His task will be to keep policy makers abreast of the Carbon Trust's efforts to tackle global warming.
Sheward will report to director of delivery and external relations Dr Garry Felgate when he takes up the post on 6 November. Felgate said Sheward's task was to make ‘stakeholders across Westminster and Whitehall understand what the Carbon Trust is doing with businesses and the public sector to accelerate development of a low-carbon economy'.
As well as championing energy efficiency measures to UK organisations, the Carbon Trust has so far invested £21.6m in low-carbon technologies including marine, biomass and solar.
Sheward takes over from Peter Mallaburn, who is now CEO of Salix, a Carbon Trust-funded business helping local authorities implement green initiatives. Mallaburn had been PA chief since the Carbon Trust's inception five years ago.
Last week, Sir Richard Branson committed all profits from his Virgin travel businesses in the next ten years - estimated at £1.6bn - to be invested in renewable energy technologies.
United Utilities is now on the hunt for Sheward's replacement. His exit follows that of PA manager Kevin Meagher to the Sector Skills Development Agency (PRWeek, 15 September).
Sheward has been United Utilities head of PA since November 2000, during which time he led a company ‘taskforce' to influence the pricing review of water and energy regulators Ofwat and Ofgem. He also set up a PA function for United Utilities call centre business Vertex.
Before that he worked as government relations manager at Severn Trent, and was at Westminster Strategy, latterly as a senior account manager.