5 ms·

Hydrogen production is a fascinating energy case study because of the many possibilities for production. Consider solar and wind. With variable production, the

by mabbo 6y ago

Hydrogen production is a fascinating energy case study because of the many possibilities for production. Consider solar and wind. With variable production, there will always be time where you have more energy produced than you need. Why not use the excess to create hydrogen and store it? Now the energy doesn't go to waste. Consider nuclear power. Nuclear doesn't scale down well- it's most efficient at a specific rate of production. But demand is quite variable- 2am on a not-so-warm-or-cold day, who needs all that extra energy? Why not use the excess to create hydrogen and store it? Now the energy doesn't go to waste. In short, the energy used to create hydrogen can be very low, provided you have a cheap means to store and move it to where it needs to be, and provided you can deal with variable production rates. If this provides an income for the energy producer, then it becomes more financially viable to use wind, solar, and nuclear- all non-CO2 emitters.

hannob 6y ago
> Why not use the excess to create hydrogen and store it? This is a very popular idea, but it doesn't work out as well as it sounds. The reason is that electrolyseurs aren't free, the capital costs are high. Not saying this is impossible, but it's challenging to make this economically feasible. One more thought is that you can basically adapt all industry production to excess energy. I think the reason people want to do this with hydrogen electrolysis is because a) it's new and b) they associate both with energy transition. But neither means it's the best option.
- epistasis 6y ago
  This is a good point. Renewable energy is getting so cheap that throwing kWh away can be cheaper than the cost of idling other capital infrastructure. We will need to rethink a lot of our economic assumptions in energy very soon. Solar farms are already designed to produce 30% more DC energy than their inverters can handle, because it's the lowest cost balance between PV panel capacity and inverter capacity. If somebody has an application for DC energy that can be co-located at solar farms behind inverters, and can be economical running only a few hours a day, there's huge amounts of nearly free energy already available.
  - mamon 6y ago
    >> Renewable energy is getting so cheap that throwing kWh away can be cheaper than the cost of idling other capital infrastructure. That's missing the point.The problem isn't "what to do with excess of energy at peak times?", it's "where do we get energy from on quiet, wind-less nights?" Solar and wind are highly unreliable, so storing energy for is the necessity. Or we can use nuclear.
    - epistasis 6y ago
      Who was making this point that I supposedly missed? Where we are in the conversation, your problem has already been addressed, and part of the solution has been to overprovision renewable generation such that we have excess electricity at many times, amounting to 50% to 200% of current electricity usage. The problem you discuss has been addressed with tons of predictions and models. It's solvable with excess generation capacity, storage, and transmission capacity. Which path we choose will depend on the relative dollar costs and political costs of each. (For example HVDC transmission would likely save us lots of money, but is so difficult politically that it is unlikely to happen.) But in any case, nearly all models show that under nearly all cost scenarios, we end up with lots of excess generation capacity, with curtailed renewables generation for a large chunk of time. This is the future we are talking about, a future where we are meeting our energy demands with all renewables, and we have lots of excess generation capacity with zero marginal cost.
      - mamon 6y ago
        >> It's solvable with excess generation capacity, storage, and transmission capacity So now you're arguing FOR energy storage? Your previous post was basically: "let's overprovision and let excessive energy go to waste, instead of building costly storage infrastructure.".
        epistasis 6y ago
        We will have a mixture of storage, over-provisioned generation, and transmission, the only question is the relative proportion. And that relative proportion will be determined by how quickly costs fall relative to each other. If a kWh storage costs 10x the amortized capital costs of a kWh solar generation, we will have a lot less storage than if storage only costs 2x the amortized capital costs of a solar kWh. If hydrogen electrolysis can become cheap in 2030, maybe we will even use hydrogen for some storage, but we will have to balance the capital costs of hydrogen generation and conversion back to electricity with everything else, which will determine how much of it gets deployed.
- newacct583 6y ago
  It's part of the puzzle. It's true that high efficiency catalytic electrolysis requires expensive materials. But at significantly lower efficiencies you can just do the same thing we all did with a battery in grade school. That's not quite free to build out, but it's close. And relying on low-efficiency energy storage to fill the gaps in production is still better than firing up a gas plant to supply the power. It seems not unlikely to me that a lot of wind and solar plants might see building out a local hydrogen electrolyzer and generator (or just sell the hydrogen) as a useful choice. But yes: there's no silver bullet, and there are a lot of very reasonable competitors in the energy storage market.
  - baybal2 6y ago
    > It's true that high efficiency catalytic electrolysis requires expensive materials. And "high" here is only 70%. And this way, you only get around 15 grams per kwh.
    - jschwartzi 6y ago
      how many mols is that? Gas is not very dense.
    - slfnflctd 6y ago
      I'd expect that as in most other cases, it would come down to payback time, wouldn't it? With the floor being "pays for itself before it reaches end of life". If it doesn't pay for its own existence, it's likely a waste of effort. But if it does, you're adding capabilities & flexibility for zero cost. I don't really see a downside, other than tying up the capital.
      - kakkan 6y ago
        Hi slfnflctd! You replied to my comment on a thread on LSD trips some 42 odd days ago, and I kind of missed it when you posted it but I just stumbled upon it today and found your comment to be really insightful and I could relate to it really well. I think I could learn more from you if you were open to a discussion. I was wondering if we could connect through email or any other platform of your choice?
- clomond 6y ago
  > The reason is that electrolyseurs aren't free, the capital costs are high. While this is definitely the reason, there is also a bigger one - that the process of turning electricity into Hydrogen is fundamentally wasteful(Energy losses), particularly when the route is electricity->hydrogen->back to electricity. Where it actually is the best option: and where most of the “Green Hydrogen” gas will likely end up being broadly used to me is looking like industrial applications like this article mentions (Steel production), along with ammonia for fertilizer production. Capital costs as you mention (combined with utilization rates) - electrolyzers to be most economical need to run 100% of the time, meaning you need “excess energy” 100% of the time. With the implication that the energy will be from variable, renewable sources - there is a fundamental disconnect between these. A main reason why batteries and other techs are likely to win out in many “utilizing excess energy” over the long run.
  - Hypx 6y ago
    No one cares about efficiency intrinsically. As long as it's cost effective, this is not an issue. One of the major improvements in modern electrolyzers is that they don't need to run 100% of the time to function. As costs come down, it's likely we can tap excess energy whenever it is available.
    - clomond 6y ago
      No one care about efficiency, sure. But efficiency in this case is the “tax” that must be paid in all cases. And you are missing my point: That as far as the options go for “tapping excess energy” hydrogen is overblown and overstated as a solution. Things like demand response and heating applications don’t have anywhere near the same kind of losses. Price and value is what actually matters.
      - Hypx 6y ago
        Then it's merely reducing the "tax" until it is no longer an issue. A combination of efficiency improvements and lower source energy cost can solve this. The alternatives have their own downsides. Usually in the form of weight or raw material usage. Since the raw material of hydrogen is water, this could easily be much cheaper than the competition.
- Hypx 6y ago
  Electrolyzer costs are dropping in a similar to way to solar power. This is likely not going to be a limiting factor pretty soon.
etaty 6y ago
Nuclear does scale up and down very fast. Reference : https://hal-edf.archives-ouvertes.fr/hal-01977209/document https://hal-edf.archives-ouvertes.fr/hal-01977209/document However because upfront construction cost is high, you want to use nuclear reactor as much as possible.
radoslawc 6y ago
Also storing hydrogen is not as easy and cheap as other gasses due to hydrogen embrittlement, high pressures and very low boiling point (-250C). But as it often is with fuel it's expansive now but soon it might be proffitable (as it was with tar sands).
hwillis 6y ago
> Nuclear doesn't scale down well- it's most efficient at a specific rate of production. But demand is quite variable- 2am on a not-so-warm-or-cold day, who needs all that extra energy? Why not use the excess to create hydrogen and store it? Now the energy doesn't go to waste. The problem is not of the energy going to waste or the plant being unable to throttle down. The problem is that fuel cost is immaterial; a plant running at 1% output power still costs 99% as much per day as a plant running at 100%. That means that building 10% oversupply is tremendously expensive. If you're using it 10% of the time, it costs 10x more per MWh than the baseload power. If hydrogen is 11% as profitable as baseload, you are only gathering another 10% revenue, and the power is still 5x as expensive as normal electricity. That would be far more expensive than any other source. You could easily estimate hydrogen economy would be worth >>10% of electricity... but only at the margin. Right now it's reasonable to say hydrogen is worth 50% of the value of electricity used to make it. For all regional grids in the US, daily peak is 30-50% higher than the daily minimum[1]. That's a huge amount of overcapacity to consume, far more than can be utilized by base industry. Having >70% nuclear and/or relying on hydrogen economy to make nuclear economical is pretty highly dependent on hydrogen vehicles. Fermi math: 142 billion gallons annual[2] @25 mpg fleet efficiency[3] translates to .9 trillion kWh @4 mi/kWh, or ~25% of annual electricity. The bottom line is that it takes a relatively minor (~15-20%) overcapacity would tap out basically all possible uses for hydrogen. [1]: https://www.eia.gov/todayinenergy/detail.php?id=42915 https://www.eia.gov/todayinenergy/detail.php?id=42915 [2]: https://www.eia.gov/energyexplained/gasoline/use-of-gasoline.php https://www.eia.gov/energyexplained/gasoline/use-of-gasoline... [3]: https://www.reuters.com/article/us-usa-autos-emissions/u-s-vehicle-fleet-sets-new-record-for-fuel-efficiency-in-2018-epa-idUSKBN20P35M https://www.reuters.com/article/us-usa-autos-emissions/u-s-v...

by mabbo 6y ago

hannob 6y ago

> Why not use the excess to create hydrogen and store it? This is a very popular idea, but it doesn't work out as well as it sounds. The reason is that electrolyseurs aren't free, the capital costs are high. Not saying this is impossible, but it's challenging to make this economically feasible. One more thought is that you can basically adapt all industry production to excess energy. I think the reason people want to do this with hydrogen electrolysis is because a) it's new and b) they associate both with energy transition. But neither means it's the best option.

epistasis 6y ago
This is a good point. Renewable energy is getting so cheap that throwing kWh away can be cheaper than the cost of idling other capital infrastructure. We will need to rethink a lot of our economic assumptions in energy very soon. Solar farms are already designed to produce 30% more DC energy than their inverters can handle, because it's the lowest cost balance between PV panel capacity and inverter capacity. If somebody has an application for DC energy that can be co-located at solar farms behind inverters, and can be economical running only a few hours a day, there's huge amounts of nearly free energy already available.
- mamon 6y ago
  >> Renewable energy is getting so cheap that throwing kWh away can be cheaper than the cost of idling other capital infrastructure. That's missing the point.The problem isn't "what to do with excess of energy at peak times?", it's "where do we get energy from on quiet, wind-less nights?" Solar and wind are highly unreliable, so storing energy for is the necessity. Or we can use nuclear.
  - epistasis 6y ago
    Who was making this point that I supposedly missed? Where we are in the conversation, your problem has already been addressed, and part of the solution has been to overprovision renewable generation such that we have excess electricity at many times, amounting to 50% to 200% of current electricity usage. The problem you discuss has been addressed with tons of predictions and models. It's solvable with excess generation capacity, storage, and transmission capacity. Which path we choose will depend on the relative dollar costs and political costs of each. (For example HVDC transmission would likely save us lots of money, but is so difficult politically that it is unlikely to happen.) But in any case, nearly all models show that under nearly all cost scenarios, we end up with lots of excess generation capacity, with curtailed renewables generation for a large chunk of time. This is the future we are talking about, a future where we are meeting our energy demands with all renewables, and we have lots of excess generation capacity with zero marginal cost.
    - mamon 6y ago
      >> It's solvable with excess generation capacity, storage, and transmission capacity So now you're arguing FOR energy storage? Your previous post was basically: "let's overprovision and let excessive energy go to waste, instead of building costly storage infrastructure.".
      - epistasis 6y ago
        We will have a mixture of storage, over-provisioned generation, and transmission, the only question is the relative proportion. And that relative proportion will be determined by how quickly costs fall relative to each other. If a kWh storage costs 10x the amortized capital costs of a kWh solar generation, we will have a lot less storage than if storage only costs 2x the amortized capital costs of a solar kWh. If hydrogen electrolysis can become cheap in 2030, maybe we will even use hydrogen for some storage, but we will have to balance the capital costs of hydrogen generation and conversion back to electricity with everything else, which will determine how much of it gets deployed.
newacct583 6y ago
It's part of the puzzle. It's true that high efficiency catalytic electrolysis requires expensive materials. But at significantly lower efficiencies you can just do the same thing we all did with a battery in grade school. That's not quite free to build out, but it's close. And relying on low-efficiency energy storage to fill the gaps in production is still better than firing up a gas plant to supply the power. It seems not unlikely to me that a lot of wind and solar plants might see building out a local hydrogen electrolyzer and generator (or just sell the hydrogen) as a useful choice. But yes: there's no silver bullet, and there are a lot of very reasonable competitors in the energy storage market.
- baybal2 6y ago
  > It's true that high efficiency catalytic electrolysis requires expensive materials. And "high" here is only 70%. And this way, you only get around 15 grams per kwh.
  - jschwartzi 6y ago
    how many mols is that? Gas is not very dense.
  - slfnflctd 6y ago
    I'd expect that as in most other cases, it would come down to payback time, wouldn't it? With the floor being "pays for itself before it reaches end of life". If it doesn't pay for its own existence, it's likely a waste of effort. But if it does, you're adding capabilities & flexibility for zero cost. I don't really see a downside, other than tying up the capital.
    - kakkan 6y ago
      Hi slfnflctd! You replied to my comment on a thread on LSD trips some 42 odd days ago, and I kind of missed it when you posted it but I just stumbled upon it today and found your comment to be really insightful and I could relate to it really well. I think I could learn more from you if you were open to a discussion. I was wondering if we could connect through email or any other platform of your choice?
clomond 6y ago
> The reason is that electrolyseurs aren't free, the capital costs are high. While this is definitely the reason, there is also a bigger one - that the process of turning electricity into Hydrogen is fundamentally wasteful(Energy losses), particularly when the route is electricity->hydrogen->back to electricity. Where it actually is the best option: and where most of the “Green Hydrogen” gas will likely end up being broadly used to me is looking like industrial applications like this article mentions (Steel production), along with ammonia for fertilizer production. Capital costs as you mention (combined with utilization rates) - electrolyzers to be most economical need to run 100% of the time, meaning you need “excess energy” 100% of the time. With the implication that the energy will be from variable, renewable sources - there is a fundamental disconnect between these. A main reason why batteries and other techs are likely to win out in many “utilizing excess energy” over the long run.
- Hypx 6y ago
  No one cares about efficiency intrinsically. As long as it's cost effective, this is not an issue. One of the major improvements in modern electrolyzers is that they don't need to run 100% of the time to function. As costs come down, it's likely we can tap excess energy whenever it is available.
  - clomond 6y ago
    No one care about efficiency, sure. But efficiency in this case is the “tax” that must be paid in all cases. And you are missing my point: That as far as the options go for “tapping excess energy” hydrogen is overblown and overstated as a solution. Things like demand response and heating applications don’t have anywhere near the same kind of losses. Price and value is what actually matters.
    - Hypx 6y ago
      Then it's merely reducing the "tax" until it is no longer an issue. A combination of efficiency improvements and lower source energy cost can solve this. The alternatives have their own downsides. Usually in the form of weight or raw material usage. Since the raw material of hydrogen is water, this could easily be much cheaper than the competition.
Hypx 6y ago
Electrolyzer costs are dropping in a similar to way to solar power. This is likely not going to be a limiting factor pretty soon.

etaty 6y ago

Nuclear does scale up and down very fast. Reference : https://hal-edf.archives-ouvertes.fr/hal-01977209/document https://hal-edf.archives-ouvertes.fr/hal-01977209/document However because upfront construction cost is high, you want to use nuclear reactor as much as possible.

radoslawc 6y ago

Also storing hydrogen is not as easy and cheap as other gasses due to hydrogen embrittlement, high pressures and very low boiling point (-250C). But as it often is with fuel it's expansive now but soon it might be proffitable (as it was with tar sands).

hwillis 6y ago

> Nuclear doesn't scale down well- it's most efficient at a specific rate of production. But demand is quite variable- 2am on a not-so-warm-or-cold day, who needs all that extra energy? Why not use the excess to create hydrogen and store it? Now the energy doesn't go to waste. The problem is not of the energy going to waste or the plant being unable to throttle down. The problem is that fuel cost is immaterial; a plant running at 1% output power still costs 99% as much per day as a plant running at 100%. That means that building 10% oversupply is tremendously expensive. If you're using it 10% of the time, it costs 10x more per MWh than the baseload power. If hydrogen is 11% as profitable as baseload, you are only gathering another 10% revenue, and the power is still 5x as expensive as normal electricity. That would be far more expensive than any other source. You could easily estimate hydrogen economy would be worth >>10% of electricity... but only at the margin. Right now it's reasonable to say hydrogen is worth 50% of the value of electricity used to make it. For all regional grids in the US, daily peak is 30-50% higher than the daily minimum[1]. That's a huge amount of overcapacity to consume, far more than can be utilized by base industry. Having >70% nuclear and/or relying on hydrogen economy to make nuclear economical is pretty highly dependent on hydrogen vehicles. Fermi math: 142 billion gallons annual[2] @25 mpg fleet efficiency[3] translates to .9 trillion kWh @4 mi/kWh, or ~25% of annual electricity. The bottom line is that it takes a relatively minor (~15-20%) overcapacity would tap out basically all possible uses for hydrogen. [1]: https://www.eia.gov/todayinenergy/detail.php?id=42915 https://www.eia.gov/todayinenergy/detail.php?id=42915 [2]: https://www.eia.gov/energyexplained/gasoline/use-of-gasoline.php https://www.eia.gov/energyexplained/gasoline/use-of-gasoline... [3]: https://www.reuters.com/article/us-usa-autos-emissions/u-s-vehicle-fleet-sets-new-record-for-fuel-efficiency-in-2018-epa-idUSKBN20P35M https://www.reuters.com/article/us-usa-autos-emissions/u-s-v...