Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Gas bill explained?

Options
  • 07-03-2009 1:54pm
    #1
    luckat
    Closed Accounts Posts: 5,366 ✭✭✭


    I'm gazing at my gas bills, which appear to be trying to inflate themselves and fly away into the stratosphere, and am puzzled by one particular figure.

    On each bill there's a number of units, and something called 'Conv factor'.

    The units are baffling enough - what on earth does 781m3 mean? 731 metres squared? What does this mean in terms of units?

    But the 'Conv factor' changes from bill to bill - sometimes 11.5059, sometimes 11.419800, and so on. What is this?

    (I also found a letter from October 2007 crowing: "We have revised our tariff structures and prices. For the second time in 2007 the average price of gas is falling". Ah, the old jokes are the best.)

    If Shell ever build their gas platform and works (hopefully well out to sea), will the government bargain a good lot of free gas out of them, by the way?


Comments

  • Options
    #2
    Max Power1
    Closed Accounts Posts: 10,272 ✭✭✭✭Max Power1


    luckat wrote: »
    I'm gazing at my gas bills, which appear to be trying to inflate themselves and fly away into the stratosphere, and am puzzled by one particular figure.

    On each bill there's a number of units, and something called 'Conv factor'.

    The units are baffling enough - what on earth does 781m3 mean? 731 metres squared? What does this mean in terms of units?

    But the 'Conv factor' changes from bill to bill - sometimes 11.5059, sometimes 11.419800, and so on. What is this?

    (I also found a letter from October 2007 crowing: "We have revised our tariff structures and prices. For the second time in 2007 the average price of gas is falling". Ah, the old jokes are the best.)

    If Shell ever build their gas platform and works (hopefully well out to sea), will the government bargain a good lot of free gas out of them, by the way?
    your meter measures gas used in units of cubic meters - that 781m3 is the difference between the reading this bill and the reading last bill.

    As gas is imported the purity is not the same. It is tested for calorific value (burn rate) at the intake points (eg the moffat intake) and the results put into a formula to give the conversion factor from m3 (as above) to kwh, which is the billing measure


  • Options
    #3
    luckat
    Closed Accounts Posts: 5,366 ✭✭✭luckat


    Thanks, Max P. Does it actually say how many units of gas I've used anywhere? 781 metres cubed doesn't have the vaunted "transparency" promised in Bord Gosh's letters.


  • Options
    #4
    dudara
    Registered Users Posts: 33,518 ✭✭✭✭dudara


    It's as Max_Power1 says. Due to the fact that the energy content of gas varies it's hard to define a standard 'unit'. Therefore they use cubic metres, which are a standard unit of volume and they attempt then to determine the energy used by multiplying by the conversion factor.


  • Options
    #5
    luckat
    Closed Accounts Posts: 5,366 ✭✭✭luckat


    Dudara - Thanks. I'm not sure what your explanation actually means, but thank you for caring.


  • Options
    #6
    Max Power1
    Closed Accounts Posts: 10,272 ✭✭✭✭Max Power1


    The standard unit that you are looking for is the units shown on your meter (which measures in meters cubed). Apart from this the conversion rate from units/m3 to KWH is varied by the effiency of the gas that billing period - normally 11.2-11.6 but theoretically could be higher/lower than that range.

    To cut a long story short there is no constant conversion factor from cubic meters to kilowatt hours (the units you are billed in)

    (By the way sorry if it comes across as a bit of a spiel - i used to work for Bord Gais!)


  • Advertisement
  • Options
    #7
    Alun
    Registered Users Posts: 21,466 ✭✭✭✭Alun


    luckat wrote: »
    Dudara - Thanks. I'm not sure what your explanation actually means, but thank you for caring.
    It's not that difficult to understand ... there's only one way for a simple mechanical meter to measure how much gas is flowing into your house and that's by volume. In this case it's cubic metres, but it could just as well be pints or gallons. I don't really know what other kind of "unit" could be employed here.

    Now when you burn 1 m3 of gas it delivers energy, measured in kWh, the same unit as used for electricity billing. The amount of energy you get from burning a unit volume (1 m3) of gas is called it's calorific value. Unfortunately, because gas comes from all kinds of different sources, and gets all mixed up together before it gets to you, this calorific value varies from tie to time, and its this figure that appears on your bill as the conversion factor. In other words if you burn 1 m3 of gas, you'll get (for example) 11.6 kWh of energy out of it.

    They could alternatively just charge you a fixed amount per m3 and say tough luck that the calorific value changes, but ultimately this is a fairer system.


Advertisement