ValueError: All objects passed were None when calling query_generation

[shuvo-cefalo]

Description

We are encountering an unhandled ValueError("All objects passed were None") when using client.query_generation for certain date ranges where ENTSO-E returns no data.
The error seems to originate from the internal year_wrapper decorator, which collects frames and attempts pd.concat(frames) even when all frames are None.

N.B: This issue happened just before the recent outage of the transparencey platform
Not sure if it's related to that.

Environment

entsoe-py version: 0.7.8
Python: 3.11
Pandas: 2

Code Snippet

import pandas as pd
from entsoe import EntsoePandasClient

client = EntsoePandasClient(api_key="...")

start = pd.Timestamp("2025-11-06", tz="Europe/Berlin")
end   = pd.Timestamp("2025-11-06", tz="Europe/Berlin")

country_code = "BE"

df = client.query_generation(country_code, start=start, end=end)

Error Message

File ".../entsoe/series_parsers.py", line 125, in _parse_timeseries_generic
    return pd.concat(series.values())
...
ValueError: All objects passed were None

[glasid]

Blame ENTSOE.

See here: #482 (comment)

[Simply-Adi]

Just encountered the issue today. Interestingly, generation data by production type appears on their web portal. But, the same can't be fetched using entsoe-py. Crazy ENTSOe api

[christianthilker]

Will I experience the same issues if I use the web-api here https://web-api.tp.entsoe.eu/api? Like, is the issue with the python wrapper (entsoe-py) or with entsoe's api itself?

[c-leblanc]

Will I experience the same issues if I use the web-api here https://web-api.tp.entsoe.eu/api? Like, is the issue with the python wrapper (entsoe-py) or with entsoe's api itself?

The problem is that some empty entry now appears in the XML sent by the web-api, causing the wrapper to crash. Some small modifications in the entsoe-py wrapper seem to fix the issue on my side.

But it also shows another problem with the web-api: at the moment when you request actual production per technology without specifying the technology, it sends back only the first technology (B01, that is biomass) instead of sending all of them as it was doing before. And this is definitely a problem with the api, not the wrapper

[glasid]

I have a pending support ticket with ENTSOE. They are looking into it...

[glasid]

Still waiting for final confirmation from ENTSOE, but it looks like the issue with the malformed XML is fixed.

[ThomasAuriel]

It works for the XML itself, but for some country, ENTSOE is providing wrong information

Here for AT

But other works currently
Here BE

[glasid]

If data itself is wrong or is missing you have to file a request with ENTSOE.