DOCKETED
Docket Number: 21-ESR-01
Project Title: Energy System Reliability
TN #: 243173
Document Title: Presentation - 2022 Summer Stack Analysis Description: N/A
Filer: Courtney Wagner
Organization: California Energy Commission
Submitter Role: Commission Staff
Submission Date: 5/20/2022 8:14:53 AM
Docketed Date: 5/20/2022
Summer Stack Analysis
Hannah Craig
Energy Assessments Division
May 20, 2021
Summer Stack Analysis
2 Purpose:
• Assess average and extreme conditions
• Inform need for contingencies
Considers extreme conditions:
• High demand days like summer 2020
• High levels of unplanned outages
• Low import availability
• Drought impacts on hydro
Planning Reserve Margin
• 6 % Operating Reserves
• 5 % Unplanned Outages
• 4 % Demand Variability
3 22.5% PRM –
Extreme Conditions
15% PRM –
Average Conditions
• 6 % Operating Reserves
• 7.5 % Unplanned Outages
• 9 % Demand Variability
Background
• Developed in 2021 in response to
Root Cause Analysis
• Inputs and assumptions
developed in collaboration with
CPUC, DWR and CAISO
• Preliminary summer 2022 results
first presented at the reliability
workshop in July 2021 and a
preliminary version was adopted
in September 2021
• Last update was in January 2022
4 Changes to Stack for September 2022
5 • Stack has been updated as new
information becomes available
• Continue to foresee a need for
significant contingency resources at
net peak in September
Changes for Final May Version
• Supply-side changes since the January Update for 2022:
• New resources revised down due to delays
• CDWR released forecast for drought impacts to summer
generation and pumping
• Emergency procurement resources moved from Stack
Analysis to contingencies
• Hourly profiles applied to new wind, solar, and batteries 6 Changes for Final May Version cont.
• CED 2021 shows higher annual
peak demand compared to CED
2020
• Actual weather normalized 2021
was ~800 MW higher compared to
previous forecast
• Other differences are largely
the result of changes in economic
drivers and the impacts of demand
modifiers on peak timing and
magnitude
7 42000
43000
44000
45000
46000
47000
48000
49000
50000
51000
2021 2022 2023 2024 2025 2026 2027 2028 2029 2030
Megawatts
CED 2020 vs 2021
CED 2020 CED 2021
Basic Assumptions
• Demand
• Peak day of each month from the
CED Adopted 2021 hourly forecast,
adjusted downward due to reduced
pumping need
• Supply
• Final Net Qualifying Capacity list
published by CAISO in October 2021
• CPUC estimates of additional
procurement
• Imports
• Average RA showings from 2016-
2021 and LD contracts for POUs
8 Megawatts July August Sept
Demand at 7-8PM 44,110 45,480 46,040
NQC List 48,170 46,380 43,950
Average RA Imports 6,010 6,440 6,560
New Supply 2022
(NQC) 1,651 1,699 2,581
New Supply 2023
(NQC) 5,350 5,436 5,996
Supply Modifications
• Wind and solar
• Hourly profiles based on generation
on high-load days from 2014-2021
• Batteries
• Discharge limited to 4 hours across
peak hours
• Hydro
• Derated based on CDWR projections
• Demand response
• From CPUC DR Allocations, adjusted
by Load Impact Protocol and
distribution loss factors
• Increased by 6% since operating
reserves aren’t carried for reduced
load
9 Megawatts July August Sept
Solar MW at 7-8PM 610 130 0
Wind MW at 7-8PM 2,450 2,130 1,230
Hydro Capacity with
Derate 4,940 4,730 4,120
Demand Response
with DLF/Reserve 1,360 1,420 1,420
New Resources
10 Megawatts 2022 2023 2024 2025 2026
Other 20 50 50 80 2,080
Wind 500 640 1,020 1,760 1,840
Solar 970 2,090 3,690 5,710 5,810
Batteries 2,450 5,870 8,250 10,220 10,350
• New resources for 2022-2023
based on procurement status
forms filed with and compiled
by CPUC staff
• Resources for 2024-2026
based on procurement orders
from 2019 and 2021 using
Preferred System Plan ratios.
• 2024-2026 assume OTC plants
and Diablo Canyon retire as
scheduled.
Online Resources
11 • New resources continue to come
online at a record pace
• About half the storage expected
between October and
September came online by April;
most solar is already here
Nameplate
Capacity
November 2020-
October 2021
October 2021-
April 2022 Total
Energy
Storage 1,230 1,130 2,360
Solar 1,380 796 2,500
Wind 340 580 920
Geothermal 12 0 12
Small Hydro 15 0 15
Hourly Wind and Solar Shapes
• Based on historic generation
on the 5 highest load days of
each month from 2014-2021,
for a total of 40 days per
month
• The hourly shapes are
weighted with 80% of the
weight going to the median
generation and 20% of the
weight going to the 20
th
percentile.
12 Wind (MW) July August Sept
ELCC Tech Factors 1,390 1,270 910
Stack Analysis
Values at 5-6 PM
(peak)
2,240 1,640 810
Stack Analysis
Values at 7-8PM
(net peak)
2,450 2,130 1,230
Solar (MW) July August Sept
ELCC Tech Factors 4,290 2,990 1,580
Stack Analysis
Values at 5-6 PM
(peak)
6,430 5,540 3,770
Stack Analysis
Values at 7-8PM
(net peak)
610 130 0
Results
13 July and August 2022
14 September 2022 – Not Meeting 22.5%
15 • Meeting 15% PRM in every
hour
• Potential need for
contingencies.
July and August 2023
16 September 2023 – Not Meeting 22.5%
17 • Meets 15% PRM for all
hours
• Potential need for
contingencies at net peak
2024
18 2025
19 2026
20 Summary
21 Summary
22 Filing Comment
23 • Comments should be submitted by May 27, 2022 to docket 21- ESR-01 at
https://efiling.energy.ca.gov/Lists/DocketLog.aspx?docketnumber =21-ESR-01
• Technical questions can be submitted to
Hannah Craig at [email protected]
Questions?
24