Costa v. Ente Nazionale Energia Elettrica (ENEL). Case No. 6/64. Judgment given on July 15, 1964 - Common Market Law Review View Costa v. Ente Nazionale Energia Elettrica (ENEL). Case No. 6/64. Judgment given on July 15, 1964 by - Common Market Law Review Costa v. Ente Nazionale Energia Elettrica (ENEL). Case No. 6/64. Judgment given on July 15, 1964 2 2 Common Market Law Review