Integration with Solcast

Hi BB,

I just found while looking to try to do what Tesla has been promising but have not yet delivered, but better - automate charging my powerwall overnight if the solar forecast is poor for the next day - based on the details of my system (size, orientation, etc.)

Solcast - currently free, currently in beta - gives you a forecast for a location, system size, tilt and azimuth based on their clever sauce, including things like cloud cover forecasts.

It looks very cool.

If they are keen (and, I suspect they might be, for PVOutput) for a collaboration, you could replace (or add to) your insolation forecast which is based on location tilt, azimuth and system size to one which is based on forecast weather. If they are not already using your system as a source of live data, I’m sure they’d be interested.

If I get this going, I’ll upload the expected (half hourly) output to an extended variable - it will be very interesting to see how well it tracks to actuals.

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I stumbled across Solcast a few weeks back too, have been uploading as a variable as comparison to my real data and finding it not too bad actually (bit hit and miss on very bad days) good enough to use it to control my Powerwall reserve level. Tesla are way way off this sort of thing, any inclusion on PVOutput would be a great idea.


This is great to see people finding the Solcast API!

I’m the lead developer at Solcast so really happy to see this use with storage. @BJReplay you’re right that we would want to ingest/use PVOutput measurements to improve forecasts for specific sites. We have a new ‘sites’ based API still in private beta that allows the ingestion of PV measurements from a system and with enough historical measurements, learns system characteristics including shading and better handle systems with multiple tilts, azimuths etc.

We’ve validated this approach to improve forecasts considerably, especially for more complex solar panel setups.

Would be open to how much interest there is in this kind of service and what people would expect this integration to look like with PVOutput.


Loving SolCast, have just sent you an email actually to see if I can get my system fine tuned a bit.

I’ve only just started this recently so there’s not alot of data but if you have a look at

this shows the cumulative energy of my Solar vs my 6am SolCast prediction cut up into 5min intervals, like insolation, cumulative to me is the best graphical way to view it as a cloudy day nothing really lines up. I also do a 10pm SolCast to determine what my Powerwall reserve should drain to or even in very low Solar days if I should charge it up using Off-peak power which plan to upload for comparison.

As BJReplay said something like the Insolation graph would be great, however I would like to see the SolCast total appear on the daily summary for comparison purposes.

Thanks for the comment. Can you clarify Solcast’s policy on third parties such as PVOutput downloading and publishing data on behalf of users that have registered API access with Solcast?

Please note the Solcast data will be public unless the account has enabled privacy.

@darren_solcast, the private API sounds really interesting. I’ll get in touch with you to work on setting it up. I came to the forum this morning to post about a glitch I’ve got setting up display of extended parameters; assuming I can work this glitch out (or give up and get all extended parameters on one access), you can see my solcast forecast (just rough 30 minute buckets at this stage) at for the last day or so. (As noted above by BB, your solcast data is public - if this is a problem, let me know and I’ll remove it).

Thanks for the question, terms for our current API are that data is not to be redistributed without prior consent. We are revisiting the ‘publishing on behalf of’ use case and how it fits with up coming new APIs.

I’ll post an update here once our internal discussions have completed.

@BJReplay , happy for you to publish our data on PVOutput for your system :thumbsup:

Not sure how often you can update the insolation graphs but our data for Australia is updated every 10 minutes for forecasts so feel free to hit it every hour if it improves your battery state control. Great stuff!

I’ve been using Solcast forecast data with Pvoutput insolation data and Efergy historical data to produce my own 24hr rolling solar and consumption forecast graphs for quite a while now with good success.

Here’s my current raw and resultant wx conditions overlay graphs, with the solcast forecast being the hump line and the colour showing variance from baseline insolation for that day. The continuous line is the hourly consumption estimate based on Efergy historical data averaged over a month from this time last year.

It would be cool to have Pvoutput do the solar forecasting automatically.

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Seems a useful idea to have accurate forecasting for demand side management, to improve self-consumption.

Just revisiting an old thread.

I’d be interested in auto upload of the the previous day’s or hour’s Solacast estimate data to compare with my actual outputs. It would need to be a combination of two uploads to account for two different panel orientations.

Is this possible?