June 29th 2011

22.73 kWh generated in 16.0 hours

A good start to the day, wonderful growth to the curve, with just a bit of chill.  Unfortunately it also turned out to be one of those days with the big fluffy clouds that people like to look up at whilst laying in the grass.  It was a wonderful sight but look what it did to the graph!  :(

June 28th 2011

New all time low!  :(

5.16 kWh generated in 15.5 hours  - Rain all day long with a proper thunderstorm (complete with lightning). And I mean proper - not one of the normal UK 10 minute jobbies - nope this bad boy stuck around for most of the day.  The down side is the lowest generation level, for a full day, that we have had yet.  I mean look at that graph, highest peak (under 1.5 kW) at 4:20 in the afternoon.  :(

June 27th 2011

23.15 kWh generated in 16.3 hours

Another example of a wonderfully clear day (you can see the basic shape of the generation curve disrupted by only a few decreases until just after lunch) impacted by heat.  Maximum temperature yesterday hit 32 degrees C (89.6 degrees F) and even though the sun was bearing down directly on the panels the max generation is only 3.2 kW for a few of the 10 minute reading periods - which is a far cry from the 3.9 kW max readings (again averaged over a 10 minute period) that we have seen numerous times.  Unfortunately we have seen only a few examples of both the mostly uninterrupted curve and the max generation readings occurring on the same day.

June 26th 2011

16.27 kWh generated in 15.7 hours

So much of the morning generation period decimated by clouds.  Things really only picked up near the peak point for power generation - yet because of the heat even then it doesn't reach the heights that we have already seen the system is capable of.

June 25th 2011

12.95 kWh generated in 15.3 hours

June 24th 2011

20.91 kWh generated in 15.8 hours

June 23rd 2011

17.79 kWh generated in 16.0 hours

June 22nd 2011

19.47 kWh generated in 16.2 hours

Yet another disappointing long day.

June 21st 2011

Here it is the longest day of the year.  The day that anyone with solar electric panels looks forward to!

13.43 kWh generated in 15.8 hours

Say what!?  I wake up hoping for the 16 hours and 46 minutes of daylight, hoping that every minute of it will be bright and sunny (with a touch of wind to keep the panels cooled and working at peak efficiency) and instead when I look out the window all I see is thick, pea soup, clouds.  :(

How green are we? :)

So we have, to date, generated 1,304.86 kWh of electricity.  But what can you do with that?  Well according to Nashville Electric Service the average American home uses 1,300 kWh of electricity a month (must be all those air conditioners - oh how I miss air conditioners in homes).

According to another site the average home in the UK uses 4,000 kWh in a year.

So we have generated enough electricity so far to power the average American home for a month or the average UK home for more than 3 months (or our house for a third of a year).  :)  Not enough for a Scifi Death Ray though.  :(

In terms of CO2 we have reduced our carbon foot print by 1,957.29 lbs of CO2 so far.  That is supposedly almost as much as you would save each year by insulating your walls and ceilings, or turning your thermostat down by 2 degrees in the winter (and up by 2 degrees in the summer - assuming you have air conditioning - have I mentioned how I miss air conditioning?), or the savings (over 6.5 years) of changing all the light bulbs in your house to the low energy florescent bulbs.  All according to Cut CO2 web site.

But lets put that CO2 into terms that matter (at least to a car nut like myself).  I could drive a Corvette C6 for 2,800 miles before generating that much CO2.  OK so that isn't a lot of miles, but boy would they be fun!  :)  Or 4,700 miles in my CRV (because I don't have a Corvette) and no the miles aren't as fun but it is more family friendly.

So right now I'm feeling pretty green and virtuous!

June 20th 2011

25.46 kWh generated in 15.5 hours

June 19th 2011

15.35 kWh generated in 16.2 hours

Inverter total power generated to date = 1246.54 kWh
Generation meter total power to date = 1244.5
difference = 2.04 kWh or 0.16%

June 18th 2011

19.38 kWh generated in 15.7 hours

Inverter total power generated to date = 1231.2 kWh
Generation meter total power to date = 1229.2 kWh
difference 2.00 or 0.16%

June 17th 2011

11.61 kWh generated in 15 hours 30 minutes (sunrise at 4:37am, sunset at 9:33pm gave 16 hours 46 minutes of daylight today - meaning cloud cover reduced generation time today by roughly 1 hour and 15 minutes)

Inverter total power generated to date = 1211.82 kWh
Generation meter total power to date = 1209.8 kWh
difference 2.02 kWh or 0.17%

June 16th 2011

10.97 kWh generated in 16.2 hours

Inverter total power generated to date = 1200.21 kWh
Generation meter total power to date = 1198.2 kWh
difference 2.01 kWh or 0.17%

June 15th 2011

15.06 kWh generated in 15.5 hours

Inverter total power generated to date = 1189.24 kWh
Generation meter total power to date = 1187.2 kWh
difference of 2.04 kWh or 0.17%

June 14th 2011

25.27 kWh generated in 16.2 hours

June 13th 2011

13.74 kWh generated in 15.3 hours

Inverter total power generated to date = 1148.91 kWh
Generation meter total power to date = 1147.0 kWh
difference of 1.92 kWh or 0.17%

June 12th 2011

14.62 kWh generated in 15.7 hours

June 11th 2011

23.18 kWh generated in 16.0 hours

June 10th 2011

19.96 kWh generated in 16.2 hours

Inverter total power generated to date = 1097.38 kWh
Generation meter total power to date = 1095.5 kWh
difference is 1.88 kWh or 0.17%

June 09th 2011

14.97 kWh generated in 15.3 hours

Inverter total power generated to date = 1077.42 kWh
Generation meter total power to date = 1075.6 kWh
difference is 1.82 kWh or 0.17%

June 08th 2011

21.50 kWh generated in 16.2 hours

Inverter total power generated to date = 1062.45 kWh
Generation meter total power to date = 1060.1 kWh
difference is 2.34 kWh or 0.22%  - last time I measured the difference was 0.18% and I wasn't expecting the percentage to change that much but as they say in Statistics 2 data points are not a trend.  So keep watching this space.

June 07th 2011

23.15 kWh generated in 15.8 hours

June 06th 2011

7.34 kWh generated in 15.2 hours (the solar panels should be glad they are not paid by the hour - otherwise I might have fired them for output like today!)

June 05th 2011

18.64 kWh generated in 15 hours

Spent the day at the Cambridgeshire Country Show (as a special treat for me)  :)

June 04th 2011

14.99 kWh generated in 15.8 hours

Forgot to get the generation meter reading again.  :(

June 03rd 2011

20.84 kWh generated in 15.8 hours

No comparison of Inverter to Generation meter total power readings today.  The data from the inverter is easy - that is stored and I can download to the computer at my leisure.  Unfortunately to get the data from the generation meter I have to go downstairs and read it manually.

Now I could use the excuse that I am still recovering from my recent foot operation (and I am) but to be honest I simply forgot.  :(  It doesn't help that I have to get the reading in the evening once we are no longer generating power (so 9pm or later nowadays) or in the morning before we start generating (i.e. roughly 5am at the moment).  Anyone who knows me will know the early morning option isn't going to happen.  So I only had 2 hours (ish) to remember to do this task.  Starting to sound like a race car driver with all the excuses!  :)

June 02nd 2011

21.22 kWh generated in 16.3 hours

We noticed recently (OK my wife noticed and now I am tracking the data to find the cause) that the total power generated to date reading on the Inverter (the bit that the data for the graphs comes from) is higher than on the Generation meter (the bit we get the feed in tariff paid base on).  So assuming that this difference is the loss due to the long cable run (the inverter is in the loft/attic a good 5 meters up) I am now tracking the differences for analysis.

Inverter total power to date = 955.99 kWh

Generation meter power to date = 954.3 kWh

difference is 1.69 kWh or roughly 0.18%

June 01st 2011

26.59 kWh generated in 16 hours

May Summary

So lets look at the month of May overall.

Average generation was 18.05 kWh daily and a total of 535.95 kWh generated in the month.

Also interesting is to see the amount of power generated each day (first graph below with green bars) vs. the total amount of time that power was generated each day (second graph below with orange bars).

I have not yet gotten around to doing any statistical analysis but it is clear that there is no strong correlation between the two for May.  Obviously there are other factors that also need to be considered but until I get a home weather station that I can pull data from I am going to be limited in what I can do.

Still gives me something to add to my birthday and Christmas wish lists!  :)

For those who are interested - according to the EU (nifty tool here) the average expected daily power generation for our location and system for May is 14.2 kWh (with a monthly average of 439 kWh).  So all my moaning and complaining is about a month that is above average.  :)

Also interesting to note is that, according to the same site, May is the month with the highest overall average power generation.  Personally I'm still hoping for more!  :)

Here's hoping for a June filled with bright sunny days, and raining nights!  :)

May 31st 2011

18.9 kWh generated in 15.8 hours

Better but I'm still looking for a 30kWh day.  :)

May 30th 2011

7.54 kWh generated in 15.0 hours.

Another example of what the graph should not look like at this time of year.  :(

May 29th 2011

12.51 kWh generated in 15.7 hours

Somewhat better but still not what I'm hoping for.

May 28th 2011

8.9 kWh generated in 15.7 hours

This is getting a bit annoying.  More clouds - still no rain.  Farmers are complaining about the crops.  Water company is starting to hint at possible hose pipe bans if things don't get better/wetter.  But I don't get sun either.  :(

No wonderful high power peaks today either.  :(

May 27th 2011

10.36 kWh generated in 15.5 hours

And I though yesterday was bad.  :)  A cool day with lots of clouds - and yet notice that one spike (3.9 kW)!

For those who are interested the Inverter (the box in the loft/attic that converts the DC power from the panels to AC that you can use in the house) gives me the data in 10 minute blocks.  So that 3.9 kW is the average of the power generated from 9:40 to 9:50am.  If only more of the day could have been like that 10 minutes.  :)

May 26th 2011

11.75 kWh generated in 15.0 hours

And today we see just how chaotic solar generation can be.  :(  Lots of clouds, with a few clear minutes, but still no rain.  Disappointing when nobody is getting what they would like.

May 25th 2011

27.46 kWh generated in 15.8 hours

Very nice curve up to and including most of the peak time for power generation for us.  Enough to put us 0.44 kWh up on yesterday!  Hey every little helps.

For those wondering over the last two years (prior to the solar panels) we used an average of 10 kWh of electricity per day.  Granted at this time of year most of that would usually be in the evening but we are learning to adapt and use power while the sun is shining (free power at that point) - the rest is going back into the grid for other people to use.  So hey you could be using green energy we generated!  :)

May 24th 2011

27.02 kWh generated in 15.8 hours

Now this is more like it.  You can see that the peak power is moving up from a few days ago (hitting just over 3.6 kW at a couple of points).  Starting to wonder if we can have a 30kWh day sometime this year (given that longest day is still a few weeks off and assuming we can get a day without the drops in power that you can see in the graph below) - something to look forward to!  :)

May 23rd 2011

18.69 kWh generated in 15.7 hours today

Generation for almost 30 minutes longer than yesterday 2 kWh down.  Shouldn't complain but why can't we have clouds (and rain) at night?  Speaking of rain the farmers, and my lovely garden loving wife, would really appreciate some.  :)

May 22nd 2011

20.95 kWh generated in 15.2 hours

As you can see today things started off very nice but from about 8:30 onwards there were plenty of clouds thus we are about 5kWh down from yesterday.  :(

May 21st 2011

25.78 kWh generated in 15.3 hours.

Now this is a nice graph - not perfect (you can see the dip at 11:40ish and the raggedness of the graph in the afternoon) but still a good idea of what the ideal shape would be.  Interestingly enough this is more generated in less time than occurred on the 20th of May.

I have a theory, still need a home weather station that I can download data onto the computer from to support or not the theory, that we generate more power on cooler sunny days than on warmer sunny days.  This was a warm day and as you can see the peak didn't hit 3.5 kW of power generated - yet on some cooler windy days (still with lots of sun) we have seen peaks of 4 kW of generation achieved.

May 20th 2011

21.84 kWh generated in 15.5 hours

May 19th 2011

21.78 kWh in 15.3 hours - a good start to the day but then lots of disruption right during the point where we should be getting the most sun/power.

May 18th 2011

10.43 kWh generated in 14.7 hours

May 17th 2011

Only 10.8 kWh today in 14.8 hours - other than a spike around 9:30am the day was pretty hopeless in terms of sunlight

May 16th 2011

12.39 kWh today in 15 hours - you can see that the morning, our best time for generation as the panels face more to the East than South, was not very good.  Even peak power for the day was down at just over 2.5 kW

May 15th 2011

17.5 kWh in 15.3 hours - like the 13th of May you can see a nice start to the morning but today the drop, whilst not as drastic as yesterday, happens sooner.

May 14th 2011

19.97 kWh generated in 15.2 hours - you can see the nice growth in the morning but then a massive drop around 10am (start of peak power normally) - could have been so much better.

May 13th 2011

Generated 24.3 kWh today with 15.3 hours of generation.  Graph below shows readings of average power generated each 10 minutes (units are kW)