The demand for energy varies constantly. To maintain the appropriate balance of power we adjust – often referred to as ramping up or down - generation output to match the real-time fluctuations in consumer demand. In industry parlance, this energy balancing act is often referred to as following load.
The Load Following Challenge
Today generation units are scheduled on a 5-minutes basis to provide the most economic solution to the expected level of variation in net load – total consumer demand less non-controllable generation and net system imports. Unanticipated deviations from the expected net load or high rates of change in net load beyond our 5-minute dispatch horizon can hinder our ability to get needed generation to ramp up quickly enough to help meet high demand. This in turn, could lead to a short-term scarcity. The continual addition of more intermittent resources and the requests from MISO stakeholders for more flexibility in scheduling practices makes this challenge even more important to address.
A Comprehensive Market Solution
We are working to provide a determined quantity of ramp capability from dispatchable generation resources to respond to the expected variability and unexpected variations of net load. Applying these determinations in the Day-Ahead and Real-Time markets helps us cost-effectively dispatch the most efficient resources to handle load swings. Our model will increase the robustness of system operations for a wider range of potential operating conditions and reduce the frequency of short-term scarcity conditions.
Ramp Capability Model
Key features of the new model include:
- Ramp capability requirements (system-wide and zonal, if required) - large enough to address the desired level of expected variability and uncertainty in the net load within a defined response time.
- Resource contribution to ramp capability, allowing for availability offers and contributions from offline units, if desired.
- Ramp capability demand curve to model the costs of not meeting the desired level variability coverage.
- Simultaneous co-optimization of the ramp capability with energy and ancillary services.
With the ramp capability model, we can accommodate our current 5-minute dispatch process or our proposed Look Ahead Dispatch, which would allow for a multi-interval market dispatch mechanism. Together these tools allow us to utilize the existing generation fleet more efficiently.
Learn more about Look-Ahead Dispatch