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Deeming export of electricity for feed-in tariff

Posted by Cathy Debenham on 25 October 2010 at 9:05 am

Deeming is usually associated with the proposed renewable heat incentive, but it is also used in the feed-in tariff to estimate the amount of electricity that is exported to the grid by microgeneration systems.

We recently received the following question: "It would be interesting and informative to find out how many people who have schemes under MCS have been able to get export meters fitted. Which electricity companies have done this and which have 'deemed' 50% off total generation as exported. Little has been written on 'deemed export' electricity, its legislative orgins, and likely future changes in this area."

I asked Ofgem what the situation is - and the answer is that installations of over 30kW must have an export meter. If they are less than 30kW it's optional, but if you do have an export meter you must use it. If you don't, the amount exported will be 'deemed' at 50% for solar PV, wind turbines, and anaerobic digestion; and at 75% for micro hydro.

At the moment it's not the utility companies that define whether or not you have an export meter. It's something which you can arrange with your installer. My solar PV system was installed in February with both generation and export meter (it cost an extra £42 + VAT). I've got a 2.1kW array of solar PV and am exporting more than half of what's generated despite working from home.

However, these rules are likely to change once the general shift to smart meters gets under way. Smart meters will include functionality to measure electricity generated and exported. I understand that some utility companies are installing smart meters now for customers who have microgeneration, even though the government is still consulting on the roll out of smart meters an there isn't yet an agreed standard. If you utility is one of these, do tell us how you're finding the smart meter in the comment section below.

NB: Since writing this blog, I have learned more about the situation - Domestic size installations can only claim the export tariff based on a meter reading if the meter is installed by their electricity supplier, and has an MPAN number. Click here to read more.

Photo by Marco Lazzaroni


If you have a question about anything in the above blog, please ask it in the comments section below.

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14 comments - read them below or add one


PHILFComment left on: 7 March 2012 at 5:00 pm

Hi Ken Dunning

                         I know exactly what you are saying. I have just had a 3.9 Kw solar system installed in February. My supplier is British Gas Unfortunately we had our old dial meter just changed to a ( non smart ) digital meter and we have a remote flow ecometer as you say.

 I understand the flow measures either way as I tested it out during a sunny period the flow meter registered high but as i turned on a light it went down, proving it was registering the outflow generated but not used.

My worry is that when I checked my new digital meter it was clocking up even though I was generating more than I was using at that point in time !!!

I assume I will end up paying for the power exported because of this. I have immediately requested a smart meter but I will have to wait and see if one is provided.

Has anybody else tried to check these digital meters ?

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kendunningComment left on: 18 January 2012 at 5:03 pm

Thanks for the replies.

Yes Fox, it looks as though my ecometer is just measuring a current flow through my meter, regardless of wether it is incoming or outgoing.

Very frustrating when trying to balance my load against my production.

I am having my export deemed.

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fox.martComment left on: 18 January 2012 at 3:30 pm

Hi Ken, 

Yes,  this is normal! However it's a bit misleading. It sounds as though your meter is measuring power flow through your main meter to to grid connection. 

So say you generate 500W from your PV system and are consuming 250W in the house, i suspect your display will show 250W..?

During the day, now your PV generation is higher and you have little on in the house, the meter will be showing what is being exported - the generation LESS any loads on in the house.

Could this be the case?

I would have thought "smart" meters would be smarter than this though?! Would be nice to have the meter clearly showing that you are exporting.

And on the topic, I imagine you are still having your export deemed? 

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Cathy Debenham

Cathy DebenhamComment left on: 17 January 2012 at 4:39 pm

Hi Ken

I'm not familiar with the smart meter or product you specify, but it might be something like the compressor on the fridge or freezer firing up that changes things. 

If the display also takes generated power into consideration, it could be the sun going behind a cloud.

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kendunningComment left on: 17 January 2012 at 2:48 pm

I have a 3.92Kw PV system and a British Gas smart meter. My remote display system for my smart meter shows the amount of electricity being used and has 3 warning lights, green, amber and red.

Now that the sun is coming out a bit I have noticed my instantaneous usage now closely follows my generated output and the amber light comes on warning of higher usage, although nothing has been switched on to cause this. There is no indication to say wether this is generated power or consumed power although the totaliser on the smart meter does not seem to count up in time with the remote sensor.

The remote sensor is a Landis + Gyr 5262A Ecometer

Does anyone understand this? And is it normal?

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Cathy Debenham

Cathy DebenhamComment left on: 12 December 2011 at 10:22 am

Ronald: It's amazing how different the costs are between the different energy companies. You may want to check out the options outlined in this blog, and think about changing your FIT supplier.

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RonaldComment left on: 10 December 2011 at 9:15 pm

This is part of an email from EON

In order to use a export meter we require Meter Operator and Data Collector contracts to be set up and a Meter Point Administration Number has to be created for export. The customer is eligible for these costs which are £400-£500 per year. Export meter figures are only used where installation are over 30kws. It would not be viable for you to use your export meter readings as the yearly costs outway the export return.

I would advise that you remain on deemed 50% export.

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Cathy Debenham

Cathy DebenhamComment left on: 5 December 2011 at 2:39 pm

Hi Ronald. This is the first time I've heard of this £100 charge. I'd be very interested to hear how you get on with your challenge, as I've never heard of anyone having to pay for an export account on a 4kW installation. The 3.1p export tariff is part of the standard feed-in tariff and, as such, my understanding is that everyone should get it automatically. Changing a meter that goes backwards is standard practice but, as far as I know, charging for it isn't.

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RonaldComment left on: 21 November 2011 at 11:02 pm

I have a 4KW system and use EON. My meter went backwards so it was changed to a combined import/export meter.  EON now refuse to pay to my export readings unless I pay them over £100 a year to set up an export account. It is my intention to challenge that through their complaints procedures.

i shall be very interested to hear of any other experiences.. 

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Fred1Comment left on: 22 April 2011 at 9:22 am

According to the DECC website, the new smart meters are microgenerator friendly.

The will measure net Export and recieve store and communicate total generation. It seems that once you have one installed you don't need to read and report your exported or generated, it is done automatically.

I understand that if you request a smart meter, some infrastructure owners/ electricity companies install for free with no annual mainenance fee.

Over the next couple of years all dwellings will have the new smart meters installed.


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Cathy Debenham

Cathy DebenhamComment left on: 21 April 2011 at 10:13 am

Hi bgriffin51

I've been doing some more digging on this issue. It sounds as if your situation is the same as mine (except that you're exporting more). Good Energy, who I'm with, came back to me to explain that to pay the export tariff based on a meter reading, rather than deeming, you need to have a meter with an MPAN number - as you do for your electricity import meter. They can install one of these meters at a charge of about £70, and there's an annual maintenance cost too, which makes it uneconomic for an installation my size.

I then spoke to someone at Ofgem, which is responsible for regulation of the rules set by DECC, and she confirmed that it is her understanding that to be accepted for export for the feed-in tariff a meter must comply with the balancing and settlement code and be installed by your electricity supplier.

We're doing more research on what's happening in practice, so watch the blog - more detail coming soon.

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bgriffin51Comment left on: 20 April 2011 at 7:28 pm

I too am having difficulty getting my supplier (Scottish Power) to accept my export meter readings. It seems to be a very grey area as to what constitutes a valid export meter. According to Scottish Power only one installed by the distribution operator. (Mine was not, it was installed at my request by my installer). anecdotal evidence is that some FIT suppliers accept the reading and some don't. Its not big money but I do export about 80% of my production (3.96 Kwp installed) and there is a principle involved.

My interpretatation of the available information is that I have a meter and I can prove that I am exporting more than 50%. It is comparable to the generation meter and can be audited should anyone want to do so. The scheme says I will be paid for what I export.

 It seems quite quite illogical and contrary to the simple tariff structure that has been put in place, that a generation meter is accepted but an export meter might not because of who installed it. Incidentally I checked with my local distributor (Southern) who confirmed that there is nothing wrong with my installation.

It seems that my export meter measures my export accurately but it is not good enough for scottish power. I am currently waiting for a response from Scottish power as to why they cannot pay. 

Has anyone else had and or resolved this issue with their FIT supplier.

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Cathy Debenham

Cathy DebenhamComment left on: 5 January 2011 at 8:43 am

Hi Chris

It's not a smart meter - it's just an identical meter to the one that measures generation - and I'm currently in discussion with my electricity company about why they don't recognise the readings from it - so until I've got a definitive answer from them - which I'll post as a new blot - I'd hang fire.

Some electricity companies do install smart meters when they replace a wheel meter - but not everyone's happy with the service they get from them. I'm doing some research on that too which will be in a future blog post.

Sorry that's not very helpful now, but hopefully I'll have a better answer in a week or two.

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Chris W

Chris WComment left on: 4 January 2011 at 5:57 pm

Cathy, can you clarify what you mean here by export meter please? Is that what some people might call a smart meter? Or is it simply an additional device installed alongside the existing meter and not replacing it?

I will shortly be having a 2.1kW system installed and I'd like to be to replace my existing 'wheel' meter with a smart meter and hoped I might be able to do so for £42!

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