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Exporting your home-generated electricity: deemed vs metered

Posted by Kate Turner on 30 September 2011 at 9:43 am

The benefits of ‘deemed’ export versus metered export of solar PV generated electricity can be a source of confusion for many domestic microgenerators, and recent research conducted by YouGen shows it causes confusion among suppliers too.

In most cases there is a charge for installing and maintaining an export meter so wrong advice can have significant consequences. If you’re not exporting sufficient electricity to compensate for the running costs you could end up losing money.

The government aims that smart meters will be installed in every home by 2019, which will provide some much needed clarity for generators who are exporting to the grid, and will make the whole process of exporting much easier. Currently it is down to the feed-in tariff supplier to ensure the right information is passed on.

A good feed-in tariff supplier will look at your estimated consumption demand to assess whether you will benefit from installing an export meter rather than claiming the ‘deemed’ rate.

[According to Ofgem export meters are optional for installations of less than 30kW, 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. - Ed]

To ensure you get the best rate of return on your investment, here are the answers to some questions that we’re often asked by our generators. We hope they’ll be helpful to those of you considering installing an export meter.

How much of the electricity I generate through my Solar PV panel is used at my property?

If there is always someone at home then it’s likely that a higher percentage of the electricity you generate will be consumed at the property instead of being exported.

Using as much of the energy you generate at home is not only a very efficient use of electricity, as it reduces the amount of electricity lost in line losses, it also means you will need to import less electricity from the grid, save money on your electricity bills and still get paid the ‘deemed’ rate of export which is currently 50% of your total generation.

I export more than 50% so is it worth me installing an export meter?

Not necessarily. If you’re away from home for most of the day then it’s likely you’ll be exporting more than 50% of your total generation.

Our rule of thumb is that, in most cases, there’s a cost attached to both installing and maintaining the export meter. For the majority of Solar PV generators under 10kW this cost is likely to outweigh any benefit..

Furthermore, it can be a very laborious process to get an export meter removed once it has been installed, so it’s worth making sure you weigh up all the benefits and drawbacks carefully before going ahead.

My installer has already fitted a device that records export. Can I provide readings from this?

No. To claim metered export under the Feed-in Tariff you must have an export meter, registered and installed under the Balancing and Settlement Code (BSC).

This would normally need to be installed by a registered Meter Operator, arranged through your supplier, and you will also need to request a separate export Meter Point Administration Number (MPAN).

Picture by Russ Allison Loar

About the author: Kate Turner is external affairs executive at Good Energy.

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

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9 comments - read them below or add one

Cathy Debenham

Cathy DebenhamComment left on: 21 June 2013 at 8:43 am

Hi JP1PFL and others with meter going backwards. Can I refer you to another thread on the website which focuses specifically on the issues surrounding meters running backwards and who is responsible if they do. If you read the blog and the comments it should answer all your questions, but if not, do ask another question there. 

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JP1PFLComment left on: 20 June 2013 at 8:27 pm

Following on from my comment re backward running meter, and after some additional research, I wonder if anybody has sought legal advice regarding the position taken by the Suppliers/ Fit administrators.?


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S&G Wooldridge Ltd

S&G Wooldridge LtdComment left on: 19 June 2013 at 3:55 pm

The answer to all these problems with export with or without meters going backwards is to install a proportional PV heating controller. 

This both stops meters going backwards but more importantly enables you to use more if not all your potentially exportable power at no extra cost.

You can then stay on the 50% deemed tariff and profit from the free use.

Beware though the simple switchers as they do not prevent your meter going backwards or fully capture all the available export power.

Even if you are on an full export tariff it can still sometimes  pay to use the proportional PV controller as your export rate is still low, so you are effectively buying your own  electricity back at the export tariff.

S&G Wooldridge make the Sola Controla see

System designs up to 27kwatts three phase are possible but the standard unit is 4 kwatt. scaleable upwards with lower cost slave units.  

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JP1PFLComment left on: 19 June 2013 at 3:00 pm

I have installed 20.75kw for nearly a year,  which has run my meter back 6000kw+.

My supplier (Eon) are now insisting they install a new meter(not smart) which will

prevent this. I have asked what will happen to the 6000kw and they are very vague about what would happen. They offer no advice regarding an Export meter.

I know that I am receiving 50% of all energy generated but I take the view that the credit should be able to be used against future use?

I am currently in dispute with Eon regarding the tariff being paid on my first 4kw system and they are anything but cooperative


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Sparky Parky

Sparky ParkyComment left on: 7 February 2012 at 12:14 pm

I am in exactly the same position as Ronald (blogged on 21/11/11) and the replies I have been getting from EON beggar belief! I have variously been told that a) my meter is not accurate enough to measure exported electricity; b) that most people export less than 50% of generated electricity; and c) that it will cost between £600 and £1000 a year to fit and maintain an export meter!

I have pointed out that they had my Smart Meter fitted, that it uses the same sensors to monitor both import and export, that it was manufactured by a reputable company that they use frequently and that it carries a C.E. marking.

My only option seems to be to devise a cunning scheme to use all the power produced. Already my wife has taken to using the washing machine only when the sun shines!

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Cathy Debenham

Cathy DebenhamComment left on: 5 December 2011 at 3:28 pm

Hi Ronald - do you know whether your export meter has an MPAN number? You need one of those for the FIT supplier to accept readings. They are issued by the distribution network operator (DNO). The charge for this sort of export meter varies enormously between suppliers as you'll see in this blog. Generally, if you are exporting only a bit over 50% of what you generate it's not economic to go down the metering route.

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RonaldComment left on: 21 November 2011 at 11:27 pm

I have an import/export meter fitted but EON will not accept my export readings without my paying an exorbitant fee every year.My original import meter went backwards. 

I export about 60% of generation. It's small money but it is a principle. Can I challenge EON.

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Fred1Comment left on: 4 October 2011 at 12:09 pm

There always seems to be at least one Infrastructure owner/ Supplier who will install for free. It may involve changing FIT company payer but that is now easy. It seems that the infrastructure owner in your particular area will almost certainly install for free, the smaller players in the game always seem to charge.

The calculation is therefore simple do you export more than 50%  ?if so get a free meter if not,  do not get a meter and be paid 50% deemed export



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Martin Fodor

Martin FodorComment left on: 30 September 2011 at 11:15 am

wouldn't it be helpful to give at least 1 example of the cost in a domestic property - this order of expense eg install, register, plus example maintenance must be known...?


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