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New Hydrolysis Record Efficiency: 30%

Discussion in 'Energy, Environment, and Policy' started by SageBrush, Oct 31, 2016.

  1. SageBrush

    SageBrush 2018: Drain the Sewer

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    Fresh from Stanford

    My first thought was "uggh," but then I remembered that wind energy is already being sold at negative cost or shut down some of the time. Today it is usually because coal plants are running preferentially but I'm sure the future holds more TOU inbalances as sustainable fuels take over more generation capacity. Even if the wind production is only reimbursed 2 cents per kWh, it means stored energy is probably less than 10 cents a kWh.
     
  2. aesculus

    aesculus Still Trying to Figure this All Out

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    I actually think hydrogen would be a very good storage mechanism. Use excess solar to fracture the water and store the hydrogen at current large gen natural gas sites. Then replay the H2 back when solar is not viable using the existing plants that have been converted to H2. No need for a distribution system for the H2 and any generation plants near a water source (many are) are good to go.
     
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  3. RichardC

    RichardC Cdn Sig & Solar Supporter

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    A few observations:

    1) Storage of hydrogen in existing pipeline infrastructure raises embrittlement concerns.

    At ambient temperature and pressures below 100 bar, the principal integrity concern for high-strength steel is hydrogen embrittlement. Hydrogen will diffuse into any surface flaws that occur due to material defects, construction defects or corrosion, resulting in a loss of ductility, increased crack growth or initiation of new cracks. These will ultimately lead to material failure [20], [21], [22] and [23]. Higher pressures are thought to increase the likelihood of material failure although no threshold value has been defined independently of other factors [24], [25] and [26]. Hydrogen can be transported at high pressures using pipes constructed of softer steels that reduce the rate of embrittlement, and there is much industrial experience in this area spanning many decades [27]. This means that existing high-pressure natural gas pipelines are not suitable for hydrogen transport, but that a new national network of high-pressure pipelines could be constructed to transport hydrogen around the UK.

    See: Conversion of the UK gas system to transport hydrogen

    2) Variable pricing and automated demand management, including critical peak pricing can play a useful role. See: The effects of critical peak pricing for electricity demand management on home-based trip generation

    3) Other large scale storage mechanisms include pumped storage, and new underwater counterparts can serve as a more efficient alternative (about twice as efficient as hydrogen). See:
    http://www.economist.com/news/science-and-technology/21709527-pumped-storage-gets-makeover-depths-imagination

    4) Use of heat pumps to heat or cool (freeze) water or other media can provide another high volume, and more efficient, energy storage option. See: Thermal energy storage - Wikipedia

    5) Use of high efficiency DC transmission circuits to connect to high head hydroelectric dams (where the dam serves as the battery).

    There are many more efficient options which don't lose 75% of the energy as does hydrogen storage.
     
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  4. aesculus

    aesculus Still Trying to Figure this All Out

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    Good synopsis of ideas and findings. Some comments:

    Agreed. That is why I would do this only at current natural gas generation sites that are located in areas with access to water.
    Calif utilities are really pushing this and it does make a difference but also causes another problem. See the 'rebound effect' or classic Duck curve caused by TOU people making up for their losses off peak. It just shoves the demand to another time period and can actually make it worse. Double edge sword.
    Pumped storage has its own issues (environmental and physical). But where it makes sense it can work. I found an interesting one that was based on cliff over the ocean. That seemed to be a good idea and not much environmental issues as screwing up ecosystems with fake lakes or worse, changing natural waterways.

    As far as CAES (compressed air storage): I worked on a few projects a number of years ago to try to use spent oil wells. Jury still out and then you had the issue of contaminants within the wells themselves. When you release the compressed air you had to try to capture/burn the pollutants. Others have used salt mines but not many of those around.
    These have been commercially available for years and do work pretty well for certain sized buildings. The applicability though is a fairly tight window and usually works best for AC applications.
    See issues with #3. The other problem is that in Calif, where we have lots of hydro (or did have before the massive droughts) there is not much of an opportunity to home run long Tx lines from the source. Maybe a hundred miles at best but usually sooner. We have a massively integrated Tx system so everyone has to jump on ASAP so the power can be routed as needed across the matrix. Plus they generally take off hydro Tx along the way to satisfy community needs. They would have to double up the Tx system in these cases to bypass all the above uses and then go back upstream with the current Tx systems. I don't see that being efficient for the small savings you get from the DC system. Plus hydro is all AC so you have the conversion losses by going to DC. Best used when you have a concentrated and distant source (ie off shore wind farms) that has no takeoffs, or very long runs to islands over water.
     
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  5. RDoc

    RDoc S85D

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    IMHO California should consider using surplus power for desalinization and/or wastewater purification plants. My understanding is that energy costs are roughly half the cost of desalinization so essentially free power would be a major help. We've had quite a bit of experience storing water.
     
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  6. TheTalkingMule

    TheTalkingMule Distributed Energy Enthusiast

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    I always thought the future would have electricity that we knew what to do with making hydrogen production and fuel cells a viable part of the equation. Elon and others have convinced me of the inefficiencies, but solar does keep getting cheaper and cheaper.....

    If we have a turbine-free solution that doesn't take too much energy/resources to manufacture and has few moving parts if any......does it matter that it's 1/2 the efficiency of solar/battery? If my yard and roof allow me to install 30kW of cheap solar, who cares if I "waste" half of it? Especially if the resource input is lower.
     
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  7. Evbwcaer

    Evbwcaer Member

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    I think the future of storage will largely be EV's that are subscribed to utility company plans which allow the car to be a bank or a generator depending on, real-time, what the utility needs and within agreed parameters.
     
  8. miimura

    miimura Active Member

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    Theoretically what you say is true. However, I feel it's better to offset other carbon based generation whenever possible. It will take a very long time to reach the point where there are time periods when there are absolutely no carbon based generators running on a large grid. The smaller the grid, the more likely this can happen. However, as was pointed out above, there are many other intermittent applications (de-sal and wastewater treatment) that could make use of very cheap electricity that don't have the efficiency losses that round-trip hydrogen has. I would also much rather see Gas-To-Liquids processes soak up excess renewables than hydrogen. Drop-in synthetic transportation fuels will be needed for a long time, if not for heavy duty transportation, then for jet fuel.
     

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