May 22, 2017

By Electronic Delivery

Honorable Kimberly D. Bose, Secretary Federal Energy Regulatory Commission 888 First Street, NE

Washington, DC 20426

Re: Docket No. ER17-1629-000, Niagara Mohawk Power Corporation d/b/a
National Grid - Ministerial Correction to Proposed Tariff Revisions

Dear Secretary Bose:

On May 19, 2017, the New York Independent System Operator, Inc. (“NYISO”), in its

role as Tariff Administrator, submitted a filing on behalf of Niagara Mohawk Power Corporation
d/b/a National Grid (“National Grid”) in the above referenced docket proposing the
establishment of a new Rate Schedule 17 to the NYISO Open Access Transmission Tariff
(“OATT”).1 After submission of the initial filing, the NYISO identified an inadvertent
administrative error with respect to the manner in which the proposed revisions to the OATT
were submitted for purposes of the Federal Energy Regulatory Commission (“FERC” or
“Commission”) eTariff system. The NYISO misidentified the location of the new Rate Schedule
within its OATT.

The NYISO hereby submits this filing to correct this ministerial error and properly

identify the location of National Grid’s proposed new rate schedule as following Section 6.16 of the OATT within FERC’s eTariff system. There are no changes to the May 19, 2017 filing letter or National Grid’s proposed Rate Schedule 17.

I.Documents Submitted

The NYISO respectfully submits the following document with this filing letter:

1. A clean version of the proposed Rate Schedule 17 as filed on May 19, 2017
(“Attachment I”); and

1 Docket No. ER17-1629-000, Niagara Mohawk Power Corporation d/b/a National Grid,
Western New York Facilities Charge Rate Schedule under the NYISO OATT (May 19, 2017).
Capitalized terms not otherwise defined herein shall have the meaning specified in Section 1 of the
OATT.

Honorable Kimberly D. Bose May 22, 2017

Page 2

2. A blacklined version of the proposed Rate Schedule 17 as filed on May 19, 2017
(“Attachment II”).

II.Proposed Effective Date

In its May 19, 2017 filing, National Grid requested an effective date of July 19, 2017
(i.e., 61 days after filing). In addition, the Combined Notice of Filings #1 issued by the
Commission on May 19, 2017 established a comment deadline of 5 p.m. ET on June 9, 2017
with respect to National Grid’s May 19, 2017 filing. Because this filing merely corrects a
ministerial error in FERC’s eTariff system and has no substantive impact on National Grid’s
May 19, 2017 filing letter or the proposed tariff revisions submitted therewith, it is respectfully
requested that: (i) National Grid’s previously requested effective date (i.e., July 19, 2017) be
retained; and (ii) the Commission’s previously established comment deadline remain unaltered.

III.Service

The NYISO will send an electronic link to this filing to: (i) the official representative of
each party to this proceeding; (ii) the official representative of each of its customers; (iii) each
participant on its stakeholder committees; (iv) the New York State Public Service Commission;
and (v) the New Jersey Board of Public Utilities. In addition, the complete filing will be posted
on the NYISO’s website at www.nyiso.com.

IV.Conclusion

The NYISO respectfully requests that the Commission accept this ministerial correction.
Respectfully submitted,

/s/ Garrett E. Bissell

Garrett E. Bissell
Senior Attorney

New York Independent System Operator, Inc.

10 Krey Blvd.

Rensselaer, New York 12144 518-356-6107

gbissell@nyiso.com

cc:Michael BardeeLarry Parkinson

Nicole BuellJ. Arnold Quinn

Anna CochraneDouglas Roe

Kurt LongoKathleen Schnorf

David MorenoffJamie Simler

Daniel NowakGary Will

6.17Schedule 17 - Rate Mechanism for the Recovery of the Western New York

Facilities Charge for Non-Bulk Transmission Facilities (“WNY-FC”)

6.17.1Applicability

6.17.1.1 Eligible Projects

This Schedule establishes the Western New York Facilities Charge (“WNY-FC”) for the recovery of the costs of certain upgrades to non-bulk transmission facilities related to any Public Policy Transmission Project that are eligible for cost recovery in accordance with the
Comprehensive System Planning Process requirements set forth in Attachment Y of the ISO
OATT.1 Niagara Mohawk Power Corporation (“NMPC”) may recover through the WNY-FC
the costs that it is eligible to recover pursuant to Attachment Y of the ISO OATT related to
certain upgrades to NMPC non-bulk transmission facilities in connection with a Public Policy
Transmission Project that the ISO has selected pursuant to Section 31.4.8.2 of Attachment Y of the ISO OATT as the more efficient or cost-effective solution to Western New York Public
Policy Transmission Need. The “Western New York Public Policy Transmission Need” relates to congestion relief in Western New York identified by the NYPSC on July 20, 2015 and
October 13, 2016, in NYPSC Case No. 14-E-0454.

The specific upgrades to NMPC non-bulk transmission facilities to address the Western
New York Public Policy Transmission Need (the “WNY Ancillary Upgrades.”) shall be
identified by the ISO in the Public Policy Transmission Planning Report for those needs.

1 Capitalized terms used in this Schedule that are not defined in this Schedule shall have the meaning set
forth in Section 31.1.1 of Attachment Y of the ISO OATT and, if not therein, in Section 1 of the OATT.

6.17.1.2 Projects Not Eligible for Cost Recovery Through the WNY-FC

This Schedule does not apply to projects that are not eligible pursuant to Attachment Y of
the ISO OATT for cost allocation and recovery under the ISO OATT, including, but not limited
to: (i) projects undertaken by Transmission Owners through the Local Transmission Owner
Planning Processes pursuant to Section 31.1.3 and Section 31.2.1 of Attachment Y of the ISO
OATT; (ii) market-based solutions to transmission needs identified in the CSPP; (iii) any non-
transmission components of an Eligible Project (e.g., generation, energy efficiency, or demand
response resources); (iv) transmission Generator Deactivation Solutions selected in the Generator
Deactivation Process pursuant to Attachment FF of the ISO OATT and eligible for cost recovery
through Schedule 16 (Section 6.16) of the ISO OATT; (v) transmission facilities eligible for cost
recovery through another rate schedule of the ISO OATT; and (vi) facilities for which costs are
recovered through the Transmission Service Charge (“TSC”) or the NYPA Transmission
Adjustment Charge (“NTAC”) determined in accordance with Attachment H of the ISO OATT.

6.17.2Revenue Requirement for WNY-FC

The WNY-FC shall be calculated in accordance with the formula set forth in Section

6.17.3. The costs that may be included in the WNY-FC revenue requirement include all

reasonably incurred costs related to the preparation of proposals for, and the development,

financing, construction, operation, and maintenance of, the WNY Ancillary Upgrades, including,
but not limited to, a reasonable return on investment and any incentives for the construction of
transmission projects approved under Section 205 or Section 219 of the Federal Power Act and
the Commission’s regulations implementing those sections, as determined by the Commission.

6.17.3Calculation and Recovery of WNY-FC and Payment of Recovered Revenue

6.17.3.1The ISO will calculate and bill the WNY-FC separately for the WNY

Ancillary Upgrades in accordance with this Section 6.17.3. The ISO shall collect
the WNY-FC from LSEs. The LSEs, including Transmission Owners,
competitive LSEs, municipal systems, and any other LSEs, serving Load in the
Load Zones and/or Subzones to which the costs of the WNY Ancillary Upgrades
have been allocated (each a “Responsible LSE”) shall pay the WNY-FC. The
costs of the WNY Ancillary Upgrades shall be allocated in accordance with the
Commission-approved cost allocation methodology for the Public Policy
Transmission Project selected to address Western New York Public Policy
Transmission Need in accordance with Section 31.5.5 of Attachment Y of the ISO
OATT.

6.17.3.2 The WNY-FC revenue requirement shall be calculated as follows: The

annual WNY-FC revenue requirement shall equal the annual Historical

Transmission Revenue Requirement (“HTRR”) for NMPC’s TSC divided by

NMPC’s gross transmission plant in service multiplied by the gross transmission
plant in service for the WNY Ancillary Upgrades. For purposes of this
calculation:

(a)NMPC’s HTRR is equal to Attachment 1 to Attachment H, Schedule 1,

line 17.

(b)NMPC’s gross transmission plant is equal to Attachment 1 to Attachment

H, Schedule 6, page 2 of 2, line 3.

In addition, to the extent that the revenues received for the WNY

Ancillary Upgrades in the prior year were greater (or less) than the annual WNY-

FC revenue requirement for the year, the current year’s WNY-FC revenue

requirement will be decreased (or increased) by that difference. The annual

WNY-FC revenue requirement will be the basis for the applicable WNY-FC Rate
($/MWh) for the Billing Period that shall be charged by the ISO to each
Responsible LSE based on its Actual Energy Withdrawals as set forth in Section

6.17.3.5.

6.17.3.3 NMPC shall request Incremental TCCs with respect to the WNY Ancillary

Upgrades in accordance with the requirements of Section 19.2.4 of Attachment M of
the ISO OATT and receive any Incremental TCCs to the extent awarded by the ISO
pursuant to such request. As it relates solely to the WNY Ancillary Upgrades,
NMPC shall not be a “Transmission Owner” for purposes of Section 20.2.5 or
Section 20.3.7 of Attachment N of the ISO OATT and accordingly shall not receive
an allocation of Net Congestion Rents under Section 20.2.5 of Attachment N of the
ISO OATT or Net Auction Revenues under Section 20.3.7 of Attachment N of the
ISO OATT.

Upgrades, shall be offered by NMPC in all rounds of the six month Sub-Auction of each Centralized TCC Auction conducted by the ISO. The ISO shall disburse the associated auction revenues to NMPC. The total amount of the auction
revenues disbursed to NMPC pursuant to this Section 6.17.3.3 shall be used in the calculation of the WNY-FC Rate, as set forth in Section 6.17.3.5. Incremental
TCCs associated with the WNY Ancillary Upgrades shall continue to be offered
for the duration of the Incremental TCCs, established pursuant to the terms of
Attachment M of the ISO OATT.

The revenue offset discussed in this Section 6.17.3.3 shall commence

upon the first payment of revenues related to Incremental TCCs associated with the implementation of the WNY Ancillary Upgrades on or after the date the
WNY-FC is implemented. The WNY-FC and the revenue offset related to
Incremental TCCs associated with the implementation of the WNY Ancillary
Upgrades shall not require and shall not be dependent upon a reopening or review of: (i) NMPC’s revenue requirements for charges set forth in another rate
schedule of the ISO OATT, or (ii) NMPC’s revenue requirements for its TSC set forth in Attachment H of the ISO OATT.

6.17.3.3.1 With respect to the WNY Ancillary Upgrades only, NMPC shall receive

the outage charges specific to Incremental TCCs as described herein and shall not
be charged O/R-t-S Congestion Rent Shortfall Charges, U/D Congestion Rent
Shortfall Charges, O/R-t-S Auction Revenue Shortfall Charges or U/D Auction
Revenue Shortfall Charges or be paid O/R-t-S Congestion Rent Surplus
Payments, U/D Congestion Rent Surplus Payments, O/R-t-S Auction Revenue

Surplus Payments or U/D Auction Revenue Surplus Payments under Section

20.2.4 and Section 20.3.6 of Attachment N of the ISO OATT. Outage charges related to any Incremental TCCs awarded by the ISO for the WNY Ancillary Upgrades shall be separately assessed to NMPC as an Expander not subject to Section 20.2.5 of Attachment N of the ISO OATT, and payable by NMPC to the ISO, pursuant to Section 19.2.4 of Attachment M of the ISO OATT for any hour in the Day-Ahead Market during which the WNY Ancillary Upgrades are
modeled to be wholly or partially out of service.

6.17.3.4 The billing units for the WNY-FC Rate for the Billing Period shall be

based on the Actual Energy Withdrawals available for the current Billing Period for those Load Zones and/or Subzones allocated the costs of the project in the manner described in Section 6.17.3.1.

6.17.3.5 Cost Recovery Methodology

The ISO shall calculate the WNY-FC for each Responsible LSE as follows:

Step 1: Calculate the $ assigned to each Load Zone or Subzone (as applicable)

Step 2: Calculate a per-MWh Rate for each Load Zone or Subzone (as applicable)

Step 3: Calculate charge for each Billing Period for each Responsible LSE in each
Load Zone or Subzone (as applicable)

Step 4: Calculate charge for each Billing Period for each Responsible LSE across all
Load Zones or Subzones (as applicable)

Where,

l = the relevant Responsible LSE;
p = the WNY Ancillary Upgrades;

z = an individual Load Zone or Subzone, as applicable; Z = set of ISO Load Zones or Subzones, as applicable; B = the relevant Billing Period;

= Actual Energy Withdrawals in Load Zone or Subzone, as applicable, z aggregated across all hours in Billing Period B;

= Actual Energy Withdrawals for Responsible LSE l in Load Zone or Subzone, as applicable, z aggregated across all hours in Billing Period B;

= the pro rata share of the annual revenue requirement for the WNY Ancillary Upgrades as set forth in 6.17.3.2 above, allocated for Billing Period B;

= the auction revenue derived from the sale of

Incremental TCCs plus Incremental TCC payments received by NMPC pursuant to Section

20.2.3 of Attachment N of the ISO OATT for the WNY Ancillary Upgrades, as discussed in

Section 6.17.3.3 above, allocated for Billing Period B. The revenues from the sale of

Incremental TCCs in the ISO’s six month Sub-Auctions of each Centralized TCC Auction shall be allocated uniformly across all hours of the Billing Period;

OutageCostAdjustmentp,B = the Outage charges determined pursuant to Section 6.17.3.3.1 above
for any hour in the Day-Ahead Market during which the WNY Ancillary Upgrades are modeled
to be wholly or partially out of service aggregated across all hours in Billing Period B; and

ZonalCostAllocationz,p = the proportion of the cost of the WNY Ancillary Upgrades allocated to
Load Zone or Subzone, as applicable, z, in the manner described in Section 6.17.3.1 above.

6.17.3.6 The ISO will collect the appropriate WNY-FC revenues each Billing

Period and remit those revenues to NMPC in accordance with the ISO’s billing and settlement procedures.

6.17.3.7Payments received by NMPC for the WNY-FC will be treated as a

revenue credit in the revenue requirement for NMPC’s TSC. After considering the revenue credit from the WNY-FC, the net cost for the WNY Ancillary
Upgrades recovered through the TSC will be deemed to be zero.

6.17.3.8 NMPC shall recalculate the WNY-FC revenue requirement each year as

part of the Annual Update process set forth in Section 14.1.9.4 of Attachment H
of the ISO OATT. The WNY-FC revenue requirement shall be separately stated
in that Annual Update, and the Annual Update shall provide supporting
documentation for the calculation of the WNY-FC revenue requirement for the
Update Year. Each Responsible LSE paying the WNY-FC shall be an “Interested
Party” with respect to any portion of the Annual Update related to the WNY-FC.
The WNY-FC revenue requirement for the first year after the WNY Ancillary
Upgrades are placed in service will be calculated retroactively to the in-service
date. The ISO shall commence charging the WNY-FC beginning with the first
billing period for the next effective Update Year, as such term is defined in
Section 14.1.9.1.66 of Attachment H of the ISO OATT, after the WNY Ancillary
Upgrades are placed into service.

6.17Schedule 17 - Rate Mechanism for the Recovery of the Western New York

Facilities Charge for Non-Bulk Transmission Facilities (“WNY-FC”)

6.17.1Applicability

6.17.1.1 Eligible Projects

6.17.1.2 Projects Not Eligible for Cost Recovery Through the WNY-FC

This Schedule does not apply to projects that are not eligible pursuant to Attachment Y of
the ISO OATT for cost allocation and recovery under the ISO OATT, including, but not limited

to: (i) projects undertaken by Transmission Owners through the Local Transmission Owner
Planning Processes pursuant to Section 31.1.3 and Section 31.2.1 of Attachment Y of the ISO
OATT; (ii) market-based solutions to transmission needs identified in the CSPP; (iii) any non-
transmission components of an Eligible Project (e.g., generation, energy efficiency, or demand
response resources); (iv) transmission Generator Deactivation Solutions selected in the Generator
Deactivation Process pursuant to Attachment FF of the ISO OATT and eligible for cost recovery
through Schedule 16 (Section 6.16) of the ISO OATT; (v) transmission facilities eligible for cost
recovery through another rate schedule of the ISO OATT; and (vi) facilities for which costs are
recovered through the Transmission Service Charge (“TSC”) or the NYPA Transmission
Adjustment Charge (“NTAC”) determined in accordance with Attachment H of the ISO OATT.

6.17.2Revenue Requirement for WNY-FC

The WNY-FC shall be calculated in accordance with the formula set forth in Section

6.17.3. The costs that may be included in the WNY-FC revenue requirement include all

reasonably incurred costs related to the preparation of proposals for, and the development,

6.17.3Calculation and Recovery of WNY-FC and Payment of Recovered Revenue

6.17.3.1The ISO will calculate and bill the WNY-FC separately for the WNY

Load Zones and/or Subzones to which the costs of the WNY Ancillary Upgrades
have been allocated (each a “Responsible LSE”) shall pay the WNY-FC. The
costs of the WNY Ancillary Upgrades shall be allocated in accordance with the
Commission-approved cost allocation methodology for the Public Policy
Transmission Project selected to address Western New York Public Policy
Transmission Need in accordance with Section 31.5.5 of Attachment Y of the ISO
OATT.

6.17.3.2 The WNY-FC revenue requirement shall be calculated as follows: The

annual WNY-FC revenue requirement shall equal the annual Historical

Transmission Revenue Requirement (“HTRR”) for NMPC’s TSC divided by

NMPC’s gross transmission plant in service multiplied by the gross transmission
plant in service for the WNY Ancillary Upgrades. For purposes of this
calculation:

(a)NMPC’s HTRR is equal to Attachment 1 to Attachment H, Schedule 1,

line 17.

(b)NMPC’s gross transmission plant is equal to Attachment 1 to Attachment

H, Schedule 6, page 2 of 2, line 3.

In addition, to the extent that the revenues received for the WNY

Ancillary Upgrades in the prior year were greater (or less) than the annual WNY-
FC revenue requirement for the year, the current year’s WNY-FC revenue
requirement will be decreased (or increased) by that difference. The annual
WNY-FC revenue requirement will be the basis for the applicable WNY-FC Rate
($/MWh) for the Billing Period that shall be charged by the ISO to each

Responsible LSE based on its Actual Energy Withdrawals as set forth in Section

6.17.3.5.

6.17.3.3 NMPC shall request Incremental TCCs with respect to the WNY Ancillary

NMPC shall in relation to the WNY Ancillary Upgrades exercise its right
to obtain and maintain in effect all Incremental TCCs, including temporary
Incremental TCCs, to which it has rights under Section 19.2.4 of Attachment M of
the ISO OATT and shall take the actions required to do so in accordance with the
procedures specified therein. Notwithstanding Sections 19.2.4.7 and 19.2.4.8 of
Attachment M of the ISO OATT, Incremental TCCs created and awarded to
NMPC as a result of implementation of the WNY Ancillary Upgrades shall not be
eligible for sale in Secondary Markets. Incremental TCCs that may be created
and awarded to NMPC as a result of the implementation of the WNY Ancillary
Upgrades, shall be offered by NMPC in all rounds of the six month Sub-Auction
of each Centralized TCC Auction conducted by the ISO. The ISO shall disburse
the associated auction revenues to NMPC. The total amount of the auction
revenues disbursed to NMPC pursuant to this Section 6.17.3.3 shall be used in the

calculation of the WNY-FC Rate, as set forth in Section 6.17.3.5. Incremental TCCs associated with the WNY Ancillary Upgrades shall continue to be offered for the duration of the Incremental TCCs, established pursuant to the terms of Attachment M of the ISO OATT.

The revenue offset discussed in this Section 6.17.3.3 shall commence

6.17.3.3.1 With respect to the WNY Ancillary Upgrades only, NMPC shall receive

Section 20.2.5 of Attachment N of the ISO OATT, and payable by NMPC to the ISO, pursuant to Section 19.2.4 of Attachment M of the ISO OATT for any hour in the Day-Ahead Market during which the WNY Ancillary Upgrades are
modeled to be wholly or partially out of service.

6.17.3.4 The billing units for the WNY-FC Rate for the Billing Period shall be

based on the Actual Energy Withdrawals available for the current Billing Period for those Load Zones and/or Subzones allocated the costs of the project in the manner described in Section 6.17.3.1.

6.17.3.5 Cost Recovery Methodology

The ISO shall calculate the WNY-FC for each Responsible LSE as follows:

Step 1: Calculate the $ assigned to each Load Zone or Subzone (as applicable)

Step 2: Calculate a per-MWh Rate for each Load Zone or Subzone (as applicable)

Step 3: Calculate charge for each Billing Period for each Responsible LSE in each
Load Zone or Subzone (as applicable)

Step 4: Calculate charge for each Billing Period for each Responsible LSE across all
Load Zones or Subzones (as applicable)

Where,

l = the relevant Responsible LSE;
p = the WNY Ancillary Upgrades;

z = an individual Load Zone or Subzone, as applicable; Z = set of ISO Load Zones or Subzones, as applicable; B = the relevant Billing Period;

= Actual Energy Withdrawals in Load Zone or Subzone, as applicable, z aggregated across all hours in Billing Period B;

= Actual Energy Withdrawals for Responsible LSE l in Load Zone or Subzone, as applicable, z aggregated across all hours in Billing Period B;

= the pro rata share of the annual revenue requirement for the WNY Ancillary Upgrades as set forth in 6.17.3.2 above, allocated for Billing Period B;

= the auction revenue derived from the sale of

Incremental TCCs plus Incremental TCC payments received by NMPC pursuant to Section

20.2.3 of Attachment N of the ISO OATT for the WNY Ancillary Upgrades, as discussed in

Section 6.17.3.3 above, allocated for Billing Period B. The revenues from the sale of

Incremental TCCs in the ISO’s six month Sub-Auctions of each Centralized TCC Auction shall be allocated uniformly across all hours of the Billing Period;

ZonalCostAllocationz,p = the proportion of the cost of the WNY Ancillary Upgrades allocated to
Load Zone or Subzone, as applicable, z, in the manner described in Section 6.17.3.1 above.

6.17.3.6 The ISO will collect the appropriate WNY-FC revenues each Billing

Period and remit those revenues to NMPC in accordance with the ISO’s billing and settlement procedures.

6.17.3.7 Payments received by NMPC for the WNY-FC will be treated as a

6.17.3.8NMPC shall recalculate the WNY-FC revenue requirement each year as

CERTIFICATE OF SERVICE

I hereby certify that I have this day served the foregoing document upon each person

designated on the official service list compiled by the Secretary in this proceeding in accordance
with the requirements of Rule 2010 of the Rules of Practice and Procedure, 18 C.F.R. §
385.2010.

Dated at Rensselaer, NY this 22nd day of May 2017.

By:/s/ John C. Cutting

John C. Cutting

New York Independent System Operator, Inc.

10 Krey Blvd.

Rensselaer, NY 12144 (518) 356-7521