Expected Energy Calculation Example 2

This document is intended to assist SCs with calculating their Expected Energy, or the amount of energy the ISO is expecting of a unit as the result of dispatches issued. The CT 4401 billable quantity and resulting compensation will be based on this expected energy.

Scenario Overview: Generator with an HA Schedule change, Self Providing Losses, Ramping Deviation, and Real Time Supplemental Dispatches.

Schedules: Previous hour’s HA Schedule: 150 MW, OR 150.44 adjusted for SLFL Current hour’s HA Schedule: 493 MW, OR 500.05 adjusted for SLFL Following hour’s HA Schedule: 493 MW, OR 500.36 adjusted for SLFL

ADS Instructions: (in their raw form): TARGET_MINUTE GO_TO SEG_NO MW_CODE OOS_MKT_SEG PRICE MIN_MW MAX_MW 0 150 1 HRLY NOBID 0 150 510 0 150 2 SLFL NOBID 0 150 510 0 150 3 RMPS SUPP 54.43 150 510 0 150 4 RMPS SUPP 91.87 150 510 0 150 5 SUPP SUPP 54.43 150 510 0 150 6 SUPP SUPP 54.43 150 510 0 150 7 SUPP SUPP 91.87 150 510 5 330 1 HRLY NOBID 0 330 510 5 330 2 SLFL NOBID 0 330 510 5 330 3 RMPS SUPP 29.272 330 510 5 330 4 RMPS SUPP 34.272 330 510 5 330 5 RMPS SUPP 54.43 330 510 5 330 6 SUPP SUPP 24.272 330 510 5 330 7 SUPP SUPP 29.272 330 510 25 390 1 HRLY NOBID 0 330 510 25 390 2 SLFL NOBID 0 330 510 25 390 3 TBD SUPP 29.272 330 510 25 390 4 TBD SUPP 34.272 330 510 25 390 5 SUPP SUPP 54.43 330 510 30 392.15 1 HRLY NOBID 0 330 510 30 392.15 2 SLFL NOBID 0 330 510 30 392.15 3 TBD SUPP 29.272 330 510 30 392.15 4 SUPP SUPP 34.272 330 510 30 392.15 5 SUPP SUPP 54.43 330 510 35 452.15 1 HRLY NOBID 0 330 510 35 452.15 2 SLFL NOBID 0 330 510 35 452.15 3 SUPP SUPP 34.272 330 510 35 452.15 4 SUPP SUPP 54.43 330 510 40 510 1 HRLY NOBID 0 330 510 40 510 2 SLFL NOBID 0 330 510 40 510 3 SUPP SUPP 54.43 330 510

Note: TBD (To Be Determined) is an extra marginal energy type used where it is not yet clear to RTMA what energy type it will fall under. In other words, at the time the dispatch went out, RTMA was not sure what category this energy should be classified as. After the fact Expected Energy calculations determine this for settlement. Summary of DOP: GOTO’S To sum the above instructions up in a simpler form for the purpose of TARGET_MINUTE GO_TO establishing the DOP, you can extract the following GOTOs 0 150 from the ADS data: 5 330 25 390 30 392.15 35 452.15 The graph of this example is provided below: 40 510

Expecte d Energy Exam ple 2 M W .1 6 0 0 .83 .59 SUPP SUPP SLFL -1.16 5 0 0 . 0 5 5 1 0 5 1 0 5 0 0 5 0 0 . 0 5 4 9 3 4 9 3 -3.64 -6.49 4 5 2 . 1 5 -10.925 -9 4 1 2 . 6 4 -11.68 4 0 0 3 9 2 . 1 5 .59 -14.18 -14.18 3 9 0 3 9 2 . 1 5 -10.52 SLFL 3 3 0 -3.25 SUPP 3 3 0 3 2 5 . 2 4 3 3 0 SLFL 3 0 0 2 7 5 . 3 8 RMPS -2.07 RMPD 2 0 0 HRLY SCHD

1 0 0 DOP

41.08 0

. 2 7 2 4 . 5 5 2 5 . 1 8 3 8 . 4 1 2 3 4 5 6 7 8 3 8 . 9 9 9 10 11 12 3 9 . 8 2 Interval / Minute

Description of Acronyms

Dispatch Operating Point (DOP) – The expected operating point of a resource as a function of time. The Dispatch Operating Point is the Final Hour-Ahead Schedule as adjusted by transmission loss self-provision, inter-hour schedule-change ramping and explicit Dispatch Instructions including pre-dispatch at minimum load due to the waiver denial process. If a resource has not been issued any Dispatch Instructions, then the Dispatch Operating Point is the Final Hour Ahead Schedule. If a resource has been issued a Dispatch Instruction, then the Dispatch Operating Point includes the expected deviation from the Final Hour Ahead Schedule as a response to the Dispatch Instruction taking into account the relevant operational ramp rate function or the relevant startup time, if applicable.

Standard Ramping Energy (RMPS) -- Energy produced or consumed due to hourly schedule changes. The schedule- change ramp for resources without bids across hours starts at 10 minutes before the beginning of the hour and ends as soon as possible, but not earlier than 10 minutes into the hour and no later than 50 minutes into the hour. A “Standard” Ramping Energy will be calculated for ISO Metered Entities that starts at 10 minutes before the beginning of the hour and ends at 10 minutes after the hour.

Ramping Energy Deviation (RMPD) – A Ramping Energy Deviation is determined for each Dispatch Interval as the difference between the total Ramping Energy and the Standard Ramping Energy. The Ramping Energy Deviation is deemed delivered and will be settled at the Settlement Interval level. Positive Ramping Energy Deviations will be paid the relevant Settlement Interval price and negative Ramping Energy Deviations will be charged the relevant Settlement Interval price. Ramping Energy Deviations are a type of IIE. Ramping Deviation occurs due to physical operating limits or Dispatch Instructions in the previous or following hour.

Self-Provided Losses (SLFL): With the implementation of Phase 1B, SCs are now able to self-provide their units’ losses. If an SC selects the self-provision option, the ISO adds on the expected loss amount to the unit’s schedule so that when the unit runs at the higher value, it will not be deviating from its schedule. This self provided amount is incorporated into the Expected Energy calculation.

Supplemental Energy (SUPP): Energy resulting from a dispatched Supplemental energy bid.

Final HA Schedule (SCHD): Unit’s final schedule as published at the close of the HA market.

Generic Expected Energy Formula Description:

To capture the “energy under the curve”, some basic geometry will be utilized. The formulas for a right triangle, square, and trapezoid are commonly used. While the formulas for triangle and square are generally known, the trapezoid may not be for some. For those that do not recall, the formula for a trapezoid is described below in italics:

If a and b are the lengths of the two parallel bases of a trapezoid, and h is its height, the area of the trapezoid is 1/2 × h × (a + b).

This formula is the numerator portion of the equations utilized in the calculations to follow. In these calculations, the denominator of 60 minutes is used to convert the calculation into MW from MW/minute for the interval in question.

Calculation Description for Settlement Interval 1: The following calculations are done at the Dispatch Interval level. Remember that a Dispatch Interval is 5 minutes, and a Settlement Interval is 10 minutes. Thus, the results of Dispatch Intervals 1 and 2 combine for Settlement Interval 1.

In order to capture the standard ramp for this hour resulting from the schedule change of 150.44 MW up to 500.05 MW, we must establish where the schedule line is on its trajectory (in orange) at the top of the hour. Keep in mind that the beginning point for the current hour’s standard deviation is half way between the previous and current hours schedules (adjusted to capture the unit’s SLFL) or, (150.44 + 500.05) / 2 = 325.24 MW.

Because the Standard Ramp begins 10 minutes before the hour and lasts until 10 minutes after the hour, the standard ramp rate is what will get the unit from 336 to 143 MW in exactly 20 minutes, which is which is (336 – 143) / 20, or 17.48 MW/minute. Thus, the unit will go 17.48 MW/minute for 10 minutes for the remainder of the ramp from minute 0 to minute 10, or 174.8 MW, taking it from 325.24 MW to 500.05 MW. The Standard Ramp Rate will be relevant when calculating the energy under the curve in relation to the changing Dispatched Operating Point, or DOP. For instance, how do we know that at minute 4.55 the standard ramp is at 404.78 MW, and at minute 5 at 412.64? We know because 4.55 minutes @ 17.48 MW/minute = 79.53 MW and 325.24 MW + 79.53 MW = 404.77 MW. We know that 5 minutes @ 17.48 MW/minute = 87.4 MW and 325.24 MW + 87.4 MW = 412.64 MW.

In Settlement Interval 1, the area over the HA schedule and under the standard ramping line is the Standard Ramping Energy (RMPS) amount. The area between the schedule line and the DOP line will be the Expected Supplemental Energy (SUPP), and the energy under the schedule line and under the SUPP is RMPD. At the top of this hour, the unit is sitting below its standard ramp at 275.38 MW, and it’s SUPP dispatch of 330 MW. Until the unit reaches 330 MW, the energy below the 330 MW and the DOP line is RMPD. Once the current hour’s dispatch is reached, the RMPD ends, and the SUPP calculation begins.

The DOP (blue line) begins at where the unit’s telemetry reports it to be at the top of the hour, which is 275.38 MW. By plotting the GOTO amounts received via ADS across the hour, you have the unit’s DOP trajectory.

Self Provided Losses (SLFL) is directly and evenly added to the HA schedule. The HA schedule is at 493 MW and after adding in the SLFL, the unit will actually have a schedule of 500.05 MW. For each dispatch interval, the SLFL calculation is the same; ((500.05 – 493) * 5) / 60 minutes = .59 MW per dispatch interval.

Calculations:

For all intervals, the HA Schedule (HRLY) amount is 493/12= 41.08 MW Dispatch Interval 1 –

RMPS = ((325.24 – 500.05) + (412.64 – 500.05) * 5 min) *.5 60 min = -10.93 MW

RMPD = (((275.38 – 330) * 5 min) / 2) 60 min

= -2.07 MW

SUPP = ((330 – 412.64) * (5 - .272 min))*.5 = 60 min

= -3.25 MW

Dispatch Interval 2 –

RMPS = ((412.64 – 500.05) * 5) *.5 60 min

= -3.64 MW

SUPP = (((330 – 412.64) + (330 – 500.05)) * 5) * .5 MW 60 min

= -10.52 MW

Therefore, the Settlement Details for Settlement Interval 1will have a STD_RAMP_QTY of 14.57 MW (-10.93 + -3.64) and an RT_DISP_QTY of 13.77 MW (-3.25 + -10.52).

Dispatch intervals 3 thru 7, and 9 thru 12 utilize the same principals as detailed for intervals 1 and 2. Apply the calculations provided above to come up with the values located in each energy segment. However, interval 8 has two pieces; the SUPP portion below the actual HA Schedule, and the SUPP portion above the adjusted SLFL area. Both of these yellow SUPP areas must be added together for the total SUPP area.

Dispatch Interval 8 –

SUPP a = ((452.15 – 493) *3.4) *.5 60 min = - 1.16 MW

SUPP b = (((40 min – 38.99 min) + ( 40 – 39.82)) * 9.95) * .5 60 min

Therefore, the SUPP total = (-1.16 + .1), or

= -1.06 MW