Mr Scott becomes only the third executive director on Renew’s board, alongside chief executive Brian May and finance director John Samuel.
Paul Scott, aged 49, has headed Renew’s nuclear contracting business, Shepley Engineers for seven years.
He reports to chief executive Brian May, who at 63 may be considering his succession strategy.
Chairman Roy Harrison said: "I am pleased to welcome Paul to the board of Renew. Over the last seven years, Paul has developed Shepley Engineers Ltd into the leading mechanical and electrical contracting business at Sellafield and since assuming the position of engineering services director in 2012, has successfully championed the integration and growth of our engineering services businesses whilst maintaining their independent brand strengths."