MISO’s Stricter Dispatch Deviation Rules: What Wind and Solar Developers Need to Know

On May 29, 2026, FERC accepted a set of MISO tariff revisions that tighten how the market can penalize resources for diverging from real-time dispatch instructions. The changes, effective June 1, 2026, are aimed at Dispatchable Intermittent Resources, such as wind and solar. For those asset types, MISO has narrowed the tolerance band from 12% to 4% and reduced the window before charges apply from four five-minute intervals to a single five-minute interval. A separate new charge, tied to the congestion a deviation causes, now applies to every resource in the market. The result for wind and solar operators means that the financial cost of straying from a dispatch target is steeper, and the time available to correct course has shortened. In this article, we will outline what has changed, why MISO made the case, and what it means for your wind and solar assets in MISO moving forward.

The center of MISO’s case rests on how much its resource mix has changed over the last few years. The system operator reports that the number of Dispatchable Intermittent Resources in its footprint has grown from roughly 165 in 2019 to about 442 in 2026, while conventional generation has steadily declined. This shift matters because Dispatchable Intermittent Resources ramp quickly, and a large fleet of fast-ramping assets deviating from dispatch at the same time creates the volatility that system operators try to avoid. 

MISO and its Independent Market Monitor attribute this challenge largely to wind resources, citing a mix of forecasting errors and a tendency to disregard dispatch instructions. When resources fail to follow dispatch, MISO says the consequences show up as frequency deviations, forcing control room operators to cap intermittent output or manually redispatch other units.

A brief definition worth mentioning is how MISO classifies a “Dispatchable Intermittent Resource” or DIR. This is a specific designation for wind and solar resources whose maximum output depends on a forecast rather than on a fuel that can be called on at will. Wind has participated under the DIR construct since 2011, and MISO extended it to solar assets in 2020. Battery storage is treated differently, which we will cover in more detail below. The new FERC rules, for the most part, are applicable to wind and solar resources.

To fully understand the changes, it helps to restate the underlying market mechanism. MISO issues a dispatch target to each resource every five minutes. A resource is permitted to operate within a tolerance band around the target without penalty. If it operates outside the band for a defined number of consecutive intervals, it incurs excessive or deficient energy deployment charges. The new order tightens both the width of the band and the number of intervals an asset can operate outside of it. 

What’s New for Wind and Solar

There are several implications for Dispatchable Intermittent Resources:

• Tolerance Bands: For wind and solar assets, the tolerance band was reduced from 12% to 4%. DIRs now have substantially less room to diverge from the dispatch target before additional charges apply. MISO’s existing min and max megawatt bounds on the band (6 MW floor and 30 MW ceiling) continue to apply. Non-DIR resources keep the 12% band.

• Grace Period: The grace period changed from four, five-minute intervals to one. Previously, a resource had to be outside the band for four consecutive intervals before facing a charge. Now, a single, five-minute interval is enough to trigger the charge. MISO instituted this change to combat a pattern of observed resources exceeding dispatch for three intervals and pulling back on the fourth to avoid penalties.
  

• Forecast and Economic Maximums Exemptions: Under the old rules, a DIR using MISO’s forecast, or whose dispatch target equaled its economic maximum, was shielded from these penalties. Now, a unit on the MISO forecast that receives a Reason Code of 2, 3, or 6 (constraint sensitivity, setpoint below economic max, override for reliability) can incur an excessive energy charge even at economic maximum.
  

• Reason Code 3: Deficient energy charges still apply only under Reason Code 3, and only when a resource has been economically curtailed. MISO was explicit that DIRs should not be penalized for under-producing when weather prevents the resource from meeting its target. 

• Excessive Energy Price: The excessive energy price was simplified. For DIRs, the price is now the lesser of the real-time LMP or the resource’s own energy offer at the dispatch target. 

What Changed for All Resources

A new congestion penalty now applies across all generation resources. MISO added a charge component equal to the marginal congestion component of the LMP to reflect the incremental congestion a resource causes when it fails to follow dispatch. This cost component applies to all resources across the system. 

The table below summarizes the changes:

For a wind or solar operator, the significance of these changes can compound if not addressed appropriately. Several practical implications stand out. 

• Response Windows: Under the four-interval rule, an asset had twenty minutes of drift before penalties were triggered. A single interval removes that cushion. Telemetry latency, control response times, and the speed at which an asset achieves a new setpoint are now direct financial risks.

• Forecast Accuracy: With exemptions gone under the key reason codes, leaning on the MISO forecast no longer protects a DIR from excessive energy charges when a curtailment order is in effect. Following the dispatch setpoint accurately (and in real time) becomes paramount to successful operations.

• Workaround Gaps Close: Operators who managed deviation by moving in and out of the band, or by exceeding dispatch for a few consecutive intervals and returning, no longer have that latitude. The one-interval rule catches that behavior and forces compliance.

• Storage: Battery assets participating as electric storage resources under FERC 841 are subject to the new marginal congestion penalty. Following the dispatch protocol for these assets now becomes a settlement issue rather than purely operational. 

MISO’s own data indicates that most DIRs can already operate within the tighter bands. The implication is that compliance is a function of operations, including accurate telemetry, real-time response, and correctly submitted rates and offers.

The through-line of MISO’s order is that telemetry, forecasting, and real-time dispatch response now translate directly into settlement outcomes. As a registered market participant in MISO, SYSO manages the full operational lifecycle for wind, solar, and storage assets, starting with dedicated real-time telemetry connectivity, so assets are genuinely tracking their dispatch targets. Our clients’ assets are managed through our 24/7 NERC-CIP compliant Network Operations Center, where operators monitor dispatch targets and deviation flags through automated alerting. Contact us today to discuss how SYSO can support your MISO assets under the new dispatch deviation rules.