Renewables: "talking 'bout my generation"

legoman62

The hottest day of the year yesterday and I made 25.76kWh.
Not quite the best I've had, but more of the same please!

Oscargrouch

legoman62 wrote: »

The hottest day of the year yesterday and I made 25.76kWh.
Not quite the best I've had, but more of the same please!

Today could top yesterday in heat; may prove to reduce gen readings.:(

sly_dog_jonah

John_Pierpoint wrote: »

Total for the day 23.91 units on the export meter (inverter was boasting 24.1).
I have managed to top 25 exported units twice in late may and again circa 21 June.

[Pedant hat on]
I think you mean generation meter. Likewise the inverter can't measure your export. But it was 3am so we'll let you off.
[Pedant hat off]

jimjames

Out of interest with generation what are the peaks that everyone is achieving per kWp? And also the kWh per year per kWp (actual or estimated)

There are lots of numbers floating around but without running them through a calculator it isn't that easy to see the best outputs.

For us we have 3kWp system, the maximum daily of just under 21kWh and estimated annual total of 3000kWh so figures are:

Daily Maximum: 7kWh per kWp
Annual total: 1000kWh per kWp

sly_dog_jonah

Yesterday was an almost perfect bell-curve of generation for us. The left axis is kWh per 15min peroid, so multiply by 4 for average power output in kW over each period (ie around 3.1-3.2kW, or about 85% of peak output). The long tail on the right is the diffuse generation when the sun has moved off the panels completely.



Our peak day was 24.4kWh or 6.6kWh/kWp. We haven't had a whole years generation but PVGIS prediction is 827kWh/kWp.

Because of our SE orientation we will never be as good as a due South system.

Yesterday's breeze helped the peak output somewhat, I imagine today's generation will be lower as it is warmer and less breezy, but still there isn't a cloud in the sky. Current output is 2.75kW and 15.4kWh already in the bag.

Forecast for next three days is more of the same, then sunny intervals for Fri/Sat. I'm pretty confident we'll now exceed PVGIS for July which seemed inconceivable only a week or so ago. :beer:

KevinG

jimjames wrote: »

For us we have 3kWp system, the maximum daily of just under 21kWh and estimated annual total of 3000kWh so figures are:

Daily Maximum: 7kWh per kWp
Annual total: 1000kWh per kWp

For my 2kWp system:

Daily maximum (so far) 6.5kWh per kWp
Annual total (first year actual): 945kWh per kWp

John_Pierpoint

John_Pierpoint wrote: »

Probably, or seagulls ?

Perfect sunshine, even the vapour trails from the jets at Stansted dispersed.
Almost perfect bell curve, though it starts with a jolt as the inverter decides to power up and ends with a long tail, partly because of the orientation, as the sun sinks.



Maximum observed output on the monitor 3.2kW, though the inverter was boasting a highest instantaneous output for the day nearer the 3.6 kWp capacity of the inverter.

Turned on the immersion (in addition to a couple of computers, light bulbs and the usual standby stuff. Got 39 watts from the panels to one on the import meter. (red flashing meters).

Afternoon temperature (in the shade) 29 centigrade.

Total for the day 23.91 units on the [STRIKE]export[/STRIKE] generation meter (inverter was boasting 24.1).
I have managed to top 25 exported units twice in late may and again circa 21 June.

John

18 panels on two strings through a Power-One Aurora 3.6 inverter. [Oh the dangers of choosing brand names]
SE facing 30 degree roof in S. Essex, with almost no shading, until sun goes round the other side of the building.
http://www.youtube.com/watch?v=T4N4NAgpqXU&feature=related

sly_dog_jonah wrote: »

[Pedant hat on]
I think you mean generation meter. Likewise the inverter can't measure your export. But it was 3am so we'll let you off.
[Pedant hat off]

sly_dog_jonah wrote: »

Yesterday was an almost perfect bell-curve of generation for us. The left axis is kWh per 15min peroid, so multiply by 4 for average power output in kW over each period (ie around 3.1-3.2kW, or about 85% of peak output). The long tail on the right is the diffuse generation when the sun has moved off the panels completely.



Our peak day was 24.4kWh or 6.6kWh/kWp. We haven't had a whole years generation but PVGIS prediction is 827kWh/kWp.

Because of our SE orientation we will never be as good as a due South system.

Yesterday's breeze helped the peak output somewhat, I imagine today's generation will be lower as it is warmer and less breezy, but still there isn't a cloud in the sky. Current output is 2.75kW and 15.4kWh already in the bag.

Forecast for next three days is more of the same, then sunny intervals for Fri/Sat. I'm pretty confident we'll now exceed PVGIS for July which seemed inconceivable only a week or so ago. :beer:

Can I say snap, your screen shot shows the same evening tail as mine.

Your graph starts a shade before 06:00, but mine starts at 04:45, but try as I may I cannot pressure it to vary from GMT;)

[I also have a little "step" at 05:00 GMT - this is I think the sun coming round the chimney or over the ridge of the SE "master bedroom" extension.]

Inverter at 10:00 GMT was reporting an internal temperature of 60 centigrade; so I improved the ventilation - don't want £500 - £1,000 of inverter turning up its toes at this young age.

Martyn1981

jimjames wrote: »

Out of interest with generation what are the peaks that everyone is achieving per kWp? And also the kWh per year per kWp (actual or estimated)

Peaks in this hot weather, holding a steady 2.7kW or 0.75kW/kWp.
Peaks in colder weather, around 3.4kW or 0.95kW/kWp.
December (shallow panels) 1.4kW or 0.4kW/kWp.

Theoretical daily max about 24. Best day 22.5.

Coming up to 1 year anniversary 9/8/12. SAP figures were approx 2,650kWh, PVGIS (climate) 2,950. Looks like we'll hit about 2,800 after the poor June, and also lost about 50 units last August as the smaller system didn't go live till 22/8/11, by which time its big brother had generated 100 units.

So I think 2,850 - 2,900 is a reasonable figure, which is approx 800kWh/kWp.

Not bad for ESE (110 deg from North, or azimuth -70) and some variable shading (trees, chimney and the upper roof to the lower mid afternoon). Pretty much does exactly what it said on the tin.

Mart.

Oscargrouch

John_Pierpoint wrote: »

Inverter at 10:00 GMT was reporting an internal temperature of 60 centigrade; so I improved the ventilation - don't want £500 - £1,000 of inverter turning up its toes at this young age.

How long into the 10 year warranty? Ideally, you need toes turning every 9 years !

legoman62

John_Pierpoint wrote: »

Can I say snap, your screen shot shows the same evening tail as mine.

Can I say "pans" as my tail is in the morning before the hump:D
Almost a mirror image.

25.76kWh yesterday and 25.3kWh at 20.33pm today