The long-term reliability of an electric power system and continuity of supply of power to consumers are critically dependent on the timely maintenance of system assets and the construction of new assets. New assets are installed in extension of the system to provide greater power transfer capability or in replacement of old equipment that has reached the end of its economic or technical life, i.e. where the probability of an irreparable failure is excessively high or repair or maintenance would be uneconomic. Both maintenance and construction work require the removal of parts of the system from service so that the relevant parts of it can be safely accessed and worked on. However, the remainder of the system must be capable of meeting minimum service standards, i.e. be capable of meeting demand without overloading of the remaining network branches, violation of voltage limits or risk of instability of the system.As electric power transmission and distribution networks in the UK age, in the next 1 to 10 years, very large parts of them will need to be replaced. The associated construction outages will be very much longer than maintenance outages; due to the 'bow wave' of asset replacements needed, the number of outages to be taken will be higher than ever before. This will occur at the same time as, following year-on-year demand growth, changes to generation patterns and greater restrictions on network owners' ability to add new circuit routes, systems are utilised to a greater degree than ever before. Moreover, still more construction outages are needed for the accommodation of new generation, in particular renewables.In order to ensure that a sufficient number of network outages of adequate length can be taken by the times at which they are required while maintaining system security, a huge effort must be expended optimising the schedule of outages. This requires detailed analysis of system security under different outage conditions and appropriate management of the risks of dependencies on availability and prices of generation, fluctuations in demand and overrun of work on the outaged network assets. The worst outcome of a failure to manage the risks would be that critical outages cannot be taken with the result that essential network assets are at greater risk of failure and that new generation / in particular renewables / cannot be accommodated.This project aims to develop methods to facilitate the meeting of the greater-than-ever challenges in the scheduling of network outages and demonstrate them by means of prototype software tools. The result will be reduction of the aforementioned risks and a more efficient and timely facilitation of the connection of renewable generation.