5 ms·

Record-breaking hydrogen electrolyzer claims 95% efficiency

37 points by taubek 5y ago

theshrike79 5y ago
"The company promises green hydrogen at around US$1.50 per kilogram within just a few years." I'm not holding my breath.
- danans 5y ago
  1kg of H2 has 33kWh of energy. So at $1.50/kg the raw hydrogen is about $0.04/kWh. For the fuel cell light duty passenger car scenario, distribution and (at best) 60% efficiency of the drivetrain could easily quadruple the cost per mile driven versus electric drivetrains. It might still make sense in a fuel cell compared to gasoline or diesel for long haul trucking, though, because weight limitations on such vehicles are a huge barrier for battery electric drivetrains. There are already test fleets of such trucks [1]. Now imagine every truck stop has a electrolyzing plant powered by local renewables. The wind generation potential of the central US is massive relative to the population, and trucking and goods shipment is an important sector in its economy. The other sector that is hard to power with batteries is flight. As far as I know , hydrogen doesn't have the energy density needed for long flights, so the hydrogen would have to be converted into some kind of syn fuel. Aviation fuel costs about $0.65 per liter. I'd like to hear from somebody who knows about the efficiency of syn fuel manufacturing about how many kgs of hydrogen you need to put into a process to get 1L of equivalent syn aviation fuel. Any more than 10kg H2 per liter of syn fuel and it's no longer cost competitive. 1. https://www.greencarreports.com/news/1133014_hyundai-will-test-500-mile-hydrogen-fuel-cell-semis-in-california https://www.greencarreports.com/news/1133014_hyundai-will-te...
  - ncmncm 5y ago
    Hydrogen has 3x the mass-energy density of kerosene, what is called "aviation fuel". However, LH2 takes up too much room to fit in the wings, so the LH2 tanks need to be somewhere else, either inboard or in nacelles. And you have to liquify it, which takes up some more energy. But the weight advantage will prove overwhelming, particularly as raw electricity costs continue on down. The reason the weight advantage is so overwhelming is that each kg of fuel not carried is another kg of cargo you can carry, instead, and collect revenue for. For example, an Airbus A320 carries typically, say, 25t of fuel and 50t of cargo. Replacing that with 8t of fuel and 67t of cargo yields a 34% revenue increase. If kerosene-fueled planes are getting a 20% gross profit margin, you can absolutely undercut them anywhere you fly. So, you pick up all of the most profitable traffic, and they are left to fly the routes you don't want. That presumes the per-joule cost of LH2 is the same as for Jet-A fuel. But as the LH2 is synthesized on-site, vs. Jet-A mined, refined, transported, and maybe carbon-taxed, a joule of LH2 could be substantially cheaper. With time, kerosene will come to be synthesized, but it needs carbon captured from somewhere, either from the air or from somebody's exhaust, and the oxygen stripped off, and hydrogen stuck on its place, and chains built up, so will cost more.
    - danans 5y ago
      > Hydrogen has 3x the energy density of kerosene, what is called "aviation fuel". You are confusing "specific energy" (energy/mass) with "energy density" (energy/volume). Hydrogen has 3x the specific energy of kerosene, but 1/4 the energy density at the same pressure.
      - ncmncm 5y ago
        For aviation, specific energy, or mass-energy density, wins. Lofted volume is cheap, lofted weight is dear.
        danans 5y ago
        You still need to compress and contain hydrogen to get an amount of energy practicable for flight. Hydrogen, even when compressed to 700 bar only provides 1.4kWh/L [1]. Kerosene provides 10kWh/L. A 747 uses 36k liters (36 cubic meters) kerosene for a 10 hour flight, or 360MWh. [2] With 700bar H2, that amount of energy requires 260k liters (260 cubic meters), not counting the thicker storage vessel needed. 260 cubic meters seems tractable (assuming you can safely loft 700 bar hydrogen), although still takes an order of magnitude more space than kerosene. Since we know how to safely loft syn fuels, and we have a fleet of aircraft that can use them, it might make more sense to go that route. It would also allow blending into the existing jet fuel supply infrastructure along with kerosene and biofuels. 1. https://www.energy.gov/eere/fuelcells/physical-hydrogen-storage https://www.energy.gov/eere/fuelcells/physical-hydrogen-stor... 2. https://science.howstuffworks.com/transport/flight/modern/question192.htm https://science.howstuffworks.com/transport/flight/modern/qu...
        ncmncm 5y ago
        Nobody would even consider lofting compressed hydrogen, under any circumstances. It is actively misleading, even dishonest, to bring it up. The topic here is LH2, liquified hydrogen.
        5y ago
aaronblohowiak 5y ago
nice, no exotic catalysts
wing-_-nuts 5y ago
If this holds true, and it's a big if, I guess this might be a pretty big deal for aviation as we try to hit net zero? Maybe it could also revive hydrogen in the automotive sector but I feel like EVs have 'won' that competition. This is probably still less efficient than lithium ion batteries but there are probably all sorts of uses that I'm not thinking about. Definitely doesn't hurt to push 'all of the above' when it comes to energy storage options. God knows we're going to need everything and the kitchen sink to stop cooking the planet.
- PaulHoule 5y ago
  I see it being useful for chemistry. For instance you might use electrolytic hydrogen as an input for https://en.wikipedia.org/wiki/Haber_process https://en.wikipedia.org/wiki/Haber_process if you don't just use the electricity on air directly https://en.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process https://en.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process
  - ncmncm 5y ago
    It seems like the second is meant to produce a nitric acid or nitrate end product, not ammonia. Maybe introducing electrolytically produced H2 and N2 immediately would yield ammonia directly without the round trip through nitric acid? If it works, there must be a name for it. Edit: https://en.wikipedia.org/wiki/Ammonia#Electrochemical https://newatlas.com/energy/green-ammonia-phosphonium-production/ https://newatlas.com/energy/fuelpositive-green-ammonia/ So, an area of active research. Looks like it can be produced electrochemically more cheaply than with today's Haber process, and Ajinomoto is putting it into production for their own needs. Parking one of these synthesizers under a wind turbine would produce farm fertilizer and fuel whenever the wind blows, cheaper than buying the mass-produced stuff off the dock at the factory. But they will have to start building them first.
willbudd 5y ago
I've always thought of capillary action as a very interesting phenomenon that can make all sorts of seemingly improbable engineering tricks possible. Great to see such an elegant application thereof here.
belorn 5y ago
Can the byproduct of the process be refined to produce medical grade oxygen?
- ncmncm 5y ago
  There will be industrial-level amounts of waste oxygen, soon. Expect LOX price to fall as fast as peak-surplus marginal electrical power, because there will be no point in liquifying it except when power is cheapest.

37 points by taubek 5y ago

"The company promises green hydrogen at around US$1.50 per kilogram within just a few years." I'm not holding my breath.

danans 5y ago
1kg of H2 has 33kWh of energy. So at $1.50/kg the raw hydrogen is about $0.04/kWh. For the fuel cell light duty passenger car scenario, distribution and (at best) 60% efficiency of the drivetrain could easily quadruple the cost per mile driven versus electric drivetrains. It might still make sense in a fuel cell compared to gasoline or diesel for long haul trucking, though, because weight limitations on such vehicles are a huge barrier for battery electric drivetrains. There are already test fleets of such trucks [1]. Now imagine every truck stop has a electrolyzing plant powered by local renewables. The wind generation potential of the central US is massive relative to the population, and trucking and goods shipment is an important sector in its economy. The other sector that is hard to power with batteries is flight. As far as I know , hydrogen doesn't have the energy density needed for long flights, so the hydrogen would have to be converted into some kind of syn fuel. Aviation fuel costs about $0.65 per liter. I'd like to hear from somebody who knows about the efficiency of syn fuel manufacturing about how many kgs of hydrogen you need to put into a process to get 1L of equivalent syn aviation fuel. Any more than 10kg H2 per liter of syn fuel and it's no longer cost competitive. 1. https://www.greencarreports.com/news/1133014_hyundai-will-test-500-mile-hydrogen-fuel-cell-semis-in-california https://www.greencarreports.com/news/1133014_hyundai-will-te...
- ncmncm 5y ago
  Hydrogen has 3x the mass-energy density of kerosene, what is called "aviation fuel". However, LH2 takes up too much room to fit in the wings, so the LH2 tanks need to be somewhere else, either inboard or in nacelles. And you have to liquify it, which takes up some more energy. But the weight advantage will prove overwhelming, particularly as raw electricity costs continue on down. The reason the weight advantage is so overwhelming is that each kg of fuel not carried is another kg of cargo you can carry, instead, and collect revenue for. For example, an Airbus A320 carries typically, say, 25t of fuel and 50t of cargo. Replacing that with 8t of fuel and 67t of cargo yields a 34% revenue increase. If kerosene-fueled planes are getting a 20% gross profit margin, you can absolutely undercut them anywhere you fly. So, you pick up all of the most profitable traffic, and they are left to fly the routes you don't want. That presumes the per-joule cost of LH2 is the same as for Jet-A fuel. But as the LH2 is synthesized on-site, vs. Jet-A mined, refined, transported, and maybe carbon-taxed, a joule of LH2 could be substantially cheaper. With time, kerosene will come to be synthesized, but it needs carbon captured from somewhere, either from the air or from somebody's exhaust, and the oxygen stripped off, and hydrogen stuck on its place, and chains built up, so will cost more.
  - danans 5y ago
    > Hydrogen has 3x the energy density of kerosene, what is called "aviation fuel". You are confusing "specific energy" (energy/mass) with "energy density" (energy/volume). Hydrogen has 3x the specific energy of kerosene, but 1/4 the energy density at the same pressure.
    - ncmncm 5y ago
      For aviation, specific energy, or mass-energy density, wins. Lofted volume is cheap, lofted weight is dear.
      - danans 5y ago
        You still need to compress and contain hydrogen to get an amount of energy practicable for flight. Hydrogen, even when compressed to 700 bar only provides 1.4kWh/L [1]. Kerosene provides 10kWh/L. A 747 uses 36k liters (36 cubic meters) kerosene for a 10 hour flight, or 360MWh. [2] With 700bar H2, that amount of energy requires 260k liters (260 cubic meters), not counting the thicker storage vessel needed. 260 cubic meters seems tractable (assuming you can safely loft 700 bar hydrogen), although still takes an order of magnitude more space than kerosene. Since we know how to safely loft syn fuels, and we have a fleet of aircraft that can use them, it might make more sense to go that route. It would also allow blending into the existing jet fuel supply infrastructure along with kerosene and biofuels. 1. https://www.energy.gov/eere/fuelcells/physical-hydrogen-storage https://www.energy.gov/eere/fuelcells/physical-hydrogen-stor... 2. https://science.howstuffworks.com/transport/flight/modern/question192.htm https://science.howstuffworks.com/transport/flight/modern/qu...
        ncmncm 5y ago
        Nobody would even consider lofting compressed hydrogen, under any circumstances. It is actively misleading, even dishonest, to bring it up. The topic here is LH2, liquified hydrogen.
        5y ago

aaronblohowiak 5y ago

nice, no exotic catalysts

wing-_-nuts 5y ago

If this holds true, and it's a big if, I guess this might be a pretty big deal for aviation as we try to hit net zero? Maybe it could also revive hydrogen in the automotive sector but I feel like EVs have 'won' that competition. This is probably still less efficient than lithium ion batteries but there are probably all sorts of uses that I'm not thinking about. Definitely doesn't hurt to push 'all of the above' when it comes to energy storage options. God knows we're going to need everything and the kitchen sink to stop cooking the planet.

PaulHoule 5y ago
I see it being useful for chemistry. For instance you might use electrolytic hydrogen as an input for https://en.wikipedia.org/wiki/Haber_process https://en.wikipedia.org/wiki/Haber_process if you don't just use the electricity on air directly https://en.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process https://en.wikipedia.org/wiki/Birkeland%E2%80%93Eyde_process
- ncmncm 5y ago
  It seems like the second is meant to produce a nitric acid or nitrate end product, not ammonia. Maybe introducing electrolytically produced H2 and N2 immediately would yield ammonia directly without the round trip through nitric acid? If it works, there must be a name for it. Edit: https://en.wikipedia.org/wiki/Ammonia#Electrochemical https://newatlas.com/energy/green-ammonia-phosphonium-production/ https://newatlas.com/energy/fuelpositive-green-ammonia/ So, an area of active research. Looks like it can be produced electrochemically more cheaply than with today's Haber process, and Ajinomoto is putting it into production for their own needs. Parking one of these synthesizers under a wind turbine would produce farm fertilizer and fuel whenever the wind blows, cheaper than buying the mass-produced stuff off the dock at the factory. But they will have to start building them first.

willbudd 5y ago

I've always thought of capillary action as a very interesting phenomenon that can make all sorts of seemingly improbable engineering tricks possible. Great to see such an elegant application thereof here.

belorn 5y ago

Can the byproduct of the process be refined to produce medical grade oxygen?

ncmncm 5y ago
There will be industrial-level amounts of waste oxygen, soon. Expect LOX price to fall as fast as peak-surplus marginal electrical power, because there will be no point in liquifying it except when power is cheapest.