Plans to create a European ID card were dropped in early 2000 due to technical, administrative and political obstacles. Instead, the experimental project STORK (Secure idenTity acrOss boRders linKed) was introduced in May 2008.
"Relying on volunteer states, the aim of the project is not to create a single ID document, but to integrate common electronic elements into national ID cards which could be used in every partner state, of which there are 18 right now. It's what you call interoperability.
The stork program also has four new pilot programs. Read more about STORK here: https://www.eid-stork.eu/