It’s about 6 years since we had our solar panels fitted so to get an overview I’ve used the monthly readings to compile a couple of graphs to see how they’re performing. You can click the graph to view a bigger version.
Firstly generation in kilowatt hours by month shows how the peak summer months generate about 6 times the power of the dullest winter months.
I’m surprised how consistent the monthly output is year to year. Leaving aside the exceptionally wet summer of 2012 which coincided with one of our inverters failing, a halving of output I failed to spot for several months, the degree of consistency gives the impression that sunshine per month, or season, averages out quite well year on year despite it often feeling like a particularly wet, or sunny, time when we are living through it!
Next yearly total against predicted total which seems to show that we met, or exceeded, predictions all years except that best forgotten 2012. Doing the sums it seems that the 2012 shortfall has almost been made good by the several years we have exceeded predictions, we are about 70 kWh short. We can expect efficiency to diminish a little over the years so I guess generating slightly over predictions is to be expected these early years.
Financially we are about where we should be having received back about half the sum we paid for the panels as Feed-in Tariff payments. A similar PV system would cost about half what we paid now which goes to show how well the FiT worked as a way to make solar popular enough for efficiencies in manufacturing and fitting to bring the price down.
Solar and wind are fantastic resources but now we urgently need affordable, efficient and sustainable ways to store the huge amounts of energy generated at peak so we can smooth out the big seasonal and hourly variations rather than be reliant on coal and gas as back-up generation. Fortunately firms like Tesla are ploughing resources into developing viable battery type local storage systems. We also need large scale grid systems though and there is little sign of our government investing meaningful sums in researching new large scale storage or even duplicating existing methods such the pumped water system that has been in use for 30 years at ‘Electric Mountain’.
We’ve been having a rather fine summer this year – day after day of hot and sunny eventually followed by a couple of downpours just when it was getting too much. I’d much rather have a bit of a heatwave than a repetition of last year’s deluge. So I thought it’d be interesting to compile the last year and a half’s solar photovoltaic generation figures into a graph and see how we were doing after last year’s lack of sunshine and further loss of generation when I didn’t notice one of the inverters was bust. (Click on the graph for full size.)
What does this tell us? Well as we know last year was rubbish – well ahead of predictions for February and March 2012, then they forecast a drought if I remember correctly and the rest of the year it rained and generation was down around 30%. So far this year we are well on target and even exceeding predictions by 50kWh for July giving us a chance to make up a bit of the approximate 500kWh we lost to weather and faulty inverter last year. So I reckon all is well with the PV set-up – let’s just hope the sun keeps giving 🙂
Jane had to take Lala to be put down shortly before Xmas. We were very sad to lose her – I probably spent more time in her company than anyone else’s over the last year – but she was suffering brief periods of what looked like great discomfort and it was time to say goodbye. She spend much of her last few days trying to get comfy on a chair, she couldn’t curl up any more, or toasting herself by the gas fire 🙁
Anyway I decided to put her big, pink, covered, litter tray up in the attic which was my first trip up there for many a month. While I was there I decided to take a look at our solar inverters and saw the red fault light was displaying on one. I’d like to say I was surprised but to be honest I’d been suspicious of our low generation readings for a couple of months and had just been too lazy to check. It has been such a miserable summer of rain, rain and rain that I hadn’t been that surprised to see our readings drop – all the same I’d been justifying poor readings to myself by thinking that despite the sun being out for a change it was at the wrong angle for the arrays and that sort of thing. I do have a power monitor rigged up to the solar AC output via a current transformer so can tell roughly what it’s generating at any particular time.
The inverters have a 10 year guarantee so I emailed Solar PVE who got right back with the suggestion I try power cycling the system. It’s important to turn it all off in the right order, AC isolator first then the DC isolators. I was also asked to give it 10 minutes for the capacitors to discharge before restarting. The fault light was still on after this so, this being just before Xmas, Solar PVE offered either to get someone out after the holidays or, if I felt I could install it myself, they could send me a replacement next day delivery. I went and had a quick look, 4 mounting screws and 3 plug-in connectors, and said I’d do it myself.
Good to their word a new inverter was sent by fast courier and it took me less than 30 minutes to install – plus the same again to negotiate the unreadable Japanese menus using the manual to set the menu and read-out language to English. The AC output was noticeably higher straight away despite it being a cloudy December day and at midday the first sunny day I saw it was generating 1500W for the first time in ages. I was left kicking myself for not checking and dealing with it earlier.
So the total generation for 2012 was down to 1548 kWh compared to about 2230 kWh for 2011, much of this down to the most wet and dismal year on record but I suspect a couple of hundred kilo-Watt hours lost due to me being too lazy to check the inverters when I first suspected a problem back in September. On the bright side the amount of electric we consumed from the grid was 1311 kWh (this obviously doesn’t include energy we’ve generated and used directly) so we are still generating much more than we are buying.
Our first full year of solar panels and Feed-in Tariff is now complete so how has it gone?
Well nothing has gone wrong so far, they’ve not blown the fuses or stopped working or made the roof leak or attracted unwanted attention from unmanned US droids or anything. Getting them registered was a bit of a faff but the delay of the electricity supplier in replacing our old meter (the one that turned backwards) when requested resulted in a £200 rebate windfall so that’s their incompetent loss. SSE Microgen have improved their FiT admin systems a lot over the year and now I get a reminder and can enter the generation meter reading on-line which results in a cheque for the correct amount arriving after a month or so. On reflection I guess I should maybe have made a fuss that the panels weren’t installed perfectly level but I don’t really care about slight cosmetic deficiencies so didn’t.
The amount of power generated exceeded the area adjusted estimate we were given by the installer by about 120kWh, it seems to have been quite a sunny year so I won’t rely on it overproducing every year but still it’s been reassuring to see the estimate become reality.
We have received a total of £987 for the first 49 weeks. The system cost just under £11,750 so we should be on for a 12 year payback time. Nationally the FiT scheme was obviously working well as a means to bring about a reduction in price via ecconomies of scale, a similar system to ours costs a bit over half the price now. FiT payments needed to be gradually reduced in-line with this but that was no excuse for the government making such a ridiculous, and seemingly illegal, hash up of introducing the changes.
The new tariff for April 2012 had already been provisionally set at the reduced level of 38p per kWh which the industry could only be expected to regard as final so suddenly puling the rug out out from under their feet in the middle of a consultation was stupid and has cost both confidence and jobs. Following the courts finding against the government hopefully the 43p tariff will now remain in place till March when the new 21p tariff comes in.
I was hoping for a reasonable time at the Eynsham 10k on the last Sunday of November but was not going for a pb as I remembered the course having a couple of minor bottlenecks and twists and turns, also last time I ran in 2009 the timing was gun to chip though this year it turned out to be chip to chip. I gave my legs a rest the day before by volunteering at Oxford parkrun instead of running and, on the day itself, only slightly regretted upping the gear on my hack fixie as I tried not to knacker myself riding out to Eynsham into a rather stiff headwind.
Dropping things at Oxford parkrun registration
We gathered at the start down the Old Witney Road dead end where I said hello to a few familar faces, lots of local clubs represented at this event as it’s got a well deserved good reputation. I was running in my Vegan Runners UK vest and despite some earlier worries the temperature was just right. Off we went, slightly downhill past the school where we would finish, through some older parts of Eynsham then out onto the road heading towards Swinford Toll Bridge where I could feel the wind on my back. Turning north I seemed slow a bit but this was very slightly uphill, I’ve yet to run a really, truly, flat course. Then out onto the A40 cycle track where the wind slowed down proceedings though I was pleased to pass a few without blowing up.
Glad to turn south, both out of the wind and slightly downhill. Then past Old Witney Road and we were into the second lap. Lots of local support cheering us round the course, being as it’s 2 laps we get a double dose. I skipped the water station as I felt fine and didn’t start flagging till the second charge along the A40 where the 9k marker had more of an ‘oh no, not another kilometre’ effect than an optimistic ‘nearly there, time to speed up’. The finish was on the school field and after letting one runner past I resolved not to let the shadow on my right shoulder also beat me. I tried hard but he trumped me just before the line and turned out to be George who was very pleased to have got a 4 minute PB. I was happy enough with my 47:48 276/612 – a course best and a season best that could have been a tiny bit faster without that wind.
What with the Eynsham effort, intervals run this Thursday and the Andy Reading 10k entered for next weekend I thought I’d settle for a slower parkrun this Saturday. I had a couple of beers the night before and while I pushed myself I stayed well clear of the vomit zone.
My Garmin reckoned I did 24:15 but the results make it 23:37 14/36, 1 second short of my pb. I’m aware there were some timing hiccups so this may or may not be genuine but I’ll accept it graciously 🙂 Edit later same day: seems timing hiccups were full scale belches so 24:15 is correct but apparently still 14th position.
What’s this got to do with solar PV? Nothing, but as a footnote about ten days ago our Generation meter reading passed 2147kWh which is the predicted annual output based on the Standard Assessment Protocol adjusted for location etc. This is the figure they quote you when selling the system and as our system was commissioned 19th January 2011 we are almost 2 months, admittedly not very productive months, ahead of target. So yah boo sucks to all the naysayers who reckon the predictions are made up or exaggerated!