A Perverse Unintended Consequence of PV and Backward Running Electricity Meters!

The visits to my blog post on backwards running electricity meters are still increasing, and the comments, both publicly and privately to me, continue to flood in.  I have now had over 1,500 visits in the last few months alone.  And people say this is not a big issue?!?  I figure the exponential leap in interest in this issue coincides perfectly with the ‘dash for PV’ that happened since the government’s announcement of the cutting of the FiT rate back in the autumn, and it’s been since Feb/March when the weather has got much more clement (and so they are beginning to generate more than they use) that this new breed of PV micro-generators are experiencing the backwards running of their electricity meters for the first time and are befuddled by it; hopping on Google to find out more and then hitting my site.

What I am noticing recently is a new worrying trend, worrying that is if you think that all these micro-generating households should be reducing their use of ‘dirty’ grid based electricity and contributing to a cleaner electricity supply.

I have had several email exchanges with people who are worried that their electricity meters are going backwards to such a degree that they are in negative amounts on their usage meters  They, for their own reasons, don’t particularly want to inform their energy supplier of the fact, but realise their need to make it look as if they are at least using some electricity so their supplier doesn’t get suspicious and suss out what is going on.

So what is their solution to this?  They are using their immersion heaters to heat up hot water, as well as using electric heating (when they have gas central heating systems) to heat their homes – when the sun isn’t shining.  Now we all know that using electricity to heat both space and water is a pretty uneconomical thing to do if you have a gas system installed – carbon wise as well as monetarily – but for these householders the monetary side isn’t relevant as they are simply trying to get back into ‘positive’ numbers, even just slightly, on their usage meter.

But think about the carbon impact of this.  The whole idea of people generating their own ‘clean’ electricity is to reduce their carbon footprint and be part of the green revolution (although, of course, some people are only interested in the revenue side of this scheme), but for people with perfectly good, and much less carbon intensive, gas heating and hot water systems in their homes, to start using grid electricity unnecessarily to heat water and space, is concerning from a carbon point of view.

I accept some people will argue I am being idealistic about this, and that they have ‘generated’ a certain amount of ‘free’ electricity, and so why shouldn’t they ‘use’ all of it, using the grid as a sort of ‘storage battery’ for their electricity which they can then use when the sun isn’t shining, but from a peak load management (domestically this is between 5-9 pm) point of view as well as a carbon reduction issue in the future, this type of behaviour is not helping. 

Related blog posts:

Being a PV generator: Lessons I have learnt Part 1

Being a PV generator: Lesson learnt Part 2

PV systems and meters running backwards: need for clear guidance




6 comments… add one
  • Prakash Ross June 2, 2012, 7:45 am

    I told my supplier a year ago about my meter going backwards and they have not come to replace it.  My meter regularly goes backwards. 
    I have not contacted them again about the problem because the contact number is an 0870 number.
    Be interested what has been the experience of others.

  • Gavin June 26, 2012, 12:09 pm

    Suppliers have an obligation to check once they have been informed of installation by the LDSO although there may be a section in your electricity suppliers agreement that they sent out but probably never bothered to read.
    Here is an overview from the Balancing and Settlement Code (BSC)
    Relevant section is on page 3, paragraph 2

  • Christopher Walker September 4, 2012, 10:47 am

    My meter is running backwards can you send me any details on this problem many thanks

  • Diane Richards October 24, 2012, 9:34 am

    I had 4kw of PV panels installed last November 2011.  My digital electricity meter has not budged since 3 Sep 12 – says I have not used any electricity since then.  My supplier phoned me to query this, after I had submitted a meter reading, but once I told them about the panels, they just seemed to think that was okay.  And they are the same company who supplies my FIT!  Obviously left and right hand don't speak to eachother.  I am concerned that I will suddenly get hit with a huge electricity bill, so am getting the Solar panel company who installed my panels, to come and check.  I must be using some grid electricity in the evenings at least.     

  • Steve November 12, 2012, 12:48 pm

    Hi, I had a 3.75Kw system fitted about 6 months ago and at the time the PV installers filled in the FIT payment form for me, I do remember a question about the meter though, were i had to enter the serial number etc and even state whether it was moving backwards. At the time i hadn't noticed it and the weather wasnt great that day, so the installer answered No and i sent the forms off. Since then i have noticed that instead on good days it moves backwards at speed and that my reading is negative now. Very interested to know where the liability stands once it all catches up, as i initially thought this was the way we saved money using the PV.

  • ron February 20, 2014, 12:15 pm

    Hi I have recently fitted a grid tie unit to my PV's and also noticed the
    meter going backwards at times and also read all the convoluted problems
    with types of meter and power people getting involved etc etc, which to me
    as a retired electronics engineer where problem solving was part of my job
    is a fairly simple problem to resolve, which does not involve anything major.
    Speaking as a guy with a few PV's on a grid tie Home made system the
    problem seems to be the "crossing point" ie the point where the amount of
    energy being generated by the home grid tie system matches the
    consumption of the household usage, if the household usage should drop
    ie a freezer switching off for instance the grid tie wants to wind the meter
    back, which from all the input seems to be the problem?
    What I intend to do is build a zero or close to zero detector, at the moment
    I don't see a problem with this, all that is needed is an inductive loop
    around the mains input wire, similar to many cheap monitors available from
    ebay, or even more simple a couple of turns of wire, this picks up an AC
    field voltage which is directly proportional to AC current flow, this will need
    to be rectified into a DC voltage with a simple bridge rectifier, this DC voltage
    will be fed to a simple DC voltage switch also available for a few pounds on Ebay
    the switching point being set to switch at zero or close to it, so now we have
    a contact closing (or opening) at close to the zero point, this could be used
    in a number of ways, either to switch off a few PV's to reduce the generation
    of energy, or switch off the grid tie converter, or better still (what I intend to do)
    divert the PV's output into a couple of large batteries, so when the domestic
    usage rises, or at night when their is no PV output the batteries will run
    the grid tie unit for a while and so no energy is lost to the system.
    Sorry if it sounds complicated, but from a technical point of view it is a simple
    answer, the advantages are there is no direct connection to any power cables
    so very safe, it removes all problems with Meters as there can't be any
    chance of power going back into the grid, and with the third option it gives
    control of extra power when it can be used best ie at night when no PV output
    I can't see any problems with suppliers as what you do with your electricity
    you buy is your business as long as it doesn't involve any problems with their
    metering, all that will happen is you have more control and your bills will
    be reduced as normal.

    Of course I may have missed something in which case I'd love to hear about it



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