Enhancing Spinning Reserve Scheduling through Ramp Rate Dependent Modeling and Limited Participation: A Scalable Market Design Framework for Grid Reliability

Remaining fossil units, which provide essential reliability services, are aging, further heightening concerns. Strong reliability margins are critical for meeting peak demand, responding to disturbances, and mitigating risks from extreme weather. Narrowing margins increase the risk of outages when resources are unavailable.

This paper focuses on operational improvements for Combined Cycle Gas Turbines (CCGTs) equipped with duct‑firing capability, which enables additional output by burning fuel in the

Heat Recovery Steam Generator (HRSG) exhaust duct. While duct burners can increase steam turbine output by 1–10% of total capacity, transitioning into this operating range requires plant reconfiguration and can take more than 15 minutes. Current reserve scheduling practices rely on a single emergency response rate (ERR), which can overestimate ramp capability in the duct‑firing zone. As a result, CCGTs may fail to deliver scheduled reserves within 10 minutes during contingencies, forcing NYISO to limit their spinning‑reserve participation and shift reserves to more expensive resources.

To address this, we propose a scalable market design framework that incorporates Multiple

Ramp Rates (MRR) for reserve procurement and a limited‑participation mechanism for the 1 duct‑firing zone. This approach aligns reserve schedules with actual ramping capability, prevents infeasible dispatch instructions, and improves reliability without significant cost impacts. Case studies using NYISO’s market simulator confirm that the proposed model enhances operational feasibility, captures otherwise stranded reserves, and supports grid reliability during emergencies.