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Making sense of LPG running costs £/kWh calculation {Merged}

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Making sense of LPG running costs £/kWh calculation {Merged}

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simpjdsimpjd Forumite
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MoneySaving Newbie
Hi,
Was hoping someone could help me understand where I'm calculating this wrong.
I'm trying to figure out the £/kWh of LPG.
Many references on the internet state around £0.07/kWh (7 pence) for LPG, which sounds reasonable.
However, the average cost per litre of LPG is around £0.50/l, which is around what we pay.
  - 1 litre of LPG / 3.85 = 1m3
  - so 1m3 of LPG = £1.925 (based on £0.50/l)
  - 1m3 * 1.02264 (correction factor) * 46 (LPG calorific value) / 3.6 (conversion) = £/kWh
  - so 1m3 = 13kWh
  - £1.925 / 13kWh = £0.1471/mWh
£0.1471/mWh is more than double £0.07/kWh......??!? So where is my maths going wrong?!
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Replies

  • bobmac62bobmac62 Forumite
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    You are paying way too much for your LPG, presumably bulk? Current price is around 30p per litre.
  • simpjdsimpjd Forumite
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    MoneySaving Newbie
    Thanks for the response! I just called up Calor our current provider, best they can do they said for 36 month contract is 40p/l. Still a 20% improvement based on my current price (amazing what a phone call can do!) however not as good as your 30p/l! Can you recommend a supplier? We use around 8,000l a year in a 2,000 tank.
  • Flt._Lt._BigglesFlt._Lt._Biggles Forumite
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    simpjd said:
    Hi,
    Was hoping someone could help me understand where I'm calculating this wrong.
    I'm trying to figure out the £/kWh of LPG.
    Many references on the internet state around £0.07/kWh (7 pence) for LPG, which sounds reasonable.
    However, the average cost per litre of LPG is around £0.50/l, which is around what we pay.
      - 1 litre of LPG / 3.85 = 1m3
      - so 1m3 of LPG = £1.925 (based on £0.50/l)
      - 1m3 * 1.02264 (correction factor) * 46 (LPG calorific value) / 3.6 (conversion) = £/kWh
      - so 1m3 = 13kWh
      - £1.925 / 13kWh = £0.1471/mWh
    £0.1471/mWh is more than double £0.07/kWh......??!? So where is my maths going wrong?!
    Are you sure the calorific value of LPG is only 46?

    Flowgas suggests it is 95
    Calor says it is Propane 95 MJ/m3 & Butane 121 MJ/m3
  • simpjdsimpjd Forumite
    10 posts
    First Post
    MoneySaving Newbie
    Also back to the maths, based on 30/p a litre, it would be much closer but coming out at 8.8p per kWh. Whereas "apparently" UK average for LPG is 7p per kWh.

    Unless my maths is wrong (please question it!) it would require an LPG price of 24p/l......is this realistic for anyone in the UK?! ....or is my maths wrong....
  • edited 15 May at 12:41PM
    Flt._Lt._BigglesFlt._Lt._Biggles Forumite
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    edited 15 May at 12:41PM
    simpjd said:
    Thanks for the response! I just called up Calor our current provider, best they can do they said for 36 month contract is 40p/l. Still a 20% improvement based on my current price (amazing what a phone call can do!) however not as good as your 30p/l! Can you recommend a supplier? We use around 8,000l a year in a 2,000 tank.
    There's a sticky thread above that discusses bulk prices of lpg
  • simpjdsimpjd Forumite
    10 posts
    First Post
    MoneySaving Newbie
    Very interesting!! I got my source from Wikipedia....know for its accuracy...haha!

    "LPG is composed mainly of propane and butane, while natural gas is composed of the lighter methane and ethane. LPG, vaporised and at atmospheric pressure, has a higher calorific value (46 MJ/m3 equivalent to 12.8 kWh/m3) than natural gas (methane) (38 MJ/m3 equivalent to 10.6 kWh/m3), which means that LPG cannot simply be substituted for natural gas."
  • Mister_GMister_G Forumite
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    simpjd said:
    Thanks for the response! I just called up Calor our current provider, best they can do they said for 36 month contract is 40p/l. Still a 20% improvement based on my current price (amazing what a phone call can do!) however not as good as your 30p/l! Can you recommend a supplier? We use around 8,000l a year in a 2,000 tank.
    Price will depend where you live.  My local independent supplier in Hampshire is currently 33ppl.  When does your contract expire?  Until it does, you wont be able to shop around. Normal contracts are 24 months, not 36 months.  No doubt Calor wont fix it for 36 months.
  • simpjdsimpjd Forumite
    10 posts
    First Post
    MoneySaving Newbie
    Contract actually expired 12 months ago (!) so I'm free to change. No they said 36m contract 12m fixed, 24 variable. In your experience is it better to find small independent over large national?
  • edited 15 May at 1:34PM
    Flt._Lt._BigglesFlt._Lt._Biggles Forumite
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    edited 15 May at 1:34PM
    simpjd said:
    Very interesting!! I got my source from Wikipedia....know for its accuracy...haha!

    "LPG is composed mainly of propane and butane, while natural gas is composed of the lighter methane and ethane. LPG, vaporised and at atmospheric pressure, has a higher calorific value (46 MJ/m3 equivalent to 12.8 kWh/m3) than natural gas (methane) (38 MJ/m3 equivalent to 10.6 kWh/m3), which means that LPG cannot simply be substituted for natural gas."
    Looks like a typo.
    The sentence you quote has no citation.
    But earlier in the wiki article it states (with a citation):
    "LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline).[8] "

    As 1kg of propane is about 0.5m3 of gas, a calorific value of 95 MJ/m3 is about right.




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