Risk-Limiting Economic Dispatch for Electricity Markets With Flexible Ramping Products

Abstract

Abstract-The expected increase in the penetration of renewables in the approaching decade urges the electricity market to introduce new products -in particular, flexible ramping products -to accommodate the renewables' variability and intermittency. A risk-limiting economic dispatch scheme provides the means to optimize the dispatch and provision of these products. In this paper, we adopt the extended loss-of-load probability as the definition of risk. We first assess how the new products distort the optimal economic dispatch by comparing to the case without such products. Specifically, using parametric analysis, we establish the relationship between the minimal generation cost and the two key parameters of the new products: the up-and downflexible ramping requirements. Such relationship yields a novel routine to efficiently solve the non-convex risk-limiting economic dispatch problem. Both theoretical analysis and simulation results suggest that our approach may substantially reduce the cost for incorporating the new products. We believe our approach can assist the ISOs with utilizing the ramping capacities in the system at the minimal cost.

Stochastic generation scheduling with variable renewable generation: methods, applications, and future trends

“…Research on flexible ramping products started only recently in academia. Flexible ramping has been studied with deterministic GS models [138, 139], and stochastic GS models with REG uncertainty [140–142]. A comparative analysis of a real‐time deterministic flexible ramping dispatch model versus a real‐time stochastic model is conducted in [140].…”

Strategic Offering for Wind Power Producers Considering Energy and Flexible Ramping Products

“…where 9is the objective function of the ISO to minimize the total generation procurement cost, load-shedding cost, and ramping shortage penalty cost; (10) and (11) are the real-time demand and generation balance equations; (12) represents the demand limitation; (13) is the transmission constraints; (14) and (15) are the generation limitations considering flexible ramping products; (16) and 17are the wind power limitations considering wind power providing flexible ramping products; (18) is the wind power limit; (19), (20), (23) and (24) are the limitations on the generation's flexible ramp products; (21) and (22) are the system's flexible ramping product requirement constraints; and (25) is the ramp shortage limitation. The variables on the right side of the colons are the dual variables associated with the corresponding equality or inequality constraints.…”

“…In these markets, wind power is usually modeled as a source that contributes to the ramp requirement; however, using wind power to increase a system's flexibility-including modeling it as a flexible ramp capacity provider-is attracting more attention due to the rapidly increasing penetration of wind power [9][10][11]. Previous literature has analyzed system flexible ramp requirements and the impacts of ramp products on market clearing [12][13][14][15][16]. The impact of wind power on flexible ramping was reviewed in [15,16].…”

Risk-Limiting Real-Time Economic Dispatch in a Power System with Flexibility Resources

“…The ever-increasing penetration of intermittent renewable energy sources (IRESs) such as wind power and photovoltaic power generation brings about higher variability and uncertainty, which poses a serious challenge to the operational flexibility of a power system [1]. Generally, it is relatively straightforward to dispatch controllable resources like conventional thermal power and hydropower units to cope with the fluctuations of the net load (referring to the user load demand not served by IRESs) when the proportion of IRESs is comparatively low [2].…”