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General: Oil or off peak electric?

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  1.  
    In my area oil is 41.5p a litre and off peak electric is 3.9p a kWh. According to Wikipedia a litre of oil gives 10.75kWh. If my boiler is 90% efficient then oil is working out at 4.28p a kWh. So should I be running my thermal store on off peak electric rather than oil? Let us assume it is dark with no wind and my mill pond is empty!
  2.  
    If your electricity is that cheap (ignoring all other issues regarding CO2 blah blah) then you're better off with off-peak electricity and a heat pump - that will potentially give you somewhere between 1.3p and 2p per effective kWh. Oil is only going to get more expensive.

    Paul in Montreal.
    •  
      CommentAuthornigel
    • CommentTimeDec 3rd 2007
     
    and when you work out that storage heaters are useless in the evenings when you want the heat most.
    You will then have to top up with peak rate electric at 9-10p Kwh.

    So if more than about 5% of your energy is from peak rate you will be worse off.

    Sounds like a bad idea financially and also environmentally.
  4.  
    I am in similar position having moved to a rented house with oil central heating. In the winter I will use the oil for heating and hot water but what about in the summer when I don't need the heating? Do I continue to use the oil for hot water or switch to the Economy 7? I suspect the boiler is ancient and will be more like 60% efficient, althought the landlord has entombed it in an un-openable wooden box... it could be anything in there.
  5.  
    How about
    kg CO2 / Kw
    oil 0.28 kg/kw
    electric 0.53 kg/kw
    peak electric off coal stations ? 1 kg/kw

    some one mentioned using post-cooking oil elsewhere in a modified boiler
    you might be able to get this cheaper
  6.  
    Posted By: nigelnd when you work out that storage heaters are useless in the evenings when you want the heat most.


    An air/water-to-water heatpump can be very effectively run at off peak times. The heat can then be used whenever you need it, evenings included, with no top-up required.

    Posted By: jamesingramsome one mentioned using post-cooking oil elsewhere in a modified boiler
    you might be able to get this cheaper


    This, unfortunately, is the same flawed logic that the biofuel proponents keep espousing. This can only work if only a tiny number of people take this route - if everyone did so, there wouldn't be enough land to grow enough food in the first place to make the used chip shop oil. I'm not saying that waste oil shouldn't be used - just that it does not scale up.

    Paul in Montreal.
  7.  
    Nigel, the OP has a thermal store. They don't want to use storage heaters.
  8.  
    Hi, When I checked into this a while back I found that you need to look very closely at the daytime rates, the standing charges etc etc as they will vary. I tried to work out how much night-time usage was required to give an overall saving or be less cost than burning oil / gas via a boiler. This was for the same reason – charging up a thermal store. The daytime rates increase as do the standing charges so it’s not a simple comparison, so you will have to think about how much elec you need and when. You need to work out a variety of usage patterns and compare it that way in a spreadsheet.
    Mike up North
    •  
      CommentAuthornigel
    • CommentTimeDec 4th 2007 edited
     
    Posted By: passivhausfanNigel, the OP has a thermal store. They don't want to use storage heaters.


    yep I noticed that too late.

    Same principle still applies in that they will at times need to use peak rate unless they oversize the thermal store in which case they will have higher thermal losses in storage.
    In which case they need to allow for storage losses.

    I cant see why anyone would contemplate using electric to heat, even if it is off peak, unless possibly with a GSHP.
  10.  
    Thanks Paul and Mike
    You are right about the extra cost of daytime units etc Mike. I am factoring them in and try to get as much daytime energy as possible from alternative sources. I will probably go for ASHP as Paul suggests, unfortunately funds will not permit much else. I also have to agree with Paul about the CO2 blah blah. I believe that the reason we should all be saving energy and not wasting resources is not because of some obtuse hypothesis about global warming, but to leave something for future generations which is not just a barren polluted planet. Global warming has been and gone many times before we even started driving 4x4s. The goal is the same the reasons are totally different.
  11.  
    Anyone know what kind of generation comes online in the UK if you increase the demand for night time electricity, what is the marginal generation type? I understand that the nuclear stations are on 24/7 when available, likewise the wind turbines, then the cheapest comes next I would guess. Would that be coal or gas at the moment?

    If, as I suspect, the oil boiler I've got here is only about 60-70% efficient, then seems like there isn't much to choose between the oil and the off-peak electric in terms of emissions, especially if the off-peak electric is provided at the margin by the most efficient power stations (I'm going off the figures James quoted above), and the electric would work out a fair bit cheaper.
    • CommentAuthorjamesingram
    • CommentTimeDec 4th 2007 edited
     
    I believe the fossil fuel generators are used to supply any increase demand as they are can be controlled , switched on an off , to some extent
    coal or gas ? it would be better if it was gas for co2 , I read somewhere it was coal , but I'm unsure
  13.  
    workaholic
    if you main interests are reducing resource waste and saving energy and your in the building trade
    how about burning the various offcuts of wood etc.
    that are always left over from work, theres a skip in every street in my town full of it.
    would it be enough to cover your lean periods
    I realise like the veg oil this is only a small scale idea, but there always room for the small things

    Jim

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