Well actually it’s nearer 7 months as I wanted to announce that we’ve actually had a cheque from SSE Microgen but now I read the small print it seems they allow themselves up to 65 days between receiving our meter reading and paying out the money so I’ll stop holding my breath. Funny how when we pay them for electricity they expect to get their money in advance by direct debit from our bank account or we have to pay an extra 6%!

Anyway I really shouldn’t complain because we are still pretty pleased with our PV installation. Following an exceptionally sunny spring we had a few gloomy weeks, though nowhere near enough rain for the vegetables, and now seem to be having lots of sunshine again as is proper for August. I tweaked my graph a little so the estimated figures better reflect those given by the installers and it seems our total wattage generated to date is a fair bit more than was predicted.

Maybe this surplus is to be expected at first as I suspect the annual estimate is averaged over the lifetime of the installation and the panel output is predicted to slowly decrease by an estimated 0.8% per year. All the same, in a society where commercial interests regularly inflate expectations to get a sale it’s sometimes very pleasing just to know you are getting what you were told to expect instead of the usual disappointment.

Early in July the electricity supplier eventually replaced our old type consumer meter* with one that doesn’t go backwards when the sun shines, over 3 months after we made them aware of the problem. To be fair they didn’t attempt to claw back the money they lost through their tardiness and promptly send us a rebate cheque for the £220 they had taken in debits for power they expected us to use over the first 6 months of the year that failed to register on their meter. The old meter ended up recording us as using only about 25 kWh between January and the start of July.

So how big is this Feed-in Tariff cheque we are waiting for? Well the generation meter* reading I submitted for period to end June was 1194.5 and the reading when installed in January was 1.7 so I think that is about 1193 kWh x 43.3p = £516.57 plus about £17.90 for the estimated power exported to the grid (half the power generated at 3p per kWh unit). £534 – a good start in paying back the £11,000 the system cost us but a long way to go yet.

* Having PV solar installed means you end up with at least 2 electric meters. The consumer meter, which we all have, provides the reading for power used which you get billed for. The generation meter records the power your solar panels generate which you hopefully get your Feed-in Tariff for. In some cases, usually by request, you also have an export meter which records the surplus power your solar panels generate which is sold on via the grid. So you export power generated minus power used at the actual time of generation (ie. you have to boil the kettle when the sun is actually out, not a moment later when it clouds over, as unused power is not stored but immediately sent to the grid for someone else to use). If you don’t have an export meter you are deemed to supply half the power you generate to the grid which is not unreasonable.

It is 3 months since our solar photovoltaic arrays were commissioned so, while it’s much too soon to say whether they were a good idea in the long run, I thought I’d write a review of how they were doing so far.

Firstly it’s worth mentioning that they’ve been no trouble – no blowing fuses or bits falling off or leaking roof or anything. I used the fact that we’d had to clear out the meter cupboard as incentive to get rid of the old and useless spare loo in there and put up some shelves instead so we are in slightly less of a mess than before if anything.

Getting registered for the feed-in tariff has been a bit of a faff though. I decided the simplest thing was to register with Scottish Southern Electric in Jane’s name as they are our current supplier and Jane’s name is on the bill. I downloaded the simple form from their website, filled it in and emailed it to the  address given with the MCS certificates etc. Meanwhile Solar PVE, the installation company, informed Southern Electric DNO as they are required to do. Despite having requested acknowledgement of my email we’d heard nothing after 2 weeks so I printed out hard copies and posted them off with a covering note to make sure they recieved it.

A couple of weeks later I got the forms sent back to me with a letter claiming that the figures on the certificate didn’t agree with those on the application form and also claiming the date of application I’d given was wrong. The figures appeared identical to me and it was obvious they had mistakenly treated the day they received the hard copy as the day of application rather than the date of the preceding email. Anyway I phoned up and talked to a helpful chap who agreed someone had got it wrong, explained that they were having to train up several new staff, and said he’d sort it out his end but I should also post the forms back with an explanatory note to cover all angles which I did.

Meanwhile, after a few dull and rather unproductive weeks, the sun came out. Early afternoon on a sunny day early in March and we seemed to be generating about 1.7 kW, two thirds of the quoted maximum, which seemed about right what with the sun still low and distant. We weren’t using that much electric a lot of the time though and I was rather surprised to find that our old style ‘spinning wheel’ consumer meter was regularly spinning backwards and lowering the reading on which we are billed.

This was an unexpected bonus but, not wanting to be accused of theft of electric, I thought I best let the suppliers know. I phoned and a helpful lady said she’d pass on the message to the appropriate dept and I would be contacted in 3 to 5 days. A week later, hearing nothing, I phoned again, the microgeneration dept this time, and was told yes they had a record of my previous call and yes they’d need to change my meter for a digital one and I would hear from them in 3 to 5 days. That was 3 weeks ago, we’ve written and emailed since but in the end it’s their problem, not ours, that we appear to have used absolutely no electric since March!

Anyway, after a bit more fuss where SSE requested a pretty irrelevant amendment to the MCS Cert direct from our installers, we have just last week received the letter of confirmation that our system is now on the national FiT register and also our contract to sign which is almost ok except they’ve spelt Jane’s surname wrong so we’ve pointed out that they better get it right before sending us a cheque. The date they owe us from is correct and we’re hopeful of a payment soon.

But is the system actually making electric? Yes it is – and lots. We’ve been having many nice sunny days and despite a bit of a slow start I now reckon we have generated very slightly more in total than the PVGIS web thingy predicted. The chart below compares our actual generation figures (blue) to a curve based on the PVGIS monthly total predictions adjusted for location, aspect etc (red). About 420kWh so far and the next few months should be a lot higher before generation drops right off next winter. So far so good!

We decided to investigate solar PV panels last Autumn. I’d vaguely thought about them before but my interest had been revived when I become aware of the guaranteed Feed-in Tariff (FiT) that was introduced in Spring 2010. At current installation prices solar panels would take a long, long time to pay for themselves just in saved electricity but the FiT guarantees 41.3p per kWh unit generated for the next 25 years – that’s more than 3 times what we currently pay per unit for electric – AND you get to use the electricity as well as being paid for it. Jane agreed it was worth looking into and not long after we were chatting with the rep from Solar PVE.

In for a penny in for a pound so I specified ‘as many as you can safely get up there’. The Solar PVE surveyor reckoned 14 180W panels, 7 each on our south east and south west facing roofs. I like to get on with things so we planned to get the panels installed in December, unfortunately our roof was buried in snow so this was impossible. But mid January the scaffolding went up and a week later the roofers arrived.

First they had to install roof bars which were secured to our rafters via solid looking roof hooks that passed underneath our old, fragile and rather mossy tiles. The roofers came equipped with spare tiles to deal with any breakages, a couple of which they used. It poured with rain the Monday morning they arrived but after sitting in the van for a bit it cleared and they managed to get all the bars up Monday and the panels mounted on Tuesday.

Meanwhile the electrician installed 2 1500W inverters in our attic. The panels generate around 24 volts DC per panel at quite high current, like a load of car batteries wired together. The inverters convert this to 230 volts AC which is then fed – via a generation meter, 2 safety isolators, a 16A MCB and a 30mA RCD – into our existing electrical installation. For safety the inverters are ‘grid-tied’ which means they cannot feed power into your installation unless they detect existing power from your electric supplier. So they won’t work in a power cut which is a pity but they won’t kill an electrician who isn’t expecting 230V coming the wrong way down the wire which is a good thing.

I get back from work Wednesday to find a note saying it’s all up and running, job done apart from removing the scaffolding (which is blocking in our wheelie bins so we’ll be glad to see the back of). I don’t like heights, when I was a lot younger I did a bit of roofing and don’t remember being scared, but somewhere along the line I’ve gone the other side of cautious. Still I doubt I’ll ever get a chance to have close look at the panels again so up I go with the camera. They don’t look like they’ll be falling off in a hurry!

All that remains, apart from a bit of tidying that I say I’ll do as Jane has had enough builders for the moment, is to claim our tariff. It is a requirement that both the panels and the installers are MCS certified, the certificates for both are emailed to me on Friday so I download the form from Southern Electric’s website and put our application in straight away. If I understand correctly it’s now just a matter of us giving them a quarterly reading and them giving us a quarterly cheque. The FiT is not government money, it is paid by the electricity supplier who will no doubt pass the cost on to the majority who are indirectly polluting by purchasing power generated by non-renewables – sneaky eh!

The Numbers

The area adjusted SAP (Standard Assessment Procedure) figures we’ve been given by Solar PVE estimate we will produce 2147 kWh units per annum for which we would get, tax free and index linked, £837 FiT + £32 for electric exported + £107 saving on our bill. From this they estimate the installation will pay back the £11,750 inc  it cost in 11 years. It is guaranteed for 10 years with output from the panels guaranteed for 25 years and a predicted useful life of 40 years. It’s also supposed to reduce our CO2 footprint by 1.2 tons a year.

Now I’m not a total fool – I bought an endowment once and that woke me up to the ability of salesmen to lie through their teeth without the authorities protecting Joe Public. So taking a look at figures from elsewhere I find that the figures from PVGIS predict a similar output, 2060 kWh per year and also that they predict an output almost 5 times higher in the summer meaning the average 2kWh per day so far in January is about on target.

So far we are pleased with the decision to have them installed, the guaranteed rate for new FiT claims will probably be reduced by 2013 so we may well have got in at the peak. Installing solar power is not going to sort out global warming or save our scarce fossil fuel resources from being wasted but at least it’s a tiny step in the right direction and, importantly, a chance to nudge the mindlessly lumbering ‘free market’ in energy in the right direction.