The introduction of wind power into an electricity-generation system on a large scale brings about challenges for the evolution and operation of this system: backup for wind power becomes a necessity. This paper defines various elements that come into play when considering backup for electricity generation from wind power. The backup is split tip in capacity backup and operational backup. The focus is set on the short-term, operational aspects of the backup provision. The effects of several short-term operation related parameters are defined and analysed. Most relevant parameters for the operation and needs for wind power backup are the load profiles, the wind power output profiles and the total amount of installed wind power. These are analysed by means of a Mixed Integer Linear Programming (MILP) model through two different methods for operational backup provision, comparing the incremental cost, generated by both methods. The first method applies wind power backup through a 100% provision of additional spinning reserves. The second method does not foresee any spinning reserve and relies on the balancing by the Transmission System Operator (TSO). Both methods result in different additional charges that are being affected by the said parameters. Both the wind profile and the total amount of installed wind power are positively related to the relative cost increase. The load profile is negatively correlated to this increase. The relationship between these parameters and the development of the incremental cost provides an understanding that allows finding better equilibria in the operational backup of wind power. (c) 2008 Elsevier Ltd. All rights reserved.