The review also includes SEO and pay-per-click activity. It is being handled by the procurement team at Scottish Power and there is no intermediary involved.
Agencies need to register their interest by next week.
The7stars, the incumbent, picked up the business in 2014, when it was reported to be worth £10 million.
The independent agency beat UM London, Arena Media and Carat Edinburgh, the 14-year incumbent. The process was handled by Creativebrief and lasted more than a year.
Leith won Scottish Power’s above-the-line account last year after a review that kicked off in April and was also overseen by Creativebrief.
Fallon was the incumbent on the ad business. It won the £7 million account in July 2013, beating Inferno, MBA and Newhaven.
The Publicis Groupe agency created Scottish Power’s most-recent ad. It explained how the brand looks at the bigger picture, such as its commitment for a "cleaner energy future", and the smaller picture by having its customer phone lines open until 10pm.