Renewables: "talking 'bout my generation"

Chris_Type_R

Or if you really want a worthwhile comparison why not adopt kWh generated/cost of panels?

Then you'd have to factor in FIT income which is effectively a capital expenditure subsidy.

The O system is just a bit of fun - East Westers could use 'EW' as their unit of measure with different scales.

O/T - how useful is a mainly E/W split in the shorter day months ? I'm looking to add 3.6kWp split across E & W roofs in order to lengthen my production window. My south roof is already mostly occupied - and to add more capacity there would require FIT approval.

JKenH

Chris_Type_R said:

Or if you really want a worthwhile comparison why not adopt kWh generated/cost of panels?

Then you'd have to factor in FIT income which is effectively a capital expenditure subsidy.

The O system is just a bit of fun - East Westers could use 'EW' as their unit of measure with different scales.

O/T - how useful is a mainly E/W split in the shorter day months ? I'm looking to add 3.6kWp split across E & W roofs in order to lengthen my production window. My south roof is already mostly occupied - and to add more capacity there would require FIT approval.

It’s not great in winter. In December I only generate about half of what I would with a South facing system. I find PVGIS over estimates winter generation potential for E-W panels. I have never got anywhere near the PVGIS estimate for December (usually around 70-80%) whereas in May (2020) I have seen 118%. 

Having said that, I think having panels on 3 elevations is great. I dislike drawing from the grid and if I could have more panels I would. Payback might take a long time but you will have the satisfaction of generating at breakfast and tea time - at least for part of the year.

legoman62

Hawaii + 0.4 O’s here today on my SW facing panels and 28 degree slope roof 🤣😂

ggmf

@Chris_Type_R - A view of my S and E roof spaces if it helps,. Think this works out out 4:1

Todays generation was 4.6 & 1.551 O's

Grandad2b

27kWh, 6.08 O's

I'll give both energy generated and 'performance'. That way anyone reading can choose which measure they find more useful.

Coastalwatch

4.5 O's about ave for June here.

JKenH

Chris_Type_R said:

Or if you really want a worthwhile comparison why not adopt kWh generated/cost of panels?

The O system is just a bit of fun - East Westers could use 'EW' as their unit of measure with different scales.

Indeed. I used to post my figures here daily and enjoyed the camaraderie. What I took issue with is the argument that posting the number on your Gen Meter is irrelevant to what the thread is all about and does not portray a level playing field as far as number reporting is concerned. 

Your score as a percentage of your daily PVGIS target would produce a more level playing field (call it a P, if you like) but that also then depends on everyone adopting the same version of PVGIS for their calculation. Some people might still be using an old PVGIS calculation from when they first got their panels. I use V5 which for me gave a figure more than 10% higher than the first version I saw when I got my panels. Maybe there is an even later version I haven’t looked for. 

I am not trying to upset the apple cart. Many people enjoy posting their score in Os but if we are too prescriptive that that is the only fair way (witness the comments in bold from an earlier post) it is likely to deter some people posting their numbers. 

Grandad2b

I take all these metrics with a very large bucket of salt. A big number means it's been sunny. My south facing array won't perform particularly well if is sunny early morning and late afternoon with a big lump of cloud in the middle whereas Ken's will show good numbers.

EricMears

JKenH said:

I am not trying to upset the apple cart. Many people enjoy posting their score in Os but if we are too prescriptive that that is the only fair way (witness the comments in bold from an earlier post) it is likely to deter some people posting their numbers. 

The raw kWh/kWp is far from being a 'level playing field !

As well as the geographical alignment,  the pitch of the roof is also highly significant.  If you really wanted a useful comparator,  I agree that something based on comparing a day's output to the figure predicted by pvgis would be more appropriate.  However,  getting an individual day's forecast from pvgis is a lot of work.

Can't say that I'm really bothered what other people got yesterday;  if I wanted to compare with anything,  I'd look at last year's output or even the average of the last ten years for my own system.

JKenH

EricMears said:

JKenH said:

I am not trying to upset the apple cart. Many people enjoy posting their score in Os but if we are too prescriptive that that is the only fair way (witness the comments in bold from an earlier post) it is likely to deter some people posting their numbers. 

The raw kWh/kWp is far from being a 'level playing field !

As well as the geographical alignment,  the pitch of the roof is also highly significant.  If you really wanted a useful comparator,  I agree that something based on comparing a day's output to the figure predicted by pvgis would be more appropriate.  However,  getting an individual day's forecast from pvgis is a lot of work.

Can't say that I'm really bothered what other people got yesterday;  if I wanted to compare with anything,  I'd look at last year's output or even the average of the last ten years for my own system.

TBH, that’s what I do. My yardstick is what I've done in previous years because, as you say, no one else has my geographical position, roof elevation and alignment. Once you do that then you see just how inconsistent our weather is. My target for a good June day is to beat what I’ve achieved in recent Junes.