Solar output in Winter

Pauljwedlock

I had a Solar PV system installed 21 days ago and thought I'd have a quick look at the meter and noticed it has generated 52.89Kw of energy since installation. It's a 4kw installation with a pretty good orientation (South).

Even though it is winter, I'd have expected it to generate slightly more than 2.5kw per day on average.

Are these readings reasonable? I'm not really sure now!!

Cardew

There is a huge thread(over 8,000 posts) in the 'green and Ethical' forum on MSE where scores of PV owners post almost daily about their generated output.


I suggest you read the last pages and/or post your question there. See


https://forums.moneysavingexpert.com/discussion/3853851

matelodave

It's not just the orientation it's the angle as well that has an effect on the power generated. Maximum power generation is when the sun is perpendicular to the panel which is only twice a year depending on the angle of the panel but round about late spring and early autumn. In the summer the sun is very high in the sky, the days are much longer so the panels get a lot of sun during the day, in the winter the days are short and the sun is very low in the sky (when it can be seen) so the panels wont generate very much at all.


Have a look at this site http://www.builditsolar.com/References/SunChartRS.htm


You can fill in your own info and you can get a month by month estimate of how much power gets generated. Bear in mind that solar generation isn't an exact science, temperature and other factors have an effect on what your panels will generate.
A 4kw array will only generate 4kw when the sun is in the optimum position with not a cloud in the sky which is possibly only one or two days a year, most of the rest of the time it will be less.

Andy_WSM

Pauljwedlock wrote: »

I had a Solar PV system installed 21 days ago and thought I'd have a quick look at the meter and noticed it has generated 52.89Kw of energy since installation. It's a 4kw installation with a pretty good orientation (South).

Even though it is winter, I'd have expected it to generate slightly more than 2.5kw per day on average.

Are these readings reasonable? I'm not really sure now!!

Totally reasonable from mid November, December, January & part of February. Things really pick up again come March.

My own system, 4kw SE orientated.

1st Dec: 811Wh (Yes, not even a kW!)
2nd Dec: 2.95kWh
3rd Dec: 7.9kWh

Yesterday (3rd) was a very good day for December. Most unusual to see those sorts of numbers, but we had a cloudless day and cold temperatures - the perfect combination for solar PV. In the Summer the same conditions will generate a touch over 30kWh due to the Suns higher position in the Sky and the longer days.

I've just had a heat pump fitted to replace my ongoing gas boiler saga, so yesterday's output was very useful indeed

Martyn1981

Pauljwedlock wrote: »

I had a Solar PV system installed 21 days ago and thought I'd have a quick look at the meter and noticed it has generated 52.89Kw of energy since installation. It's a 4kw installation with a pretty good orientation (South).

Even though it is winter, I'd have expected it to generate slightly more than 2.5kw per day on average.

Are these readings reasonable? I'm not really sure now!!

Hiya and welcome. Your best bet would be to look at PVGIS which will give you a very accurate guestimate of average generation for your location and set up.

There's a walkthrough on how to use it in section 5 of the PV FAQs.

BTW November (especially the last couple of weeks) was pretty poor.

Mart.

Smiley_Dan

It was a bad November. Many people have reported "worst November ever".

Pauljwedlock

Thank you all. I'll follow up all the advice posted.

My mind is a little more at ease when I hear that others have similar readings. Looking forward to the summer!!!!

dprice1164

Smiley_Dan wrote: »

It was a bad November. Many people have reported "worst November ever".

+1 here in Worcestershire. The worst Nov since my installation in 2011. Overall though, 2014's been the best year and it's not over yet.

Andy_WSM

I've just managed to get my data online, using an energyhive that matelodave pointed me in the direction of. You can see it here - today is another poor solar day: http://wattson.energyhive.com/dashboard/AndyW