Renewables: "talking 'bout my generation"

1961Nick

JKenH wrote: »

I just did a couple of PVGIS calcs for your location, pitch and azimuth. PVGIS-CMSAF produced 129.5 Os and PVGIS-ERA5 produced 126.5 Os. I don’t know which of these or the other two options we should be quoting but I have been using ERA5 as I presumed when Coastalwatch referred to PVGIS5 this is the one he was using. This produced 111 Os for May for my combined system.

I've redone my estimate using V5 PVGIS-CMSAF & reduced the loss from 14% to 9.5% to reflect the improved performance of the new inverter.

Annual 4000 kWh -1000 O's
May 527 kWh - 131.75 O's

JKenH

1961Nick wrote: »

I've redone my estimate using V5 PVGIS-CMSAF & reduced the loss from 14% to 9.5% to reflect the improved performance of the new inverter.

Annual 4000 kWh -1000 O's
May 527 kWh - 131.75 O's

How should I calculate my system losses? There is quite a run from the panels to the inverters of between 30 and 50 feet from the nearest/furthest on each roof. EU efficiency of my inverters is quoted as 97.1%.

1961Nick

JKenH wrote: »

How should I calculate my system losses? There is quite a run from the panels to the inverters of between 30 and 50 feet from the nearest/furthest on each roof. EU efficiency of my inverters is quoted as 97.1%.

I've used the difference between the maximum metered output & 4kWh - I have a pulse counting monitor so it's accurate.

KevinG

1961Nick wrote: »

I've used the difference between the maximum metered output & 4kWh - I have a pulse counting monitor so it's accurate.

The maximum I've seen recently on my pulse-counting monitor from my 8-year-old 2 kWp array is 2,023W. Got 4.23 Os yesterday, which isn't bad and I should exceed May PVGIS today.

Martyn1981

1961Nick wrote: »

PVGIS is 110.5 O's for May.....unless PVGIS has changed since 2013?

Yep, as later posts have confirmed, PVGIS has evolved. There was the addition of climate effects which changed things, especially if coastal (cooling breezes), and then upward revisions as they found 10yr solar levels were higher than the older 10yr baseline they were using.

My results have been pretty much spot on, ranging from around 95% to 105%, which I assume reflects the small(ish) amount of shading I have, v's others on here who I think have tended to do better than PVGIS.

Typically, I think most people have found the numbers to be a bit conservative, possibly reflecting that 14% default losses they've stuck with, despite rising efficiencies in inverters, and possibly the shift from panel ratings of -5% to +5% when I got PV, to a range of zero to +5% by mid decade.

Lot's of nice little lifts, but of course, now you won't beat target by as much, or as often, so not sure if I've given good or bad news. .

1961Nick

Martyn1981 wrote: »

Yep, as later posts have confirmed, PVGIS has evolved. There was the addition of climate effects which changed things, especially if coastal (cooling breezes), and then upward revisions as they found 10yr solar levels were higher than the older 10yr baseline they were using.

My results have been pretty much spot on, ranging from around 95% to 105%, which I assume reflects the small(ish) amount of shading I have, v's others on here who I think have tended to do better than PVGIS.

Typically, I think most people have found the numbers to be a bit conservative, possibly reflecting that 14% default losses they've stuck with, despite rising efficiencies in inverters, and possibly the shift from panel ratings of -5% to +5% when I got PV, to a range of zero to +5% by mid decade.

Lot's of nice little lifts, but of course, now you won't beat target by as much, or as often, so not sure if I've given good or bad news. .

With the old inverter & tree shading I had no chance of hitting the V5 figure. With the tree now gone & a new Sofar inverter I have a chance of getting beyond 4000 kWh (1000 O's) some years. A reasonable target would be more like 950 - 975 O's.

I got the classic calculator working on my iPad & the figures entered for the original estimate back in 2013 were correct.

KevinG

3.5 Os today and past May PVGIS but obviously a long way short of last year.

legoman62

3.6 O's today...and passed April total:T

Oscargrouch

Shocking day today; just not good enough...4.72 O's..:(...

Coastalwatch

3.1 today so not there yet or equalled Aprils total. Getting close though!