The problem ...

Our problem began when we installed Solar PV electricity generation panels & an inverter.

The solar PV system was not a problem, but ...

The micro-generation Feed-in-Tariff (FiT) scheme seemed too good to ignore, we were still in time to get the installation & commissioning done before the government's first review was due in March 2012 (though it was expected to be earlier).  


So after my dad did a lot of research and got many quotes, we followed his lead and had JA Solar panels and a Fronius inverter installed by the local Leeds company, Eclipse Solar, on Friday 18th November 2011.


The guys from Eclipse were very helpful, from the first discussion to the clearing up after the scaffolding was removed, they were all quite efficient, very friendly and got the job done in good time.


The process of registering our system with our then electricity supplier E.ON was relatively painless, Eclipse had helped with all the tricky bits of the complicated forms and we soon had our FiT number which meant we'd be paid for every unit we generated from Unit 1.


The first three months were good compared to the expected levels of generation - Dec - Feb were all ahead of the prediction and on 22nd Feb I submitted our first FiT generation meter reading of 474 units.  By the time we received the £200 payment from E.ON directly into the nominated bank account, we were well into March and some very good weather.  

The good weather was great and helped with better generation figures but it showed we had a problem ...

As the days became longer and sunnier, it seemed that whenever there was a very good week for generation (sunny, light cloud) we had a particularly heavy week for imported electricity usage.  This seemed strange because although we were not paranoid about electricity use (we'd had a simple clamp-meter but this was rendered impractical when we began micro-generating) we were careful.


It was even stranger as the explanation I was offered could not be true.  This was that seeing the sunny weather we were switching everything on to capitalise but actually were overdoing it and having to import more.  I knew this was wrong because again, though we were being careful about switching things on, it was rare that we were able to do this in the day as we all work and are not able to organise our lives and our appliance use around what the sun and clouds are doing!

This suggestion was useful though, because it set me thinking ...  

I wondered whether the extra generation during those sunnier weeks could possibly be contributing to our apparently imported electricity usage.


At first this was a relaxed, inquisitive curiosity - after the (still record) bumper week of generation at the end of March, I was concerned but not convinced.  With a very full working life & a busy family home, I soon found this was not a priority and believed that it was pure coincidence.


In mid-June, after the next peak week, I started looking again, more worried about what I'd seen in the stats I'd collected - that there really was an issue.  By the time the 3rd week of high generation came (early July) I was almost neurotic and obsessed, so keen was I to find the source of the problem.


I started reading blogs and forum posts about solar PV generation and the issues, in particular reading about analogue meters going backwards (ours was digital so that wasn't the issue).  I wanted to see where I might find the right kind of people: helpful, knowledgeable, friendly and open to stupid questions, so I could post my own:

• "Is it possible that our Solar PV generation & export during sunnier weeks is contributing to excessive electricity import during those same weeks?"

But even before asking my question, on 5th July, 3 months after I'd begun noticing the unusual trend and 8 months after it had started, I found the answer.


A very helpful contributor to the MoneySavingExpert.com forums, furndire, had been having terrible trouble convincing her electricity company that there was a problem, after she had Solar PV panels installed.  She wrote about the saga here: WARNING SOLAR PANELS & some Siemens S2AS-100/ Siemens S1AS-100 Meters.


Guess what I did next!
That's right, I went out to see what meter we have ... and yes, it's a Siemens S2AS-100 meter!

I couldn't believe it ... I was right, the sneaking suspicion I'd had was true and the thing I'd not dared to believe was actually the case: our incoming meter was faulty and was adding to our incoming readings every unit we were generating but not using and therefore exporting to the National Grid.  

I also could not believe that others, including furndire had had this problem more than a year before and I hadn't known about it.  What's more, they'd had to persuade their power suppliers of their problem without being able to point them to a set of forum posts about the known issue, as I could.  Thank goodness I was able to use their story to support mine, I can only imagine the frustration they must have had of trying to battle without that support.


Actually it isn't a fault in the meter but a bug - it has an in-built anti-tamper feature which means that it can be programmed to add units of electricity passing in either direction across the meter to the "Used, incoming, imported, chargeable electricity units" reading.  This feature was included so that if people tried to defraud the utility company by switching the terminals on the meter (so it appeared as though electricity was only leaving the property and they were not using anything) the meter would also register it as being used and therefore charge for it.


Needless to say, this meter, at least in the way its internal software was programmed on ours, was totally unsuitable for use in a micro-generation scenario.  This was not noticed by Eclipse, their surveyor or electricians, nor by E.ON when we registered our system and began to sell them electricity.


I cannot be too critical of Eclipse as when I spoke to them this month (July 2012) I was the first person they'd heard of with this problem.  Nevertheless, it is a known issue and it would have prevented a great deal of trouble if they'd known / noticed this during installation.  


This problem is difficult to diagnose though as it is only really obvious in the summer when the days are longer and sunnier and more is generated than can be used.  Additionally as it is a rare situation most companies, even large ones, do not acknowledge that it can happen or know what to do when it does.

The solution, or at least the search for it ... that's a story for another day!

• To be continued .....