A question about Smart Meters Mpans and Economy 7

  • 20 September 2021
  • 6 replies

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 @Mads or @Nataly 

I don’t want to hijack  this thread  or complicate it for @Sylviebb so I have posted  this question separately, although it is related to the linked thread it’s important enough to me to merit it’s own thread. anyway.

 I would be very very  grateful if you could get a definitive answer for me. It’s complicated (or at least I think it is - but then simple things always seem complicated to me). 

Here is my question in several parts:

The question is predicated upon the old assumption that those who could have an E7 tariff had to have a split rate supply meaning their mpan started with 2, indicating the supply was split rate (one supply not 2) That may no longer be case with smart meters, which has confused the issue for me, so with that in mind…

Part 1. What happens to your mpan when you have a smart meter fitted? The answer to this may affect the thrust of  some of the subsequent questions .

Part 2. If an Economy 7 customer  with an mpan starting with 2 and a conventional meter has a smart meter fitted and moves to a single rate tariff on the SM will the mpan then be changed to then start with 1?  If so who instigates the change?

Part 3. If the answer is yes and they subsequently try to move back to an E7 tariff will they be able to select an E7 tariff (assuming the meter database is updated) or will the mpan being single rate prevent that and they would have to then request a supply change back to E7, or will it then be OK and they will b able to select an E7 tariff and if they do will their mpan change again to start with a 2?
(You need to look at the question in relation to the original thread but it does stand alone)

Part 4.Is the answer no and their mpan split rate status should not change when a SM is fitted? 

In light of the fact that the timing arrangements change when a SM is fitted I would expect a change to that section of the mpan, (which incidentally wan never designed to accommodate SMs anyway)  but that isn’t the cause of my confusion which is based on what is, effectively, a simple premise, which is

Part 5: Is it the case then that anyone with a smart meter should, if the energy supplier has put the technology in place, be allowed to select an E7 tariff WHETHER OR NOT THEY WERE ORIGINALLY ON E7.

I appreciate this may take some time to untangle or have I over complicated it?




6 replies

Hey @woz 

Just letting you know we haven’t forgotten about you or your questions here. :grinning:

As I’m sure you can imagine, things are quite busy here at PP at the moment, so it’s taking a bit longer than usual. 

Once we get some info from our Smart gurus, we’ll be sure to update you! 

Not sure you asked enough questions. :wink:

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LOL thanks! no hurry...

Hi @woz 

Once an MPAN is assigned, this wouldn’t change. It’s a supply number which is basically a unique identifier, and doesn’t describe the type of meter at the property. That means nothing happens to the MPAN if a smart meter is fitted, or if you change from single rate to dual rate (and vice versa).

What does change is the meter details, which are used within the industry (between suppliers) when arranging works, billing, or switching a supply for example. 

So - the meter details would change, to reflect that they're dual-rate, but it won't affect the MPAN at all.

To answer part 5 - yes. Part of the design of smart is to enable this kind of functionality change without needing to exchange the meter every time. However, the practicality of doing this is currently still being worked through. Technically the meters can enable this, but there are long-term industry impacts that are making this tricky at the moment.


For a bit more info, too, just wanted to highlight that the bottom number here is the MPAN - but the top number refers to supply data, used by suppliers, which can change. 


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Thanks @Nataly 

A semantic but important point, and the source of much confusion, the whole 21 digits is sometimes referred to as the mpan by many sources on the internet including Wikipedia, but your explanation is correct in that the UNIQUE identifier is the bottom 13 digits, so with that in mind...

I’m still very unclear, so save this one for when you get back from the wedding…hope you enjoyed it!

Does this mean that anyone who has a smart meter fitted, and who goes onto a single rate tariff, no matter what the previous supply data was before they had a meter fitted whether they were dual or single rate , and who then has a supply designation starting with 1 because you changed it from 2 to 1, will be able to select an economy 7 tariff with ANY subsequent supplier  (assuming the supplier offers an E7 tariff)

This is very important to me  (and about a million other people).

More to the point are all suppliers singing from the same hymn sheet with this? It would appear not in the case of the post referred to above.

Hi @woz 

That depends on the supplier. 

In terms of the ‘no matter what the previous supply data was’ - the technology enables that to happen, but there are still details being worked through. For example, if a meter is currently single rate, is signed up for a dual-rate tariff with a new supplier and then that new supplier can't communicate with the meter… They'd be trying to bill a dual-rate tariff on a single-rate meter then. That’s just one example of the complications!

In terms of a Member with supply data starting with 1 - they currently couldn’t switch to Pure Planet’s economy 7 tariff, as outlined when it was released. But they potentially could with another supplier. 

Hope that helps explain some of the complications but it is… well.. complicated! 

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@Nataly Thanks for getting back on this, that’s helpful, and indeed it is complicated. 

I have some more questions at the end, no urgency in replying, whenever will do.

In future should this arise I shall point the questioner at this thread and they can end up being just as confused as I am! (well not quite as confused as I was but it’s clear from your reply that giving a definitive answer about what will happen is now nigh on impossible because of the ifs -and- buts) because...

What was a situation where someone could not switch to a split rate supply unless they had an mpan indicating that their “supply” was split rate (this notwithstanding your earlier pint that the first line of the mpan is now configurable by the supplier, maybe it always was but it never or rarely happened?), we now appear to be in a situation where

  1. Those without smart meters on a single rate supply can not choose an economy 7 tariff if they are  not prepared to have their meter changed to a SM. In those circumstances  if the customer insists on a change to E7, presumably they would need to apply in writing to their supplier to ask for their supply to be designated as split rate?  Or would they just be told it isn’t possible unless they agree to a SM??  This used to be something the dno was involved in, I have no idea how or whether this is now possible. Can you clarify
  2. As above but those without SM’s with a dual rate conventional meter who wish to change to a single rate without having a SM, this is a slightly different proposition to above because some suppliers (BG for example) will allow either a split rate (E7 ) tariff or a single rate tariff on a dual rate conventional meter WITHOUT  as far as I know a change in designation to the top line of the mpan (I don’t know if this is still the case, is it?  But I do know first hand that was the case as I was in that group, but SM’s were only a demon in the goverment’s eye at that time) 
  3. Those with SM’s (smets2) who have always been single rate, could now in theory, were their supplier configured appropriately, choose to switch to an E7  tariff, and if they so desired back again whenever they wished. Is that right?

I think those questions in conjunction with the caveats that you mentioned earlier cover most  bases,  apart from the I don’t know what I don’t know clause as I’m still unclear on the relationship or flow chart if you like between the supplier, DNO and DCC in all of this as to how it actually works in practice, who is suppose to tell who what.

If anyone else is sufficiently interested I’d welcome opinions/thoughts/knowledge.

and I found this, not that I understand it.. yet…


DNO =District network Operator, TO = Transmission Operator, (or TSO?), SO= System Operator (DSO?)


DNO =District network Operator, TO = Transmission Operator, SO= System Operator (DSO?)

some acronym help needed? 1 2 3 

Maybe I should apply for a job...