Daily pv production

I had forgotten about May 23… as the rest of 23 was a disaster…I always look fondly back at '22 we had a number of good weeks from March on that year and on a whole that was my best year so far.

Yeah this month will be a record breaker and if it holds out I will break the 1 MWh (6.1 kWp).. Lets not forget also August '22 which is been my best month ever at 924 kWh May '23 was only 923 kWh…😎

96.4kwh produced in Arklow today,the highest so far,will it break the 100 before the month is out? We are at 1502kwh already for the month so far,surpassing my wildest expectations

26 south facing ground mounted 575 watt panels

Nice, just broke 70 again, what a month.

just surpassed 2 megawatt hours production for May with 7 days to go

23x575w panels south

Got my system installed Tuesday, yesterday was its first full run at it.

12E, 8W and 4S

Very happy lad !

I see what your doing there, it's sort of clever, but I'm not sure it'll work doing what your doing as the efficiencies between solar thermal and solar pv are not the same. Solar thermal is about 2x as efficient in capturing the raw energy coming from the sun and converting it into usable energy than PV. So your sort of comparing apples and oranges a little.

I think the "best" way in having a look at PV estimations has always been PVGIS.

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

1. Hit your location on the map you want to model and then
2. Supply the orientation, size, slope and away you go.

It's not perfect, but from my own experiences in South Dublin City it gives me within 10%. (usually under forecasting my production - i.e. I generate more than it thinks I'd get)

So pumping in 6kwp of panels in south cork (facing due south), you get….

I wouldn't get too hung up on "self-use", he'll get paid for whatever surplus he has. More surplus = faster pay back timeline for the installation.

Aside: in 99% of cases, if you can afford it…..always (always) go for the bigger system, it makes more financial sense in the long run.

I see where your going with the efficiency factors etc, but it's actually far more complicated than whats needed here. The following depends a little on the tariffs your on, but it's "ball park" really as tariffs will change of course over time. But you'll find that this works well.

From PVGIS you can see that a 6.0kwp system above in Cork (facing due south) should generate in around 5850 kwhr. Let's say you export -all- of that at a FIT rate of €0.20/kwhr. (I'm using Energia's rate of €0.20) That gives you €1170 in savings for the year.

Of course, you won't be exporting everything as you'll be using some/all of that solar electricity instead of your "day rate" (assuming €0.30) here. So your "lower bound" is €1170 in savings and then if you uses ALL of that electricity at day rate your "upper bound" is 5585 x €0.30 = €1755.

Since you mentioned that his usage is about 3500/year, you can ballpark a saving of roughly half way in between. So you'll be looking at €1500/year in savings.

Note: As mentioned the above depends a little on tariffs, but so does every model.

Can't say why you've not seen those numbers, but we can get some good "1st hand" knowledge from the forum. @ECO_Mental as I recall has an unobstructed south facing panels in cork city - and has regularly posted superb numbers.

Eco, how to the PVGIS forecasts hold up to your actuals?

Generally, historically from numerous posters, PVGIS generally is in and about the right figure. It's within 5% or so for me, with it generally being lower than the actuals I get. Similar story from other posters over the years.

As with all forecasts though there's a level of variability. Will depend on if your chimney shades the panels at some time of the year, or branches from a tree etc.

Did someone say they needed a graph!!!!😎

@bullit_dodger @John.G

See below….I have an EV and a HP…Only got hr EV mid way though 2022

Yes thats correct…I dont worry about how much I export or use of my PV it just works away ..all my big loads such as EV, HP are all scheduled to come on at 2am to 5am when the unit rates are 6.5cent/kWh and then get 18cent per/kWh for PV. I do put on my HP at 12pm to just boost up the HW and hopefully the PV will cover most of this

Where do you see the PVGIS generated output of 6.09mWh/year, the one I've included in the PVGIS data in the

I think that's that what ECO_Mental has in his chart…..

The dotted line is what PVGIS is estimating that ECO will generate in kwhr and then the actuals are beating the estimates that PVGIS is saying he'll get. You add all them up and you get the 6.09mWh

This is consistent with nearly everyone who's posted on the forums over the last couple of years that actuals "tend" to beat the PVGIS by 0-10%.

I think your over complicating it with watts/m^2 etc. Yeah, in theory you could work out all the numbers using that. I've done it myself for my own installation, but it's very subjective to many factors. Slope of the roof has to be taken into consideration, the exact orientation, how well your panels do in diffused light (some are better than others).

Basically a good rule of thumb seems to be PVGIS. It's going to be "in or about" the numbers that you will receive in actuality when you have the system installed. It's not perfect, but for 99% of people it should be fine to make a call on the viability of a system

Yeah, it does, presumably with South facing panels + roof slope of 35C which is selectable on the data sheet, is there a more advanced version that shows the expected output for different orientations other than south?

Edit: It does give the Azimuth angle.

grid use on my system in Arklow since April has averaged about a half to quarter of a kilowatt hour a day or less mainly surges probably when something starts up

Nothing basically

26 500w panels and 15kw of batteries