Feed-in tariffs explained Meters running backwards

An electricity meter

Some electricity meters run backwards with solar panels, when electricity is exported

Since the feed-in tariff scheme launched in April 2010, some households with solar PV panels have experienced their electricity-usage meters (otherwise known as supply or mains meters) running backwards.  

So every time the solar panels are exporting to the grid - because the panels are generating electricity which is not being used in the house - the mains electricity meter starts turning backwards. The result is lower electricity bills for the householder, as the reading will be less than expected. 

This seems to happen mainly with analogue meters without an in-built 'backstop', as the flow of electricity goes the other way round (out instead of in).

Affected solar panel owners

One in four Which? members who have solar PV have noticed their electricity-usage meters running backwards, according to our January 2013 survey of 1,300 Which? members. However, the numbers of those affected may actually be higher than this, as a significant number of respondents - around 20% - told us they didn't know whether or not their usage meter is running backwards, with several explaining that they never look at their meters. 

Some households noticed that their meters were running in reverse, but incorrectly believed that this was simply because they were generating their own electricity. 

Some people were warned by their solar PV installer that their meter might run backwards. But for most of those who noticed, it was unexpected.

Inaccurately low bills

If your electricity-supply meter runs backwards, it will show a false low reading - leading to an inaccurate bill. Some meters have even been showing negative readings, leaving households in credit. Because of this financial advantage, some households may have been tempted to stay quiet about the problem, getting free electricity on top of the savings they are making from their feed-in tariff. 

Others have wrongly thought that their meters are supposed to go backwards from having solar PV. 'I thought this was normal,' one member told us.

As around half a million solar PV systems have been installed in the UK already, this could mean a large amount of electricity is being, or has been, consumed for free - often unknowingly. This might potentially lead to increases in electricity costs if suppliers seek to make up for unplanned losses. 

What's more, solar PV customers, many of whom have been unaware that their meters are running backwards, are sometimes being landed with unexpected electricity bills retrospectively once their supplier finds out that their meter is going backwards. The bill is worked out from an estimation of what their usage would have been if their meter had been working properly.

Solar PV panels

About 500,000 solar PV panels have been installed in the UK

Who is responsible for upgrading the meter?

Over two thirds of respondents to our survey said they were unclear about who should upgrade the meter when the current one runs backwards.

It should really be the responsibility of the solar PV installer to check that the meter is fit for purpose and for the installer (if it's the same company as the supplier) or the household (if the FIT installer is different to the supplier) to then inform the supplier if it needs upgrading. 

But because this problem wasn't initially expected, it wasn't made procedure from the start.

What you can do

Regulator Ofgem told us: 'Where a customer suspects that the installation of electricity-generating equipment has affected the operation of their import-supply meter and it is no longer accurately measuring the electricity supplied to them, they should contact their import supplier at the earliest opportunity. Once the supplier is aware that the meter may not be suitable, it is its responsibility to take any necessary steps to ensure the meter is appropriate.'

In cases where the FIT installer is the same company as the electricity supplier, internal communications should - though often don't - ensure that the supplier becomes aware that a household has an unsuitable meter.

However, it is difficult for an energy supplier to find out that this problem is occurring if the installer hasn't notified the supplier that the meter will need to be upgraded. In such cases, the supplier can only find out by doing a standard meter check - normally undertaken every two years minimum - or by analysing discrepancies in a household's monthly bills.

Over two thirds of our survey respondents with meters running backwards told us they have informed their supplier; of these, 62% have had their meters upgraded at no extra cost, while 18% are awaiting a resolution. A small number were charged by the supplier to have their meter upgraded, though we are assured by the big six suppliers that this isn't their policy.

What do the energy suppliers say?

We asked some larger energy suppliers to tell us their view on the meter problem:

British Gas

British Gas told us: 'As the majority of installs are not completed by British Gas, we therefore rely on the customer to inform us that their meter is running backwards. However, as the customer notifies us every three months of their meter reading, we are normally able to identify, at that stage, if the meter is running backwards.'

EDF Energy

EDF said: 'The initial responsibility for identification of meters that have no 'backstop' lies with the surveyor/installer of the microgeneration system. They should advise the customer on this. However, installer knowledge in this area when the FIT was introduced was limited. Microgeneration Certification Scheme installer training, accreditation and quality-assurance procedures have all been updated since introduction to include checking for meters suspected of having no backstop.'


SSE believes it is the responsibility of both the energy supplier and the customer: 'SSE has a list of compliant meters that we check at the registration stage of FITs. If the customer has an incompatible meter, then we exchange it for them. In addition, we have a two-year meter read obligation. It is also suggested that consumers check their meters when they receive an estimated bill.'

Will I be billed retrospectively?

Should your supplier find out, it has a right to charge you retrospectively...

So if you notice your meter running backwards, should you tell your supplier or not?

It might be tempting not to as you will benefit from lower electricity bills. But beware that should the supplier find out, it has a right to charge you retrospectively for up to a year for the electricity you have used but have not been charged for.

Energy suppliers are deciding whether - and how much - to bill for energy usage retrospectively on a case-by-case basis. Most say they understand that, in the majority of cases, the customer is initially unaware of the problem. And so might, for instance, seek to recover only a proportion of the costs, worked out by looking at usage patterns after the meter has been upgraded.

However, once you have told your supplier that your usage meter is running backwards, the company has a period of one year in which to issue a bill for past usage. After this period, you don't legally have to pay a bill issued retrospectively.

Consumers who feel they have been unfairly billed in relation to this issue, or who have been charged to have their usage meter upgraded, should contact the Energy Ombudsman.

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