I am interested in analysing the level of concentration in electricity markets in Europe. Eurostat publishes some indicators (such as the n of companies that produce 95% of eletricity RCMPY_NEG95) (link here) but there are huge differences between countries. I find a bit hard to believe that this is not a reporting error.
I tried with the JRC PPDB, which has eic codes. These codes are (If I understood correctly) generated by ENTSO‑E, and can be connected to a “responsible party”. The problem there is that the companies I end up with are often of the same parent company (e.g. Engie España and Engie Cartagena). services like opencorporates (https://opencorporates.com/) do not have the data to link to parent companies. Any interesting data source to at least validate the eurostat indicators ?