RELIANCE ON NONUTILITY GENERATION IN PLANNING CUSTOMER DELIVERY SYSTEMS

This paper describes a probabilistic approach for determining the port ion of Non-Utility Generation capacity. (NUG ''Credit''). that can be relied on as a firm resource when assessing the adequacy of the Ontari o Hydro customer delivery system. The proposed method is based on the criterion that the reliability of supply to the customers on the deliv ery system should not be affected by the addition of a NUG to that sys tem. Calculations to determine the reliability level consider the syst em load profile, system contingencies, the lend forecast and its uncer tainty, the NUG size and the NUG forced outage rate as well as the unc ertainty of the in-service date of new facilities. Sensitivity studies are conducted to determine the factors that largely affect the NUG cr edit. The paper also presents an approximate method for estimating the NUG credit. The method is simple and easy to apply and does not requi re the detailed calculations of the exact method. A comparison of the exact and approximate methods is illustrated using some numerical exam ples.