super high (thermodynamic) efficiency with some combined heat recovery system won’t/can’t be cheap in that many locations.
Mike
Is it? It seems that would only be the case if the cost of energy inputs for fuel were a particularly significant part of the overall cost structure of owning and operating the vehicle. But that might not be the case for FCEV’s relative to BEV’s. Even retail electricity is only a few cents per mile cost in a BEV - if FCEV fuel is 2-3x that cost, they can still be competitive. Heck, ICE’s have a fuel cost today of 4x or more that cost, and they’re still competitive.
FCEV’s are never going to compete on the cost of fuel - their advantage would be (presumably) faster refueling times, lower weight, and (if they are to be a thing) lower vehicle costs. Like ICE’s relative to BEV’s today.
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Very true. But I guess you haven’t put it all together yet. Not only are fuel cells and their green hydrogen fuel 2-3x the cost, the whole process, capital investment, distribution much more expensive.
Recall the True Zero hydrogen stations in CA charging $36/kg? If you calculate it out comparing the Murai to a Tesla Model 3 that is like paying about $2.00/kwh for electricity. And that is for 2/3rds of the hydrogen made from fossil fuels…so the “true” price only goes up from there when they actually have zero emissions. And it won’t really be zero since the entire pipeline of parts to build the hydrogen infrastructure will be much more fossil fuel intensive than some EV chargers most likely.
Mike
BEV long distance trucks require one very improbable thing to happen. FCEV long distance trucks require two very improbable things to happen.
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Hmmm, I look at it this way:
- If human drivers are still required, BEV trucks don’t require anything particularly improbable because drivers already have to stop every 8 or 10 hours for a long period of rest time. The batteries can charge during that required rest period (I’ve been told that tandem drivers are quite rare and many outfits frown upon them, presumably because they can’t really determine which of the two drivers actually pressed the “I’m driving now” button).
- If the trucks drive themselves, BEV trucks will have a very big problem. They will have to stop every 8 to 10 hours to charge even though the robo-driver could theoretically continue and drive straight through. I suppose it’ll be mitigated somewhat by scheduling charging during traffic periods, but there will still be plenty of unwanted downtime.
FCEV will very likely never hit worthwhile relative efficiency, so FCEV will likely only be used for niche cases where, despite the higher cost (lower efficiency = higher cost), they may be appropriate. Hydrogen in general may be widely used for energy storage and likely stored locally to avoid the high costs and efficiency losses of transport, distribution, etc. For example, a nuclear plant could run all night, produce hydrogen, and then that hydrogen could be used for peak energy demand during the day when the nuclear needs to be augmented. Same for solar during the day, or wind during the very windy days.
Sure. There’s no doubt that today there’s an obvious advantage to BEV’s relative to FCEV’s on everything except the time involved in actually refueling (getting to a refueling station probably makes it a longer process).
The reason one might encourage hydrogen to keep plugging is in response to the possibility that a fully developed hydrogen transportation system might have more utility than a BEV system, either in whole or in part. Batteries are great at storing energy, but they’re heavy and slower to fill than hydrogen tanks. Those characteristics that make them better suited to stationary storage than transportation storage.
So when you get past physics, and into economics, that might end up mattering. We don’t know if it will! It very well might not. The cost of hydrogen will almost certainly always be higher than electricity, so unless the economies of scale that have yet to be implemented in hydrogen as a major alternative fuel supply are really high, it might not be viable. And if there were no hiccups with EV uptake once subsidies start to…subside, you might not even consider it as an alternative.
But…what if end-users don’t end up adopting EV’s like we want? What if charging time is a deal-breaker for them? What if the cost of EV’s stays stubbornly high, once the overcapacity and subsidies get squeezed out of the Chinese suppliers? Lots of what-ifs, and they may be very low probability what-ifs…but if the fate of the planet is at stake, you kind of want to have Plan B a little past the drawing board stage just in case you have to pull the trigger.
Big long distance trucks would both
- Benefit enormously from using robotically fast exchangable batteries, and
- Have the size to make the added volume needed for an extremely reliable automated exchange mechanism quite reasonable
Truck pulls into automated battery exchange station, robots go clickety clack and a few minutes truck is ready to keep on going.
What am I missing?
d fb
Cost and time.
It costs money to have surplus batteries lying around - the battery is a very expensive part of any EV, and certainly more expensive in a semi. It costs money to design that battery so it’s removable, and in a location where it can be removed quickly, rather than integrated into the systems of the truck.
And because the batteries are so expensive, you never want to swap yours out for someone else’s. You don’t know whether theirs is damaged or later in its useful life. So realistically, you’re only going to swap within your fleet - which makes logistics and management and re-balancing battery locations an expensive proposition.
These batteries weigh at least 4 or 5 tons - so the equipment necessary to remove it and switch it out will be expensive. Every “fueling” station requires the machinery to do it. And that’s not going to be instantaneous - so either you have multiple machinery (cost) or lots of queueing (time).
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