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Hydrogen-producing rooftop solar panels nearing commercialization

11 points by danboarder 4y ago

cinntaile 4y ago
15% is a little better than i expected. Is this for situations where you have so much excess capacity that batteries don't make sense? Why would someone install so much excess capacity though? At that point it probably makes more sense to use a molten salt solution?
- brtkdotse 4y ago
  Batteries make sense on the scale of days. My coming solar installation will yield ~250% of my usage may-September and 10% of my January usage. I’d rather store the summer excess production until winter.
  - cinntaile 4y ago
    I guess the price of adding additional solar panels was pretty small compared to the labour and inverter costs or why is it so overdimensioned? I don't think private homes will have their own hydrogen production and storage facilities, this is more for industrial scale facilities.
    - solarkraft 4y ago
      In some countries you can sell your excess solar electricity at decent prices, this may have been a part of the motivation.
      - brtkdotse 4y ago
        That’s the case here and currently the economics are in my favor (I’ll probably be able to sell for more than I buy). That however, can change swiftly.
    - simne 4y ago
      > I don't think private homes will have their own hydrogen production and storage facilities May be you right, but people already use compressed air storage's to store energy at private homes. Sure, they are low pressure, for safety.
      - chopin 4y ago
        Where? In Germany I never heard of this. How much energy can these store?
        simne 4y ago
        I've hear, in France air energy has wide adoption, even few decades ago, before electricity, exists compressed air ring in Paris. In Germany still exists lot of recognizable buildings, where stored methane. Some of them converted to culture/arts centers, because their specific design, not suitable for living or work (large cylinders).
      - cinntaile 4y ago
        Do you have any examples? I know these CAES are sometimes used on an industrial scale but I haven't heard of small scale solutions for individual homes.
        simne 4y ago
        You just looking wrong direction. Low pressure solutions are not shown on TV, because on highly concurrent market, need something more distinguished. But LOW pressure really easy achievable with plumbing technologies.
        cinntaile 4y ago
        It would be good to have some examples, to prove that this actually exists.
        simne 4y ago
  - fbdab103 4y ago
    Having not run the numbers, that sounds like it would never be profitable for a home installation to solar->hydrogen->storage for months->burn as needed. Lot of capital on the various required components. Edit: I guess if you wanted to go fully off-grid, this would be a useful option.
    - danboarder 4y ago
      I also think these solar-hydrogen systems will benefit from scale as the marginal cost of production drops. Examples like the cost of producing microwave ovens, for example, have dropped from thousands to less than one hundred dollars with economies of scale. As a manufacturing sector of competing parts suppliers emerges, we will see price come down to benefit home owners.
- Schroedingersat 4y ago
  If you live somewhere the seasonality index is high (2ish), you can either buy winter electricity (or use a generator for off grid) or you can run a third of your electricity through a fuel cell/electrolyser combo. This makes full off grid more achievable and (where it doesn't then become legally enforced to have a cinnection) breaks utility monopoly and puts a backstop on price gouging. I'm not sure how long the window is between this becoming viable and batteries becoming cheaper than hydrogen storage is though.
- rasz 4y ago
  or even a water heater
bamboozled 4y ago
Would be great if one could fill up a hydrogen fuel cell car with that.
Tagbert 4y ago
I’m not convinced that building a combined unit for solar and hydrogen production is more beneficial than having separate components. You are inherently limited by the lifetime of the least durable component. Having them be separate lets you replace whichever component fails without needing to replace both. The electricity for a rooftop solar panel can easily be run to a ground-based hydrogen generator. The hydrogen component surely increases the weight of the unit to more than a plain solar panel so installation would be harder and overall weight on the roof greater. If the hydrogen generator needs maintenance, it would be much easier for a ground-based unit than rooftop units.
- feet 4y ago
  Or the combined units could just be repairable instead of being replaceable?
westurner 4y ago
Is this more or less flammable than rooftop solar? Could adjacent H2O and CO2 capture and storage help mitigate hydrogen fire risk?
- c_o_n_v_e_x 4y ago
  I really cringe at the thought of H2 at home for multiple reasons. - a wide explosive concentration range (LEL to UEL). The wider the range, the more opportunity you have for encountering an explosive mix if there's a leak. - a low ignition energy. A small static discharge has more than enough energy to ignite H2. - It's a functionally difficult gas to work with. It's an escape artist. You have to use the right materials. You have issues like embrittlement, hydrogen stress cracking. It's not great from a volumetric energy density perspective - more watts are required for pumping X units of energy than a fuel with a higher energy density. To bump up the energy density, you compress it and or liquefy it.. which costs energy, you've got high working pressures, and are possibly dealing with cryogenics as well.
  - westurner 4y ago
    FWIU actually Green hydrogen is where they're actually considered the total "path to value". Charge the grid with it; whatever it is, if it's "economical": charge the grid with it. > [ Hydrogen Safety: https://en.wikipedia.org/wiki/Hydrogen_safety https://en.wikipedia.org/wiki/Hydrogen_safety ; videos: [ ]] >> Contents: Prevention, Inerting and purging, Ignition source management (two rocks, HVAC, lighting, ), Mechanical integrity and reactive chemistry, Leaks and flame detection systems, Ventilation and flaring (all facilities that process Hydrogen must have anti-static ventilation systems), Inventory management and facility spacing, Cryogenics, Human factors, Incidents, *Hydrogen codes and standards*, Guidelines* Would capturing CO2 and water with the same or adjacent PV/TPV+ panels help mitigate Hydrogen Hazard? FWIU, Aerogels and hydrogels can be made from CO2.
    - c_o_n_v_e_x 4y ago
      A possibility would be to put the H2 into a different storage medium like ammonia or methanol, rather than storing it as gaseous hydrogen.
avmich 4y ago
> They claim it produces 250 liters of hydrogen per day "Mole of any gas under normal conditions - ~300K, 1 atm - occupies 22.4 liters of volume (Avogadro's law)". Mole of hydrogen (H2) has the mass 2 grams. 250 liters corresponds to 250 / 22.4 = 11.16... moles = 22.32... grams. So the unit above makes ~22 grams of hydrogen per day. A better article with more data would certainly be welcome.

11 points by danboarder 4y ago

15% is a little better than i expected. Is this for situations where you have so much excess capacity that batteries don't make sense? Why would someone install so much excess capacity though? At that point it probably makes more sense to use a molten salt solution?

brtkdotse 4y ago
Batteries make sense on the scale of days. My coming solar installation will yield ~250% of my usage may-September and 10% of my January usage. I’d rather store the summer excess production until winter.
- cinntaile 4y ago
  I guess the price of adding additional solar panels was pretty small compared to the labour and inverter costs or why is it so overdimensioned? I don't think private homes will have their own hydrogen production and storage facilities, this is more for industrial scale facilities.
  - solarkraft 4y ago
    In some countries you can sell your excess solar electricity at decent prices, this may have been a part of the motivation.
    - brtkdotse 4y ago
      That’s the case here and currently the economics are in my favor (I’ll probably be able to sell for more than I buy). That however, can change swiftly.
  - simne 4y ago
    > I don't think private homes will have their own hydrogen production and storage facilities May be you right, but people already use compressed air storage's to store energy at private homes. Sure, they are low pressure, for safety.
    - chopin 4y ago
      Where? In Germany I never heard of this. How much energy can these store?
      - simne 4y ago
        I've hear, in France air energy has wide adoption, even few decades ago, before electricity, exists compressed air ring in Paris. In Germany still exists lot of recognizable buildings, where stored methane. Some of them converted to culture/arts centers, because their specific design, not suitable for living or work (large cylinders).
    - cinntaile 4y ago
      Do you have any examples? I know these CAES are sometimes used on an industrial scale but I haven't heard of small scale solutions for individual homes.
      - simne 4y ago
        You just looking wrong direction. Low pressure solutions are not shown on TV, because on highly concurrent market, need something more distinguished. But LOW pressure really easy achievable with plumbing technologies.
        cinntaile 4y ago
        It would be good to have some examples, to prove that this actually exists.
        simne 4y ago
- fbdab103 4y ago
  Having not run the numbers, that sounds like it would never be profitable for a home installation to solar->hydrogen->storage for months->burn as needed. Lot of capital on the various required components. Edit: I guess if you wanted to go fully off-grid, this would be a useful option.
  - danboarder 4y ago
    I also think these solar-hydrogen systems will benefit from scale as the marginal cost of production drops. Examples like the cost of producing microwave ovens, for example, have dropped from thousands to less than one hundred dollars with economies of scale. As a manufacturing sector of competing parts suppliers emerges, we will see price come down to benefit home owners.
Schroedingersat 4y ago
If you live somewhere the seasonality index is high (2ish), you can either buy winter electricity (or use a generator for off grid) or you can run a third of your electricity through a fuel cell/electrolyser combo. This makes full off grid more achievable and (where it doesn't then become legally enforced to have a cinnection) breaks utility monopoly and puts a backstop on price gouging. I'm not sure how long the window is between this becoming viable and batteries becoming cheaper than hydrogen storage is though.
rasz 4y ago
or even a water heater

bamboozled 4y ago

Would be great if one could fill up a hydrogen fuel cell car with that.

Tagbert 4y ago

I’m not convinced that building a combined unit for solar and hydrogen production is more beneficial than having separate components. You are inherently limited by the lifetime of the least durable component. Having them be separate lets you replace whichever component fails without needing to replace both. The electricity for a rooftop solar panel can easily be run to a ground-based hydrogen generator. The hydrogen component surely increases the weight of the unit to more than a plain solar panel so installation would be harder and overall weight on the roof greater. If the hydrogen generator needs maintenance, it would be much easier for a ground-based unit than rooftop units.

feet 4y ago
Or the combined units could just be repairable instead of being replaceable?

westurner 4y ago

Is this more or less flammable than rooftop solar? Could adjacent H2O and CO2 capture and storage help mitigate hydrogen fire risk?

c_o_n_v_e_x 4y ago
I really cringe at the thought of H2 at home for multiple reasons. - a wide explosive concentration range (LEL to UEL). The wider the range, the more opportunity you have for encountering an explosive mix if there's a leak. - a low ignition energy. A small static discharge has more than enough energy to ignite H2. - It's a functionally difficult gas to work with. It's an escape artist. You have to use the right materials. You have issues like embrittlement, hydrogen stress cracking. It's not great from a volumetric energy density perspective - more watts are required for pumping X units of energy than a fuel with a higher energy density. To bump up the energy density, you compress it and or liquefy it.. which costs energy, you've got high working pressures, and are possibly dealing with cryogenics as well.
- westurner 4y ago
  FWIU actually Green hydrogen is where they're actually considered the total "path to value". Charge the grid with it; whatever it is, if it's "economical": charge the grid with it. > [ Hydrogen Safety: https://en.wikipedia.org/wiki/Hydrogen_safety https://en.wikipedia.org/wiki/Hydrogen_safety ; videos: [ ]] >> Contents: Prevention, Inerting and purging, Ignition source management (two rocks, HVAC, lighting, ), Mechanical integrity and reactive chemistry, Leaks and flame detection systems, Ventilation and flaring (all facilities that process Hydrogen must have anti-static ventilation systems), Inventory management and facility spacing, Cryogenics, Human factors, Incidents, *Hydrogen codes and standards*, Guidelines* Would capturing CO2 and water with the same or adjacent PV/TPV+ panels help mitigate Hydrogen Hazard? FWIU, Aerogels and hydrogels can be made from CO2.
  - c_o_n_v_e_x 4y ago
    A possibility would be to put the H2 into a different storage medium like ammonia or methanol, rather than storing it as gaseous hydrogen.

avmich 4y ago

> They claim it produces 250 liters of hydrogen per day "Mole of any gas under normal conditions - ~300K, 1 atm - occupies 22.4 liters of volume (Avogadro's law)". Mole of hydrogen (H2) has the mass 2 grams. 250 liters corresponds to 250 / 22.4 = 11.16... moles = 22.32... grams. So the unit above makes ~22 grams of hydrogen per day. A better article with more data would certainly be welcome.