I see much the same with my monthly statements too. I’ve not checked all of them but in the handful I did check the quoted calorific value on page 6 was lower than the figure derived by working backwards from kWh to volume.

That made me curious.

So I downloaded daily calorific values from http://mip-prod-web.azurewebsites.net/DataItemExplorer  and calculated the 30 day average calorific values for my sample of bills.  Using these I got a much closer agreement to the declared kWh I am charged. Sufficiently close that I’m content that I’m not being overcharged.

I found some legislation that says declared calorific values must always be less than actual and it may be that OVO have decided to under declare or are provided with a deliberate underdeclaration for the bills by a third party. 

I agree with you that the statements are not self-consistent.

Interesting comments.

The fact is that the Account Statements we receive are generated automatically by computers and therefore the Calorific Value used in the calculation must be available to be stated in the Statement. The value quoted on page 6 of the Statement has not been correct 3 times in the last 6 Statements that I have received.

I would be surprised if it were not a legal requirement for all of the facts on a Statement to be correct thus allowing the recipient to check the calculations.

Since the figure on page six is rounded to  1 decimal place and the average for the month is effectively to three decimal places the probability of it being correct are rather slim. “Correct” results relying mostly on the kWh figure itself being rounded.

The volume consumption figure has a fairly broad error band so the starting figure for the calculation is likely wrong too. Close but still wrong. The computer can never do better than the quality of the information it is fed. 

I do hope that someone from OVO can give us the official line, 

The average of the daily calorific value for the period of the bill is truncated to one decimal place.

Ofgem gave advice to domestic suppliers concerning this as follows.

This means that for a given gas billing period, suppliers should truncate the average CV to one decimal place. Rounding average CV is not consistent with the Regulations, nor is calculating to more than one decimal place.

Full details here https://1drv.ms/b/s!AjsHn14E9BxMjB5Mwd4gK0fL_teJ?e=7h9Z2H

I understand that Ovo calculates the vol to kwh using the CV derived as above.

The billing software was then fed the vol and kwh but not the CV.  The billing software then worked out the CV based on the vol and kwh.  Due to errors in rounding in this back calculation the CV on the bill did not always match the CV that was used!

I have been told this has now been fixed.

@Russell   Intriguing.  Do you know when it was fixed or when you were told it had been fixed?

I’m going to check my bills and historical data much more thoroughly.  My bill of 10th Jan 2020 did not use the figure on page 6 , The February bill however has used the page 6 CV.

@NoPoke you prompted me to check again and I see that my bills for October 2019 and November 2019 have CV’s quoted on the bills that are incorrect. I guess it has not been fixed yet!

However, there is agreement with the CV’s downloaded from National Grid from the link that you previously mentioned.

For my October bill     CV on bill = 39.0   Vol (m3) = 125 and kWh = 1388

Calculating the kWh from the vol and CV shown on the bill

kWh= vol * volume correction * CV / 3.6

                = 125 * 1.02264 * 39.0/3.6  = 1,384.825 rounding to nearest kWh = 1385

The average CV for the billing period from National Grid data is 39.1290322580645 and truncating to first decimal place gives 39.1

kWh = 125 * 1.02264 * 39.1/3.6  = 1388.37583333333 rounding to nearest kWh gives 1388

There are further ways to check the accuracy of the CVs used by OVO.

Firstly you can obtain the CV figures themselves for any period of dates by visiting the website for National Gas Grid here. These figures are submitted daily by all Gas Transporters (GDNs) across Great Britain.

Secondly, if there are technical issues which prevent sampling from occurring, then the Gas Transporter must apply the lowest CV which has been recorded during the year. In the case of a new site, where there isn’t a year’s record, the CV is deemed to be 37MJ.

 Yes @Monk96 there are indeed legal requirements which apply to this matter! Search for the Thermal Energy Regulations if you want to investigate further.

I suspect that there is not much I (or we) can do about how the monthly CV figure is worked out but I really think that OVO should quote on the monthly statements (page 6) the value, correct to 1 decimal place, that has been used to calculate the kWh amount.

In the last 6 months I have had at least 3 statements where the quoted CV was not what was used in the kWh calculation. Admittedly it is only 0.1 in error but it is still wrong.

In any other industry, if I were to issue an account statement to any of my customers, he would have the right to be given all of the information required to check that the account has been calculated correctly.

That’s a good point @Monk96. If the regulations state that it should be correct to one decimal point, then that’s what the bill should show.

@Eva_OVO - can you draw this to the attention of a member of the Compliance Team please?

As the CV is going to be falling in future, it’s important to get this right now. Otherwise the %age error will be getting worse.

Thanks for raising, @Monk96, this has been addressed by the compliance team before @Transparent, here is what they advise on the matter:

There is currently a display issue on some statements that has been raised to our Technical Support Team to look into further, which has caused the correct calorific value truncated to one decimal place to be used for billing purposes, however then when the billing system reverses the calculation a rounding error sometimes occurs as the reverse calculation rounds instead of truncating which can give a different outcome. Our Tech Support Team are currently aware of this and looking into a fix, however as with any changes to systems, things need to be tested extremely thoroughly to avoid causing wider issues which may have a larger impact on our members.

@Monk96 if you could reach out to the team, we’ll ensure your account is looked into, you can send us a message on Facebook, Twitter and our Help centre has online chat!

I hope this helps! 

@Amy_OVO   I am not on Facebook or Twitter so cannot “reach out to the team” in either of those ways and I am reluctant to contact via email as I believe I would lose my Rewards Bonus for a month if I did so.

There has to be a way to include the value of the CV used in the kWh calculation and then print this value in the Statement - this has to be just a few lines of code.

The figure on page 6 is supposed to be that very value. 

@Monk96 if the problem is actually within the Billing System software, then the fix won’t be quick.

As they indicated, there are extensive verification checks before anyone is allowed to alter code on a live billing system!

I’m bemused that the software “reverses the calculation” to print it on our invoices. As the original CV figure was truncated, the billing software no longer has those digits available to it!

Working backwards gives a very real possibility of a divide by zero error when a customer consumes no gas during a billing period.

For low usage working backwards can yield a range of potentially valid CV values. But which one should the billing software pick? ​​​​​​ If it has say five valid values then it only has a 20% chance of picking the value that was used in the forward calculation. 

Worse still @Amy_OVO wrote:

...this has been addressed by the compliance team before @Transparent…

I must be losing my touch. It’s been at least 12 months since I was last pipped to the post by OVO’s internal teams!

I have found the time to go thru all of my Statements (24 since March 2018) and found that, until Oct 2019, the CV quoted on page 6 could be used to produce the kWh figure used for calculating the bill. I have now had errors in Nov 2019, Jan 2020 and Feb 2020. 

So, I wonder if some change in the billing occurred around then that is now producing the errors that are being discussed. I know that the errors are ±0.1 but there must be a way to eliminate any errors.

Great detective work @Monk96 

But don’t make it too easy for the programmers. They get paid to look back through the changes-log for stuff like this.

All you get is a gold star 

Latest Statement (for Feb 2020 to Mar 2020) works out exactly to the penny when using the quoted CV.     

Let us hope that it continues in this way.

Glad to hear it @Monk96 !

Well there you go - after complaining that the gas CV quoted on the account statements was not always correct - what has OVO gone and done?

They are now omitting the value altogether! The new statement format does not give the value used when the bill was calculated - just states that it could range from “37.5 to 43.0”.

As OVO has done away with the Self Service Reward as a result of comments from Ofgem about the way it was applied, I will be sourcing a new supplier that will give me a better deal. Pity as I had been pretty satisfied with the OVO deal and the way is has been handled but we must get the best deals that are available out there, musn’t we?

Well, that’s not great to read at all, @Monk96 

Feedback like this is always valued here at OVO. I’ll do my best to find some context behind why this CV calculation was updated - all I know was that it proved to be very difficult to show accurately for each member’s bill. 

We’re not going anywhere, we’ll continue to try and do what’s good for our members, and work towards a zero carbon world. Hopefully you’ll join up with us again somewhere down the road!

As I said, I was satisfied that the deal I had was acceptable whilst it included the Rewards scheme but its withdrawal makes all the difference. Incidentally, I had a look on the OVO Energy web site and looked for a quotation. When I looked at the figures, there was still a mention of a Rewards scheme so it would appear that potential new customers are being led to think that they will be getting this scheme applied to their deal. In May I received an email saying that the Rewards scheme would end in July so It is a bit odd that it is still being mentioned in any new quotations?

I would have thought that it was a legal (?) requirement that the energy bill should state ALL of the facts that are necessary to show that the bill has been calculated correctly? The bill calculation must have had the gas CV factor included somewhere in the figures so why cannot it be added into the statement. If I can do it using an EXCEL spreadsheet I would think your programmers should be able to get their heads round this situation.

Perfect bit of info above from Transparent, make sure to have a read of this @Monk96 ^^

As for the ‘Online Discount’ or ‘Self Service Reward’ still showing on quote pages, this is something we need to double check. It shouldn’t be showing, for new or renewing customers, and that’s been the case for around 10 months.  Leave this with us :) 

Daily billing will make for a long monthly statement. Each days use should be detailed otherwise it isn't daily billing.