The paper presents different network flow algorithms to handle the linear and nonlinear unit I/O characteristics of the daily fuel scheduling problem with hourly and daily fuel constraints. Results of a 17 unit/17 contract test system results are presented to illustrate the highlights of the proposed methodologies. Due to differences in the degrees of uncertainty in fuel, generating and load data constraints in different time periods, the overall problem of fuel resource scheduling of an electric utility is decomposed into long term (weeks to year), short term (days to week), near term (hours to day) and real-time (minutes to hour) problems. This paper addresses the near term resource dispatch of the daily fuel scheduling problem for optimum allocation of fuels to different generating units in the system to meet the hourly load requirement subject to hourly and daily constraints. The hourly constraints consist of unit operating limits and operating characteristics, fuel consumption limits by a single unit or combination of units, and fuel supply limits. The daily limits on fuel supply from each contract constitute the set of daily constraints. In addition, a unit can burn more than one fuel and a contract can supply fuel to more than one generating unit. In the daily fuel scheduling problem, the representation of the I/O characteristics of the units determine the complexity of the optimization problem. The paper proposes a method to consider the piecewise linear IHR characteristics of the units.