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Renewable Energy: Hydrogen "storage" for self-sufficiency via renewables?

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  1.  
    • CommentAuthorJoiner
    • CommentTimeJun 28th 2012
     
    Furtling around looking for more info on the Fiat engine-based (Totem) CHP system and stumbled across this...

    http://www.esru.strath.ac.uk/Documents/MSc_2006/ete.pdf
    • CommentAuthordickster
    • CommentTimeJun 28th 2012
     
    Can't remember whether there was a link in the forum to an MIT lecture by team who have developed a chip, that when in water and with sunlight on it, H2 is given off on one side and O on the other. Seemed brilliant to me.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 28th 2012
     
    Trouble with hydrogen is that it is hard to store. Why gasoline and diesel are so useful.
    • CommentAuthorJoiner
    • CommentTimeJun 28th 2012
     
    It's what's called "future-tech". Feasible, but not yet viable - although it's a toss-up on what terms!
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 28th 2012 edited
     
    Get some atmospheric CO2 and some hydrogen from electrolysis, a big pile of energy and force them together to make a few trillion molecules and we coudl then either:
    Burn it again
    Bury it

    Burning hydrogen in air produces more than just water NO and NOX are produced too.
  6.  
    And don't forget, just how dangerous Hydrogen is. The regulations surrounding its use are ferocious. Its got one of the lowest ignition temperatures, lowest ignition energies, widest explosive concentrations....It is not to be taken lightly
    • CommentAuthorJoiner
    • CommentTimeJun 28th 2012
     
    Can I suggest that you write to the author of the paper and tell him that? :wink:
  8.  
    This article on hydrogen for energy includes interesting comments

    http://www.guardian.co.uk/environment/blog/2012/jun/28/boat-engineering-hydrogen-power
    • CommentAuthorSeret
    • CommentTimeJun 28th 2012
     
    Not to mention that to store it as a gas in a sensible volume you're looking at very high pressure and to store it as a liquid you're looking at very low temps. Plus it's explody as hell and doesn't play nicely with steel.

    Metal hydride storage maybe? I know there's some folks deploying it for real in the field, although it's far from mature.
    • CommentAuthorJoiner
    • CommentTimeJun 28th 2012
     
    Has anyone else actually READ the paper?

    Ah well. To save anyone else telling us how explosive and leaky the stuff is...

    "Hydrogen storage facility: For the hydrogen storage, the technology of metal hydride would be very attractive
    for the HARI system, but pressurized storage of gaseous hydrogen was the only commercially viable option at that time. The hydrogen store consists of 48 mild steel cylinders, each with a volumetric capacity of 0.475Nm³
    and a wall thickness of 38mm for a weight of about one ton. These cylinders would provide a total of 576Nm³ of
    stored hydrogen at 25bar. But since the cylinders can withstand a pressure of 137bar, a 4kW hydraulic
    compressor (able to pump up to 11Nm3/h at a feed pressure of 25bar with a ratio of 1:8) is used to raise the
    hydrogen pressure, providing 2856Nm³ of hydrogen at full capacity. This gives an equivalent storage capacity of
    about 3800kWh when the hydrogen is converted back to electricity, providing up to 3 weeks of cover without any renewable energy input."

    "Avoiding leakage was one of the biggest challenges of running a hydrogen system. Besides helium, hydrogen has the smallest molecular size of any element, which means that hydrogen molecules can escape through the tiniest openings, where all other gases couldn’t pass. All leaks have been eliminated at West Beacon Farm, which represents an outstanding performance."

    There you go. :wink:
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 29th 2012
     
    So the same amount of energy as 400 lt of diesel
  12.  
    Posted By: dimengineer: Hydrogen is...not to be taken lightly

    Haha, nice one!

    I always thought this idea had legs, avoids the low energy density problem with hydrogen, and some of the explody problems too http://en.wikipedia.org/wiki/Methanol_economy
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 29th 2012
     
    Posted By: WillInAberdeenI always thought this idea had legs

    I like that idea too, just too costly at the moment.
    • CommentAuthorJoiner
    • CommentTimeJun 29th 2012
     
    "So the same amount of energy as 400 lt of diesel "

    :wink: But it doesn't have to be extracted from miles below a desert or sea bed, transported half way round the world and then processed in a massive chemical complex (with its own inherent explosive dangers http://www.bbc.co.uk/news/uk-wales-south-west-wales-13635757 ) and shipped miles in tankers to depots where it is stored before local distribution to whoever wants it. You can process the stuff in a building behind one of your barns, or at the top of your orchard if you're that lucky.

    And even a row of terraced houses in a quiet little Cornish backwater could beneift from the technology if such a CHP plant was installed. :winkkiss:
  15.  
    Posted By: SteamyTea
    Posted By: WillInAberdeenI always thought this idea had legs

    I like that idea too, just too costly at the moment.


    Not if your in Germany or Sweden who are pushing ahead with the technology with direct methane injection into there national gas grid systems.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 29th 2012
     
    Posted By: JoinerYou can process the stuff in a building behind one of your barns, or at the top of your orchard if you're that lucky.

    That's the dream.
    Takes a lot of energy to make it though, may be better to just use that energy directly.
    Some things do not scale well, energy production is one of them.

    Find me an RE system that can supply 4.5 MWh.y^-1 from a land area of 60 m^2 and still have a usable house on it, and costs less than £500/year and I may consider it.
    This is the problem with RE, it is a very diffused energy source, why using less is the important bit.
    • CommentAuthorJoiner
    • CommentTimeJun 29th 2012
     
    Problem is, if you take that kind of thinking to its logical conclusion (as an economist would) there is no point working to develop the technology further.

    A challenge...

    How many inventions (or technologies) have come out of mistakes or unintended consequences when working on what was, at the time, the main subject of study, regardless of whether that main subject of study went on to become established?

    I'm ruling out post-it notes and penicillin at the start.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 29th 2012
     
    Posted By: JoinerProblem is, if you take that kind of thinking to its logical conclusion (as an economist would) there is no point working to develop the technology further.

    If the physics does not stack up though, you are best ditching the idea. There is nothing new in using hydrogen as a fuel, or in storing it.. One has to question why it is not everywhere if it was so obvious and easy to do (compared to oil).
    It is only when the alternative is more expensive that a substitute rises to the top.
    Take Nuclear Power, we had a 20-30 year push and got about 25% pf pur electrical power from it at one stage, since then there has been a steady decline. There are all sorts of reasons for this, but I suspect that the steady price of coal (in absolute terms) over the last 25 years and the reduction in gas prices (in relative terms) over the last 40 has played the biggest part.
    Not saying it is proper to do this, but it is the way it is.

    The best way to reduce fossil fuel use is to use less. How you do that is another matter, but I suspect that it is not technology driven.
  19.  
    Posted By: SteamyTea
    Posted By: JoinerYou can process the stuff in a building behind one of your barns, or at the top of your orchard if you're that lucky.

    That's the dream.
    Takes a lot of energy to make it though, may be better to just use that energy directly.
    Some things do not scale well, energy production is one of them.

    Find me an RE system that can supply 4.5 MWh.y^-1 from a land area of 60 m^2 and still have a usable house on it, and costs less than £500/year and I may consider it.
    This is the problem with RE, it is a very diffused energy source, why using less is the important bit.


    I have thought of applying my industrial technology to the domestic market but for £500 per year its just not worth it.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 29th 2012
     
    And that is the problem, my domestic energy bill is just that, way too cheap. What would yours cost and fit on my plot?
  21.  
    Posted By: SteamyTeaAnd that is the problem, my domestic energy bill is just that, way too cheap. What would yours cost and fit on my plot?


    I would need more details to give a proper estimate.

    Would the output of say a Otag Lion be suitable ie 2kw electric 8kw heat if so it gives me something to work with if not what sort of figures are you looking at bearing in mind minimum and peak requirements. Also what roof slope space available split north south east and west.
  22.  
    Quick look at prices gives £200 per m2 for thermal solar panels and £1 per watt for the thermal oil Teg's in addition allow £2k for a suitable size insulated thermal oil tank.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 30th 2012 edited
     
    Right, 28 m^2 of roof at 35°, split 50-50 NE and SW. Total area to work with (assuming no planning restraints) 60 m^2m of which house covers half. Garden is on the NE side.
    Energy use is 4.5 MWh a year, but hoping to get it down to at least 4 MWh.
    Charts below shows 3 days in Jan, pretty typical, I am happy with the temperatures in the house (the logger is in the kitchen so rest of house a bit cooler). 22nd was a miserable day by the looks of it.
    Do a price as an academic exercise.
      Energy Use 21 to 23 Jan GBF.jpg
      Temp and Solar 21 to 23 Jan.jpg
  24.  
    Would you be looking at changing any of your electrical appliances to thermal oil appliances. ie Cooker, Kettle, Washing machine, Tumble dryer. If not then I will assume peak electric requirement will be 2kw.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJun 30th 2012
     
    I could, from an academic point of view.
    At the moment would be just over 4 kW.
    If heating diesel is £0.90 /lt, has about 11 kWh of energy in it and can can run a generator at 25% efficiency, that would work out at £0.33/kWh, or about 3 times I pay at moment.
    As my load is about 280W(e), and my heating/water load is 330W(h), that means I need a 2.1 kW diesel engine on the generator. About 50 kWh•day-1 (48 kWh•day^1 Challenge, funny how that number crops up :cool:). That would use 4.4 lt•day^1 or about £4 (for the winter). Water heating uses 4.25 kWh•day^-1, so the non heating season load is 280W(e) and 180W(h), at the same efficiencies that works out at 1.65 kW motor, 3..6 lt•day^1 or £3.24
    Say my heating season is 120 days, that is £1280•year^1 or 2.5 times what I currently pay. Add to that buying and installing the kit, £5000, and assume the generator lasts 10 years (£200•year^1) and the rest lasts 30 years (£100•year^1), that is now about £1600•year^1, or 3.2 times what I pay.
    Now I can say with certainty that my current storage heaters and DHW will last 25 years (as they have), but let us say that they have to be replaced today, would cost about £2000 I estimate (£80•year^1). So that makes my real energy costs £580•year^1. 2.8 times cheaper.
    So diesel powered CHP is a non starter, not got a clue what bottled gas costs per kWh, but I am sure someone else can work it out.
    Chart below is combined energy use.
      Sum of All 21 to 23 Jan GBF.jpg
  26.  
    Steamy

    Just going through some rough calculations the minimum spend to be self sufficient would be in the region of 10k for a thermal oil system producing peak 4kw output and upto 40kw thermal. Breakdown of costs £4K for thermal TEG's, £2k for insulated thermal oil storage tank, £4k for 20 m2 of thermal solar. Obviously the larger the quantity of thermal solar panels and the bigger the thermal store the more robust will be the system in covering cloudy days. Total backup could be provided by an additional £3k spent on a Dunsley Yorkshire boiler but I know your not a fan of biomass.

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