If you have an old 'analogue' electricity meter, and a solar PV system installed you may sometimes find you meter running backwards.
We occasionally get asked about this, and if it is a problem, so the following article has been written to put people's minds at rest.
Take the case of Paula Owen who says:
If the householder is not informed that it is a problem at the commissioning stage, and doesn't really understand what is happening (I only realised there might be an issue because through the summer I was generating more than I was using, so had a negative meter reading situation) is it their responsibility, are they legally liable? Or is it the responsibility of the FiT payment suppler to check the meter type?
Firstly, Paula's case is quite rare, since the old ‘spinning disc’ meters are not that common and most of them have a ratchet to stop them going backwards.
A decent MCS accredited solar PV installer should know about this and provide you with an explanation of what will happen when they complete your installation.
If your meter goes backwards you are going to be better off, since you will pay less for your electricity, and you do not really need to worry about this as it is not your problem.
The problem lies between the District Network Operator (DNO) and the Public Electricity Supplier (PES) that supplies your property.
The DNO gets the G83 notification (telling them you have PV) and it is their responsibility to change the meter but it is the PES that suffers if they don’t (meter changing can only be done by DNO).
So in practice the DNO rarely changes the meter unless the PES requests and pays for it. But the PES doesn't really know whether the meters will run backwards or not. However you are under no obligation to tell them, and are not liable for 'their' meter running backwards.
At some point the PES should catch on because at some point your meter reading may be less than the previous reading. At that point they will need to chase up the DNO to get the meter swapped out.
But, from experience, communication with the DNO is not easy at the best of times, and they have much bigger worries (like people trying to connect huge renewable energy installations to the grid etc).
Paula buys her electricity from Ecotricity (a zero carbon supplier) and was keen not to benefit at their expense, so she followed up and told them about her old meter, which they then got changed by EDF (the DNO in her area) within a few weeks. An amazingly prompt service for a DNO, although that was probably more to do with Ecotricity's persistence than anything else.
As a general rule if your electricity meter is running backwards, unless you really like your electricity supplier, it's best to keep quiet. The longer they take to notice and sort things out the better off you will be.