By Amanda Durish Cook

CARMEL, Ind. — Market participants have united to develop a trio of alternatives to MISO’s plan to crack down on generators that fail to follow dispatch instructions, while the RTO has softened its position on moving ahead with a nearly final proposal.

Stakeholders representing 13 member companies began meeting to address the issue after MISO last November revealed its plan to tighten tolerances for uninstructed deviations based on a generator’s ramp rate. MISO currently flags generators that deviate from dispatch by more than an 8% over four consecutive intervals.

During a Feb. 8 Market Subcommittee meeting, DTE Energy’s Nick Griffin said informal meetings with MISO staff and the Independent Market Monitor to “brainstorm” on the topic have produced three proposals to curb deviations:

• Rely on MISO’s proposal requiring a generator to move at least half its offered ramp rate, but use a more generous ramp rate multiplier;
• Use a standard 6% deviation tolerance from dispatch signals; or
• Employ an “energy mileage” concept that would set a tolerance based on how much electricity a unit actually moved over a one-hour period compared to how much it was asked to move.

Griffin said all three encourage generators to follow dispatch signals.

“We don’t want units to drag on the system and be paid for dragging on the system,” he said.

However, Griffin said MISO’s solution must consider the “operational limits of resources, including wind forecasting and coal mill and boiler feed pump limits.”

Stakeholders have repeatedly called for a softer uninstructed deviation threshold than what MISO is proposing.

Before this month, MISO was close to wrapping up a final approach on stricter rules using Monitor David Patton’s proposal requiring generators to move at half their offered ramp rate, with a 20-minute grace period before being flagged and possibly losing make-whole payments. Last fall, ‎Ameren Missouri urged MISO to keep the percentage threshold, saying it could be constricted to 7 or 6% over time. The company also asked the RTO to focus only on generators that fail to move for an hour after dispatch instructions. (See Ameren Calls for Milder MISO Response to Uninstructed Deviations.)

MISO staff are now offering two new proposals developed after the informal stakeholder meetings. The first is a slightly modified approach of the RTO’s original proposal, with a cap of 12% of the dispatch level instead of the previously proposed 10%, leaving more tolerance for fast-ramping units.

The second is a performance-based approach similar to the “energy mileage” concept that partly decouples MISO’s uninstructed deviation rules from price volatility make-whole payments, preventing a generator’s deviation from immediately triggering ineligibility for those payments. In those instances, MISO would rely on an hourly price volatility make-whole payment calculation based on generator performance, ensuring that unit owners are incentivized to submit accurate ramp rates and then perform to them. The payments are designed for resources that either fail to cover production costs in the market, or have their day-ahead margins eroded by intra-hour price spikes.

MISO Market Quality Manager Jason Howard said the RTO still plans to have a final proposal readied for filing in time for the April subcommittee meeting, and that he would return to the subcommittee in March after gauging stakeholder reception to the two new proposals. MISO is also considering holding a workshop to ensure stakeholders understand what it is proposing, Howard said, although no date has been set.