Can You Get Your Own Solar Data Out?

A buyer's advisor asks for three years of 15-minute data. An availability dispute needs the readings of a month two years ago. A new O&M contractor takes over and wants the history. That is usually the day an owner finds out whether the raw data can still be had.

We have seen it more than once: the portal no longer had the older raw readings, or the export kept failing.

Why it happens

A monitoring portal is built to show what is happening now. Keeping years of raw readings at full resolution, ready for export, is not its main job, and nobody has to have done anything wrong for them to be missing:

• Retention. Some portals keep full resolution only for a while, and older data only as hourly or daily values.
• Export limits. An export may be capped by rows, by date range or by number of devices, or time out on long periods.
• Interfaces. An interface may deliver only recent days, or only some of the channels.
• Accounts. The portal account may belong to the EPC or the O&M contractor, and leave with them.

You can't tell any of this from the dashboard. It looks the same whether the data from three years ago is there or not.

Three questions to settle now

1. Can the raw readings of every plant be exported at full resolution, through an interface or as a file?
2. How long does the portal keep them at that resolution?
3. What comes with you when you change portal or O&M contractor, and whose account is it?

How to test it in an afternoon

1. Pick one plant and an old month: the oldest month you would want in a dispute or a sale.
2. Export inverter energy, the grid meter and irradiance at the finest resolution offered.
3. Count the values. A 31-day month in 15-minute steps has 2,976 values per channel. In a month in which the clocks change, there are four more or four fewer.
4. Check the resolution. Are older months still in 5 or 15 minutes, or only hourly?
5. Try the interface too, if there is one. Note where it breaks: which period, which device, which error.
6. Write it down per portal. What you found is your record of what can be had and what can't.

Doing it yourself

The test tells you where you stand today. The lasting answer is a copy of the raw readings in storage you control, collected as they arrive and kept as they arrived.

That takes a collection job per portal, the storage, a daily check that the data came in complete, and someone who notices when it stops. Starting the collection is easy. Noticing that it quietly stopped three weeks ago is the hard part.

Or let us do it

With portal access, the report on one plant and one month answers the first two questions along the way: what we could export, at what resolution, how far back, and where the export broke. If it doesn't work, that is the first finding. After that, the raw data can be collected as it arrives and stays in your own storage, unchanged, for as long as you want. The history stays yours when a portal or a contractor goes.

More for owners: can you get your own data out?

See also

• Taking Over a Solar Plant: The Data to Ask For
• Two Dates for Every Number