January 1, 2021 Outage Coordination To: NEPOOL Participants From

2021-2023 Current Year and First Future Year Annual Maintenance Schedule

January 1, 2021

Outage Coordination

To: NEPOOL Participants

From: Rachel Wilkins-Thurman

Subject: 2021-2023 Current Year and First Future Year Annual Maintenance Schedule

Following this transmittal letter, you will find the current ISO New England Annual Maintenance Schedule (AMS) dated January 1, 2021 which reflects all planned resource outage requests as well as long duration Forced Outages for January 9, 2021 – January 13, 2023 as of December 29, 2020.

Each company submitting resource outage requests should consider the data market sensitive in accordance with the ISO New England Information Policy, which can be found at: http://www.iso- ne.com/static-assets/documents/regulatory/tariff/attach_d/attachment_d.pdf

2021-23 OPERABLE CAPACITY ANALYSIS The two-year Operable Capacity Analysis presently forecasts the lowest Long Term Operable Capacity Margin (LTOCM) for the next 12 months as follows:

• Winter 2021: 2,535 MW for week beginning January 9, 2021 • Spring 2021: 4,313 MW for week beginning April 10, 2021 • Summer 2021: -612 MW for week beginning September 11, 2021 • Fall 2021: 206 MW for week beginning September 25, 2021

If you have any questions concerning this edition of the AMS or Operable Capacity Analysis, contact Long- term Outage Coordination by email at [email protected].

ISO New England Inc. iso-ne.com One Sullivan Road isonewswire.com

Holyoke, MA 01040 -2841 @isonewengland

iso-ne.com/isotogo ISO-NE PUBLIC iso-ne.com/isoexpress

ISO-NE 2021-23 OPERABLE CAPACITY ANALYSIS January 1, 2021 - 50-50 FORECAST using CSO MW This analysis is a tabulation of weekly assessments shown in one single table. The information shows the operable capacity situation under assumed conditions for each week. It is not expected that the system peak will occur every week during June, July, August, and Mid September.

STUDY EXTERNAL NON PLANNED ALLOWANCE FOR GEN AT RISK OPER RESERVE WEEK (Week AVAILABLE Active Capacity NODE AVAIL COMMERCIAL OUTAGES CSO UNPLANNED DUE TO GAS NET OPCAP PEAK LOAD REQUIREMENT NET LOAD OPCAP MARGIN Beginning, OPCAP MW Demand MW CAPACITY MW CAPACITY MW MW OUTAGES MW SUP MW SUPPLY MW FORECAST MW MW OBLIGATION MW MW Saturday) [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] 1/9/2021 30,425 441 1,130 19 322 2,800 3,887 25,006 20,166 2,305 22,471 2,535 1/16/2021 30,425 441 1,130 19 457 2,800 3,641 25,117 20,166 2,305 22,471 2,646 1/23/2021 30,425 441 1,130 19 380 2,800 3,269 25,566 19,933 2,305 22,238 3,328 1/30/2021 30,418 427 1,142 19 336 3,100 2,958 25,612 19,933 2,305 22,238 3,374 2/6/2021 30,418 427 1,142 19 222 3,100 2,646 26,038 19,652 2,305 21,957 4,081 2/13/2021 30,418 427 1,142 19 684 3,100 2,335 25,887 19,622 2,305 21,927 3,960 2/20/2021 30,418 427 1,142 19 657 3,100 1,868 26,381 19,346 2,305 21,651 4,730 2/27/2021 30,459 533 1,025 19 1,279 2,200 1,502 27,055 18,308 2,305 20,613 6,442 3/6/2021 30,459 533 1,025 19 1,943 2,200 1,190 26,703 17,941 2,305 20,246 6,457 3/13/2021 30,459 533 1,025 19 2,209 2,200 318 27,309 17,736 2,305 20,041 7,268 3/20/2021 30,459 533 1,025 19 1,737 2,200 0 28,099 17,352 2,305 19,657 8,442 3/27/2021 30,446 537 1,025 19 977 2,700 0 28,350 16,759 2,305 19,064 9,286 4/3/2021 30,446 537 1,025 19 4,974 2,700 0 24,353 16,134 2,305 18,439 5,914 4/10/2021 30,446 537 1,025 19 6,839 2,700 0 22,488 15,870 2,305 18,175 4,313 4/17/2021 30,446 537 1,025 19 6,662 2,700 0 22,665 15,335 2,305 17,640 5,025 4/24/2021 30,446 537 1,025 19 4,679 2,700 0 24,648 15,057 2,305 17,362 7,286 5/1/2021 30,446 537 1,025 19 4,759 3,400 0 23,868 15,029 2,305 17,334 6,534 5/8/2021 30,446 537 1,025 19 3,489 3,400 0 25,138 18,118 2,305 20,423 4,715 5/15/2021 30,446 537 1,025 19 2,815 3,400 0 25,812 19,152 2,305 21,457 4,355 5/22/2021 30,446 537 1,025 19 1,428 3,400 0 27,199 20,113 2,305 22,418 4,781 5/29/2021 29,078 520 1,208 19 511 2,800 0 27,514 24,981 2,305 27,286 228 6/5/2021 29,078 520 1,208 19 15 2,800 0 28,010 24,981 2,305 27,286 724 6/12/2021 29,078 520 1,208 19 35 2,800 0 27,990 24,981 2,305 27,286 704 6/19/2021 29,078 520 1,208 19 15 2,800 0 28,010 24,981 2,305 27,286 724 6/26/2021 29,078 520 1,208 19 15 2,800 0 28,010 24,981 2,305 27,286 724 7/3/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 7/10/2021 29,078 520 1,208 19 35 2,100 0 28,690 24,981 2,305 27,286 1,404 7/17/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 7/24/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 7/31/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 8/7/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 8/14/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 8/21/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 8/28/2021 29,078 520 1,208 19 15 2,100 0 28,710 24,981 2,305 27,286 1,424 9/4/2021 29,078 520 1,208 19 1,315 2,100 0 27,410 24,981 2,305 27,286 124 9/11/2021 29,078 520 1,208 19 2,051 2,100 0 26,674 24,981 2,305 27,286 -612 9/18/2021 29,078 520 1,208 19 3,285 2,100 0 25,440 20,759 2,305 23,064 2,376 9/25/2021 29,458 520 1,135 19 5,159 2,800 0 23,173 20,662 2,305 22,967 206 10/2/2021 29,458 520 1,135 19 7,894 2,800 0 20,438 14,921 2,305 17,226 3,212 10/9/2021 29,458 520 1,135 19 6,285 2,800 0 22,047 14,959 2,305 17,264 4,783 10/16/2021 29,458 520 1,078 19 6,129 2,800 0 22,146 15,941 2,305 18,246 3,900 10/23/2021 29,458 520 1,135 19 6,239 2,800 0 22,093 16,329 2,305 18,634 3,459 10/30/2021 29,458 520 1,135 19 3,728 3,600 0 23,804 16,548 2,305 18,853 4,951 11/6/2021 29,458 520 1,135 19 2,866 3,600 78 24,588 16,671 2,305 18,976 5,612 11/13/2021 29,458 520 1,135 19 1,866 3,600 816 24,850 17,037 2,305 19,342 5,508 11/20/2021 29,458 520 1,135 19 1,324 3,600 1,426 24,782 17,822 2,305 20,127 4,655 11/27/2021 29,458 520 1,135 19 756 3,600 2,038 24,738 18,587 2,305 20,892 3,846 12/4/2021 29,482 521 1,135 19 584 3,200 2,206 25,167 18,906 2,305 21,211 3,956 12/11/2021 29,482 521 1,135 19 312 3,200 2,685 24,960 19,213 2,305 21,518 3,442 12/18/2021 29,482 521 1,135 19 292 3,200 2,908 24,757 19,224 2,305 21,529 3,228 12/25/2021 29,482 521 1,135 19 292 3,200 3,269 24,396 19,291 2,305 21,596 2,800 1/1/2022 29,482 521 1,135 19 292 2,800 3,892 24,173 19,581 2,305 21,886 2,287 1/8/2022 29,482 521 1,135 19 292 2,800 3,887 24,178 20,075 2,305 22,380 1,798 1/15/2022 29,482 521 1,135 19 292 2,800 3,736 24,329 20,075 2,305 22,380 1,949 1/22/2022 29,482 521 1,135 19 292 2,800 3,269 24,796 20,075 2,305 22,380 2,416 1/29/2022 29,482 521 1,135 19 292 3,100 2,958 24,807 19,839 2,305 22,144 2,663 2/5/2022 29,482 521 1,135 19 292 3,100 2,646 25,119 19,555 2,305 21,860 3,259 2/12/2022 29,482 521 1,135 19 292 3,100 2,335 25,430 19,524 2,305 21,829 3,601 2/19/2022 29,482 521 1,135 19 292 3,100 1,868 25,897 19,246 2,305 21,551 4,346 2/26/2022 29,482 521 1,135 19 347 3,100 1,557 26,153 18,197 2,305 20,502 5,651 3/5/2022 29,482 521 1,135 19 632 2,200 975 27,350 17,826 2,305 20,131 7,219 STUDY EXTERNAL NON PLANNED ALLOWANCE FOR GEN AT RISK OPER RESERVE WEEK (Week AVAILABLE Active Capacity NODE AVAIL COMMERCIAL OUTAGES CSO UNPLANNED DUE TO GAS NET OPCAP PEAK LOAD REQUIREMENT NET LOAD OPCAP MARGIN Beginning, OPCAP MW Demand MW CAPACITY MW CAPACITY MW MW OUTAGES MW SUP MW SUPPLY MW FORECAST MW MW OBLIGATION MW MW Saturday) [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] 3/12/2022 29,482 521 1,135 19 632 2,200 353 27,972 17,618 2,305 19,923 8,049 3/19/2022 29,482 521 1,135 19 1,827 2,200 0 27,130 17,231 2,305 19,536 7,594 3/26/2022 29,458 520 1,135 19 1,956 2,700 0 26,476 16,631 2,305 18,936 7,540 4/2/2022 29,458 520 1,135 19 4,441 2,700 0 23,991 16,000 2,305 18,305 5,686 4/9/2022 29,458 520 1,135 19 4,511 2,700 0 23,921 15,733 2,305 18,038 5,883 4/16/2022 29,458 520 1,135 19 3,515 2,700 0 24,917 15,192 2,305 17,497 7,420 4/23/2022 29,458 520 1,135 19 3,315 2,700 0 25,117 14,911 2,305 17,216 7,901 4/30/2022 29,458 520 1,135 19 3,850 3,400 0 23,882 14,883 2,305 17,188 6,694 5/7/2022 29,458 520 1,135 19 3,317 3,400 0 24,415 17,925 2,305 20,230 4,185 5/14/2022 29,458 520 1,135 19 2,186 3,400 0 25,546 18,968 2,305 21,273 4,273 5/21/2022 29,458 520 1,135 19 1,816 3,400 0 25,916 19,937 2,305 22,242 3,674 5/28/2022 29,458 520 1,135 19 668 3,400 0 27,064 24,861 2,305 27,166 -102 6/4/2022 28,471 591 1,192 19 292 2,800 0 27,181 24,861 2,305 27,166 15 6/11/2022 28,471 591 1,192 19 292 2,800 0 27,181 24,861 2,305 27,166 15 6/18/2022 28,471 591 1,192 19 292 2,800 0 27,181 24,861 2,305 27,166 15 6/25/2022 28,471 591 1,192 19 292 2,800 0 27,181 24,861 2,305 27,166 15 7/2/2022 28,471 591 1,192 19 292 2,100 0 27,881 24,861 2,305 27,166 715 7/9/2022 28,471 591 1,192 19 292 2,100 0 27,881 24,861 2,305 27,166 715 7/16/2022 28,471 591 1,192 19 292 2,100 0 27,881 24,861 2,305 27,166 715 7/23/2022 28,471 591 1,192 19 292 2,100 0 27,881 24,861 2,305 27,166 715 7/30/2022 28,471 591 1,192 19 0 2,100 0 28,173 24,861 2,305 27,166 1,007 8/6/2022 28,471 591 1,192 19 0 2,100 0 28,173 24,861 2,305 27,166 1,007 8/13/2022 28,471 591 1,192 19 0 2,100 0 28,173 24,861 2,305 27,166 1,007 8/20/2022 28,471 591 1,192 19 0 2,100 0 28,173 24,861 2,305 27,166 1,007 8/27/2022 28,471 591 1,192 19 0 2,100 0 28,173 24,861 2,305 27,166 1,007 9/3/2022 28,471 591 1,192 19 19 2,100 0 28,154 24,861 2,305 27,166 988 9/10/2022 28,471 591 1,192 19 787 2,100 0 27,386 24,861 2,305 27,166 220 9/17/2022 28,471 591 1,192 19 772 2,100 0 27,401 20,603 2,305 22,908 4,493 9/24/2022 28,471 591 1,192 19 1,327 2,100 0 26,846 20,504 2,305 22,809 4,037 10/1/2022 28,711 591 1,147 19 1,794 2,800 0 25,874 14,773 2,305 17,078 8,796 10/8/2022 28,711 591 1,147 19 2,216 2,800 0 25,452 14,811 2,305 17,116 8,336 10/15/2022 28,711 591 1,147 19 1,990 2,800 0 25,678 15,803 2,305 18,108 7,570 10/22/2022 28,711 591 1,147 19 974 2,800 0 26,694 16,195 2,305 18,500 8,194 10/29/2022 28,711 591 1,147 19 2,083 3,600 0 24,785 16,416 2,305 18,721 6,064 11/5/2022 28,711 591 1,147 19 1,245 3,600 409 25,214 16,540 2,305 18,845 6,369 11/12/2022 28,711 591 1,147 19 891 3,600 816 25,161 16,910 2,305 19,215 5,946 11/19/2022 28,711 591 1,147 19 891 3,600 1,426 24,551 17,702 2,305 20,007 4,544 11/26/2022 28,711 591 1,147 19 169 3,600 2,038 24,661 18,475 2,305 20,780 3,881 12/3/2022 28,801 591 1,147 19 0 3,200 2,478 24,880 18,813 2,305 21,118 3,762 12/10/2022 28,801 591 1,147 19 0 3,200 2,685 24,673 19,123 2,305 21,428 3,245 12/17/2022 28,801 591 1,147 19 0 3,200 2,908 24,450 19,135 2,305 21,440 3,010 12/24/2022 28,801 591 1,147 19 0 3,200 3,269 24,089 19,201 2,305 21,506 2,583 12/31/2022 28,801 591 1,147 19 0 2,800 3,892 23,866 19,495 2,305 21,800 2,066 1/7/2023 28,801 591 1,147 19 0 2,800 3,887 23,871 19,993 2,305 22,298 1,573 1. Available OPCAP MW based on resource Capacity Supply Obligations, CSO. Does not include Settlement Only Generators. 2. The active demand resources known as Real-Time Demand Response (RTDR) will become Active Demand Capacity Resources (ADCRs) and can participate in the Forward Capacity Market (FCM). These resources will have the ability to obtain a CSO and also participate in the Day-Ahead and Real-Time Energy Markets. 3. External Node Available Capacity MW based on the sum of external Capacity Supply Obligations (CSO) imports and exports. 4. New resources and generator improvements that have acquired a CSO but have not become commercial. 5. All Planned outages for the period. This value would also include any known long-term Forced Outages. 6. Allowance for Unplanned Outages includes forced outages and maintenance outages scheduled less than 14 days in advance per ISO New England Operating Procedure No. 5 Appendix A. 7. Generation at Risk due to Gas Supply pertains to gas fired capacity expected to be at risk during cold weather conditions or gas pipeline maintenance outages. 8. Net OpCap Supply MW Available (1 + 2 + 3 + 4 - 5 - 6 - 7 = 8) 9. Peak Load Forecast as provided in the 2020 CELT Report and adjusted for Passive Demand Resources assumes Peak Load Exposure (PLE) of 25,125 and does include credit of Passive Demand Response (PDR) and behind-the-meter PV (BTM PV) 10. Operating Reserve Requirement based on 120% of first largest contingency plus 50% of the second largest contingency. 11. Total Net Load Obligation (9 + 10 = 11) 12. Net OPCAP Margin MW = Net Op Cap Supply MW minus Net Load Obligation (9 - 11 = 12) ISO-NE 2021-2023 OPERABLE CAPACITY ANALYSIS -CSO- -50/50 FORECAST 10,000

8,000

6,000

4,000

Operable Capacity Margin (MW) 2,000

-2,000 1/9/2021 2/6/2021 3/6/2021 4/3/2021 5/1/2021 8/7/2021 9/4/2021 1/8/2022 2/5/2022 3/5/2022 4/2/2022 7/9/2022 8/6/2022 9/3/2022 1/7/2023 1/23/2021 2/20/2021 3/20/2021 4/17/2021 5/15/2021 5/29/2021 6/12/2021 6/26/2021 7/10/2021 7/24/2021 8/21/2021 9/18/2021 10/2/2021 1/22/2022 2/19/2022 3/19/2022 4/16/2022 4/30/2022 5/14/2022 5/28/2022 6/11/2022 6/25/2022 7/23/2022 8/20/2022 9/17/2022 10/1/2022 10/16/2021 10/30/2021 11/13/2021 11/27/2021 12/11/2021 12/25/2021 10/15/2022 10/29/2022 11/12/2022 11/26/2022 12/10/2022 12/24/2022

January 9, 2021- January 13, 2023, W/B Saturday Forecast Temperature and Load

New England’s system load patterns have undergone changes associated with the ongoing pandemic. These changes have resulted in a reduction of overall energy usage, as well as the timing of load ramps and peak energy usage. Due to the potentially dynamic nature of the pandemic and impact to load patterns, ISO-NE will be publishing a 21-day load forecast until load patterns stabilize. The 21-day load forecast has been created by ISO-NE for utilization by generators for increased situational awareness and provide assistance to coordinate outages in the near term time horizon. The system load forecast is created by blending weather data from two vendor forecasts to create an hourly electric demand for 21 days. This forecast is not precise due to its long range, but it can be utilized as a gauge for evaluating system demand impacted by weather. This will help limit the risk to system reliability due to generators scheduling required maintenance outages during these unprecedented times.

Note for Generator Outages

To be implemented less than 15 calendar days from today: Contact Generation Outage Coordinator at [email protected] or 413-535-4378

To be implemented greater than 15 calendar days from today: Contact Connor Corsi at [email protected] or 413-540-4596

Forecast Temperature and Load Hourly Demand (MW) Hourly Temperature (F) 20,000 70

65 18,000 60

55 16,000 50 F) ° 14,000 45

MW 40 12,000 35 ( Temperature

30 10,000 25

8,000 20 1/1… 1/2… 1/3… 1/4… 1/5… 1/6… 1/7… 1/8… 1/9… 1/10… 1/11… 1/12… 1/13… 1/14… 1/15… 1/16… 1/17… 1/18… 12/29… 12/30… 12/31… Day and Time (hourly granularity)