Real-time economic dispatch (RTED) is performed every 5-15 min with the static snapshot forecast data. During the period between two consecutive schedules, generators participate in managing power imbalance, based on participation factors (PFs) from previous economic dispatch (ED). In modern power systems with considerable renewable energy sources that have high variability, this conventional approach may not adequately accommodate the economic implication of the said variability. This paper proposes the evaluation of “best-fit” PFs by taking into account the minute-to-minute variability of solar, wind, and load demand, for a scheduling period. Since “best-fit” PFs are evaluated only once, i.e., at the start of scheduling interval, the dimensionality of optimization problem remains the same as that of conventional approach. The proposed approach is suggested for sequential and dynamic variants. Results for two test systems have been obtained to verify the benefit of the proposed approach