I know who you are and I’ve seen how much electricity you consume:  the Supreme Court of Spain holds that data derived from the measurement of the individual consumption of electric energy such as the hours in which the light is used, the rooms in which it is used or the appliances that are plugged in, are personal data.

They are, therefore, protected by the Organic Law on Data Protection by considering that they are private behavior habits of the consumer that can be accessed by a third party, in this case, the operator that measures the electricity meters.

Because the data is used for the purpose of inspection by the relevant supervisory authority, consent of the end user is not required for the collection.

Details from Confidencial Judicial.