Daily pv production

E/W 8.4kw even split.

205kwh for the month

163kwh here from 4kwp south east, 3kwp north west

330kWh from 11.6kW se/sw array

Wow - 0.7Kwhr forecasted for today (Monday 4th) - winter really is here. :-(

There's a good few messages over in the "automation" thread, but in a nutshell Met Eireann have an API and you can call it with your latt/long and it will return an XML file. For me in south Dublin that's http://metwdb-openaccess.ichec.ie/metno-wdb2ts/locationforecast?lat=53.27;long=-6.32         

It'll return a bunch of hourly reports such as tomorrow.... at 11am to 12pm (aside: I think that's a bug in the xml below for the end time it should be 12)

<time datatype="forecast" from="2023-12-05T11:00:00Z" to="2023-12-05T11:00:00Z">
<location altitude="163" latitude="53.2700" longitude="-6.3200">
<temperature id="TTT" unit="celsius" value="1.6"/>
<windDirection id="dd" deg="263.7" name="W"/>
<windSpeed id="ff" mps="2.4" beaufort="2" name="Svak vind"/>
<windGust id="ff_gust" mps="5.3"/>
<globalRadiation value="71.4" unit="W/m^2"/>
<humidity value="92.4" unit="percent"/>
<pressure id="pr" unit="hPa" value="1015.0"/>
<cloudiness id="NN" percent="55.1"/>
<lowClouds id="LOW" percent="55.1"/>
<mediumClouds id="MEDIUM" percent="0.0"/>
<highClouds id="HIGH" percent="0.0"/>
<dewpointTemperature id="TD" unit="celsius" value="0.3"/>
</location>
</time>

The interesting bit above is the "globalRadiation" value of 71.4 for 11am->12pm. So I sum all the hourly globalradiation values up for tomorrow, I'll get a total "daily radiation" value of like 508 (or something). So now I know what tomorrows radiation value is.

I also have my historical "actual" kwhr value for my system in a database, so I can compute an average over say the last 10 days, that 1000 "radiation" will generate "x" kwhr and from that I can compute an estimate for today/tomorrow.

It's not perfect. Ultimately if the forecast from Met Eireann is garbage, then I'll get garbage forecast.....but to be fair to them, they do a good job on most days which as you can see equates to pretty decent forecasts.

Today my estimate was for 0.7kWhr and I ended up with 0.5kwhr. That's close enough to be fair.

I've used Solcast, and on clear sky days.....it's pretty good, but on days which are changeable it's all over the place.

Don't think I've seen the forecast this low...

Well today was the single worst day I've ever had for PV. Based in Cork. 3.3kW inverter, peak of probably about 5.5kW from 12 panels in the summer.

Yield for today = 0.00kWh. It was tragic. Overcast, thick cloud, mist and rain. Never have I seen the likes of it.

Worst day ever for my setup. Granted there was a power outage 9=6pm so my roof panels were offline but still shocking return from ground mount system.

On plus side changeover switch allowed power to whole house all day uninterrupted

0.9kWh yesterday from a 6.8kW array

See ye in six weeks.

yeah id say im averaging 2kwh these days.. what id forgotten is even on a really sunny day... my peak kwp is only about 1/3rd of the summer equivalent.. ive seen 1kwh at times.. even 1.9... this week but in the summer that would be 5

Had a quote from a seller who claimed a 2.9kwp system (7 panels) could achieve 3,000kwh a year off an average year of 1,000 hours of sunlight. Roof is south facing with a pitch of 40 degrees. He said the panels they install are double sided so give an extra 10% of generation from the underside of them. Is 3,000kw hours a year realistic from such a small 2.9kwp system? Or is the salesman using optimistic figures?