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Renewable Energy: Technologies for coping with a fluctuating energy supply

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    • CommentAuthorkev67
    • CommentTimeDec 4th 2011 edited
     
    Storing larges amounts of electrical energy has always been difficult, which makes it tricky to match power supply to demand, particularly when that supply comprises some widely fluctuating renewable energy sources.

    Electric cars have been mooted as being useful for regulating power supply. The idea being that vehicle batteries can be charged up on windy nights. The batteries may even assist in supplying the grid at times of peak load. Personally, I am sceptical. People are not going to be happy if they can't drive their cars in the morning because it's not been very windy recently.

    It's been suggested that in future that some home appliances could be fitted with chips that would allow them to be switched off for short periods of time at peak load: freezers, washing machines and that sort of thing. I would think that was more a short term measure though. It might help level energy demand during commercial breaks in world cup matches, but I doubt it would be very helpful for making use of a fluctuating wind resource.

    Water heating or storage heating are other options, I suppose.

    We could connect a cable to Scandanavia to pump their hydro.

    I wonder if certain industries could be incentivised to help. For example, the Haber-Bosch process for manufacturing nitrogen fertilisers usually relies on methane for its source of hydrogen, but it could use electrolysis. Fertilisers can be stockpiled. I imagine these days the process is highly automated, so labour costs associated with employees standing around idle or having to work anti-social hours would not be such a consideration.

    What else is there?
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 4th 2011
     
    Posted By: kev67What else is there?


    Large refrigeration systems are already turned on and off, as are stand by generators and some industries that use vast amounts of electrical energy, like aluminium smelting I am led to believe.

    DamnHD is your man on this subject, he knows a bit about it.
    • CommentAuthortony
    • CommentTimeDec 4th 2011
     
    "The Grid" use it as a place to dump and take energy from, ideally as and when but to best advantage for all by smart metering and smart pricing.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 4th 2011 edited
     
    I am not so sure the public really understand how price banding will work. We have enough trouble with mobile phone tariffs and our current utility companies have been heavily criticised for not having clear pricing.
    This is going to have to be sorted out before true two way communications between, customers, supplier and generators can take place.

    It is one thing to ask people to 'keep and eye on the meter' and a totally different thing to turning their washing machine or fridge off remotely. Going to be a long slog to educate people that they cannot have what they want when ever they want at the lowest price.

    I have just had my latest bill in:
    1st 252 kWh at 14.69p (day rate)
    then
    15.24p for the rest

    1st 506 kWh at 5.56p (night rate)
    then
    5.77p for the rest.

    Standing charge was 75 days at 16.43p/day and then 18p/day

    Seems the timing of the night rate is 11pm to midnight then 1am till 6am.

    I am pretty good at knowing what is going on and understanding it, and try my hardest to use the heavy loads at night (generally just the washing machine/water heating/space heating). My next heavy load is the kettle and then probably cooking. Not as if I can time shift them, or showering.

    Purely as an aside the bill had my annual usage on it. Last 12 months was 4.761 MWh, about 1.2 MWh under what I expected to use. Total charge was £506.60 or a mean of 9.4p/kWh.

    100g (17.6p worth) of Tesco's cheapest lentils (about the cheapest form of food energy there is) contains 436 kJ or 0.12 kWh or £1.46/kWh. Electricity really is too cheap.
    • CommentAuthorGavin_A
    • CommentTimeDec 5th 2011
     
    Posted By: SteamyTea
    Posted By: kev67What else is there?


    Large refrigeration systems are already turned on and off

    I didn't know this was particularly widespread yet.

    I'm sure there's a hell of a long way to go on this still.
  6.  
    Posted By: SteamyTea100g (17.6p worth) of Tesco's cheapest lentils (about the cheapest form of food energy there is) contains 436 kJ or 0.12 kWh or £1.46/kWh. Electricity really is too cheap.


    That's too low - 100g lentils is 353Calories = 1477kJ = 0.41kWh, so about 42p/kWh - still cheap though.

    Paul in Montreal.
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 5th 2011 edited
     
    There's various time scales at which things can be turned on and off to help the grid, from daily cycles or predicted 'bad days' selected some time in advance down to more-or-less cycle-by-cycle 'fast frequency response'. Here is a slightly ageing paper of mine, presented in abbreviated form to CIBSE:

    http://www.earth.org.uk/note-on-dynamic-demand-value.html

    Rgds

    Damon

    PS. I strongly favour adding extensive biomass (MSW incineration after recyclables have been extracted, biomass, AD) as an energy storage for winter to help fill in holes in wind generation, though I'm not clear of realistic capacity.

    PPS. I believe that the GB grid has ~2GW of demand-controllable load available, though my numbers may be hopelessly old or wrong.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 5th 2011
     
    Posted By: Paul in MontrealThat's too low - 100g lentils is 353Calories = 1477kJ = 0.41kWh, so about 42p/kWh - still cheap though.

    Just took the figures from the Tesco site, still either way, electricity is too cheap to encourage the majority to change habits.
    http://www.tesco.com/groceries/Product/Details/?id=256534728
    • CommentAuthorJoiner
    • CommentTimeDec 5th 2011
     
    So are you burning lentils to fuel your CHP system then?
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 5th 2011 edited
     
    Almost, they are good for producing biogas, have my own transportable store to share with others:shamed:
    •  
      CommentAuthorted
    • CommentTimeDec 5th 2011
     
    Other methods of storing electricity:

    - flywheels
    - compressed air
    - hydrogen
    - Vanadium Redox batteries
    • CommentAuthorJoiner
    • CommentTimeDec 5th 2011
     
    Interesting, thought-provoking read there, Damon. Realistic prospect?
  13.  
    Posted By: SteamyTea
    Posted By: Paul in MontrealThat's too low - 100g lentils is 353Calories = 1477kJ = 0.41kWh, so about 42p/kWh - still cheap though.

    Just took the figures from the Tesco site, still either way, electricity is too cheap to encourage the majority to change habits.
    http://www.tesco.com/groceries/Product/Details/?id=256534728


    Ah, the tesco figure is for cooked lentils, I was assuming dried.

    Paul in Montreal.
    • CommentAuthorowlman
    • CommentTimeDec 5th 2011
     
    Posted By: SteamyTea; Almost, they are good for producing biogas, have my own transportable store to share with others.

    I guess you're a supporter of onshore wind then ST? Are you veggie, or do you just like pulses? :bigsmile:
    • CommentAuthorowlman
    • CommentTimeDec 5th 2011
     
    Posted By: kev67...........What else is there?

    Already done, but seems good to me; push water uphill, to drive turbines on the way down. Almost instantaneous response? SIting may be a problem.
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 5th 2011
     
    Joiner: it's already happening, it's simply a matter of degree.

    Rgds

    Damon
    •  
      CommentAuthorfostertom
    • CommentTimeDec 5th 2011 edited
     
    Posted By: SteamyTeaDamnHD ... he knows a bit about it
    no need to get personal - he's only the messenger
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 5th 2011
     
    owlman: the UK has already used most available sites (two more are being considered by SSE I think) unless we are prepared to (for example) flood a large chunk of the Lake District for storage. Plus, as with other storage methods, there's a loss involved (~20--25%).

    Rgds

    Damon
    •  
      CommentAuthorfostertom
    • CommentTimeDec 5th 2011
     
    Posted By: DamonHDincineration after recyclables have been extracted
    That's dangerous - who defines what's recyclable? Agreed that anything biomass might as well be burnt, as left to rot (unless retrievable for building products, boards etc). What about lo grade plastics and other oil feedstock stuff? we shd carry on landfill-stockpiling that, because it sure will be quarryable and re-preocessable in future - or even now if virgin oil weren't still so cheap
    • CommentAuthorowlman
    • CommentTimeDec 5th 2011
     
    Posted By: DamonHD.......owlman: the UK has already used most available sites (two more are being considered by SSE I think) unless we are prepared to (for example) flood a large chunk of the Lake District for storage. Plus, as with other storage methods, there's a loss involved (~20--25%).

    Has anyone to your knowlege Damon looked at dropping the water into disused mineshafts or caverns for instance and then just pump it back to the surface. Admittedly you would still need the above ground storage and the losses would still be the same, plus maybe pollutants, but you could mitigate that, there may be a bit of thermal gain on the way back up though.
    • CommentAuthorJoiner
    • CommentTimeDec 5th 2011
     
    Jeez, it's been staring us in the face for years and we've just let it go. You fools!

    http://www.technologyreview.com/energy/22103/

    And what aboutwomen drivers waving their arms about whilst talking to their passenger, who needs battery-fuelled cars?
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 5th 2011 edited
     
    Posted By: owlmanHas anyone to your knowlege Damon looked at dropping the water into disused mineshafts


    Yes they have, Dr. Dean Miller of Exeter University (though he has left now and I think gone to Canada) did a large study on it. Trouble is that mines are full of very nasty chemicals and groundwater/land will become highly polluted. Not for nothing that the Red River, that flows from one of our last working tin mine is called the Red River. Shall we rename Redruth to DeadRuth as historically the average age is very low in that town.

    As for onshore wind, personally I think we should be getting on with it, it is cheap and quick, easy to decommission. Give the RE industry a few years to work out the best ways to install then out at sea and then move the land based ones (as long as they can be refurnished to the marine environment) and then start to install them out there.
    If I had my way I would have installed the largest available one in PZ instead of that tiny thing they have (think it is a 50kW). It would send a fantastic message out that the 'Green Peninsular' really is (and contrast with St. Michaels Mount in a nice way).

    As for the other wind issue, Mutton Dhansak is my dish of choice :bigsmile:
    • CommentAuthorJoiner
    • CommentTimeDec 5th 2011
     
    "easy to decommission"

    The only thing going for it, really, unless for your own use and subject to all the considerations outlined by 'Windy', or was it 'Gusty'(?).
    • CommentAuthorRobinB
    • CommentTimeDec 5th 2011
     
    Posted By: SteamyTea...Electricity really is too cheap.


    I read yesterday that fuel poverty is when you spend more than 10% or your income on fuel. At the risk of sounding mean that doesn't seem too big a chunk of anyone's income to me. Is it?

    I also heard that many lower paid London workers spend 1/3 of their wages on commuting which seems a lot more crazy.
    • CommentAuthorRobinB
    • CommentTimeDec 5th 2011
     
    Have worried I AM sounding mean. I absolutely think people should be able to afford to stay warm enough to be healthy!
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 5th 2011
     
    Yes, RobinB, but some people will prioritise the infamous fags and plasma TV ahead of (say) insulation and draught-proofing, and then be in 'poverty'.

    Rgds

    Damon
    •  
      CommentAuthorfostertom
    • CommentTimeDec 5th 2011
     
    Feckless (a favourite Irish term, used by the disapproving Victorian English of the natives they'd invaded, and since then by the natives of each other). As in Guinless.
    •  
      CommentAuthorSteamyTea
    • CommentTimeDec 5th 2011
     
    Posted By: RobinBI read yesterday that fuel poverty is when you spend more than 10% or your income on fuel

    That is the problem of using a percentage.
    Possibly what should be said is that spending (domestic) over £250/person/pa on energy is too much, that way the large families are protected. Another way to look at is if I bough a huge car that did 20 MPG should I be allowed to complain about the price of fuel when there are alternatives.
    •  
      CommentAuthorDamonHD
    • CommentTimeDec 5th 2011
     
    I'm not sure that I want to 'protect'/encourage 'large' families, ie above about replacement rate, here in the UK.

    I half tut at my friends with 3 or more.

    Rgds

    Damon
    • CommentAuthorJoiner
    • CommentTimeDec 5th 2011
     
    You're only jealous because they've had sex three times! :devil:

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