MBA won the business following a final round of pitches that included 12 agencies. The above-the-line account will be worth around £10 million next year.
In February, EDF Energy, the UK's fourth-largest domestic gas and electricity supplier, put out a tender for its advertising account in a bid to find greater cohesion across its portfolio of brands.
The company completed the rebranding of its operation last month.
EDF Energy, which has 4.9 million customers, owns the domestic brands London Energy (previously London Electricity), Seeboard En-ergy and SWEB Energy (previously South Western Electricity Board).
The company, which according to Nielsen Media Research spent £6 million above the line last year, is now planning a major return to TV to promote its new brands.
SWEB and Seeboard are expected to be the most heavily promoted brands using above-the-line media.
A creative and media review kicked off in March last year but was not completed. It stalled following the departure of its managing director, Jon Kinsey, and the later resignation of the sales and marketing director, Gary Tubb. Tubb was replaced by Peter Hofman, who was previously the managing director at Seeboard.