Flowgate Allocation Method

Examples of Proportional Curtailment of FIRM PTP and GTL

Proportional Curtailment of Firm PTP and Firm GTL – Problem Statement

• Provide equal treatment of FIRM Point-to-Point (PTP) Transaction impacts and FIRM Generation-to-Load (GTL) Impacts during a TLR event– Flowgate allocation does not “downgrade” FIRM PTP and GTL transactions to NON-FIRM– TLR curtailment of FIRM contributions requires the issuance of a TLR-5 or higher– FIRM contributions are NOT curtailed in TLR-3a, TLR-3b and TLR-4

• Allocations are based on forecasted/reserved (Expected) FIRM usage of flowgates up to but not exceeding the flowgate limit– Expected FIRM usage is determined in the Day-Ahead and Hour-Ahead– All Expected FIRM contributions to the flow on the flowgate are included– The total Expected FIRM contributions does not exceed the flowgate limit:

• BAs and TSPs are allocated FIRM limits to their contribution on the flowgate that equals its total Expected FIRM contributions

– The total Expected FIRM contributions exceeds the flowgate limit:• BAs and TSPs are allocated FIRM limits to their contribution on the flowgate proportional to their

contribution• FIRM contributions are placed in two curtailment buckets – LAST TO CUT (LTC) and FIRST TO CUT

(FTC)– Nomenclature:

• PTP transactions: FTC = 7-F LTC = 7-FC• GTL: FTC = 7-FN LTC = 7-FCN

– FIRM contributions in FTC and LTC are determined in real-time based on current system conditions

– LTC: FIRM contributions in the LTC bucket are those that do NOT exceed the Expected FIRM usage of the flowgate for FIRM PTP and GTL impacts

– FTC: FIRM contributions in the FTC bucket are those that exceed the Expected FIRM usage of the flowgate for FIRM PTP and GTL impacts

Proportional Curtailment of Firm PTP and Firm GTL - Example

• Flowgate limit: 500 MW

Entity DA/HA Firm GTL Impact

DA/HA Firm PTP Impact

GTL Firm Limit

PTP Firm Limit

A 150 75

B 160 120 80 60

C 160 80

D 120 200 60 100

E 40 50 20 25

Total 480 520 240 260

1,000 500

Proportional Curtailment of Firm PTP and Firm GTL - Example

• Flowgate limit: 500 MW

Entity GTL Firm Limit

PTP Firm Limit

RT Firm GTL

Impact

RT Firm PTP

Impact

Over (Under)

Allocation

A 75 80 5

B 80 120 40

B 60 50 (10)

C 80 80 0

D 60 100 40

D 100 80 (20)

E 20 10 (10)

E 25 30 5

Total 240 260 310 240 50

500 550

FTC and LTC Calculations• TLR 5-a requires curtailment of 65 MW of FIRM transactions after exhausting all

NON-FIRM curtailments– 65 MW of relief will be provided pro-rata from 90 MW of FTC (7-FC and 7-FCN), using

the same TLR pro-rata formulas– 460 MW of LTC (7-F and 7-FN) are not curtailed

Entity GTL Firm Limit

PTP Firm Limit

RT Firm GTL

Impact

RT Firm PTP

Impact

Over (Under)

Allocation

FTC LTC

A 75 80 5 5 75

B 80 120 40 40 80

B 60 50 (10) 0 50

C 80 80 0 0 80

D 60 100 40 40 60

D 100 80 (20) 0 80

E 20 10 (10) 0 10

E 25 30 5 5 25

Total 240 260 310 240 50 90 460

500 550 550

Proportional Distribution of Under-Allocated Amounts to Over-Allocated GTL/PTP – Issues To Be Resolved

• Sum of all LTC (7-F and 7-FN) in Real-Time can be smaller than the flowgate limit– Only the over-allocated entities/transactions are “penalized” for over-

allocating• Remaining of flowgate limit can be reassigned to over-

allocated entities/transactions so that LTC equals the flowgate limit– Reduces the FTC bucket size– Distribution Proportion Options:

• FIRM limits of over-allocated entities/transactions• Real-Time over-allocation impact• Real-Time impacts• Other

– If TLR-5 cannot be resolved with curtailments from FTC bucket, may need to curtail pro-rata the LTC bucket• Entities/Transaction that do not over-allocate may be curtailed (see next

examples)

Option 2: Proportional Distribution of Under-Allocated Amounts to Over-Allocated GTL/PTP – Proportional to Firm Limit

• Under-allocation from:– Entity B PTP: 10 MW– Entity D PTP: 20 MW– Entity E GTL: 10 MW– Total: 40 MW

• Distribute under-allocation among over-allocating entities:– Entity A PTP: 75 MW– Entity B GTL: 80 MW– Entity D GTL: 60 MW– Entity E PTP: 25 MW– Total: 240 MW

• Allocation Adjustment Ratio: (240+40)/240 = 1.17• Adjusted Firm Limit:

– Entity A PTP: 75 * 1.17 =87.8 MW– Entity B GTL: 80 * 1.17 =93.6 MW– Entity D GTL: 60 * 1.17 =70.2 MW– Entity E PTP: 25 * 1.17 =29.3 MW– Total: 240 MW

Option 2: Proportional Distribution of Under-Allocated Amounts to Over-Allocated GTL/PTP – Proportional to Firm Limit

• Adjustment factor of 1.17 applied to firm limits of over-allocated PTP/GTL (needs iterative process to use all under allocation amounts)

• TLR 5-a requires curtailment of 65MW of FIRM transactions after exhausting all NON-FIRM curtailments– All 56.9 MW of FTC (7-FC and 7-FCN) will be curtailed– 8.1 MW of the 493.1 MW of LTC (7-F and 7-FN) will be curtailed pro-rata

• Total LTC is adjusted to equal total limit of the flowgateEntity GTL

Firm Limit

PTP Firm Limit

RT Firm GTL Impact

RT Firm PTP Impact

Over (Under) Allocation

Adj. GTL F-Limit

Adj. PTP F-Limit

FTC LTC

A 75 80 5 87.8 0 80

B 80 120 40 93.6 26.4 93.6

B 60 50 (10) 50 0 50

C 80 80 0 80 0 80

D 60 100 40 70.2 29.8 70.2

D 100 80 (20) 80 0 80

E 20 10 (10) 10 0 10

E 25 30 5 29.3 0.7 29.3

Total 240 260 310 240 50 253.8 247.1 56.9 493.1

500 550 500.9 550

Option 3: Proportional Distribution of Under-Allocated Amounts to Over-Allocated GTL/PTP – Proportional to Real-Time Over-Allocation

• Under-allocation from:– Entity B PTP: 10 MW– Entity D PTP: 20 MW– Entity E GTL: 10 MW– Total: 40 MW

• Distribute under-allocation among over-allocating entities:– Entity A PTP: 5 MW– Entity B GTL: 40 MW– Entity D GTL: 40 MW– Entity E PTP: 5 MW– Total: 90 MW

• Allocation Adjustment Ratio: 40/90 = 0.44• Adjusted Firm Limit:

– Entity A PTP: 75 + 5*0.44 = 77.2 MW– Entity B GTL: 80 + 40*0.44 = 97.6 MW– Entity D GTL: 60 + 40*0.44 = 77.6 MW– Entity E PTP: 25 + 5*0.44 = 27.2 MW– Total: 279.6 MW

Option 3: Proportional Distribution of Under-Allocated Amounts to Over-Allocated GTL/PTP – Proportional to Real-Time Over Allocation

• Adjustment factor of 0.44 applied to over-allocated firm limits (no iterative process needed)

• TLR 5-a requires curtailment of 65MW of FIRM transactions after exhausting all NON-FIRM curtailments– All 50.4 MW of FTC (7-FC and 7-FCN) will be curtailed– 14.6 MW of the 499.6 MW of LTC (7-F and 7-FN) will be curtailed pro-rata

• Total LTC is adjusted to equal total limit of the flowgateEntity GTL

Firm Limit

PTP Firm Limit

RT Firm GTL Impact

RT Firm PTP Impact

Over (Under) Allocation

Adj. GTL F-Limit

Adj. PTP F-Limit

FTC LTC

A 75 80 5 77.2 2.8 77.2

B 80 120 40 97.6 22.4 97.6

B 60 50 (10) 50 0 50

C 80 80 0 80 0 80

D 60 100 40 77.6 22.4 77.6

D 100 80 (20) 80 0 80

E 20 10 (10) 10 0 10

E 25 30 5 27.2 2.8 27.2

Total 240 260 310 240 50 265.2 234.4 50.4 499.6

500 550 499.6 550