Renewables: "talking 'bout my generation"

Coastalwatch

0.16 O and running out of Time.... magazine!

Merlin139

Still below my worst December total and way behind PVGIS.

0.272 O's

Netexporter

The sunniest places in the UK, the past two days, have been my two nearest Shipping Forecast coastal stations, rather frustratingly.

QrizB

My PVGIS prediction for December is 80kWh.

I only have good records for five of thirteen previous years but in those five I've never hit it; my best was 76kWh.

Today I'm at 73kWh for the month, and the sun is shining brightly. I'm hopeful of today making this my best December ever and possibly even matching PVGIS before the month is out

Martyn1981

QrizB said:

My PVGIS prediction for December is 80kWh.

I only have good records for five of thirteen previous years but in those five I've never hit it; my best was 76kWh.

Today I'm at 73kWh for the month, and the sun is shining brightly. I'm hopeful of today making this my best December ever and possibly even matching PVGIS before the month is out

Just wondering if you (like me) have gone with the 'gross' PVGIS estimate, and not allowed/subtracted anything for shade?

My thinking, despite having some shade, was to compare against the best figures, if only to see how actual generation compares. TBF, I've typically been close to or just above the targets, which I assume reflects the slightly pessimistic default losses, that PVGIS uses, v's real life.

But now, since winter 2024, my Dec/Jan (and to a lesser degree Nov & Feb) results look terrible due to the DC side batts. The less generation, the more grid charging, and thus the greater charging losses that show up on my net meter reading.

The last two days have actually resulted in a small reduction on my meter ...... which is kinda funny, but perhaps cheating if I try to claim the virtual wooden spoon each day.  

SuzeQStan

SuzeQStan said:

SuzeQStan said:

1/2 a kwh here - practically nothing - thank goodness we can charge the solar battery at nite on IOG

Groundhog Day….. 🙄

3rd time distinctly lacking charm.  0.5 x kWh 

Coastalwatch

1.4 O's today so a good day tomorrow might just bring pvgis back within spitting distance. 

If you'll pardon the expression!

theharebreaks

0.12 O's yesterday and 0.58 O's today.  If it is as forecast tomorrow, I might just make PVGIS estimate

Merlin139

The Sun was seen here today, but not for long!

0.77 O's

Todays effort moved the standings from 12th and last to 9th and only on 72.1% of PVGIS for December.

NedS

0.6 O's today, which puts us at 99.9% PVGIS and with a sunny day forecast tomorrow, I'm pretty confident we will generate the missing 200W 

Martyn1981 said:

QrizB said:

My PVGIS prediction for December is 80kWh.

I only have good records for five of thirteen previous years but in those five I've never hit it; my best was 76kWh.

Today I'm at 73kWh for the month, and the sun is shining brightly. I'm hopeful of today making this my best December ever and possibly even matching PVGIS before the month is out

Just wondering if you (like me) have gone with the 'gross' PVGIS estimate, and not allowed/subtracted anything for shade?

My thinking, despite having some shade, was to compare against the best figures, if only to see how actual generation compares. TBF, I've typically been close to or just above the targets, which I assume reflects the slightly pessimistic default losses, that PVGIS uses, v's real life.

But now, since winter 2024, my Dec/Jan (and to a lesser degree Nov & Feb) results look terrible due to the DC side batts. The less generation, the more grid charging, and thus the greater charging losses that show up on my net meter reading.

The last two days have actually resulted in a small reduction on my meter ...... which is kinda funny, but perhaps cheating if I try to claim the virtual wooden spoon each day.  

Interesting about the shading. I never quite appreciated just how low the sun is in the sky in December, and how even low trees and buildings some distance away can still cause shading at the beginning and end of the day. We are due south facing, but the panels see no sun before 9:30am and it's completely gone by 3:30. Next door also has a chimney which casts a moving shadow all day over our lower row of panels which I hadn't even considered (and isn't an issue other times of year). I'm going to guess that an east/west split array would be more impacted by shading than a single south array as the early morning and late afternoon sun would be most impacted by the sun being so low in the sky.

Last December we achieved 70% of PVGIS, this month we should exceed PVGIS. Our best day was 2.64 O's (Christmas day). It is also highly dependant on just a couple of good days as we can achieve almost 10% of our monthly predicted generation on a single good day. I'm guessing ~3 O's would be a theoretically perfect December day for a south facing array with no shading.