However, the contracts are only on a short-term basis as RWE is planning to consolidate all of its disparate accounts into one media and creative network to create a global brand identity.
The media review was triggered in September by Npower's incumbent agency, Manning Gottlieb OMD, winning the £10 million media planning and buying account for the rival utilities group EDF Energy. EDF owns Seeboard, SWEB and London Electricity.
Npower's creative account was previously held by TBWA\London but has lain dormant for some time. Npower has retreated from above-the- line advertising in recent months - it has terminated its £2 million sponsorship of Channel 4's homes programming and its cricket coverage,
The German-owned utility company RWE is looking for agencies to handle its first international brand campaign in its core markets of Germany, the UK and the US.
The move is likely to put an end to both the Npower and the Thames Water brands. RWE's other interests are gas, electricity, water, waste management and other utility-related services.
The Aegis-owned Vizeum won the account following a four-way pitch against PHD, Walker Media and BLM.
Npower and Vizeum refused to comment.