It is understood that National Grid has asked a number of agencies for written submissions and will hold face-to-face meetings with shortlisted agencies during the coming weeks.
Brunswick has held the account since 2007, when it picked it up from Citigate Dewe Rogerson.
It is thought that financial PR heavyweights including Finsbury, FTI Consulting and Tulchan Communications are in contention.
Chris Mostyn, head of corporate media relations, commented: 'We are very pleased with the quality of advice and service we receive from Brunswick. Our procurement rules require us to hold competitive tenders at regular intervals, and this is part of that process. Brunswick is among the firms invited to participate.'
Brunswick declined to comment.
It is thought the brief encompasses financial comms and corporate positioning, and will take effect in the New Year.
National Grid owns and runs the UK’s electricity network and has also operated the gas transmission network since its merger with Transco in 2002.
A key issue for the successful agency will be supporting the firm’s comms through energy regulator Ofgem’s review of electricity and gas network pricing. The review will set price controls for eight years and are designed to provide stronger incentives for networks to manage costs.
More generally, the Government is pushing for a ‘greening’ of the UK energy supply in a bid to lower carbon emissions and increase energy from alternative sources.
A City PR source added that relations with the investor community may need smoothing after the company launched a rights issue last year to a mixed response.