Under SMD, the Real-Time dispatch software does not constrain the dispatch to the operating limits if a generator's actual output is not within the operating limits.  The Lead Participant/Designated Entity is responsible for maintaining the operating limits through redeclarations to ISO-NE, and is also responsible for maintaining operation within those operating limits.  

There are instances where the State Estimator solution will, at times, produce values that may differ from the generator's output as measured by field telemetry.  This problem is not an issue when the DDP produced by the dispatch software is within operating limits.  

We recommend that when a generator receives a DDP that is greater than the EcoMax, that the generator instead operate at EcoMax.  We also recommend that when a generator receives a DDP that is less than the EcoMin, that the generator instead operate at EcoMin.  

Please note that operating limits must reflect the physical capability of the generator (unless self-scheduling), and a redeclaration may be the appropriate remedy in certain situations as described in the examples below.  As part of this interim solution, the ISO-NE will be monitoring the Real-Time application of the "Not Following DDP" flags and ensuring that the flags are set appropriately for the dispatch instructions issued.  Generators that received DDPs that are above or below operating limits and continue to operate at the appropriate limit will not be penalized for not following dispatch instructions.  The "Not Following DDP" flags may continue to be seen on the RIG in these instances, but will be removed prior to the settlement process.  This is similar to the approach for Minimum Generation Emergency as described in Manual 11, in the last paragraph of Section 2.5.16.2.

Examples:

General Assumptions: 

EcoMin = 100MW Offer Price at EcoMin is $40/MW

EcoMax = 200 MW Offer Price at EcoMax is $70/MW.

Case A:

Actual output per telemetry = 200 MW

State Estimator Solution = 204 MW

Ex-ante nodal price at the generator node = $80/MWHr

In this case, the UDS solution would produce a DDP of 204 MW because, based on the State Estimator value, the generator is operating above its EcoMax and a DDP back to EcoMax would make the unit less economic relative to the ex-ante nodal dispatch rate.  Based on the interim solution, this generator should operate in this example at 200 MW or redeclare the EcoMax to 204 MW if the generator is physically capable of operation at 204 MW.

Case B:

Actual output per telemetry = 103 MW

State Estimator Solution = 96 MW

Ex-ante nodal price at the generator node = $30/MWHr

In this case, the UDS solution would produce a DDP of 96 MW because, based on the State Estimator value, the generator is operating below its EcoMin and DDP back to EcoMin would make the unit more uneconomic relative to the ex-ante nodal dispatch rate.  Based on the interim solution, this generator should operate in this example at 100 MW or redeclare the EcoMin to 103 MW if physically unable to operate below 103 MW.  Please note, if this generator had submitted a self-schedule and was in this condition, the rules require the generator to operate at the self-schedule or EcoMin, and a redeclaration would not be allowed in this case.

Generator owners are required to schedule any testing or maintenance activity that can impact normal operation or expected availability of their resource(s).  NEPOOL Operating Procedure 5 describes in detail the rules and requirements for the scheduling of generator tests, reductions or outages.

Generator owners are also responsible for submitting bids and offers that reflect or support the testing or maintenance activity being performed.  For example, if an owner has scheduled a test that requires that the generator operate at half load from 10:00 to 12:00, then the generator must submit the following:

• A self-schedule with an EcoMin value set to half load for hours ending 11 and 12.  A self-schedule ensures that the generator will not be dispatched economically below the half load level or EcoMin ensuring that the test can be performed.  When self-scheduling, the generator must recognize the generator parameters, such as minimum runtime, that were submitted to ISO-NE.
• An EcoMax value set to half load for hours ending 11 and 12.  This ensures the unit will not be dispatched economically above the half load level or EcoMax ensuring that the test can be performed.  It also ensures that ISO-NE does not rely on reserve capability above the half load level during the testing activity.

Start-up Times and Minimum Run and Down Times must be adjusted by the Lead Participant/Designated Entity to consider the inability of the SMD commitment software to recognize start-up and shutdown profiles.  In the Interim Market design, the start-up and shutdown times were from synchronization to de-synchronization of the generator.  Once on-line and synchronized per the start-time, the generator then ramped to the economic minimum per the start-up profile and released itself for economic dispatch once that level was achieved.  With SMD, the first hour of operation in the DAM clearing is converted into a start-time, but this time does not include the time to synchronize and the start-up profile.  To ensure that the resource can physically meet the commitment produced  out of the SMD software, the Lead Participant/Designated Entity should adjust the Minimum Down Time parameter to include shut-down and start-up profiles, and could consider excluding these profiles in the Minimum Run Time.  Start-up times may need to be adjusted as well to ensure that the time reflects the total time required from receipt of start-up instruction to operation at EcoMin and released for dispatch.

Another option is to manage availability for dispatch through the use of Maintenance Outage for economic reasons per NEPOOL Operating Procedure 5 processes.  In short, generators can be granted approval to an outage that is for economic reasons provided there is sufficient generation available to meet capacity requirements.  If a request of this type is approved by ISO-NE, the Participant is obligated to make best efforts to restore the Generator to service as requested by ISO-NE in the event of an actual or anticipated OP 4 implementation.

1. Participants bidding LEG resources must, in concert with the ISO-NE Forecasters and in conjunction with the setting of the LEG flag, redeclare the hourly profile of LEG hourly max limits prior to 0001 of the operating day to agreed upon values.  This will ensure that any RAA updates do not overwrite the LEG limits.  Once an initial redeclaration has been entered, updates may be submitted in accordance with rules and procedures.
2. When redeclaring the LEG hourly max limits, the Participants need to make sure that any LEG hourly max limit does not equal the EcoMin in any hour.  At least one MW of separation in limits ensures the unit will not be deemed a "non-dispatchable" LEG unit by the software.  The dispatch software will produce DDP's for non-dispatchable LEG units that are equal to actual output, and if the actual output is above the LEG hourly max limit in this case, the dispatch software will not produce an economic DDP equal to or below the LEG hourly max limit.  
3. Designated Entities should not follow a DDP that violates the LEG hourly max limit unless an electronic or verbal emergency dispatch instruction is received.

• Bid the unit as a LEG resource
• Submit a self-schedule to the DAM that will carry forward the Real-Time Market, or submit a self-schedule into the Real-Time Market (a self-schedule is required for submission of a EcoMin greater than physical capability).
• During the re-offer period, contact the ISO-NE Forecaster and request the LEG option be set to "On" for the resource.  Also confirm during this call the hourly LEG Hourly Max limits you would like enforced during the operating day.

A LEG resource that has the LEG option set to "On" is economically dispatched between the EcoMin (the EcoMin is the self-scheduled value for units with self-schedules) and the LEG Hourly Max limits.  Capability above the LEG Hourly Max up to EcoMax is available for dispatch in emergency conditions only, such as response to a contingency.  There are conditions that have already been identified that will result in the software providing DDPs for economic dispatch outside of the bandwidth between EcoMin and LEG Hourly Max limits. 

An issue has been identified relating to the Real-Time dispatch of LEG resources.  Scenarios may develop where the Desired Dispatch Point (DDP) for a LEG resource may violate an economic dispatch maximum (LEG hourly max limit) and result in an overrun of the maximum energy available for the operating day.  A temporary remedy requires that the Lead Participant/Designated Entity follow the three guidelines listed in the previous FAQ when utilizing the LEG option.

A LEG resource may also submit price-based offers above its self-schedule amount or EcoMin and ration output accordingly.  In these instances, it is generally advisable to contact Market Monitoring if the submitted offers differ from typical offer patters, e.g. if the unit normally self-schedules all output but begins to submit price-based offers designed to ration limited available MWs.