noun
electric company
Refers to a company that generates, transmits, or sells electricity; often used for power utilities.
東京電力は日本最大の電気会社です。
Tokyo Electric Power Company is the largest electric company in Japan.
More specifically refers to a power utility company; 電気会社 is broader and can include any company dealing with electricity.
Compound of 電気 (electricity) and 会社 (company).