Solar panel production figures

Ron-ski said:
For me the efficiency is the only metric to fairly compare how different systems, with different sizes are performing, oh and that it annoys the hell out of Katie :D

Now the mist has burned off its a bright sunny day down here as well.
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Well actually the figure that more interests me is the % free energy or total energy cost - ie I don't really care about efficiency if we can get to zero bills (indeed, that's exactly what I'm looking at at the moment - ie installing extra panels in a marginally less efficient spot to further reduce my bills.

I think this is a really cool period we're in where we have the ability to radically reduce our living costs with nerd power from guys like you (and the occasional girly engineer!). Basically I've taken our electricity costs, oil heating costs, petrol costs and so on, added them together and I'm plotting ways to reduce them as close as possible to zero. So if I can get a 80% reduction in these annual costs in ten years, then that's far more interesting than efficiency!
 
Efficiency indeed also comes from usage, if you can use near to 100% of the solar you generate, then it's natively more efficient than exporting to the grid.

Every kWh you sell at a discount is one you could be using as if it was full price. £0.15 earnt vs £0.34 saved, the saved figure will always win.
 
katie279 said:
Well actually the figure that more interests me is the % free energy or total energy cost - ie I don't really care about efficiency if we can get to zero bills (indeed, that's exactly what I'm looking at at the moment - ie installing extra panels in a marginally less efficient spot to further reduce my bills.

I think this is a really cool period we're in where we have the ability to radically reduce our living costs with nerd power from guys like you (and the occasional girly engineer!). Basically I've taken our electricity costs, oil heating costs, petrol costs and so on, added them together and I'm plotting ways to reduce them as close as possible to zero. So if I can get a 80% reduction in these annual costs in ten years, then that's far more interesting than efficiency!
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Absolutely agree, ultimately at a household level it's all about savings, or being more environmentally friendly. The efficiency figure is purely for meaningful comparison.
SoliD said:
Think you'll struggle with 30+kwh once it warms up! 3.2kwh system right?
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I think he may just get 30, possibly, my 4kw system has never produced 30kWh in a day (28 being the max IIRC, 26 more often), but it's not all South facing, it's split across two roof's, 90 degrees to each other.

Started generating at 7:58, by 10am was generating 2kw and had generated 2.1kWh, going to be a good day if the sun stays out.
 
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Ron-ski said:
Absolutely agree, ultimately at a household level it's all about savings, or being more environmentally friendly. The efficiency figure is purely for meaningful comparison.


I think he may just get 30, possibly, my 4kw system has never produced 30kWh in a day (28 being the max IIRC, 26 more often), but it's not all South facing, it's split across two roof's, 90 degrees to each other.

Started generating at 7:58, by 10am was generating 2kw and had generated 2.1kWh, going to be a good day if the sun stays out.
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yup i was on 2kwh produced at 9:55 today and the we had a lot of fog and mist between 7 and 9am and currently exporting at 2.2kwhs
 
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Ron-ski said:
I think he may just get 30, possibly, my 4kw system has never produced 30kWh in a day (28 being the max IIRC, 26 more often), but it's not all South facing, it's split across two roof's, 90 degrees to each other.

Started generating at 7:58, by 10am was generating 2kw and had generated 2.1kWh, going to be a good day if the sun stays out.
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Yeah at a push! on a clear sky day late may when its still cooler but days are fairly long. I got 43 one day last year in July during the really hot spell, and 40+ 7 days that month on a system pretty much double the size.
 
I really like the idea of the combined solar and thermal panels… it’s really just win win - keep the panels cooler with active cooling and steal the heat for your hot water.

Shame they aren’t yet very common

If I was doing a new build and starting from scratch I’d definitely be going that route and adding a heat pump for the rest.
 
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SoliD said:
Yeah at a push! on a clear sky day late may when its still cooler but days are fairly long. I got 43 one day last year in July during the really hot spell, and 40+ 7 days that month on a system pretty much double the size.
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im looking at those 17hr long sunny days in june/july.........and being south facing, its going to produce a lot of solar on a clear day
 
Zeeflyboy said:
I really like the idea of the combined solar and thermal panels… it’s really just win win - keep the panels cooler with active cooling and steal the heat for your hot water.

Shame they aren’t yet very common

If I was doing a new build and starting from scratch I’d definitely be going that route and adding a heat pump for the rest.
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In Cyprus they've been using hot water panels for decades. But they still don't support solar because of the power company monopoly they have there, and their grid isn't set up for export either.
 
Welshman said:
im looking at those 17hr long sunny days in june/july.........and being south facing, its going to produce a lot of solar on a clear day
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As I said, i'm double your array, 3deg off South and I only got 43 at max, reckon you'll get one or two days of 30kwh, but when it's toasty it'll knock back your production some.
 
SoliD said:
As I said, i'm double your array, 3deg off South and I only got 43 at max, reckon you'll get one or two days of 30kwh, but when it's toasty it'll knock back your production some.
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and thats good for me...one or two days, im also 1500ft above sea level, my toasty is prob a few degrees lower than sea level toasty in portsmouth. But lets see in the summer, be good to see if we can get it. it would also mean around 27kwh of export too.....
 
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