Can a energy source (diesel/gasoline) be compared with an electric storage/battery ?

NO !

Gasoline/diesel burn up, are gone.... Batteries can be recharged...but how is the electricity generated for charging ?
On site, Lanzarote, 95% from diesel and heavy oil !

So all e-cars that are charged on the island's e-grid are practically internal combustion vehicles with the advantage of the very efficient electric drive.