4000 watts and counting

So today we topped the 4000 watt mark on a couple of occasions. Not for too long, but long enough to be recorded by the OWL unit. The highest we've seen on the monitor is 4094W, but the average minute values recorded were 0.67 KWH in a minute which is a 4020W average.

I'm glad at this point that I have an over-rated inverter as a few extra watts are always welcome in making the meter tick over that little bit faster. 

So far the weather this month has been very up and down. Generally the weather has been better than forecast, but we've not had any classically sunny days - lots of cloud mixed in, some rain, hail (twice today), rainbows, frosts and biting winds. As such I'm impressed the system is doing as well as it is, given the target requires over 10kWh per day I'm pleased to be on track and a little ahead (currently 15% up on the monthly cume). Whilst April will probably not be quite as good as March (with its exceptional 2-week spell of clear weather), it should really start to rack the units up. 

I expect we'll complete our first megawatt-hour tomorrow - we closed on 999.77kWh today according to my records. This would be a nice milestone to pass.

Peak Power

I'm just going through the point at which the sun is perpendicular to the solar array so am expecting some interesting peak readings in the next few days. Unfortunately today, the weather didn't quite play ball - early sun was quickly diluted by 10am but occasional breaks in the cloud gave some interesting high readings (if only temporary). 

The highest I noted was just over 3900 watts, and there were several readings well in excess of 3800, which is interesting given the system is only rated to 3430 watts, although the inverter is 4400 watts. There is a theory that says these peaks only occur when the sun is broken by cloud, the panels are cooler and more efficient, and hence you cannot get these peak readings on a clear day as the system cannot run at that level of output for long periods of time. 

I shall wait and watch for this over the next few days - we are due to get periods of early sun for the rest of the week, surely one decent patch of blue sky will coincide with the mid-day sun's alignment. Here's hoping.

Peace in our time?

The ongoing war of our time on the cuts to the feed-in-tarriffs seems to be coming to and end - the higher FIT rate will be extended to March, but there are severe cuts in the pipeline between now and the summer. (See telegraph article).

As someone who was fortunate to have solar PV installed in November 2011, I have watched with interest, but with the smugness that comes from knowing that I'm alright. 

What I always find interesting in these cases are the comments from the public that accompany these stories - I'm now a passionate advocate of solar PV. Whilst I can see the points being made on the basis of cost, there is no disputing that the systems are inherently productive and clean, and I hope at some point in the future there is a breakthrough to make the systems standard on all properties. Small changes in efficiency, cost and/or storage of excess energy built up over a period of years could revolutionize the way we generate and consume electricity, Here's hoping eh?

Hmmm

It's been an interesting month so far, the weather has shown many hints as to what the solar panels are capable of, but never really delivered that well. Hence the run rate chart for March is ticking along nicely, but without ripping up any trees. At the moment the yield for March is looking to be similar to February. I'm just waiting for the magical moment when the weather breaks for a few days (it might be now) and we get glorious uninterrupted sun for a while - that's got to be worth 40 kWhs in the bank in one go.

I have to say that now I can see the system doing it's thing day in day out I am impressed. Now that the days are longer and the sun's angle is much higher, even cloudy days create a healthy reading on the Owl meter - 700+ watts when the sun isn't out is not to be sniffed out, and peak readings over 3000 watts are always welcome! I need to reach about 900 watts to be self sufficient, so this is always the unofficial target to my way of thinking.

We finally received our first payment from the power company a few weeks ago, as expected this was just over £180 and a BACS transfer receipt came by mail. It's good to know that things can only really get better from here on as we go into the better part of the year.

I've been having some thoughts about adjusting the run rate charts to allow for varying sun angle and day length. For example during March the days are two hours longer at the end of the month than the beginning and the sun is many degrees higher. Hence the productivity of the system and the target should not be linear, and should accelerate towards the end of the month. I may well experiment with this and see what the results will look like, at its simplest level this will change the 'run rate' target into a form of parabola with which to compare performance.

Charts not working

Arrrrgh

Is about the easiest way to say it. Every month it's the same, as a try and roll the data forward a month the charts on the right start playing up. Last night after some playing I gave up. I know that's not the right attitude, but having had a very long week, with virtually no free time, I decided enough was enough.

So a few glasses of wine later, the chart were furthest from my mind. And hey presto today, we're working again. Eh?

Next plan is to create more add-ins but in unique code windows and take it from there. Here's hoping for a simple run at it and no major problems. As if I'd be so lucky.

Postscript:

So after much fiddling and having to regenerate every chart from scratch it's back up and running. And then not again. So more cut and paste of the scripts. This is getting tiresome - looks like the chart controls have been updated too, which could have a bearing on things. Not very impressed at the moment.

February Final Stats - 135% achieved

A few points...

So lots to say and no time to type it in!

A few highlights of the month to far:

1. Firstly a fantastic start to the month – four days of near perfect weather put nearly 50 kWh in the bank. This shows the value of the system even in the winter months. I’ve had a few good days since, but nothing like this for a run. It certainly makes the monthly target seem very achievable even after only a few days in.

2. Snow. I was very worried about snow having read a couple of blogs where it had completely killed the output for several days. However, despite having 2-4 inches on two occasions, the snow just fell off within an hour or so of dawn. I think the angle of the roof helped a lot, but either way productivity remained as per a normal cloudy day and all was well.

3. High power. A couple of days ago the Owl read an almighty 3.511 kW output – technically higher than the system (give or take for noise) and this was continuous. We’ve also seen extended periods of 3kW too, so hitting some of the summer targets seem quite possible. I’ve been tracking the day length and sun’s angle in detail, and there does seem to be a distinct change in February – as the angle improves, so does the day length, but also the peak power output (typically about 11:20am for me). At this rate I expect to hit closer to 4kW come optimal conditions – thankfully the inverter and wiring is rated for this, so no worries.

4. Money. I submitted my first meter reading - 410 kWh for the first quarter, which should translate to a little over 180 quid. I look forward to seeing it appear in the bank in the next few weeks, but come summer we could see some nice return on investment.

5. Day length. The last few days have been interesting. Although the weather forecast isn’t great the lighter cloud and better solar angle means that I can get 1kWh out when there is light cloud and over 3kW when there’s a bit of blue. This is quite encouraging for when the weather picks up. It’s nice to see the Owl ticking over and knowing that the house is self-sufficient for long periods.

6. Month complete. Ok, not quite but the February quota is nearly done (all bar the shouting) with a good week yet to go. It’d be nice to hit 120% for month end, but that’s probably asking a bit much.