Technical question - Bulb's method of converting Gas usage to kWh ?

Does Bulb use the same formula as other suppliers : viz - Gas usage x 39.5 (calorific value) x 1.02264 (volume correction) / 3.6 = kWh.

@victor, the calorific value of UK mains gas varies so I suspect that part of the formula at least changes depending month to month and by location.

I suspect you’re right about the rest though but I’ve not personally had a bill yet (the calculation is apparently on the bottom).

In my one year experience with EDF, it was the volume correction that changed (slightly) monthly, but of course it may just be an arbitrary correction to the real calorific value. Cheers for the reply.

Seems that the EDF equation bears no relation to the one quoted in your link, so Bulb’s version will undoubtedly be something different again - esp as 10% of their gas is from a different source with (probably) radically different calorific properties.

Do I as a consumer actually get Bulb’s gas ? I guess not and what I got last month I will continue to get this month but just pay someone else. It’s my location that determines my gas.

@victor, I don’t see a calculation for kWh on the page I linked?

I suspect the calculation for Bulb will be very similar to the one you mentioned.

It’s unlikely that you get much (if any) of the electricity or gas purchased by Bulb, however some people in the UK will.

You will still pay based on the (approximate) calorific value of the gas being supplied to your property, rather than the calorific value of what the bio-methane plants add in somewhere else in the country.

The calorific value of methane is lower than natural gas (at close to 40MJ/m2 compared to 43MJ/m2) but not enough for it to make much of a difference.

Yes, you are correct - I didn’t read the site’s details well enough. I checked on this site : https://www.businessenergy.com/gas/kwh-calculator.html and it’s pretty much a standard equation with ~ 39 being the CV. So unlikely that Bulb’s data will be much different.

Taken from my bill, they have an example at the bottom;

*Explaining your gas usage
Not all gas is created equal. We convert gas units
from your meter into kWh to make sure the
energy output of your gas is priced consistently.

We do this using the following formula:
Meter units used 68
Volume conversion factor x 1.00
Metric units = 68
Volume correction x 1.02264
Calorific value x 39.4
Convert to kWh ÷ 3.6
Energy used 761 kWh

So basically yes the calculation is as per what you though, calorifc value is slightly lower but that may vary.

Thanks very much.

Does the Volume conversion factor change or is it 2.83 for everybody ?

I think the volume correction is pretty static as I have never known it to change in the last few years, what does change (or can) is the Calorific value as they use an average figure each month, they also use different entry points throughout the UK so it can also vary from region to region. In real terms the CV does not make much difference to your monthly bill, maybe a few pence at most.
There are websites for the National Grid which allows you to check the CV for your area for given dates.

As a rough and ready calculation, kWh is about 11·1 × metered units.

My metered units this month were 229 with a CV of 39·1, so that’s 2543·5 kWh costing £72·51.
If the CV had been 39·0, it would be 2537 kWh costing £72·34.
Or with a CV of 39·2, it would be 2550 kWh costing £72·68.

My question is about the ‘volume conversion factor’, not the ‘volume correction’. Tom6685 's comments above indicate that his vol conv factor is 1.00 whilst mine is 2.83. Confused I am !

My question is about the 'volume conversion factor', not the 'volume correction'. Tom6685 's comments above indicate that his vol conv factor is 1.00 whilst mine is 2.83. Confused I am !

Are you on the old style meter (cubic feet)

Yes, my meter is the cubic feet type. So that’s why the need for conversion to cubic meters, I assume ?

Yes, my meter is the cubic feet type. So that's why the need for conversion to cubic meters, I assume ?
That is correct.

Thanks for your help with that, Mowcius.

All-star thread.

the monthly Calorific Value, and the full relevant calculation are shown at the bottom of the Bulb bill.

the monthly Calorific Value and full calculation are shown at the bottom of the Bulb bill.

Hi… Is the calorific value averaged for the month or the amount it is on the I am invoiced? Thank you

They use an average for the current month to work out your Bill, The CV at the bottom of your statement was an example but I believe it now reflects your actual average but haven’t checked lately to see if it has changed.

You can get your CV average from the link below if you want to double check it.
http://mip-prod-web.azurewebsites.net/DataItemExplorer/Index