THE average gross pay of a 50 year old employee in the ESB is £24,873 a year, the House was told. The gross cost to the ESB's payroll, including PRSI and pension contributions, is £28,592. Employees pay pension contributions of 8.5 per cent. The Minister for Transport, Energy and Communications, Mr Lowry, gave the information to the FF spokesman, Mr Seamus Brennan, in a written reply.