Utah Compressed Air Energy Storage (CAES) Project Phase 1 ... · Utah Compressed Air Energy Storage...

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Utah Compressed Air Energy Storage (CAES) Project Phase 1

Economic Evaluation using PLEXOS Tao Guo, Ph.D., Regional Director, WEST Coast - USA Guangjuan Liu, Ph.D., Senior Consultant Xiaolong Wang, Consultant Yannick Degeilh, Ph.D., Consultant Energy Exemplar, LLC 3013 Douglas Blvd, Suite 120 Roseville, CA 95661 U.S.A.

Prepared for City of Burbank Water and Power 164 W. Magnolia Blvd. Burbank, CA 91502-1720 Schulte Associates LLC 2236 Coley Forest Place Raleigh, NC 27607

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List of Acronyms

ANL – Argonne National Laboratory AS PSH – Adjustable Speed Pumped-storage Hydro Generator AS – Ancillary Services BA – Balancing Area BAA – Balancing Authority Area BPA – Bonneville Power Administration BWP – City of Burbank Water and Power CAES – Compressed Air Energy Storage CAISO – California Independent System Operator COI – California-Oregon Interface DA – Day-Ahead DOE – US Department of Energy FS PSH – Fixed Speed Pumped-storage Hydro Generator GWh – Gigawatt-hours HA – Hour-Ahead LTPP – Long Term Procurement Plan NREL – National Renewable Energy Laboratory OPF – Optimal Power Flow PACW – Pacific Corps West PNNL – Pacific Northwest National Laboratory PSH – Pumped-storage Hydro Generator RPS – Renewable Portfolio Standards RT – Real Time SCED – Security Constrained Economic Dispatch SCUC – Security Constrained Unit Commitment TEPPC – Transmission Expansion Planning and Policy Committee WI – Western Interconnection WECC – Western Electricity Coordinating Council WWSIS – Western Wind and Solar Integration Study

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Executive Summary

Energy Exemplar was engaged by Schulte Associates LLC, consultant for the City of Burbank Water and Power (BWP), for the economic evaluation of the Utah CAES Project using PLEXOS, an integrated power market simulation software suite.

The Utah CAES Project Phase 1 is proposed to be a 300 MW generation facility located at Delta, Utah and connected to the Intermountain Power Project (IPP) substation. This project has transmission access to Southern California through the DC-Tie from the Intermountain substation to the Adelanto substation close to the Los Angeles Basin. Phase I is an initial effort leading to a larger, 1200 MW CAES/renewable energy combination project to follow.

In order to capture the benefit of this Utah CAES project in detail, a WECC database with the nodal transmission representation was prepared and configured to be as close to reality as possible. The WECC system is simulated for years 2020 to 2025.

Assumptions

The database prepared for this study was originally from the WECC TEPPC 2024 Common Case database version 1.51 [1]. It has been converted to a PLEXOS database and further updated with California-specific assumptions, and renewable generation profiles and flexibility reserve requirements. The TEPPC 2024 database covers the entire footprint of the Western Interconnection (WI), including the provinces of British Columbia and Alberta in Canada, and Comision Federal de Electricidad (CFE) in northern Mexico. The additional assumption updates include

California low frequency modeling. In the California transmission operation, certain low frequency reliability requirements are modeled for BANC, TID, SCE, SDGE, and IID. 25% of the area loads are covered by the local generations with moving mass such as thermal or hydro generators.

Renewable Generation Profiles. The simulations are performed at the hourly interval. The hour-ahead wind and solar generation profile forecasts are derivated from the 5-minute “actual” wind and solar generation profiles. The 5-minute “actual” wind and solar generation profiles in year 2024 were received from NREL [6] based on year 2006 for the entire WECC footprint. The one-hour persistency forecast technique is used to generate the hour-ahead wind and solar generation profiles. The solar generators include the solar generators with and without the tracking system.

Regional loads. The Hour-Ahead (HA) regional load profiles in year 2020 were received from Pacific Northwest National Laboratory (PNNL) for the WECC VGS

1 There was no release note published for TEPPC 2024 Common Case version 1.5.

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study [5]. The load profiles in year 2020 were updated for year 2024 for the given annual peaks and load energies using the PLEXOS time series “build” function.

Contingency, Flexibility and Regulation Reserves. The contingency, flexibility and regulation reserve requirements were generated based on the 5-minute actual net loads and the HA net loads in BAAs (a BAA net load is the BAA load less the solar and wind generation in the BAA).

Modeling Approach and Scope

The study is performed using the PLEXOS Energy-Ancillary Service-DC-OPF co-optimization capability.

The simulations are performed for each of the years 2022 to 2025 for the cases without and with the Utah CAES project. All cases included the existing, 1900 MW IPP coal plant in operation.

Results and Findings

The findings of this study are summarized below. All the results mentioned here are based on the annual measurement from the simulations for years 2020 to 2025. The cost and revenue values are measured based on real, 2014 US dollars including real escalation to the year shown, but excluding general inflation.

WECC Production Cost

The WECC total production cost saving by year due to the Utah CAES project, including the reserve provision shortfall cost reductions (i.e., “ancillary services”), are listed in the following chart. In addition to reserve provisions, production costs include fuel, variable operating and maintenance (O&M) costs, startup costs, and carbon emissions (CO2) costs for resources in and serving California.

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5,000

10,000

15,000

20,000

25,000

30,000

35,000

2020 2021 2022 2023 2024 2025

WECC Total Production Cost Savings in 000$ due to Utah CAES Project (Including Reserve Shortfall Cost Reduction)

Production Cost Savings

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It is noticed that, when the renewable energies reach 20% in WECC and 37% in California (including the OOS renewables) in year 2023, the WECC production cost savings due to the Utah CAES project sharply increase to nearly 20 million dollars. This step change is not due to a year-to-year discontinuity in Plexos model input assumptions. Instead, it appears to represent a “tipping point” inflection in the WECC system’s needs for storage as the California RPS approaches 38% to 40%.

Utah CAES Project Operation Performance

Utah CAES Project earns energy arbitrage revenue and AS revenues. The following charts display the Utah CAES project operation, operating costs, energy and AS revenues, and net operating revenues.

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200

400

600

800

1,000

1,200

1,400

2020 2021 2022 2023 2024 2025

CAES Generation and Total Reserve Provisions (GWh) by Year

Generation Reserve Provision

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5,000

10,000

15,000

20,000

25,000

2020 2021 2022 2023 2024 2025

CAES Operating Cost (000$) by Year

Generation Cost Pumping Cost

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5,000

10,000

15,000

20,000

25,000

2020 2021 2022 2023 2024 2025

CAES Operating Revenue (000$) by Year

Energy Revenue AS Revenue

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The Utah CAES project net operating revenue is calculated as

Net Revenue = Energy Revenue (LMP x Generation) + Reserve Revenue (Reserve Shadow Price x Reserve Provision) – Fuel and VO&M Cost – Pumping Cost (LMP x Pumping Load)

Usually, the net revenue represents the profit of the project that is operated as an Independent Power Producer (IPP) in a power market.

One can notice that the net revenue increases from 3 million dollars in year 2020 to 11 million dollars in year 2025.

Size of the CAES Storage Cavern

Thourgh the storage size of the Utah CAES Project is defined as 7.2 GWh, the max compressing energy is 0.54 GWh the represents nearly 2 consecutive hours’ full capacity (300 MW) compressing; the max discharging energy is 1.22GWh that represents nearly 4 consecutive hours’ full capacity (300 MW) discharging.

Impact on Other Generators

The following table shows the generation changes in WECC by generator type due to the Utah CAES project.

The following can be observed.

1. With the Utah CAES project, the Coal generation (“COAL” in the table) in WECC is reduced with the Utah CAES project in years 2020 and 2021, but increased from year 2022 to year 2025.

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2,000

4,000

6,000

8,000

10,000

12,000

2020 2021 2022 2023 2024 2025

CAES Net Operating Revenue (000$) by Year

Net Revenue

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2. With the Utah CAES Project, the CC and CT generation2 (“CC” and “CT” in the table) in WECC is increased in years 2020 and 2021, but reduced from year 2022 to year 2025.

From the observation point 1, the CO2 production in WECC is reduced in years 2020 and 2021 but increased in years 2022 to 2025.

With the renewable generation increase from year 2020 to year 2025 and due to the Utah CAES project, the activities of the pumped storage generators (“PSH” in the table) and the energy storage generators (“ES” in the table) are increased. The Utah CAES project shares the reserve provisions from the PSH and ES facilities so that the PSH and ES facilities can generate more energy.

2 In the WECC TEPPC database, the CT generator category includes co-generation facilities.

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WECC Generation in GWh by Generator Type

Generator Type

2020 2021 2022 2023 2024 2025

Base CAES (Base-CAES)






CAES - 84 (84) - 109 (109) - 124 (124) - 172 (172) - 208 (208) - 233 (233)

Coal 234,733 234,494 239 234,365 234,239 126 233,883 234,159 (276) 232,996 233,360 (364) 232,459 232,552 (93) 231,666 232,208 (542)

Hydro 239,574 239,605 (31) 239,588 239,591 (2) 239,572 239,540 32 239,553 239,527 26 239,531 239,563 (32) 239,583 239,580 2

Nuclear 56,561 56,561 - 56,561 56,561 - 56,561 56,561 (0) 56,561 56,561 (0) 56,561 56,561 (0) 56,561 56,561 (0)

Others 5,328 5,381 (52) 5,307 5,358 (51) 5,267 5,310 (42) 5,296 5,313 (17) 5,311 5,332 (22) 5,354 5,379 (25)

ST 2,266 2,317 (51) 2,343 2,315 28 2,330 2,351 (22) 2,359 2,355 4 2,426 2,466 (40) 2,478 2,502 (23)

Bio 18,351 18,414 (63) 18,300 18,349 (49) 18,197 18,236 (38) 18,120 18,166 (46) 18,018 18,083 (65) 17,961 18,000 (39)

CC 253,264 253,245 19 253,102 253,505 (403) 253,988 253,418 570 254,355 254,050 305 254,733 254,559 174 255,371 254,840 530

CT 35,663 35,756 (93) 36,937 36,611 327 37,563 37,807 (244) 39,104 39,028 76 40,412 40,328 84 41,698 41,587 111

DR-EE 3,099 3,099 - 3,409 3,409 - 3,750 3,750 - 4,125 4,125 - 4,537 4,537 - 4,990 4,990 -

ES 1,387 1,449 (62) 1,449 1,502 (53) 1,504 1,552 (48) 1,542 1,589 (47) 1,587 1,616 (29) 1,603 1,645 (42)

Geo 27,222 27,222 (0) 27,211 27,210 1 27,199 27,200 (1) 27,187 27,188 (2) 27,183 27,183 (0) 27,172 27,179 (7)

Small Hydro 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 -

PSH 3,846 4,003 (158) 3,972 4,108 (136) 3,983 4,137 (155) 4,056 4,214 (157) 4,122 4,256 (134) 4,196 4,347 (151)

PV-BTM 15,677 15,677 - 17,145 17,145 - 18,613 18,613 - 20,081 20,081 - 21,549 21,549 - 23,017 23,017 -

Solar 40,031 40,031 - 43,780 43,780 (0) 47,527 47,527 (0) 51,268 51,268 0 55,001 55,002 (0) 58,722 58,723 (1)

Wind 60,083 60,083 - 65,709 65,709 - 71,336 71,336 - 76,962 76,962 - 82,583 82,588 (5) 88,208 88,213 (4)

Total 1,001,362 1,001,699 (337) 1,013,456 1,013,779 (323) 1,025,550 1,025,898 (347) 1,037,842 1,038,236 (394) 1,050,292 1,050,661 (369) 1,062,860 1,063,282 (422)

The following table shows the generation changes in California by generator type due to the Utah CAES project.

The followings can be observed.

1. With the Utah CAES project, the Coal generation (“COAL” in the table) in California is increased slightly in years 2020 and 2025;

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2. With the Utah CAES Project, the CC and CT generation3 (“CC” and “CT” in the table) in California is increased in years 2020 and 2021, but reduced from year 2022 to year 2025.

3. California Net Import reduced gradually from year 2020 to year 2025 due to the renewable generation increases in California. However, with the Utah CAES Project, the California net import is reduced in year 2020 and 2021 but increased in years 2022 to 2025 as opposed to the cases without the Utah CAES Project.

4. With the renewable generation increase from year 2020 to year 2025 and due to the Utah CAES project, the activities of the pumped storage generators (“PSH” in the table) and the energy storage generators (“ES” in the table) are increased. The Utah CAES project shares the reserve provisions from the PSH and ES facilities so that the PSH and ES facilities can generate more energy.

Combining the observations of points 2 and 3, the CO2 production in California is increased in year 2020 and 2021 and is reduced in years 2022 to 2025. That is opposite to the trend of the CO2 production in WECC. These trends go in opposite directions over time because as load increases gradually and renewables increase over the study period, higher-cost natural gas-fired generation in California (compared to elselwhere in WECC) is at the margin more often later in the planning period. As a result, natural gas-fired generation in California is more likely to be offset by CAES generation during the latter part of the study period.


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California Generation in GWh by Generator Type

Generator Type

2020 2021 2022 2023 2024 2025







CAES - 84 (84) - 109 (109) - 124 (124) - 172 (172) - 208 (208) - 233 (233)

Coal 11,198 11,265 (68) 11,094 11,147 (53) 10,971 11,005 (34) 10,816 10,849 (33) 10,702 10,730 (29) 10,586 10,622 (35)

Hydro 35,016 34,995 21 34,993 34,996 (3) 34,973 34,991 (17) 34,928 34,934 (6) 34,927 34,916 11 34,928 34,929 (1)

Nuclear 17,114 17,114 - 17,114 17,114 - 17,114 17,114 (0) 17,114 17,114 (0) 17,114 17,114 (0) 17,113 17,113 (0)

Others 270 287 (18) 278 300 (22) 280 297 (16) 297 302 (5) 313 320 (8) 325 332 (8)

ST 1,580 1,627 (47) 1,642 1,612 31 1,607 1,627 (20) 1,596 1,611 (14) 1,594 1,640 (46) 1,598 1,611 (13)

Bio 9,891 9,909 (18) 9,798 9,815 (17) 9,667 9,699 (32) 9,553 9,577 (23) 9,414 9,434 (20) 9,283 9,317 (34)

CC 83,535 83,569 (34) 82,211 82,386 (176) 81,109 80,948 161 80,392 80,037 355 79,509 79,194 315 78,032 77,410 621

CT 9,462 9,480 (18) 9,593 9,548 45 9,631 9,620 10 9,689 9,722 (33) 9,768 9,722 45 9,829 9,780 49

DR-EE 3,099 3,099 0 3,409 3,409 - 3,750 3,750 - 4,124 4,124 - 4,537 4,537 - 4,990 4,990 0

ES 1,387 1,449 (62) 1,449 1,502 (53) 1,504 1,552 (48) 1,542 1,589 (47) 1,587 1,616 (29) 1,603 1,645 (42)

Geo 14,476 14,476 0 14,466 14,464 1 14,455 14,454 0 14,443 14,443 (0) 14,441 14,439 1 14,431 14,436 (5)

Small Hydro 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0

PSH 3,393 3,551 (159) 3,531 3,660 (129) 3,556 3,705 (149) 3,644 3,789 (145) 3,711 3,836 (126) 3,769 3,913 (143)

PV-BTM 12,022 12,022 - 13,147 13,147 - 14,273 14,273 - 15,399 15,399 - 16,524 16,524 - 17,650 17,650 -

Solar 34,361 34,361 0 37,579 37,579 (0) 40,794 40,795 (0) 44,005 44,005 0 47,207 47,207 (0) 50,397 50,398 (1)

Wind 16,203 16,203 (0) 17,721 17,721 - 19,238 19,238 - 20,756 20,756 (0) 22,273 22,273 0 23,790 23,790 -

CA Total Gen 257,212 257,698 (486) 262,231 262,715 (485) 267,128 267,397 (268) 272,503 272,626 (123) 277,825 277,917 (92) 282,530 282,377 154

Net Import 63,018 62,869 149 61,962 61,790 172 60,933 61,003 (70) 59,524 59,774 (250) 58,203 58,470 (266) 57,496 58,060 (564)

Total 320,230 320,566 (336) 324,192 324,505 (313) 328,061 328,399 (338) 332,027 332,400 (373) 336,028 336,386 (358) 340,026 340,437 (411)

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Contributions to emission reductions

With the Utah CAES Project, due to the Coal generation reduction in WECC in years 2020 and 2021 but increase in years 2022 to 2025, the CO2 production in WECC is reduced in years 2020 and 2021 but increased in years 2022 to 2025.

With the Utah CAES Project, the coal generation in California is increased slightly for all years. This happens in part because the IPP Coal facility, whose generation increases with CAES, is included in the California totals. However, due to the CC and CT generation increase in California in years 2020 and 2021 but reduction in years 2022 to 2025, the CO2 production in California is increased in years 2020 and 2021 but reduced in years 2022 to 2025.

Year

WECC CO2 Production (1000 ton) CO2 Cost ($000) only in CA

Base CAES

CO2 Reduct

ion

CO2 Reduction (%) Base CAES

CO2 Cost

Reduction

CO2 Cost

Reduction (%)

2020 370,528 370,378 150 0.04% 1,286,122 1,288,657 (2,535) -0.20%

2021 371,032 370,925 107 0.03% 1,273,065 1,275,707 (2,642) -0.21%

2022 371,566 371,750 (185) -0.05% 1,261,043 1,260,293 750 0.06%

2023 371,979 372,156 (178) -0.05% 1,252,827 1,250,945 1,882 0.15%

2024 372,702 372,723 (21) -0.01% 1,244,758 1,242,042 2,716 0.22%

2025 373,347 373,634 (287) -0.08% 1,229,569 1,224,093 5,476 0.45%

.

Contribution to Renewable Generation Integration

The pumping mode of the Utah CAES project operation can absorb over-generation from the solar and wind generation. The Utah CAES Project helps reduce solar and wind generation curtailment from 0 GWh in year 2020 to 5.11 GWh (0.61 GWh Solar generation curtailment reduction and 4.5 GWh wind generation curtailment reduction) in year 2025.

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Changes in STS Transmission Line Constraints

Though the flow in STS transmission line (IPPDC-Tie) is always from North (Utah) to South (Southern California), one can observe that, at the hourly level,

In most CAES compressing hours, the flow from North to South is decreased as opposed to the flow in the Base Case. This indicates that some generation flows from Southern California to Utah to provide compressing energy for the Utah CAES project.

In most CAES generating hours, the flow from North to South is increased as opposed to the flow in the Base Case. This indicates that some generation from the Utah CAES flows to Southern California.

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10.00

20.00

30.00

40.00

50.00

60.00

2020 2021 2022 2023 2024 2025

WECC Solar and Wind Generation Curtailment (GWh) without and with Utah CAES Project

Solar Curtailment in Base Solar Curtailment in CAES

Wind Curtailment in Base Wind Curtailment in CAES

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Table of Contents 1 Introduction ................................................................................................................17 2 Database Preparation and Assumption Revisions ......................................................19

2.1 Database Preparation .......................................................................................... 19

2.2 Assumptions Updates ......................................................................................... 20 2.2.1 California Low Frequency Modeling.......................................................... 20 2.2.2 Renewable Generation Profiles ................................................................... 20 2.2.3 Regional Loads ........................................................................................... 20 2.2.4 Renewable Portfolio Standard .................................................................... 22

2.2.5 Contingency, Flexibility and Regulation Reserves ..................................... 37

2.2.6 Utah CAES Project Representation ............................................................ 38

2.2.7 Gas Forecast ................................................................................................ 41 2.2.1 Emission Market Modeling for California .................................................. 44 2.2.2 CAISO Export Transmission Charge.......................................................... 44

3 Modeling Approaches ................................................................................................45

3.1 PLEXOS SCUC/ED Algorithm ......................................................................... 45 4 Simulation Results .....................................................................................................49

4.1 Total WECC System Production Cost ............................................................... 49 4.2 Utah CAES Project Performance as Independent Power Producer (IPP) .......... 50 4.3 Total Generation and Generation Cost Changes by Generator Type ................. 54

4.4 Solar and Wind Generation Curtailment ............................................................ 68 4.5 Emissions Production ......................................................................................... 68

4.6 Intermountain Power Plant Production .............................................................. 69

4.7 Intermountain Power Plant DC-Tie.................................................................... 71

5 Findings ......................................................................................................................73 5.1 WECC Production Cost ..................................................................................... 74

5.2 Utah CAES Project Operation Performance ...................................................... 75 5.3 Impact on Other Generators ............................................................................... 77

5.4 Contributions to Emission Reductions ............................................................... 82 5.5 Contribution to Renewable Generation Integration ........................................... 82 5.6 CAES Storage Cavern Capacity ......................................................................... 83

6 References ..................................................................................................................85

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List of Figures

Figure 1-1 Utah CAES Project Site ............................................................................................... 17 Figure 2-1 Diagram of WECC Load Regions (Source: WECC) .................................................... 19 Figure 2-2 Illustration of a CAES operation ................................................................................... 39 Figure 2-3 CAES Compressing Mode Representation.................................................................. 40 Figure 2-4 CAES Generating Mode Representation ..................................................................... 40 Figure 3-1 PLEXOS Security Constrained Unit Commitment and Economic Dispatch Algorithm 45 Figure 4-1 STS Flow versus Utah CAES Project Operation in a Typical Day of May, 2025......... 72 Figure 5-1 WECC Retail Loads and Renewable Generation ........................................................ 73 Figure 5-2 WECC RPS % .............................................................................................................. 73 Figure 5-3 California Retail Load and Renewable Generation ...................................................... 74 Figure 5-4 California RPS in % ...................................................................................................... 74 Figure 5-5 WECC Total Production Cost Saving due to Utah CAES Project .............................. 75 Figure 5-6 Utah CAES Project Generation and Total Reserve Provision (GWh) ......................... 75 Figure 5-7 Utah CAES Operating Costs ........................................................................................ 76 Figure 5-8 Utah CAES Energy and AS Revenues ........................................................................ 76 Figure 5-9 Utah CAES Project Net Operating Revenue................................................................ 77 Figure 5-10 WECC Renewable Generation Curtailment without and with Utah CAES Project .... 83

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List of Tables

Table 2-1 Total Annual Energy Demand for BAAs in WECC for Year 2024 (GWh) ..................... 22 Table 2-2 RPS by Technology and BAA for Year 2020 ................................................................ 25 Table 2-3 RPS by Technology and BAA for Year 2021 ................................................................ 27 Table 2-4 RPS by Technology and BAA for Year 2022 ................................................................ 29 Table 2-5 RPS by Technology and BAA for Year 2023 ................................................................ 32 Table 2-6 RPS by Technology and BAA for Year 2024 ................................................................ 34 Table 2-7 RPS by Technology and BAA for Year 2025 ................................................................ 36 Table 2-8 Mapping of Load Regions and Contingency Reserve Sharing Groups ........................ 38 Table 2-9 Characteristics of Utah CAES Project Representation in PLEXOS .............................. 40 Table 2-10 Gas Price Forecast for Year 2024 by Month ............................................................... 43 Table 2-11 Thresholds for Tiered CO2 Allowance Charge for Energy Import from NW into

California ........................................................................................................................................ 44 Table 4-1 Penalty Prices for Reserve Provision Shortfall ............................................................. 49 Table 4-2 WECC Production Cost Savings due to Utah CAES Project ........................................ 50 Table 4-3 Utah CAES Project Value as an Independent Power Producer ................................... 53 Table 4-4 WECC Generation and Generation Cost Changes Due to Utah CAES Project .......... 60 Table 4-6 California Generation and Generation Cost Changes Due to Utah CAES Project ...... 67 Table 4-7 WECC Renewable Curtailment Reduction Due to Utah CAES Project ........................ 68 Table 4-8 WECC CO2 Reduction and CA CO2 Cost Reduction Due to Utah CAES Project ....... 69 Table 4-9 Intermountain Power Plant Generation and AS Service .............................................. 70 Table 4-10 IPP DC-Tie flows with and without Utah CAES Project .............................................. 72 Table 5-1 WECC Generation Changes by Generator Type due Utah CAES Project ................... 79 Table 5-2 California Generation Changes by Generator Type Due to Utah CAES Project .......... 81 Table 5-3 WECC CO2 Reduction and CA CO2 Cost Reduction Due to Utah CAES Project. ...... 82

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1 Introduction

Energy Exemplar was engaged by Schulte Associates LLC for the Utah Compressed Air Energy Storage (CAES) project economic evaluation on behalf of the City of Burbank Water and Power, using PLEXOS, the Integrated Energy Model4.

This report presents the study assumptions, simulation solutions and analysis. As shown in Figure 1-1, the Utah CAES Project Phase 1 is proposed to be a 300 MW generation, 300 MW compression facility located at Delta, Utah and connected to the Intermountain Power Project (IPP) substation. This project has transmission access to Southern California through the DC-Tie from the IPP substation to the Adelanto substation close to the Los Angeles Basin.

In order to capture the benefit of the Utah CAES project in detail, a WECC database with the nodal transmission representation was prepared and configured to be as realistic as possible.

In this study, Energy Exemplar performed a Base Case study from year 2020 to year 2025 to better understand the Utah CAES project’s value for those years. The Base Case for these years and the case with the Utah CAES project for these years are simulated to quantify the Utah CAES project benefit to the WECC system.

Figure 1-1 Utah CAES Project Site

4 For more information about PLEXOS, visit www.energyexemplar.com

http://www.energyexemplar.com/

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For the rest of the report, Section 2 describes Database Preparation and Assumption Revisions; Section 0 describes

Emission Market Modeling for California

The California CO2 Market is modeled in this study. The CO2 price is 0.01248$/lb (or about $25/ton) and the commitment and dispatch price of the thermal generators in California includes the CO2 cost component.

The import energy from outside of California is charged with the GHG allowance as well. The energy imported from Northwest is charged at the tiered rate: at $0.523/MWh below the thresholds and $11.97/MWh above the thresholds. The thresholds follow the following patterns.

Thresholds for the Tiered CO2 Allowance Charge for Energy Import from NW into California

Threshold (MW) Time Period

1120 M01

1003 M02

1258 M03

2266 M04,D1-15

2471 M04,D16-30

3249 M05

2482 M06

1498 M07

920 M08,D1-15

268 M08,D16-31

146 M09

1 M10

97 M11

1 M12 Table 2-11 Thresholds for Tiered CO2 Allowance Charge for Energy Import from NW into California

The GHG allowance charge for the energy import from Southwest to California is constant of $11.97/MWh.

1.1.1 CAISO Export Transmission Charge

Any energy export from CAISO is charged at $10.83/MWh for the transmission usage.

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Modeling Approaches; Section 4 presents Simulation Results; Section 5 summarizes Findings.

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2 Database Preparation and Assumption Revisions

2.1 Database Preparation

The database prepared for this study was originally from the WECC TEPPC 2024 Common Case database version 1.55 [1]. It has been converted to a PLEXOS database and further updated with California-specific assumptions, and renewable generation profiles and contingency, flexibility and regulation reserve requirements. The TEPPC 2024 database covers the entire footprint of the Western Interconnection (WI). As shown in Figure 2-1, there are total of 43 load regions in this footprint, representing the Balance Authority Areas (BAAs), trading hubs, and/or the BAA’s sub-regions in the United States, plus the provinces of British Columbia and Alberta in Canada, and Comision Federal de Electricidad (CFE) in northern Mexico.

Figure 2-1 Diagram of WECC Load Regions (Source: WECC)

5 There was no release note published for TEPPC 2024 Common Case version 1.5.

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The entire WI network consists of over 19,000 buses, over 25,000 transmission lines and over 5,300 generators (including the renewables). For the detailed descriptions of the TEPPC 2024 Common Case database, please refer to reference [1].

2.2 Assumptions Updates

There are further assumption updates in the areas of California low frequency reliability requirements, WECC renewable generation profiles, and flexibility reserve requirements. This section provides some highlights of the major assumption updates.

2.2.1 California Low Frequency Modeling

In the California transmission operation, certain low frequency reliability requirements are modeled for BANC, TID, SCE, SDGE, and IID. 25% of these area loads are covered by the local generation with moving mass such as thermal or hydro generators.

2.2.2 Renewable Generation Profiles

The 5-minute “actual” wind and solar generation profiles in year 2024 were received from NREL [6] based on year 2006 for the entire WECC footprint. The one-hour persistency forecast technique is used to generate the hour-ahead wind and solar generation profiles. The solar generators include solar generators with and without tracking systems.

2.2.3 Regional Loads

The Day-Ahead (DA) and Hour-Ahead (HA) load forecasts and 5-minute Real Time (RT) “actual loads” in year 2020 were received from Pacific Northwest National Laboratory (PNNL) for the WECC VGS study [5]. Based on the three sets of loads in year 2020, the three sets of loads are built for year 2024 for the given annual peaks and load energies using the PLEXOS time series “build” function. The BAA’s annual peak and load energies are from [1]. A summary of the total annual energy demand for the BAAs in WECC are listed in the following table6.

6 Please refer to Figure 2-1 for the load area acronyms

22 | P a g e

Demand Energy by BAAs in Year 2024

Load Regions

Gross Load in GWh (Including Transmission and Distribution losses) Retail Load in GWh

AESO 113,279 102,631

AZPS 36,149 32,751

AVA 14,592 13,220

BCHA 68,475 62,038

BPAT 60,903 55,178

CFE 14,475 13,114

CHPD 4,231 3,833

DOPD 1,829 1,657

EPE 10,814 9,798

IPFE 2,815 2,551

GCPD 5,253 4,759

IID 4,756 4,309

LDWP 35,296 31,978

IPMV 5,461 4,948

NEVP 29,213 26,467

NWMT 12,004 10,876

PAID 7,138 6,467

PAUT 32,078 29,063

PAWY 11,152 10,104

PACW 23,826 21,586

CIPB 52,500 47,565

CIPV 65,779 59,596

PGE 24,946 22,601

PNM 16,248 14,721

PSCO 43,025 38,980

PSEI 27,001 24,463

CISC 115,287 100,633

SCL 10,528 9,538

CISD 25,953 22,756

BANC 18,321 16,599

SPPC 15,336 13,895

SRP 40,145 36,371

TEPC 15,498 14,041

TIDC 3,045 2,759

TPWR 5,427 4,916

IPTV 11,865 10,750

WACM 32,164 29,141

WALC 5,380 4,874

WAUW 735 666

23 | P a g e

Demand Energy by BAAs in Year 2024

Load Regions

Gross Load in GWh (Including Transmission and Distribution losses) Retail Load in GWh

VEA 551 500

WECC Total 1,023,475 922,694

CA Total 321,489 286,695

CAISO Total 260,071 231,050 Table 2-1 Total Annual Energy Demand for BAAs in WECC for Year 2024 (GWh)

When generating the BAA loads for other years, the load growth rate is assumed 1.231% as stated in [9] in the State of California. The same load growth rate is assumed for other BAAs as an approximation.

2.2.4 Renewable Portfolio Standard

The Renewable Portfolio Standard (RPS) in each BAA is obtained from variety of sources [1], [7], and [8]. The RPS percentage of a BAA is calculated as follows

𝑅𝑃𝑆% = 𝑅𝑃𝑆(𝐺𝑊ℎ) − 𝑃𝑉_𝐵𝑇𝑀(𝐺𝑊ℎ)

𝐿𝑜𝑎𝑑(𝐺𝑊ℎ) − 𝑃𝑉_𝐵𝑇𝑀(𝐺𝑊ℎ)

Where 𝑃𝑉_𝐵𝑇𝑀 is the solar and distributed generation behind the meter.

The RPS percentage in California is growing from 33% in year 2020 to 42% in year 2025, assuming 3% to 4% of RPS from Out Of State (OOS). In years 2020 to 2025, only the wind and solar generation are assumed to grow in the WECC.

The renewable energy and load energy for years 2020 to 2025 by BAA and by technology are listed in the following tables.

24 | P a g e

RPS in GWh by Technology and BAA in Year 2020

Region Bio Geo Small Hydro PV-BTM Solar

Solar Thermal Wind

Total RPS

Total RPS w/o PV-BTM

Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 5,371 8,139 8,139 97,799 97,799 8%

AVA 1,456 - - 13 - - 292 1,761 1,748 12,598 12,585 14%

AZPS 50 - - 716 - 707 2,410 3,884 3,168 31,209 30,493 10%

BANC 15 134 197 329 1,120 - 55 1,850 1,521 15,817 15,488 10%

BCHA 2,922 - - - - - 1,429 4,351 4,351 59,117 59,117 7%

BPAT 3,804 - 10 105 45 - 12,724 16,689 16,584 52,580 52,475 32%

CFE - 5,653 - - 10 - 16 5,679 5,679 12,497 12,497 45%

CHPD - - - 3 - - - 3 - 3,653 3,650 0%

CIPB 310 - - 2,226 1,584 - 487 4,607 2,381 45,326 43,100 6%

CIPV 6,064 8,080 2,639 2,791 9,547 10 3,348 32,479 29,688 56,790 53,999 55%

CISC 2,938 2,577 431 5,227 12,251 2,782 9,563 35,769 30,542 95,895 90,667 34%

CISD 215 185 115 1,158 4,158 246 1,376 7,452 6,294 21,685 20,527 31%

DOPD - - - 1 - - - 1 - 1,579 1,578 0%

EPE - - - 21 222 - - 244 222 9,336 9,315 2%

GCPD - - - 3 - - - 3 - 4,535 4,532 0%

IID 860 3,103 110 95 1,277 16 - 5,461 5,366 4,106 4,011 134%

IPFE - - - 9 - - 142 151 142 2,431 2,421 6%

IPMV - 135 - 9 - - 731 876 867 4,715 4,706 18%

IPTV 253 248 - 13 - - 299 813 800 10,244 10,231 8%

LDWP 95 - 708 622 2,523 - 1,137 5,085 4,463 30,472 29,851 15%

NEVP - - - 181 462 184 - 828 646 25,221 25,040 3%

NWMT - - 43 23 - - 1,277 1,343 1,320 10,364 10,341 13%

25 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

PACW 361 - 19 61 - - 975 1,417 1,355 20,570 20,508 7%

PAID - - - 8 - - 477 485 477 6,163 6,155 8%

PAUT - 845 - 106 805 - - 1,756 1,650 27,694 27,589 6%

PAWY - - - 20 - - 2,905 2,925 2,905 9,628 9,609 30%

PGE 108 - - 58 2 - 867 1,035 977 21,537 21,479 5%

PNM - - - 153 166 - 1,939 2,258 2,105 14,028 13,875 15%

PSCO 32 - - 505 118 - 5,038 5,692 5,188 37,145 36,640 14%

PSEI 232 - - 16 - - 1,289 1,537 1,520 23,311 23,295 7%

SCL - - - 6 - - - 6 - 9,089 9,083 0%

SPPC 26 6,575 - 93 34 320 1,471 8,519 8,426 13,240 13,147 64%

SRP 257 - - 781 436 2 - 1,476 695 34,659 33,878 2%

TEPC - - - 323 228 - 105 655 333 13,380 13,058 3%

TH_Mead - - - - - 279 - 279 279 - - 0%

TH_PV - - - - 777 - - 777 777 - - 0%

TIDC - - 23 56 - - - 79 23 2,629 2,573 1%

TPWR 165 - - 4 - - - 168 165 4,685 4,681 4%

WACM - - - 242 29 - 402 674 431 27,769 27,526 2%

WALC - - - 222 - 884 - 1,106 884 4,645 4,423 20%

WAUW - - - 1 - - 135 137 135 635 633 21%

VEA - - - - - - - - - 476 476 0%

WECC Total 22,930 27,535 4,296 16,199 35,795 5,430 56,262 168,448 152,249 879,250 863,051 18%

CA 10,496 14,079 4,224 12,503 32,460 3,054 15,966 92,782 80,279 273,196 260,693 31%

26 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

Total

CAISO Total 9,526 10,842 3,186 11,402 27,540 3,038 14,774 80,307 68,905 220,171 208,769 33%

Table 2-2 RPS by Technology and BAA for Year 2020



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 5,874 8,642 8,642 98,985 98,985 9%

AVA 1,456 - - 14 - - 320 1,790 1,776 12,750 12,736 14%

AZPS 50 - - 783 - 773 2,636 4,243 3,460 31,588 30,804 11%

BANC 15 134 197 360 1,225 - 60 1,991 1,631 16,009 15,649 10%

BCHA 2,922 - - - - - 1,563 4,485 4,485 59,834 59,834 7%

BPAT 3,804 - 10 115 50 - 13,916 17,894 17,780 53,218 53,103 33%

CFE - 5,653 - - 11 - 17 5,681 5,681 12,649 12,649 45%

CHPD - - - 3 - - - 3 - 3,697 3,694 0%

CIPB 310 - - 2,434 1,732 - 533 5,010 2,575 45,876 43,441 6%

CIPV 6,064 8,080 2,639 3,052 10,441 11 3,662 33,949 30,896 57,479 54,426 57%

CISC 2,938 2,577 431 5,717 13,398 3,043 10,459 38,562 32,845 97,058 91,341 36%

CISD 215 185 115 1,266 4,548 269 1,505 8,102 6,835 21,948 20,682 33%

DOPD - - - 1 - - - 1 - 1,598 1,597 0%

EPE - - - 23 243 - - 267 243 9,450 9,426 3%

27 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

GCPD - - - 4 - - - 4 - 4,590 4,587 0%

IID 860 3,103 110 103 1,397 18 - 5,591 5,487 4,156 4,052 135%

IPFE - - - 10 - - 155 165 155 2,460 2,450 6%

IPMV - 135 - 10 - - 800 945 935 4,772 4,762 20%

IPTV 253 248 - 14 - - 327 842 828 10,368 10,354 8%

LDWP 95 - 708 680 2,759 - 1,243 5,486 4,806 30,842 30,162 16%

NEVP - - - 198 506 201 - 905 707 25,527 25,329 3%

NWMT - - 43 25 - - 1,397 1,465 1,440 10,490 10,465 14%

PACW 361 - 19 67 - - 1,067 1,514 1,447 20,819 20,752 7%

PAID - - - 8 - - 522 530 522 6,237 6,229 8%

PAUT - 845 - 115 880 - - 1,841 1,725 28,030 27,915 6%

PAWY - - - 21 - - 3,177 3,199 3,177 9,745 9,724 33%

PGE 108 - - 64 3 - 948 1,122 1,058 21,798 21,735 5%

PNM - - - 167 182 - 2,120 2,469 2,302 14,198 14,031 16%

PSCO 32 - - 552 129 - 5,510 6,223 5,670 37,596 37,044 15%

PSEI 232 - - 18 - - 1,410 1,659 1,641 23,594 23,576 7%

SCL - - - 7 - - - 7 - 9,199 9,192 0%

SPPC 26 6,575 - 102 37 350 1,609 8,699 8,597 13,401 13,299 65%

SRP 257 - - 854 476 3 - 1,590 736 35,079 34,226 2%

TEPC - - - 353 249 - 115 717 364 13,543 13,190 3%

TH_Mead - - - - - 305 - 305 305 - - 0%

TH_PV - - - - 850 - - 850 850 - - 0%

TIDC - - 23 61 - - - 84 23 2,661 2,600 1%

28 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

TPWR 165 - - 4 - - - 169 165 4,742 4,738 3%

WACM - - - 265 32 - 440 737 472 28,105 27,840 2%

WALC - - - 243 - 967 - 1,210 967 4,701 4,458 22%

WAUW - - - 2 - - 148 149 148 642 641 23%

VEA - - - - - - - - - 482 482 0%

WECC Total 22,930 27,535 4,296 17,716 39,147 5,939 61,531 179,094 161,378 889,915 872,200 19%

CA Total 10,496 14,079 4,224 13,674 35,500 3,340 17,461 98,773 85,099 276,510 262,836 32%

CAISO Total 9,526 10,842 3,186 12,470 30,119 3,322 16,158 85,622 73,152 222,842 210,372 35%




Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 6,377 9,145 9,145 100,186 100,186 9%

AVA 1,456 - - 16 - - 347 1,819 1,803 12,905 12,890 14%

AZPS 50 - - 850 - 840 2,862 4,602 3,752 31,971 31,120 12%

BANC 15 134 197 391 1,330 - 65 2,132 1,741 16,204 15,813 11%

BCHA 2,922 - - - - - 1,697 4,619 4,619 60,560 60,560 8%

BPAT 3,804 - 10 125 54 - 15,107 19,100 18,976 53,863 53,739 35%

CFE - 5,653 - - 12 - 19 5,684 5,684 12,802 12,802 44%

29 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

CHPD - - - 3 - - - 3 - 3,742 3,739 0%

CIPB 310 - - 2,643 1,881 - 578 5,412 2,769 46,432 43,789 6%

CIPV 6,064 8,080 2,639 3,314 11,335 12 3,975 35,419 32,105 58,176 54,862 59%

CISC 2,938 2,577 431 6,206 14,546 3,303 11,354 41,355 35,149 98,235 92,029 38%

CISD 215 185 115 1,375 4,937 292 1,633 8,751 7,377 22,214 20,839 35%

DOPD - - - 1 - - - 1 - 1,618 1,616 0%

EPE - - - 25 264 - - 289 264 9,564 9,539 3%

GCPD - - - 4 - - - 4 - 4,646 4,642 0%

IID 860 3,103 110 112 1,516 19 - 5,721 5,608 4,206 4,094 137%

IPFE - - - 11 - - 168 179 168 2,490 2,479 7%

IPMV - 135 - 11 - - 868 1,014 1,004 4,830 4,819 21%

IPTV 253 248 - 15 - - 355 871 856 10,494 10,479 8%

LDWP 95 - 708 738 2,996 - 1,350 5,887 5,149 31,216 30,478 17%

NEVP - - - 215 549 219 - 983 767 25,836 25,621 3%

NWMT - - 43 27 - - 1,516 1,586 1,559 10,617 10,590 15%

PACW 361 - 19 73 - - 1,158 1,611 1,538 21,072 20,999 7%

PAID - - - 9 - - 567 576 567 6,313 6,304 9%

PAUT - 845 - 125 955 - - 1,926 1,801 28,370 28,245 6%

PAWY - - - 23 - - 3,449 3,472 3,449 9,863 9,840 35%

PGE 108 - - 69 3 - 1,029 1,209 1,140 22,063 21,994 5%

PNM - - - 181 197 - 2,302 2,680 2,499 14,370 14,189 18%

PSCO 32 - - 599 140 - 5,982 6,753 6,153 38,052 37,452 16%

PSEI 232 - - 19 - - 1,530 1,781 1,762 23,880 23,861 7%

SCL - - - 8 - - - 8 - 9,311 9,303 0%

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Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

SPPC 26 6,575 - 110 40 380 1,747 8,878 8,768 13,564 13,453 65%

SRP 257 - - 927 517 3 - 1,704 777 35,505 34,578 2%

TEPC - - - 383 270 - 125 778 395 13,707 13,324 3%

TH_Mead - - - - - 331 - 331 331 - - 0%

TH_PV - - - - 923 - - 923 923 - - 0%

TIDC - - 23 66 - - - 89 23 2,693 2,627 1%

TPWR 165 - - 4 - - - 169 165 4,799 4,795 3%

WACM - - - 288 35 - 478 800 512 28,446 28,158 2%

WALC - - - 264 - 1,049 - 1,313 1,049 4,758 4,494 23%

WAUW - - - 2 - - 161 162 161 650 648 25%

VEA - - - - - - - - - 488 488 0%

WECC Total 22,930 27,535 4,296 19,233 42,499 6,447 66,799 189,740 170,507 900,710 881,477 19%

CA Total 10,496 14,079 4,224 14,845 38,539 3,626 18,956 104,765 89,920 279,864 265,019 34%

CAISO Total 9,526 10,842 3,186 13,537 32,698 3,606 17,541 90,937 77,399 225,545 212,007 37%




Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

31 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 6,880 9,648 9,648 101,401 101,401 10%

AVA 1,456 - - 17 - - 375 1,847 1,831 13,062 13,045 14%

AZPS 50 - - 917 - 906 3,088 4,961 4,044 32,359 31,441 13%

BANC 15 134 197 421 1,435 - 70 2,272 1,851 16,400 15,979 12%

BCHA 2,922 - - - - - 1,830 4,753 4,753 61,294 61,294 8%

BPAT 3,804 - 10 134 58 - 16,299 20,306 20,171 54,517 54,382 37%

CFE - 5,653 - - 13 - 20 5,686 5,686 12,957 12,957 44%

CHPD - - - 3 - - - 3 - 3,787 3,784 0%

CIPB 310 - - 2,851 2,029 - 624 5,814 2,963 46,995 44,144 7%

CIPV 6,064 8,080 2,639 3,575 12,229 13 4,289 36,888 33,313 58,881 55,306 60%

CISC 2,938 2,577 431 6,696 15,693 3,564 12,250 44,148 37,452 99,427 92,731 40%

CISD 215 185 115 1,483 5,326 315 1,762 9,401 7,918 22,484 21,000 38%

DOPD - - - 2 - - - 2 - 1,637 1,636 0%

EPE - - - 28 285 - - 312 285 9,680 9,653 3%

GCPD - - - 4 - - - 4 - 4,702 4,698 0%

IID 860 3,103 110 121 1,636 21 - 5,851 5,730 4,257 4,136 139%

IPFE - - - 12 - - 181 193 181 2,520 2,508 7%

IPMV - 135 - 12 - - 937 1,084 1,072 4,888 4,877 22%

IPTV 253 248 - 16 - - 383 900 884 10,621 10,605 8%

LDWP 95 - 708 797 3,232 - 1,456 6,288 5,492 31,595 30,798 18%

NEVP - - - 232 592 236 - 1,060 828 26,150 25,918 3%

NWMT - - 43 29 - - 1,636 1,708 1,679 10,746 10,717 16%

PACW 361 - 19 79 - - 1,249 1,708 1,629 21,327 21,249 8%

PAID - - - 10 - - 612 621 612 6,390 6,380 10%

32 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

PAUT - 845 - 135 1,031 - - 2,011 1,876 28,714 28,579 7%

PAWY - - - 25 - - 3,721 3,746 3,721 9,983 9,958 37%

PGE 108 - - 74 3 - 1,110 1,296 1,221 22,331 22,256 5%

PNM - - - 196 213 - 2,483 2,892 2,696 14,545 14,349 19%

PSCO 32 - - 647 151 - 6,454 7,283 6,636 38,513 37,867 18%

PSEI 232 - - 21 - - 1,651 1,903 1,883 24,170 24,149 8%

SCL - - - 8 - - - 8 - 9,424 9,415 0%

SPPC 26 6,575 - 119 43 410 1,885 9,058 8,939 13,728 13,609 66%

SRP 257 - - 1,000 558 3 - 1,818 818 35,935 34,936 2%

TEPC - - - 413 292 - 135 839 426 13,873 13,460 3%

TH_Mead - - - - - 358 - 358 358 - - 0%

TH_PV - - - - 996 - - 996 996 - - 0%

TIDC - - 23 72 - - - 94 23 2,726 2,655 1%

TPWR 165 - - 5 - - - 169 165 4,858 4,853 3%

WACM - - - 311 37 - 515 863 553 28,791 28,481 2%

WALC - - - 285 - 1,132 - 1,417 1,132 4,816 4,531 25%

WAUW - - - 2 - - 173 175 173 658 656 26%

VEA - - - - - - - - - 494 494 0%

WECC Total 22,930 27,535 4,296 20,750 45,851 6,956 72,068 200,386 179,636 911,636 890,886 20%

CA Total 10,496 14,079 4,224 16,016 41,579 3,912 20,451 110,757 94,741 283,259 267,243 35%

CAISO 9,526 10,842 3,186 14,605 35,277 3,891 18,925 96,251 81,646 228,281 213,675 38%

33 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

Total




Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 7,383 10,151 10,151 102,631 102,631 10%

AVA 1,456 - - 18 - - 402 1,876 1,858 13,220 13,202 14%

AZPS 50 - - 985 - 972 3,313 5,320 4,336 32,751 31,767 14%

BANC 15 134 197 452 1,540 - 75 2,413 1,961 16,599 16,147 12%

BCHA 2,922 - - - - - 1,964 4,886 4,886 62,038 62,038 8%

BPAT 3,804 - 10 144 62 - 17,490 21,511 21,367 55,178 55,034 39%

CFE - 5,653 - - 14 - 22 5,689 5,689 13,114 13,114 43%

CHPD - - - 4 - - - 4 - 3,833 3,830 0%

CIPB 310 - - 3,060 2,177 - 670 6,217 3,157 47,565 44,506 7%

CIPV 6,064 8,080 2,639 3,836 13,123 14 4,602 38,358 34,522 59,596 55,759 62%

CISC 2,938 2,577 431 7,185 16,840 3,824 13,145 46,940 39,755 100,633 93,448 43%

CISD 215 185 115 1,592 5,716 338 1,891 10,051 8,459 22,756 21,165 40%

DOPD - - - 2 - - - 2 - 1,657 1,655 0%

EPE - - - 30 305 - - 335 305 9,798 9,768 3%

GCPD - - - 4 - - - 4 - 4,759 4,755 0%

IID 860 3,103 110 130 1,755 22 - 5,981 5,851 4,309 4,179 140%

34 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

IPFE - - - 12 - - 195 207 195 2,551 2,538 8%

IPMV - 135 - 12 - - 1,005 1,153 1,141 4,948 4,935 23%

IPTV 253 248 - 17 - - 411 930 912 10,750 10,732 9%

LDWP 95 - 708 855 3,468 - 1,563 6,689 5,834 31,978 31,123 19%

NEVP - - - 249 635 253 - 1,138 888 26,467 26,218 3%

NWMT - - 43 31 - - 1,756 1,830 1,799 10,876 10,845 17%

PACW 361 - 19 84 - - 1,341 1,805 1,721 21,586 21,502 8%

PAID - - - 10 - - 656 667 656 6,467 6,457 10%

PAUT - 845 - 145 1,106 - - 2,096 1,951 29,063 28,918 7%

PAWY - - - 27 - - 3,993 4,020 3,993 10,104 10,077 40%

PGE 108 - - 80 3 - 1,191 1,383 1,303 22,601 22,521 6%

PNM - - - 210 229 - 2,665 3,103 2,893 14,721 14,511 20%

PSCO 32 - - 694 162 - 6,926 7,813 7,119 38,980 38,286 19%

PSEI 232 - - 22 - - 1,772 2,026 2,003 24,463 24,441 8%

SCL - - - 9 - - - 9 - 9,538 9,529 0%

SPPC 26 6,575 - 128 46 440 2,023 9,237 9,110 13,895 13,767 66%

SRP 257 - - 1,073 599 3 - 1,932 859 36,371 35,298 2%

TEPC - - - 443 313 - 144 901 457 14,041 13,598 3%

TH_Mead - - - - - 384 - 384 384 - - 0%

TH_PV - - - - 1,069 - - 1,069 1,069 - - 0%

TIDC - - 23 77 - - - 100 23 2,759 2,682 1%

TPWR 165 - - 5 - - - 170 165 4,916 4,912 3%

WACM - - - 333 40 - 553 926 593 29,141 28,807 2%

35 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

WALC - - - 305 - 1,215 - 1,520 1,215 4,874 4,569 27%

WAUW - - - 2 - - 186 188 186 666 664 28%

VEA - - - - - - - - - 500 - 0%

WECC Total 22,930 27,535 4,296 22,267 49,203 7,464 77,336 211,032 188,765 922,694 899,928 21%

CA Total 10,496 14,079 4,224 17,187 44,619 4,198 21,946 116,748 99,561 286,695 269,008 37%

CAISO Total 9,526 10,842 3,186 15,673 37,856 4,175 20,308 101,566 85,893 231,050 214,877 40%




Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

AESO 2,768 - - - - - 7,886 10,654 10,654 103,876 103,876 10%

AVA 1,456 - - 19 - - 429 1,905 1,885 13,380 13,361 14%

AZPS 50 - - 1,052 - 1,038 3,539 5,679 4,627 33,148 32,097 14%

BANC 15 134 197 483 1,644 - 80 2,554 2,071 16,800 16,317 13%

BCHA 2,922 - - - - - 2,098 5,020 5,020 62,791 62,791 8%

BPAT 3,804 - 10 154 67 - 18,682 22,717 22,563 55,847 55,693 41%

CFE - 5,653 - - 15 - 23 5,691 5,691 13,274 13,274 43%

36 | P a g e



Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

CHPD - - - 4 - - - 4 - 3,880 3,876 0%

CIPB 310 - - 3,268 2,326 - 715 6,619 3,351 48,142 44,874 7%

CIPV 6,064 8,080 2,639 4,098 14,016 14 4,916 39,828 35,730 60,319 56,221 64%

CISC 2,938 2,577 431 7,675 17,987 4,085 14,041 49,733 42,058 101,853 94,179 45%

CISD 215 185 115 1,700 6,105 361 2,020 10,700 9,000 23,032 21,332 42%

DOPD - - - 2 - - - 2 - 1,677 1,675 0%

EPE - - - 32 326 - - 358 326 9,917 9,885 3%

GCPD - - - 5 - - - 5 - 4,817 4,812 0%

IID 860 3,103 110 139 1,875 24 - 6,110 5,972 4,361 4,222 141%

IPFE - - - 13 - - 208 221 208 2,582 2,568 8%

IPMV - 135 - 13 - - 1,074 1,222 1,209 5,008 4,994 24%

IPTV 253 248 - 18 - - 439 959 940 10,880 10,862 9%

LDWP 95 - 708 913 3,705 - 1,669 7,090 6,177 32,366 31,453 20%

NEVP - - - 266 679 270 - 1,215 949 26,788 26,522 4%

NWMT - - 43 33 - - 1,875 1,951 1,918 11,008 10,975 17%

PACW 361 - 19 90 - - 1,432 1,902 1,812 21,848 21,758 8%

PAID - - - 11 - - 701 712 701 6,545 6,534 11%

PAUT - 845 - 155 1,182 - - 2,182 2,027 29,415 29,260 7%

PAWY - - - 29 - - 4,265 4,294 4,265 10,226 10,198 42%

PGE 108 - - 85 3 - 1,273 1,469 1,384 22,876 22,790 6%

PNM - - - 224 244 - 2,846 3,315 3,090 14,900 14,675 21%

PSCO 32 - - 741 173 - 7,397 8,343 7,602 39,453 38,712 20%

PSEI 232 - - 24 - - 1,892 2,148 2,124 24,760 24,736 9%

SCL - - - 10 - - - 10 - 9,654 9,644 0%

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Solar Thermal Wind

Total RPS


Retail Load

Retail load after

PV-BTM RPS%

SPPC 26 6,575 - 136 50 470 2,160 9,417 9,281 14,063 13,927 67%

SRP 257 - - 1,146 640 4 - 2,046 900 36,812 35,666 3%

TEPC - - - 474 334 - 154 962 489 14,212 13,738 4%

TH_Mead - - - - - 410 - 410 410 - - 0%

TH_PV - - - - 1,141 - - 1,141 1,141 - - 0%

TIDC - - 23 82 - - - 105 23 2,793 2,711 1%

TPWR 165 - - 5 - - - 170 165 4,976 4,971 3%

WACM - - - 356 43 - 590 989 633 29,494 29,138 2%

WALC - - - 326 - 1,298 - 1,624 1,298 4,934 4,607 28%

WAUW - - - 2 - - 199 201 199 674 672 30%

VEA - - - - - - - - - 506 506 0%

WECC Total 22,930 27,535 4,296 23,784 52,555 7,973 82,605 221,678 197,894 933,886 910,103 22%

CA Total 10,496 14,079 4,224 18,358 47,658 4,484 23,441 122,740 104,382 290,172 271,815 38%

CAISO Total 9,526 10,842 3,186 16,741 40,434 4,460 21,692 106,880 90,140 233,852 217,112 42%


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2.2.5 Contingency, Flexibility and Regulation Reserves

2.2.5.1 Contingency Reserves

The requirements for contingency reserves, i.e. spinning and non-spinning reserves, are defined for 28 reserve regions. The mapping between the reserve regions and the load regions is specified in the following table.

Reserve Region Load Region

AESO AESO

APS AZPS

AVA AVA

BCTC BCHA

BPA

BPAT

CHPD

DOPD

GCPD

SCL

TPWR

Burbank Burbank

CAISO

CIPB

CIPV

CISC

CISD

VEA

CFE CFE

EPE EPE

Glendale Glendale

IID IID

IPC

IPFE

IPMV

IPTV

LDWP LDWP

NVE

NEVP

SPPC

NWMT NWMT

PAC

PAID

PAUT

PAWY

PACW

PGN PGE

PNM PNM

PSC PSCO

PSE PSEI

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Reserve Region Load Region

SMUD BANC

SRP SRP

TEP TEPC

TIDC TIDC

WACM WACM

WALC WALC

WAUW WAUW Table 2-8 Mapping of Load Regions and Contingency Reserve Sharing Groups

The spinning reserve requirement of a reserve region is 3% of the loads of the load regions in the reserve region. The spinning reserve is provided by the eligible on-line generators in the regions. The non-spinning reserve requirement of a reserve region is 3% of the loads of the load regions in the reserve region. The non-spinning reserve is provided by the eligible on-line generators and the off-line quick startup generators in the region [3].

2.2.5.2 Regulation up and Regulation Down Reserves

The requirements of the regulation up and regulation down reserves are defined as 1% of the loads of the load regions in the reserve region. The regulation up and regulation down reserves are provided by the eligible on-line generators in the regions.

2.2.5.3 Flexibility Up and Flexibility Down Reserves

The requirements of the hourly flexibility up and flexibility down reserve for a reserve region are calculated based on the distribution of the 5-minute net load (load less solar and wind generation) less the hourly net load forecast in the reserve region [6]. The flexibility up and down reserve requirements are determined at 95 percent of the distribution.

2.2.6 Utah CAES Project Representation

A Compressed Air Energy System (CAES) operation can be illustrated in the following diagram.

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Figure 2-2 Illustration of a CAES operation

In the Utah CAES Project Phase 1, two CAES trains of equipment will be built with each train including 150 MW of both compressing and generating capacity. The storage cavern size for each train is 7.2 GWh (representing 48 hours of storage at full 150 MW generation output).

A CAES is modeled in PLEXOS as a pumped storage generator with 80% cycle efficiency and a CT generator. For purposes of the Plexos modeling, the compressing mode and generating mode are illustrated in the following diagrams.

~

Gen=0 MWh

Gen=150 MWh

Fuel=0 Btu

~

Gen=150 MWh

Storage

CAES in Compressing Mode

Gen=120 MWh

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Figure 2-3 CAES Compressing Mode Representation

Figure 2-4 CAES Generating Mode Representation

The following table summarizes the characteristics of the CAES project.

Utah CAES Properties Value

Trains 2

Max Cap per Train (MW) 150

Min Cap per Train (MW) 20

Max Ramp Rate per Train (MW/min) 30

Fuel Burned at Max Capacity per Train(mmBtu)

656.25

Heat Rate at CT Max Capacity of 50 MW per Train (Btu/kWh)

13,125

Heat Rate at Max Capacity of 150 MW per Train (Btu/kWh)

4,375

Max Compressing Load per Train (MW) 150

Min Compressing Load per Train (MW) 90

Storage (GWh) 7.2

Cycle Efficiency 80% Table 2-9 Characteristics of Utah CAES Project Representation in PLEXOS

The generation heat rate of 13,125 Btu/kWh shown in the above figure is based on the assumption that natural gas input to the CAES facility provides about one-third of the

Gen=50 MWh

Fuel=656.256 mm Btu

Heat Rate=13,125 Btu/kWh

~

Gen=100 MWh

~

Gen=150 MWh

Storage

CAES in Generating Mode

Gen=100 MWh

42 | P a g e

energy for generation (the rest coming from the stored energy). For Plexos modeling purposes, the 13,125 Btu/kWh figure is calculated by taking three times the actual heat rate of a CAES facility (i.e., 4,375 Btu/kWh applicable to 100% of the generation ouput energy7). The Plexos model then uses the 13,125 Btu/kWh figure for one-third of the generation output energy to determine CAES fuel costs.

The CAES project is capable of providing contingency reserves, regulation up and down reserves, and flex up and down reserves, in both compressing mode and generating mode.

Each 150 MW CAES train was assumed to be capable of compressing at the same time that the other CAES train was generating, and vice versa. The Plexos results showed this would happen only occasionally—and typically during ramping events when the needs for compression or generation would toggle from one to the other.

Energy Exemplar also initially tested the results of allowing the compressor mode and the generation mode of an individual train to operate at the same time. The Plexos results in this test showed this approach of operating significantly decreased the economic benefits of the CAES facility. As a result, for the balance of of the study it was assumed that each CAES train would either be in compression mode or generation mode in a particular time period—but not both at the same time.

2.2.7 Gas Forecast

The gas price assumption was originally from CEC IEPR 2013 [2]. The following table lists the Gas Price Forecast by Month for the year 2024 in real 2014 dollars.

7 “Lessons from Iowa: Development of a 270 Megawatt Compressed Air Energy Storage Projecy in Midwest Independent System Operator – A Study for the DOE Energy Storage Systems Program”, Robert H. Schulte, Nicholas Critelli, Hr., Kent Holst, and Georgianne Huff. Sandia Report, SAND2012-0388, January 2012.

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2024 Gas Price Forecast ($/mmBtu in Real 2014 dollars)

BAA or Region M01 M02 M03 M04 M05 M06 M07 M08 M09 M10 M11 M12

AESO 3.66 3.85 3.83 3.64 3.68 3.70 3.46 3.53 3.30 3.81 3.98 3.93

Arizona North 4.24 4.21 4.08 4.11 4.13 4.10 4.12 4.09 3.92 4.07 4.23 4.48

Arizona South 4.46 4.43 4.30 4.35 4.37 4.26 4.29 4.27 4.11 4.27 4.44 4.71

Baja 4.57 4.54 4.39 4.44 4.46 4.36 4.39 4.37 4.19 4.37 4.56 4.86

Baja California 4.57 4.54 4.39 4.44 4.46 4.36 4.39 4.37 4.19 4.37 4.56 4.86

BC Hydro 3.93 3.91 3.81 3.77 3.78 3.56 3.55 3.57 3.44 3.64 4.01 4.17

California Blythe 4.37 4.34 4.20 4.25 4.27 4.17 4.20 4.18 4.01 4.18 4.36 4.65

California Kern River 4.67 4.64 4.51 4.55 4.57 4.47 4.50 4.48 4.31 4.48 4.66 4.95

California Mojave 4.70 4.75 4.58 4.57 4.55 4.59 4.43 4.41 4.29 4.54 4.78 4.95

California PG&E BB 4.45 4.50 4.33 4.32 4.30 4.35 4.18 4.15 4.04 4.29 4.53 4.70

California PG&E LT 4.82 4.87 4.70 4.69 4.66 4.71 4.54 4.52 4.41 4.66 4.89 5.07

California San Juan Valley 4.33 4.31 4.17 4.21 4.23 4.14 4.17 4.15 3.97 4.14 4.32 4.61

California SDGE 5.15 5.12 4.97 5.02 5.04 4.93 4.96 4.94 4.74 4.93 5.14 5.45

California SoCal Gas 5.02 4.99 4.84 4.89 4.91 4.80 4.84 4.81 4.63 4.81 5.01 5.31

California SoCal Gas B 5.02 4.99 4.84 4.89 4.91 4.80 4.84 4.81 4.63 4.81 5.01 5.31

California SoCal Gas B Other 5.02 4.99 4.84 4.89 4.91 4.80 4.84 4.81 4.63 4.81 5.01 5.31

Colorado 4.13 4.11 4.12 3.90 3.71 3.80 3.74 3.54 3.60 3.87 3.93 4.51

Gas to CAES 3.99 3.97 3.97 3.76 3.57 3.66 3.60 3.40 3.46 3.73 3.78 4.36

Idaho North 3.87 3.86 3.75 3.72 3.73 3.50 3.49 3.51 3.39 3.59 3.97 4.14

Idaho South 3.99 3.97 3.87 3.84 3.85 3.62 3.61 3.63 3.50 3.70 4.08 4.24

Montana 3.76 3.95 3.94 3.75 3.78 3.79 3.55 3.62 3.39 3.91 4.08 4.03

Nevada North 4.52 4.50 4.50 4.27 4.07 4.18 4.10 3.90 3.96 4.25 4.30 4.92

Nevada South 4.70 4.67 4.53 4.58 4.60 4.50 4.53 4.51 4.33 4.51 4.69 4.98

Nevada South California 4.70 4.67 4.53 4.58 4.60 4.50 4.53 4.51 4.33 4.51 4.69 4.98

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2024 Gas Price Forecast ($/mmBtu in Real 2014 dollars)

BAA or Region M01 M02 M03 M04 M05 M06 M07 M08 M09 M10 M11 M12

New Mexico North 4.12 4.10 3.98 4.02 4.03 3.94 3.97 3.95 3.80 3.95 4.11 4.36

New Mexico South 4.27 4.25 4.13 4.17 4.19 4.09 4.11 4.09 3.94 4.09 4.25 4.51

Oregon 3.83 4.03 4.01 3.81 3.85 3.87 3.61 3.68 3.44 3.98 4.16 4.10

Oregon Malin 4.02 4.06 3.91 3.90 3.88 3.93 3.78 3.76 3.66 3.89 4.10 4.26

Synthetic Gas 5.02 4.99 4.84 4.89 4.91 4.80 4.84 4.81 4.63 4.81 5.01 5.31

Texas West 3.98 3.96 3.84 3.88 3.90 3.80 3.82 3.81 3.65 3.80 3.96 4.22

Utah 3.99 3.97 3.97 3.76 3.57 3.66 3.60 3.40 3.46 3.73 3.78 4.36

Washington 4.30 4.29 4.18 4.14 4.15 3.91 3.90 3.92 3.79 4.00 4.40 4.57

Wyoming 4.13 4.11 4.11 3.90 3.71 3.80 3.73 3.54 3.60 3.87 3.92 4.50 Table 2-10 Gas Price Forecast for Year 2024 by Month

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2.2.8 Emission Market Modeling for California

The California CO2 Market is modeled in this study. The CO2 price is 0.01248$/lb (or about $25/ton) and the commitment and dispatch price of the thermal generators in California includes the CO2 cost component.

The import energy from outside of California is charged with the GHG allowance as well. The energy imported from Northwest is charged at the tiered rate: at $0.523/MWh below the thresholds and $11.97/MWh above the thresholds. The thresholds follow the following patterns.

Thresholds for the Tiered CO2 Allowance Charge for Energy Import from NW into California

Threshold (MW) Time Period

1120 M01

1003 M02

1258 M03

2266 M04,D1-15

2471 M04,D16-30

3249 M05

2482 M06

1498 M07

920 M08,D1-15

268 M08,D16-31

146 M09

1 M10

97 M11

1 M12 Table 2-11 Thresholds for Tiered CO2 Allowance Charge for Energy Import from NW into California

The GHG allowance charge for the energy import from Southwest to California is constant of $11.97/MWh.

2.2.9 CAISO Export Transmission Charge

Any energy export from CAISO is charged at $10.83/MWh for the transmission usage.

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3 Modeling Approaches

3.1 PLEXOS SCUC/ED Algorithm

PLEXOS’ Security Constrained Unit Commitment (SCUC) algorithm consists of two major logics: Unit Commitment using Mixed Integer Programming and Network Applications. The SCUC/ED simulation algorithm is illustrated in the following figure.

Figure 3-1 PLEXOS Security Constrained Unit Commitment and Economic Dispatch Algorithm

The unit commitment and economic dispatch (UC/ED) logic performs the Energy-AS co-optimization using Mixed Integer Programming enforcing all resource and operation constraints. The UC/ED logic commits and dispatches resources to balance the system energy demand and meet the system reserve requirements.

The resource schedules from the UC/ED are passed to the Network Applications logic. The Network Applications logic solves the DC-OPF to enforce the power flow limits and nomograms. The Network Applications logic also performs the contingency analysis if the contingencies are defined. If there are any transmission limit violations, these transmission limits are passed to the UC/ED logic for the re-run of UC/ED. The iteration continues until all transmission limit violations are resolved. Thus the co-optimization solution of Energy-AS-DC-OPF is reached.

The same algorithm for the SCUC/ED is used by many ISO market scheduling software (some ISO market scheduling software may use AC-OPF in the Network Applications).

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One of the advantages of the MIP algorithm is its transparency. Any cost component or constraint in the MIP formula can be examined and explained.

The MIP mathematical formulation for the Energy-AS-DCOPF-PSH co-optimization can be illustrated by the following formula.

min ∑ {∑ [𝑐𝑘𝑡 ∙ 𝑔𝑘

𝑡 + 𝑠𝑐𝑘𝑡 ∙ (𝑢𝑘

𝑡 − 𝑢𝑘𝑡−1) + ∑ 𝑎𝑠𝑐𝑘,𝑎𝑠

𝑡 ∙ 𝑎𝑠𝑘,𝑎𝑠𝑡

𝐴𝑆

𝑎𝑠=1

]

𝐾

𝑘=1

}

𝑇

𝑡=1

Subject to

∑ 𝑔𝑘𝑡

𝐾

𝑘=1

+ 𝑒𝑓𝑓𝑔 ∙ 𝑔𝑝𝑠ℎ𝑡 = ∑ 𝑙𝑜𝑎𝑑𝑙

𝑡

𝐿

𝑙=1

+ 𝑝𝑢𝑚𝑝𝑝𝑠ℎ𝑡 + ∑ 𝑙𝑜𝑠𝑠𝑚

𝑡

𝑀

𝑚=1

∀𝑡,

(Energy Balance Constraint)

𝑠𝑡𝑜𝑡 = 𝑠𝑡𝑜𝑡−1 − 𝑔𝑝𝑠ℎ𝑡 + 𝑒𝑓𝑓𝑝 ∙ 𝑝𝑢𝑚𝑝𝑝𝑠ℎ

𝑡 ∀𝑡,

(PSH Storage Balance Constraint)

∑ 𝑎𝑠𝑘,𝑎𝑠𝑡

𝐾

𝑘=1

≥ 𝑎𝑠𝑎𝑠𝑡,𝑚𝑖𝑛 ∀𝑡, 𝑎𝑠,

(AS 𝑎𝑠 Requirement Constraints)

𝑎𝑠𝑘,𝑎𝑠𝑡,𝑚𝑖𝑛 ≤ 𝑎𝑠𝑘,𝑎𝑠

𝑡 ≤ 𝑎𝑠𝑘,𝑎𝑠𝑡,𝑚𝑎𝑥 ∀𝑡, 𝑎𝑠, 𝑘,

(Generator 𝑘 AS capacity Constraints)

𝑔𝑘𝑡,𝑚𝑖𝑛 ∙ 𝑢𝑘

𝑡 ≤ 𝑔𝑘𝑡 ± ∑ 𝑎𝑠𝑘,𝑎𝑠

𝑡

𝐴𝑆

𝑎𝑠=1

≤ 𝑔𝑘𝑡,𝑚𝑎𝑥 ∙ 𝑢𝑘

𝑡 ∀𝑡, 𝑘,

(Generation and AS Capacity Constraints)

𝑔𝑘𝑡 − 𝑔𝑘

𝑡−1 ± ∑ 𝑎𝑠𝑘,𝑎𝑠𝑡

𝐴𝑆

𝑎𝑠=1

≤ 𝑟𝑎𝑚𝑝𝑘𝑡,𝑚𝑎𝑥 ∙ 𝑢𝑘

𝑡 ∀𝑡, 𝑘,

(Generation and AS Ramp Capacity Constraint)

𝑓𝑗𝑡,𝑚𝑖𝑛 ≤ 𝑓𝑗

𝑡 = ∑ 𝑃𝑇𝐷𝐹𝑗𝑐,𝑘 ∙ (𝑔𝑘

𝑡 − 𝑙𝑜𝑎𝑑𝑘𝑡 )

𝐾

𝑘=1

≤ 𝑓𝑗𝑡,𝑚𝑎𝑥 ∀𝑡, 𝑗, 𝑐

(Transmission line 𝑗 Limit Constraints )

𝑖𝑗𝑐,𝑡,𝑚𝑖𝑛 ≤ ∑ 𝐼𝑙𝑖𝑛𝑒𝑗

𝑖 ∙ 𝑓𝑗𝑐,𝑡

𝑗∈𝑖

≤ 𝑖𝑗𝑐,𝑡,𝑚𝑎𝑥 ∀𝑡, 𝑖, 𝑐

(Interface 𝑖 Limit Constraints ) Generator Chronological Constraints

Resource Constraints User-Defined Constraints

Where

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𝑔𝑘𝑡 - Generation from generator 𝑘 at interval 𝑡;

𝑐𝑘𝑡 - Generation cost of generator 𝑘 at interval 𝑡;

𝑢𝑘𝑡 - Unit commitment status of generator 𝑘 at interval 𝑡; 1=on-line, 0=off-

line

𝑠𝑐𝑘𝑡 - Startup / shut down cost of generator 𝑘 at interval 𝑡;

𝑎𝑠𝑘,𝑎𝑠𝑡 - AS provision from generator 𝑘 to AS 𝑎𝑠 at interval 𝑡;

𝑎𝑠𝑐𝑘,𝑎𝑠𝑡 - AS provision cost of generator 𝑘 to AS 𝑎𝑠 at interval 𝑡;

𝑒𝑓𝑓𝑔 - PSH generating efficiency;

𝑒𝑓𝑓𝑝 - PSH pumping efficiency;

𝑔𝑝𝑠ℎ𝑡 - PSH generation at interval 𝑡;

𝑝𝑢𝑚𝑝𝑝𝑠ℎ𝑡 - PSH pump at interval 𝑡;

𝑙𝑜𝑎𝑑𝑙𝑡 - Load at bus 𝑙 at interval 𝑡;

𝑙𝑜𝑠𝑠𝑚𝑡 - Transmission losses of line 𝑚 at interval 𝑡;

𝑔𝑘𝑡,𝑚𝑖𝑛 - Min capacity of generator 𝑘 at interval 𝑡;

𝑔𝑘𝑡,𝑚𝑎𝑥 - Max capacity of generation 𝑘 at interval 𝑡;

𝑟𝑎𝑚𝑝𝑘𝑡,𝑚𝑎𝑥 - Max ramp up / down rate;

𝑎𝑠𝑎𝑠𝑡,𝑚𝑖𝑛 - Min AS requirement for AS 𝑎𝑠 at interval 𝑡;

𝑎𝑠𝑘,𝑎𝑠𝑡,𝑚𝑖𝑛 - Min AS provision of generator 𝑘 for AS 𝑎𝑠 at interval 𝑡;

𝑎𝑠𝑘,𝑎𝑠𝑡,𝑚𝑎𝑥 - Max AS provision of generator 𝑘 for AS 𝑎𝑠 at interval 𝑡;

𝑃𝑇𝐷𝐹𝑗𝑐,𝑘 - Power Transfer Distribution Factor of bus 𝑘 to transmission line 𝑗 for

post-contingency network 𝑐 (𝑐 = 0 is the pre-contingency network);

𝑓𝑗𝑐,𝑡 - Line flow in transmission line 𝑗 at interval 𝑡 for post-contingency

network 𝑐;

𝑓𝑗𝑐,𝑡,𝑚𝑖𝑛 - Min line flow of transmission line 𝑗 at interval 𝑡 for post-contingency

network 𝑐;

𝑓𝑗𝑐,𝑡,𝑚𝑎𝑥 - Max line flow of transmission line 𝑗 at interval 𝑡 for post-contingency

network 𝑐;

𝐼𝑙𝑖𝑛𝑒𝑗𝑖 - Line coefficient of transmission line 𝑗 in interface;

𝑖𝑗𝑐,𝑡,𝑚𝑖𝑛 - Min interface flow of interface 𝑖 at interval 𝑡 for post-contingency

network 𝑐;

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𝑖𝑗𝑐,𝑡,𝑚𝑎𝑥 - Max interface flow of interface 𝑖 at interval 𝑡 for post- contingency

network 𝑐;

The PSH pumping and generating are incorporated in Constraints “(Energy Balance Constraint)” and “(PSH Storage Balance Constraint)”. By doing so, the PSH operation is co-optimized with other variables: energy, ancillary services, power flow, etc. This formula is different from other legacy PSH dispatch algorithms: i.e., generating a thermal cost curve, then dispatching PSH against the thermal cost curve, and finally re-dispatching thermal generators with the PSH operation frozen. Incorporating the PSH operation into the MIP problem formulation, PSH’s, thus CAESs, impact to the energy market, ancillary service market and the transmission power flow will be captured.

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4 Simulation Results

The simulations without and with the Utah CAES project are performed for years 2020 to 2025. This section presents the simulation solution major results and analyses of the Utah CAES Project benefits.

4.1 Total WECC System Production Cost

The total production cost reduction is the most important index to measure the system level benefit with the Utah CAES project installed. The total production cost is calculated as

𝑇𝑜𝑡𝑎𝑙 𝑃𝑟𝑜𝑑 𝐶𝑜𝑠𝑡

= ∑(𝐹𝑢𝑒𝑙 𝐶𝑜𝑠𝑡 + 𝑉𝑂&𝑀 𝐶𝑜𝑠𝑡 + 𝑆𝑡𝑎𝑟𝑡 𝑢𝑝 & 𝑆ℎ𝑢𝑡 𝑑𝑜𝑤𝑛 𝐶𝑜𝑠𝑡

𝑔

+ 𝐸𝑚𝑖𝑠𝑠𝑖𝑜𝑛 𝐶𝑜𝑠𝑡)

𝑤ℎ𝑒𝑟𝑒 𝑔 𝑖𝑠 𝑔𝑒𝑛𝑒𝑟𝑎𝑡𝑜𝑟 1, 2, 3, ….

In addition, the BAA reserve provision shortfall cost is part of the system cost components. The BAA reserve provision shortfall is the BAA inability to meeting the contingency, regulation or flexibility reserve requirements. The different type of reserve provision shortfalls are priced at the following table.

Reserve Shortfall Price

($/MW)

Spinning 250

Non-spinning 210

Regulation Up 250

Regulation Down 260

Flex Up 200

Flex Down 80 Table 4-1 Penalty Prices for Reserve Provision Shortfall

The production cost savings due to the Utah CAES for years 2020 to 2025 are listed in the following table.

WECC Production Cost Savings with Utah CAES

Year Cost ($000) Base ($000) CAES ($000)

Savings ($000)

Saving Rate($/kW-year)

2020

Total Generation Cost 17,812,436 17,806,817 5,619 Reserve Provision

Shortfall Cost 11,533 11,020 513 Total System Cost 17,823,969 17,817,836 6,132 20.44

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WECC Production Cost Savings with Utah CAES

Year Cost ($000) Base ($000) CAES ($000)

Savings ($000)

Saving Rate($/kW-year)

2021


Shortfall Cost 14,736 12,820 1,916 Total System Cost 17,861,181 17,855,625 5,556 18.52

2022


Shortfall Cost 15,922 16,024 (103) Total System Cost 17,914,604 17,906,381 8,222 27.41

2023



2024



2025



Table 4-2 WECC Production Cost Savings due to Utah CAES Project

As the renewable generation increases from 168,448 GWh (18% RPS) in WECC or 92,782 GWh (31% RPS) in California for year 2020 to 221,678 GWh (22% RPS) in WECC or 122,740 (38% RPS) in California for year 2025, the WECC production cost savings due to the Utah CAES project increases from 6.132 million dollars for year 2020 to 31.752 million dollars for year 2025. The reserve provision shortfall costs are included in the production cost savings calculation.

4.2 Utah CAES Project Performance as Independent Power Producer (IPP)

The Utah CAES Project operational performance is measured by its 𝑁𝑒𝑡 𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑛𝑔 𝑅𝑒𝑣𝑒𝑛𝑢𝑒, which is calculated as

𝑁𝑒𝑡 𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑛𝑔 𝑅𝑒𝑣𝑒𝑛𝑢𝑒= 𝐸𝑛𝑒𝑟𝑔𝑦 𝑅𝑒𝑣𝑒𝑛𝑢𝑒 + 𝐴𝑆 𝑅𝑒𝑣𝑒𝑛𝑢𝑒 − 𝑃𝑢𝑚𝑝 𝐶𝑜𝑠𝑡 − 𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝐶𝑜𝑠𝑡

𝑤ℎ𝑒𝑟𝑒,

52 | P a g e

𝐸𝑛𝑒𝑟𝑔𝑦 𝑅𝑒𝑣𝑒𝑛𝑢𝑒 = ∑ 𝐿𝑀𝑃𝑡

𝑡

× 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛𝑡

𝑡 = ℎ𝑜𝑢𝑟 1, 2, 3, ….

𝐴𝑆 𝑅𝑒𝑣𝑒𝑛𝑢𝑒 = ∑ 𝑅𝑒𝑠𝑒𝑟𝑣𝑒 𝑃𝑟𝑖𝑐𝑒𝑠,𝑡

𝑠,𝑡

× 𝑅𝑒𝑠𝑒𝑟𝑣𝑒 𝑃𝑟𝑜𝑣𝑖𝑠𝑖𝑜𝑛𝑠,𝑡

𝑡 = ℎ𝑜𝑢𝑟 1, 2, 3, ….

𝑠 𝑟𝑒𝑝𝑟𝑒𝑠𝑒𝑛𝑡𝑠 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑡 𝐴𝑆 𝑚𝑎𝑟𝑘𝑒𝑡𝑠, 𝑙𝑖𝑘𝑒 𝑠𝑝𝑖𝑛, 𝑛𝑜𝑛 − 𝑠𝑝𝑖𝑛, 𝑓𝑙𝑒𝑥 𝑢𝑝, 𝑓𝑙𝑒𝑥 𝑑𝑜𝑤𝑛, 𝑟𝑒𝑔𝑢𝑝, 𝑟𝑒𝑔𝑑𝑛, 𝑒𝑡𝑐.

𝑃𝑢𝑚𝑝 𝐶𝑜𝑠𝑡 = ∑ 𝐿𝑀𝑃𝑡

𝑡

× 𝑃𝑢𝑚𝑝 𝐿𝑜𝑎𝑑𝑡

𝑡 = ℎ𝑜𝑢𝑟 1, 2, 3, ….

𝑂𝑝𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝐶𝑜𝑠𝑡 = ∑ 𝐹𝑢𝑒𝑙 𝐶𝑜𝑠𝑡𝑡

𝑡

+ 𝑉𝑂&𝑀 𝐶𝑜𝑠𝑡𝑡 + 𝑆𝑡𝑎𝑟𝑡 𝐶𝑜𝑠𝑡𝑡

𝑡 = ℎ𝑜𝑢𝑟 1, 2, 3, ….

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The Utah CAES Project value as an Independent Power Producer

Year 2020 2021 2022 2023 2024 2025

Item Value Rate Value Rate Value Rate Value Rate Value Rate Value Rate

Generation (GWh) 85

109

124

174

208

233 Pump (GWh) 70

91

103

143

173

189

Generating Hours/Year 889 10% 1,091 12% 1,208 14% 1,464 17% 1,717 20% 1,968 22%

Compressing Hours/Year 658 7% 817 9% 878 10% 1,165 13% 1,381 16% 1,503 17%

Fuel Burnt (GBTU) 367

478

541

751

908

1,021 Spinning (GWh) 214

231

253

265

300

314

Reg Up + Flex Up (GWh) 289

340

368

405

422

473

Reg Dn + Flex Dn (GWh) 43

63

82

124

160

183

Non-spin (GWh) 30

29

29

28

26

25 VOM Cost ($000) 312 $2.03 406 $2.03 460 $2.03 639 $2.03 772 $2.03 857 $2.03

Gen Cost ($000) (=Fuel Cost + VOM Cost) 1,679 $3.72 2,184 $3.72 2,499 $3.77 3,466 $3.77 4,204 $3.78 4,709 $3.77

Emission Cost ($000) 536 $0.0125 698 $0.0125 790 $0.0125 1,096 $0.0125 1,326 $0.0125 1,490 $0.0125

Total Gen Cost ($000) (=Gen Cost + Start Cost

+ Emission Cost) 2,215 $26.39 2,882 $26.39 3,289 $26.58 4,563 $26.59 5,531 $26.64 6,199 $26.57

Pump Cost ($000) (=Pump x LMP) 2,793 $39.97 3,554 $39.07 3,943 $38.27 5,379 $37.63 6,350 $36.72 6,766 $35.80

Energy Revenue ($000) (= Gen x LMP) 5,287 $63.00 6,732 $61.63 7,555 $61.05 10,214 $59.51 12,119 $58.37 13,590 $58.25

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The Utah CAES Project value as an Independent Power Producer

Year 2020 2021 2022 2023 2024 2025

Item Value Rate Value Rate Value Rate Value Rate Value Rate Value Rate

Reserve Revenue ($000) (=Reserve

Provision x Reserve Shadow Price) 2,978 $5.18 3,628 $5.47 4,676 $6.40 6,467 $7.87 8,493 $9.34 10,794 $10.84

Net Revenue ($000) (=Energy Revenue +

Reserve Revenue - Total Gen Cost - Pump

Cost) 3,257 $38.82 3,924 $35.92 4,998 $40.40 6,739 $39.27 8,731 $42.05 11,419 $48.95

Generation CF (%) 3.2%

4.1%

4.7%

6.5%

7.9%

8.9% Table 4-3 Utah CAES Project Value as an Independent Power Producer

As the renewable generation increases from 168,448 GWh (18% RPS) in WECC or 92,782 GWh (31% RPS) in California for year 2020 to 221,678 GWh (22% RPS) in WECC or 122,740 (38% RPS) in California for year 2025, the net operating profit of the Utah CAES Project increases from 3.257 million dollars for year 2020 to 11.419 million dollars for year 2025.

At the beginning of the simulation period, the initial volume in the cavern is assumed to be half of the full cavern capacity. At the end of the simulation period, the ending volume in the cavern is half of the full cavern capacity. Although the storage size of the Utah CAES Project is defined as 7.2 GWh, the max compressing energy is 0.54 GWh the represents nearly 2 consecutive hours’ full capacity (300 MW) compressing; the max discharging energy is 1.22GWh that represents nearly 4 consecutive hours’ full capacity (300MW) discharging.

55 | P a g e

4.3 Total Generation and Generation Cost Changes by Generator Type

Another interesting measurement to understand the impact from the Utah CAES project installation is how the existing generators in different categories will react to the Utah CAES project. The following table shows the generation and generation cost changes in WECC by generator type due to the Utah CAES project. Please note that

1. Total generation and generation cost increases from years 2020 to 2025. 2. CHP generators are grouped in the generator type CT so that the CT generation

cost rate ($/MWh) is lower than the CC generation cost rate ($/MWh). 3. California thermal generator cost includes the CO2 cost. 4. The total generation increases in the case of the Utah CAES project due to the

pumped-storage generator and energy storage generator operation activity increases.

The followings can be observed for the WECC Region overall:

Due to the Utah CAES project,

1. The Coal generation (“Coal” in the table) decreases in years 2020 and 2021, but increases in years 2022 to 2025.

2. The CC and CT generation (“CC” and “CT” in the table) increases in years 2020 and 2021, but decreases in years 2022 to 2025.

3. The activities of the pumped storage generators (“PSH” in the table) and energy storage generators (“ES” in the table) increase in years 2020 to 2025. The PSH and ES generation and pumping increases with the Utah CAES Project because the CAES facility takes reserve duties away from the PSH units and ES units, enabling more energy generation from the PSH and ES units since they are cheaper than the Utah CAES Project in energy generation mode.

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WECC Generation and Generation Cost Changes Due to the Utah CAES Project

Year Generator

Type

Generation (GWh)

Generation Reduction

Total Generation Cost ($000)

Generation

Cost Reduction

Generation Cost Rate ($/MWh)



Base CAES

2020

CAES - 84 (84) - 2,215 (2,215) - 26.39

Coal 234,733 234,494 239 5,523,053 5,519,232 3,820 23.53 23.54

Hydro 239,574 239,605 (31) - - - - -

Nuclear 56,561 56,561 - 1,294,762 1,294,762 - 22.89 22.89

Others 5,328 5,381 (52) 74,989 76,981 (1,992) 14.07 14.31

ST 2,266 2,317 (51) 65,936 68,121 (2,185) 29.10 29.40

Bio 18,351 18,414 (63) 523,462 525,711 (2,249) 28.53 28.55

CC 253,264 253,245 19 9,107,075 9,096,470 10,605 35.96 35.92

CT 35,663 35,756 (93) 1,144,071 1,144,236 (165) 32.08 32.00

DR-EE 3,099 3,099 - - - - - -

ES 1,387 1,449 (62) - - - - -

Geo 27,222 27,222 (0) 79,088 79,089 (1) 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

PSH 3,846 4,003 (158) - - - - -

PV-BTM 15,677 15,677 - - - - - -

Solar 40,031 40,031 - - - - - -

Wind 60,083 60,083 - - - - - -

Total 1,001,362 1,001,699 (337) 17,812,436 17,806,817 5,619 17.79 17.78

2021

CAES - 109 (109) - 2,882 (2,882) - 26.39

Coal 234,365 234,239 126 5,512,446 5,510,040 2,406 23.52 23.52

Hydro 239,588 239,591 (2) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

Nuclear 56,561 56,561 - 1,294,761 1,294,761 - 22.89 22.89

Others 5,307 5,358 (51) 74,747 76,698 (1,952) 14.08 14.31

ST 2,343 2,315 28 69,407 68,133 1,274 29.62 29.43

Bio 18,300 18,349 (49) 521,640 523,358 (1,717) 28.51 28.52

CC 253,102 253,505 (403) 9,095,656 9,103,328 (7,672) 35.94 35.91

CT 36,937 36,611 327 1,198,733 1,184,551 14,182 32.45 32.36

DR-EE 3,409 3,409 - - - - - -

ES 1,449 1,502 (53) - - - - -

Geo 27,211 27,210 1 79,055 79,054 2 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

PSH 3,972 4,108 (136) - - - - -

PV-BTM 17,145 17,145 - - - - - -

Solar 43,780 43,780 (0) - - - - -

Wind 65,709 65,709 - - - - - -

Total 1,013,456 1,013,779 (323) 17,846,446 17,842,805 3,641 17.61 17.60

2022

CAES - 124 (124) - 3,289 (3,289) - 26.58

Coal 233,883 234,159 (276) 5,498,665 5,507,347 (8,682) 23.51 23.52

Hydro 239,572 239,540 32 - - - - -

Nuclear 56,561 56,561 (0) 1,294,760 1,294,761 (0) 22.89 22.89

Others 5,267 5,310 (42) 73,605 75,258 (1,653) 13.97 14.17

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

ST 2,330 2,351 (22) 68,949 69,821 (872) 29.59 29.69

Bio 18,197 18,236 (38) 517,977 519,333 (1,356) 28.46 28.48

CC 253,988 253,418 570 9,133,836 9,101,657 32,178 35.96 35.92

CT 37,563 37,807 (244) 1,231,868 1,239,867 (7,999) 32.79 32.79

DR-EE 3,750 3,750 - - - - - -

ES 1,504 1,552 (48) - - - - -

Geo 27,199 27,200 (1) 79,022 79,024 (2) 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

PSH 3,983 4,137 (155) - - - - -

PV-BTM 18,613 18,613 - - - - - -

Solar 47,527 47,527 (0) - - - - -

Wind 71,336 71,336 - - - - - -

Total 1,025,550 1,025,898 (347) 17,898,682 17,890,357 8,325 17.45 17.44

2023

CAES - 172 (172) - 4,563 (4,563) - 26.59

Coal 232,996 233,360 (364) 5,472,868 5,483,211 (10,343) 23.49 23.50

Hydro 239,553 239,527 26 - - - - -

Nuclear 56,561 56,561 (0) 1,294,760 1,294,760 (0) 22.89 22.89

Others 5,296 5,313 (17) 75,379 75,744 (365) 14.23 14.26

ST 2,359 2,355 4 70,585 70,006 579 29.92 29.72

Bio 18,120 18,166 (46) 515,378 516,995 (1,617) 28.44 28.46

CC 254,355 254,050 305 9,159,764 9,131,922 27,841 36.01 35.95

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

CT 39,104 39,028 76 1,299,732 1,293,244 6,487 33.24 33.14

DR-EE 4,125 4,125 - - - - - -

ES 1,542 1,589 (47) - - - - -

Geo 27,187 27,188 (2) 78,985 78,990 (5) 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

PSH 4,056 4,214 (157) - - - - -

PV-BTM 20,081 20,081 - - - - - -

Solar 51,268 51,268 0 - - - - -

Wind 76,962 76,962 - - - - - -

Total 1,037,842 1,038,236 (394) 17,967,451 17,949,436 18,015 17.31 17.29

2024

CAES - 208 (208) - 5,531 (5,531) - 26.64

Coal 232,459 232,552 (93) 5,458,596 5,461,573 (2,977) 23.48 23.49

Hydro 239,531 239,563 (32) - - - - -

Nuclear 56,561 56,561 (0) 1,294,758 1,294,759 (1) 22.89 22.89

Others 5,311 5,332 (22) 76,733 77,271 (538) 14.45 14.49

ST 2,426 2,466 (40) 73,394 74,923 (1,530) 30.25 30.38

Bio 18,018 18,083 (65) 512,058 514,269 (2,211) 28.42 28.44

CC 254,733 254,559 174 9,185,331 9,160,664 24,667 36.06 35.99

CT 40,412 40,328 84 1,363,910 1,356,125 7,785 33.75 33.63

DR-EE 4,537 4,537 - - - - - -

ES 1,587 1,616 (29) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

Geo 27,183 27,183 (0) 78,974 78,975 (1) 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

PSH 4,122 4,256 (134) - - - - -

PV-BTM 21,549 21,549 - - - - - -

Solar 55,001 55,002 (0) - - - - -

Wind 82,583 82,588 (5) - - - - -

Total 1,050,292 1,050,661 (369) 18,043,755 18,024,090 19,664 17.18 17.16

2025

CAES - 233 (233) - 6,199 (6,199) - 26.57

Coal 231,666 232,208 (542) 5,438,639 5,452,995 (14,356) 23.48 23.48

Hydro 239,583 239,580 2 - - - - -

Nuclear 56,561 56,561 (0) 1,294,755 1,294,756 (1) 22.89 22.89

Others 5,354 5,379 (25) 78,786 79,582 (796) 14.71 14.80

ST 2,478 2,502 (23) 75,720 76,535 (815) 30.55 30.59

Bio 17,961 18,000 (39) 510,358 511,645 (1,288) 28.41 28.42

CC 255,371 254,840 530 9,223,219 9,179,558 43,661 36.12 36.02

CT 41,698 41,587 111 1,428,952 1,421,676 7,275 34.27 34.19

DR-EE 4,990 4,990 - - - - - -

ES 1,603 1,645 (42) - - - - -

Geo 27,172 27,179 (7) 78,943 78,964 (20) 2.91 2.91

Small Hydro 4,278 4,278 - - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PSH 4,196 4,347 (151) - - - - -

PV-BTM 23,017 23,017 - - - - - -

Solar 58,722 58,723 (1) - - - - -

Wind 88,208 88,213 (4) - - - - -

Total 1,062,860 1,063,282 (422) 18,129,371 18,101,910 27,461 17.06 17.02 Table 4-4 WECC Generation and Generation Cost Changes Due to Utah CAES Project

The following table shows the generation and generation cost changes in California by generator type due to the Utah CAES project. Please note that

1. Total generation and generation cost increases from years 2020 to 2025. 2. CHP generators are grouped in the generator type CT so that the CT generation cost rate ($/MWh) is lower than the CC

generation cost rate ($/MWh). 3. California thermal generator cost includes the CO2 cost. 4. The net import to California is reduced as the renewable generation increased from year 2020 to 2025.

The followings can be observed for the WECC Region overall:

Due to the Utah CAES project,

1. The Coal generation (“Coal” in the table) is slightly increased in years 2020 to 2025. 2. The CC and CT generation (“CC” and “CT” in the table) is increased in years 2020 and 2021, but decreased in years 2022 to

2025. 3. The net import to California is reduced in year 2020 and 2021 but is increased from year 2022 to year 2025.

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4. The activities of the pumped storage generators (“PSH” in the table) and energy storage generators (“ES” in the table) increase in years 2020 to 2025 as the renewable generation increases from year 2020 to 2025. Again, the PSH and ES generation and pumping increases with the Utah CAES Project because the CAES facility takes reserve duties away from the PSH units and ES units, enabling more energy generation from the PSH and ES units since they are cheaper than the Utah CAES Project in energy generation mode.

California Generation and Generation Cost Changes Due to the Utah CAES Project

Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

2020

CAES - 84 (84) - 2,215 (2,215) - 26.39

Coal 11,198 11,265 (68) 518,000 520,909 (2,908) 23.53 23.54

Hydro 35,016 34,995 21 - - - - -

Nuclear 17,114 17,114 - 392,540 392,540 - 22.89 22.89

Others 270 287 (18) 15,132 15,929 (797) 14.07 14.31

ST 1,580 1,627 (47) 44,274 46,259 (1,984) 29.10 29.40

Bio 9,891 9,909 (18) 322,493 323,196 (703) 28.53 28.55

CC 83,535 83,569 (34) 3,744,441 3,740,820 3,621 35.96 35.92

CT 9,462 9,480 (18) 340,554 340,776 (222) 32.08 32.00

DR-EE 3,099 3,099 0 - - - - -

ES 1,387 1,449 (62) - - - - -

Geo 14,476 14,476 0 42,203 42,203 0 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,393 3,551 (159) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 12,022 12,022 - - - - - -

Solar 34,361 34,361 0 - - - - -

Wind 16,203 16,203 (0) - - - - - CA Internal Total 257,212 257,698 (486) 5,419,639 5,424,847 (5,208) 17.79 17.78

Net Import 63,018 62,869 149

CA Total 320,230 320,566 (336)

2021

CAES - 109 (109) - 2,882 (2,882) - 26.39

Coal 11,094 11,147 (53) 513,518 515,819 (2,301) 23.52 23.52

Hydro 34,993 34,996 (3) - - - - -

Nuclear 17,114 17,114 - 392,539 392,539 - 22.89 22.89

Others 278 300 (22) 15,711 16,724 (1,013) 14.08 14.31

ST 1,642 1,612 31 46,903 45,605 1,298 29.62 29.43

Bio 9,798 9,815 (17) 319,204 319,841 (637) 28.51 28.52

CC 82,211 82,386 (176) 3,693,277 3,697,299 (4,022) 35.94 35.91

CT 9,593 9,548 45 349,250 346,178 3,072 32.45 32.36

DR-EE 3,409 3,409 - - - - - -

ES 1,449 1,502 (53) - - - - -

Geo 14,466 14,464 1 42,171 42,168 4 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,531 3,660 (129) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 13,147 13,147 - - - - - -

Solar 37,579 37,579 (0) - - - - -

Wind 17,721 17,721 - - - - - - CA Internal Total 262,231 262,715 (485) 5,372,575 5,379,055 (6,481) 17.61 17.60

Net Import 61,962 61,790 172

CA Total 324,192 324,505 (313)

2022

CAES - 124 (124) - 3,289 (3,289) - 26.58

Coal 10,971 11,005 (34) 508,201 509,721 (1,520) 23.51 23.52

Hydro 34,973 34,991 (17) - - - - -

Nuclear 17,114 17,114 (0) 392,539 392,539 (0) 22.89 22.89

Others 280 297 (16) 15,920 16,678 (758) 13.97 14.17

ST 1,607 1,627 (20) 45,401 46,185 (785) 29.59 29.69

Bio 9,667 9,699 (32) 314,537 315,657 (1,120) 28.46 28.48

CC 81,109 80,948 161 3,660,697 3,647,084 13,613 35.96 35.92

CT 9,631 9,620 10 353,750 352,843 907 32.79 32.79

DR-EE 3,750 3,750 - - - - - -

ES 1,504 1,552 (48) - - - - -

Geo 14,455 14,454 0 42,139 42,138 1 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,556 3,705 (149) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 14,273 14,273 - - - - - -

Solar 40,794 40,795 (0) - - - - -

Wind 19,238 19,238 - - - - - - CA Internal Total 267,128 267,397 (268) 5,333,184 5,326,135 7,049 17.45 17.44

Net Import 60,933 61,003 (70)

CA Total 328,061 328,399 (338)

2023

CAES - 172 (172) - 4,563 (4,563) - 26.59

Coal 10,816 10,849 (33) 501,648 503,105 (1,457) 23.49 23.50

Hydro 34,928 34,934 (6) - - - - -

Nuclear 17,114 17,114 (0) 392,538 392,539 (0) 22.89 22.89

Others 297 302 (5) 17,083 17,103 (20) 14.23 14.26

ST 1,596 1,611 (14) 45,087 45,510 (422) 29.92 29.72

Bio 9,553 9,577 (23) 310,638 311,440 (802) 28.44 28.46

CC 80,392 80,037 355 3,644,571 3,623,366 21,205 36.01 35.95

CT 9,689 9,722 (33) 359,560 360,773 (1,213) 33.24 33.14

DR-EE 4,124 4,124 - - - - - -

ES 1,542 1,589 (47) - - - - -

Geo 14,443 14,443 (0) 42,105 42,105 (0) 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,644 3,789 (145) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 15,399 15,399 - - - - - -

Solar 44,005 44,005 0 - - - - -

Wind 20,756 20,756 (0) - - - - - CA Internal Total 272,503 272,626 (123) 5,313,231 5,300,504 12,727 17.31 17.29

Net Import 59,524 59,774 (250)

CA Total 332,027 332,400 (373)

2024

CAES - 208 (208) - 5,531 (5,531) - 26.64

Coal 10,702 10,730 (29) 496,797 498,087 (1,290) 23.48 23.49

Hydro 34,927 34,916 11 - - - - -

Nuclear 17,114 17,114 (0) 392,537 392,537 (1) 22.89 22.89

Others 313 320 (8) 18,217 18,396 (179) 14.45 14.49

ST 1,594 1,640 (46) 44,967 46,828 (1,862) 30.25 30.38

Bio 9,414 9,434 (20) 305,954 306,624 (670) 28.42 28.44

CC 79,509 79,194 315 3,624,001 3,601,467 22,534 36.06 35.99

CT 9,768 9,722 45 368,766 364,664 4,102 33.75 33.63

DR-EE 4,537 4,537 - - - - - -

ES 1,587 1,616 (29) - - - - -

Geo 14,441 14,439 1 42,098 42,094 4 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,711 3,836 (126) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 16,524 16,524 - - - - - -

Solar 47,207 47,207 (0) - - - - -

Wind 22,273 22,273 0 - - - - - CA Internal Total 277,825 277,917 (92) 5,293,337 5,276,228 17,109 17.18 17.16

Net Import 58,203 58,470 (266)

CA Total 336,028 336,386 (358)

2025

CAES - 233 (233) - 6,199 (6,199) - 26.57

Coal 10,586 10,622 (35) 491,968 493,535 (1,566) 23.48 23.48

Hydro 34,928 34,929 (1) - - - - -

Nuclear 17,113 17,113 (0) 392,533 392,534 (1) 22.89 22.89

Others 325 332 (8) 19,019 19,305 (285) 14.71 14.80

ST 1,598 1,611 (13) 45,208 45,615 (407) 30.55 30.59

Bio 9,283 9,317 (34) 301,645 302,785 (1,140) 28.41 28.42

CC 78,032 77,410 621 3,577,000 3,541,557 35,443 36.12 36.02

CT 9,829 9,780 49 376,866 373,503 3,363 34.27 34.19

DR-EE 4,990 4,990 0 - - - - -

ES 1,603 1,645 (42) - - - - -

Geo 14,431 14,436 (5) 42,070 42,086 (16) 2.91 2.91

Small Hydro 4,206 4,206 0 - - - - -

PSH 3,769 3,913 (143) - - - - -

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Year Generator

Type

Generation (GWh)



Generation

Cost Reduction




Base CAES

PV-BTM 17,650 17,650 - - - - - -

Solar 50,397 50,398 (1) - - - - -

Wind 23,790 23,790 - - - - - - CA Internal Total 282,530 282,377 154 5,246,310 5,217,118 29,192 17.06 17.02

Net Import 57,496 58,060 (564)

CA Total 340,026 340,437 (411) Table 4-5 California Generation and Generation Cost Changes Due to Utah CAES Project

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4.4 Solar and Wind Generation Curtailment

In the pumping mode, the Utah CAES project can absorb some of the over-generation from the solar and wind generators. Table 4-6 shows that the Utah CAES project helps reduce the solar and wind generation curtailment in WECC, though the magnitude of the solar and wind generation curtailment reduction is not significant. In year 2022, the solar generation curtailment slightly increases with the Utah CAES project.

The renewable generation curtailment is calculated by these formulas

𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐶𝑢𝑟𝑡𝑎𝑖𝑙𝑚𝑒𝑛𝑡= 𝐷𝑒𝑓𝑖𝑛𝑒𝑑 𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛 𝑃𝑟𝑜𝑓𝑖𝑙𝑒− 𝐴𝑐𝑡𝑢𝑎𝑙 𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐺𝑒𝑛𝑒𝑟𝑎𝑡𝑖𝑜𝑛

𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐶𝑢𝑟𝑡𝑎𝑖𝑙𝑚𝑒𝑛𝑡 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 (𝐺𝑊ℎ)= 𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐶𝑢𝑟𝑡𝑎𝑖𝑙𝑚𝑒𝑛𝑡𝐵𝑎𝑠𝑒 − 𝑅𝑒𝑛𝑒𝑤𝑎𝑏𝑙𝑒 𝐶𝑢𝑟𝑡𝑎𝑖𝑙𝑚𝑒𝑛𝑡𝐶𝐴𝐸𝑆

WECC Solar and Wind Curtailment (GWh) Curtailment Reduction (GWh)

Year Base CAES

Solar Wind Solar Wind Solar Wind

2020 - - - - - -

2021 0.15 - 0.05 - 0.10 -

2022 2.05 - 1.92 - 0.13 -

2023 9.18 - 9.38 - (0.21) -

2024 24.67 4.95 24.42 - 0.24 4.95

2025 52.35 6.34 51.74 1.85 0.61 4.50 Table 4-6 WECC Renewable Curtailment Reduction Due to Utah CAES Project

4.5 Emissions Production


With the Utah CAES Project, the coal is increased slight for years 2020 to 2025. However, due to the CC and CT generation increase in California in years 2020 and 2021 but reduction in years 2022 to 2025, the CO2 production in California is increased in years 2020 and 2021 but reduced in years 2022 to 2025.

The CO2 reduction in ton and in percentage is calculated as follows.

𝐶𝑂2 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 (𝑠ℎ𝑜𝑟𝑡 𝑡𝑜𝑛) = 𝑇𝑜𝑡𝑎𝑙 𝐶𝑂2𝑏𝑎𝑠𝑒 − 𝑇𝑜𝑡𝑎𝑙 𝐶𝑂2𝐶𝐴𝐸𝑆

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𝐶𝑂2 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛 (%) =𝐶𝑂2 𝑅𝑒𝑑𝑢𝑐𝑡𝑖𝑜𝑛(𝑠ℎ𝑜𝑟𝑡 𝑡𝑜𝑛)

𝑇𝑜𝑡𝑎𝑙 𝐶𝑂2(𝑠ℎ𝑜𝑟𝑡 𝑡𝑜𝑛)𝑏𝑎𝑠𝑒

Year


Base CAES

CO2 Reduct

ion


CO2 Cost

Reduction

CO2 Cost

Reduction (%)

2020 370,528 370,378 150 0.04% 1,286,122 1,288,657 (2,535) -0.20%

2021 371,032 370,925 107 0.03% 1,273,065 1,275,707 (2,642) -0.21%

2022 371,566 371,750 (185) -0.05% 1,261,043 1,260,293 750 0.06%

2023 371,979 372,156 (178) -0.05% 1,252,827 1,250,945 1,882 0.15%

2024 372,702 372,723 (21) -0.01% 1,244,758 1,242,042 2,716 0.22%

2025 373,347 373,634 (287) -0.08% 1,229,569 1,224,093 5,476 0.45% Table 4-7 WECC CO2 Reduction and CA CO2 Cost Reduction Due to Utah CAES Project

4.6 Intermountain Power Plant Production

The existing, coal-fired Intermountain Power Plant (IPP) operation is examined in this study. The following table shows the IPP operation for years 2020 to 2025. The observations can be listed as follows.

1. The IPP generation increases slightly with the Utah CAES project. This indicates that the IPP provides a certain amount of compressing energy to the Utah CAES project.

2. The IPP provides less spinning and regulation up reserves as the Utah CAES project provides spinning and regulation up reserves.

3. The IPP provides slightly more flex up reserve with the Utah CAES project. 4. The IPP provides slightly less regulation down and flex down reserves with the

Utah CAES project.

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Intermountain Power Plant Generation and AS Service

Generation (GWh)

Spinning / Regulation up

Reserve (GWh)

Flex Up Reserve (GWh)

Regulation / Flex down

Reserve (GWh)

Replacement Reserve (GWh)

Capacity Factor (%)

Year Generator Base CAES Base CAES Base CAES Base CAES Base CAES Base CAES

2020

Intermountain1 6,016 6,050 103 61 317 340 405 403 - - 82 82

Intermountain2 5,090 5,123 110 63 436 477 304 305 - - 68 69

Total 11,106 11,173 213 124 753 818 355 354 - - 75 75

2021

Intermountain1 5,962 5,988 113 64 336 373 437 424 - - 81 81

Intermountain2 5,054 5,074 109 63 463 501 341 342 - - 68 68

Total 11,016 11,062 222 127 799 874 389 383 - - 74 75

2022

Intermountain1 5,893 5,921 117 65 367 398 471 458 - - 80 80

Intermountain2 5,008 5,020 106 63 489 520 375 364 - - 67 67

Total 10,900 10,941 223 127 856 918 423 411 - - 74 74

2023

Intermountain1 5,806 5,827 121 72 388 425 493 493 - - 79 79

Intermountain2 4,961 4,973 112 62 500 541 403 388 - - 66 67

Total 10,767 10,800 233 134 887 966 448 441 - - 73 73

2024

Intermountain1 5,729 5,754 121 70 412 452 520 517 - - 78 78

Intermountain2 4,934 4,937 108 62 519 551 421 410 - - 66 66

Total 10,663 10,691 229 132 932 1,003 471 464 - - 72 72

2025

Intermountain1 5,651 5,677 131 70 431 477 534 531 - - 77 77

Intermountain2 4,896 4,905 104 63 531 561 451 437 - - 66 66

Total 10,547 10,583 235 132 963 1,039 493 484 - - 71 71 Table 4-8 Intermountain Power Plant Generation and AS Service

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4.7 Intermountain Power Plant DC-Tie

The Intermountain Power Plant (IPP) DC-tie from Utah to Southern California is examined in this study. The IPP DC-Ties is a bi-circuit DC transmission line called the Southern Transmission System (STS). The following table shows the IPP DC-Tie Capacity Factors for both circuits for years 2020 to 2025. The typical annual flow on the STS is from North (Utah) to South (Southern California) and the polarity of flow does not reverse to South to North. This is representative of the operation of the baseload IPP coal plant in Utah, for which the STS was originally built, providing most of its energy service to Southern California. In some years, the flow from North to South increases with the Utah CAES project, and decreases in some other years. There is no pattern that can be recognized from year 2020 to year 2025.

Line

26114_INTERMTX To 26011_ADELANTX_1

26116_INTERMTY To 26012_ADELANTY_1 Total Flow (GWh)

Year

Base CAES Base CAES Base CAES

Flow Increase (GWh)

2020 Load Factor (%) 76.4% 77.5% 75.7% 75.5% 16,038 16,118 81

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

2021 Load Factor (%) 76.1% 76.3% 76.8% 76.2% 16,110 16,069 (41)

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

2022 Load Factor (%) 77.6% 77.1% 76.2% 76.2% 16,208 16,154 (54)

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

2023 Load Factor (%) 77.5% 77.1% 76.0% 77.0% 16,187 16,239 51

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

2024 Load Factor (%) 77.5% 76.8% 76.7% 77.5% 16,252 16,260 8

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

2025 Load Factor (%) 76.8% 76.9% 76.9% 76.7% 16,206 16,188 (19)

Load Factor Back (%) 0.0% 0.0% 0.0% 0.0% - - -

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Table 4-9 IPP DC-Tie flows with and without Utah CAES Project

However, if examining the hourly flow as shown in the following chart, one can observe that:

1. In the CAES compressing hours (red curve), the flow from North to South (green curve) is decreased as opposed to the flow in the Base Case (purple curve). This indicates that some generation flows from Southern California to Utah to provide compressing energy for the Utah CAES project.

2. In the CAES generating hours (blue curve), the flow from North to South (green curve) is increased as opposed to the flow in the Base Case (purple curve). This indicates that some generation from the Utah CAES flows to Southern California.

Figure 4-1 STS Flow versus Utah CAES Project Operation in a Typical Day of May, 2025

0

50

100

150

200

250

300

350

0

500

1000

1500

2000

2500

3000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

STS

DC

-Tie

Flo

w M

Wh

STS Flow versus Utah CAES Project Operation

North-South Flow in CAES

North-South Flow in Base

CAES Generation

CAES Pump Load

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5 Findings

The retail load, renewable energy, and RPS % in WECC and California are listed in the following charts.

Figure 5-1 WECC Retail Loads and Renewable Generation

Figure 5-2 WECC RPS %

-

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

1,000,000

2020 2021 2022 2023 2024 2025

WECC Retail Load and Renewable Generation in GWh

Retail Load Renewable Generation

0%

5%

10%

15%

20%

25%

2020 2021 2022 2023 2024 2025

WECC RPS in %

RPS %

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Figure 5-3 California Retail Load and Renewable Generation

Figure 5-4 California RPS in %

California has a few out of state (OOS) renewable projects that are approximately between 3% and 4% of the retail load in California.

The findings from the simulation result analyses are listed as follows in real, 2014 dollars including escalation but excluding general inflation.

5.1 WECC Production Cost

The WECC total production cost savings due to the Utah CAES Project by year, including the reserve provision shortfall cost reductions, are listed in the following chart.

-

50,000

100,000

150,000

200,000

250,000

300,000

350,000

2020 2021 2022 2023 2024 2025

California Retail Load and Renewable Generation in GWh

Retail Load Renewable Generation OOS Renewable Generation

0%

5%

10%

15%

20%

25%

30%

35%

40%

45%

2020 2021 2022 2023 2024 2025

California RPS in %

RPS % OOS RPS%

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Figure 5-5 WECC Total Production Cost Saving due to Utah CAES Project

It is noticed that, when the renewable energies reach 20% in WECC or 37% in California (including the OOS renewables) in year 2023, the WECC production cost savings due to the Utah CAES project sharply increase to nearly 20 million dollars.

5.2 Utah CAES Project Operation Performance

The Utah CAES Project earns energy arbitrage revenue and AS revenue. Usually, the net operating revenue represents the profit of the project that is operated as an Independent Power Producer (IPP) in a power market.

The following charts display the Utah CAES project operation, operation costs, energy and AS revenues, and net operating revenues.

Figure 5-6 Utah CAES Project Generation and Total Reserve Provision (GWh)

-

200

400

600

800

1,000

1,200

1,400

2020 2021 2022 2023 2024 2025

CAES Generation and Total Reserve Provisions (GWh) by Year

Generation Reserve Provision

-

5,000

10,000

15,000

20,000

25,000

30,000

35,000

2020 2021 2022 2023 2024 2025

WECC Total Production Cost Savings in 000$ due to Utah CAES Project (Including Reserve Shortfall Cost Reduction)

Production Cost Savings

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Figure 5-7 Utah CAES Operating Costs

Figure 5-8 Utah CAES Energy and AS Revenues

-

5,000

10,000

15,000

20,000

25,000

2020 2021 2022 2023 2024 2025

CAES Operating Cost (000$) by Year

Generation Cost Pumping Cost

-

5,000

10,000

15,000

20,000

25,000

2020 2021 2022 2023 2024 2025

CAES Operating Revenue (000$) by Year

Energy Revenue AS Revenue

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Figure 5-9 Utah CAES Project Net Operating Revenue

The Utah CAES project net operating revenue is calculated as

Net Operating Revenue = Energy Revenue (LMP x Generation) + Reserve Revenue (Reserve Shadow Price x Reserve Provision) – Fuel and VO&M Cost – Pumping Cost (LMP x Pumping Load)

One can notice that the net revenue increases from 3 million dollars in year 2020 to 11 million dollars in year 2025.

5.3 Impact on Other Generators

The following table shows the generation changes in WECC by generator type due to the Utah CAES project.

The following can be observed:

1. With the Utah CAES project, the Coal generation (“COAL” in the table) in WECC is reduced with the Utah CAES project in years 2020 and 2021, but increased from year 2022 to year 2025.

2. With the Utah CAES Project, the CC and CT generation8 (“CC” and “CT” in the table) in WECC is increased in years 2020 and 2021, but reduced from year 2022 to year 2025.

From the observation point 1, the CO2 production in WECC is reduced in years 2020 and 2021 but increased in years 2022 to 2025.

With the renewable generation increase from year 2020 to year 2025 and due to the Utah CAES project, the activities of the pumped storage generators (“PSH” in the table)


-

2,000

4,000

6,000

8,000

10,000

12,000

2020 2021 2022 2023 2024 2025

CAES Net Operating Revenue (000$) by Year

Net Revenue

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and the energy storage generators (“ES” in the table) are increased. The Utah CAES project shares the reserve provisions from the PSH and ES facilities so that the PSH and ES facilities can generate more energy.

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WECC Generation in GWh by Generator Type

Generator Type

2020 2021 2022 2023 2024 2025







CAES - 84 (84) - 109 (109) - 124 (124) - 172 (172) - 208 (208) - 233 (233)

Coal 234,733 234,494 239 234,365 234,239 126 233,883 234,159 (276) 232,996 233,360 (364) 232,459 232,552 (93) 231,666 232,208 (542)

Hydro 239,574 239,605 (31) 239,588 239,591 (2) 239,572 239,540 32 239,553 239,527 26 239,531 239,563 (32) 239,583 239,580 2

Nuclear 56,561 56,561 - 56,561 56,561 - 56,561 56,561 (0) 56,561 56,561 (0) 56,561 56,561 (0) 56,561 56,561 (0)

Others 5,328 5,381 (52) 5,307 5,358 (51) 5,267 5,310 (42) 5,296 5,313 (17) 5,311 5,332 (22) 5,354 5,379 (25)

ST 2,266 2,317 (51) 2,343 2,315 28 2,330 2,351 (22) 2,359 2,355 4 2,426 2,466 (40) 2,478 2,502 (23)

Bio 18,351 18,414 (63) 18,300 18,349 (49) 18,197 18,236 (38) 18,120 18,166 (46) 18,018 18,083 (65) 17,961 18,000 (39)

CC 253,264 253,245 19 253,102 253,505 (403) 253,988 253,418 570 254,355 254,050 305 254,733 254,559 174 255,371 254,840 530

CT 35,663 35,756 (93) 36,937 36,611 327 37,563 37,807 (244) 39,104 39,028 76 40,412 40,328 84 41,698 41,587 111

DR-EE 3,099 3,099 - 3,409 3,409 - 3,750 3,750 - 4,125 4,125 - 4,537 4,537 - 4,990 4,990 -

ES 1,387 1,449 (62) 1,449 1,502 (53) 1,504 1,552 (48) 1,542 1,589 (47) 1,587 1,616 (29) 1,603 1,645 (42)

Geo 27,222 27,222 (0) 27,211 27,210 1 27,199 27,200 (1) 27,187 27,188 (2) 27,183 27,183 (0) 27,172 27,179 (7)

Small Hydro 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 - 4,278 4,278 -

PSH 3,846 4,003 (158) 3,972 4,108 (136) 3,983 4,137 (155) 4,056 4,214 (157) 4,122 4,256 (134) 4,196 4,347 (151)

PV-BTM 15,677 15,677 - 17,145 17,145 - 18,613 18,613 - 20,081 20,081 - 21,549 21,549 - 23,017 23,017 -

Solar 40,031 40,031 - 43,780 43,780 (0) 47,527 47,527 (0) 51,268 51,268 0 55,001 55,002 (0) 58,722 58,723 (1)

Wind 60,083 60,083 - 65,709 65,709 - 71,336 71,336 - 76,962 76,962 - 82,583 82,588 (5) 88,208 88,213 (4)

Total 1,001,362 1,001,699 (337) 1,013,456 1,013,779 (323) 1,025,550 1,025,898 (347) 1,037,842 1,038,236 (394) 1,050,292 1,050,661 (369) 1,062,860 1,063,282 (422)

Table 5-1 WECC Generation Changes by Generator Type due Utah CAES Project

The following table shows the generation changes in California by generator type due to the Utah CAES project.

The followings can be observed.

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1. With the Utah CAES project, the Coal generation (“COAL” in the table) in California is increased slightly in years 2020 and 2025;

2. With the Utah CAES Project, the CC and CT generation9 (“CC” and “CT” in the table) in California is increased in years 2020 and 2021, but reduced from year 2022 to year 2025.

3. California Net Import reduced gradually from year 2020 to year 2025 due to the renewable generation increases in California. However, with the Utah CAES Project, the California net import is reduced in year 2020 and 2021 but increased in years 2022 to 2025 as opposed to the cases without the Utah CAES Project.

4. With the renewable generation increase from year 2020 to year 2025 and due to the Utah CAES project, the activities of the pumped storage generators (“PSH” in the table) and the energy storage generators (“ES” in the table) are increased. The Utah CAES project shares the reserve provisions from the PSH and ES facilities so that the PSH and ES facilities can generate more energy.

Combining the observations of points 2 and 3, the CO2 production in California is increased in year 2020 and 2021 and is reduced in years 2022 to 2025. That is opposite to the trend of the CO2 production in WECC. These trends go in opposite directions over time because as load increases gradually and renewables increase over the study period, higher-cost natural gas-fired generation in California (compared to elselwhere in WECC) is at the margin more often later in the planning period. As a result, natural gas-fired generation in California is more likely to be offset by CAES generation during the latter part of the study period.


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California Generation in GWh by Generator Type

Generator Type

2020 2021 2022 2023 2024 2025







CAES - 84 (84) - 109 (109) - 124 (124) - 172 (172) - 208 (208) - 233 (233)

Coal 11,198 11,265 (68) 11,094 11,147 (53) 10,971 11,005 (34) 10,816 10,849 (33) 10,702 10,730 (29) 10,586 10,622 (35)

Hydro 35,016 34,995 21 34,993 34,996 (3) 34,973 34,991 (17) 34,928 34,934 (6) 34,927 34,916 11 34,928 34,929 (1)

Nuclear 17,114 17,114 - 17,114 17,114 - 17,114 17,114 (0) 17,114 17,114 (0) 17,114 17,114 (0) 17,113 17,113 (0)

Others 270 287 (18) 278 300 (22) 280 297 (16) 297 302 (5) 313 320 (8) 325 332 (8)

ST 1,580 1,627 (47) 1,642 1,612 31 1,607 1,627 (20) 1,596 1,611 (14) 1,594 1,640 (46) 1,598 1,611 (13)

Bio 9,891 9,909 (18) 9,798 9,815 (17) 9,667 9,699 (32) 9,553 9,577 (23) 9,414 9,434 (20) 9,283 9,317 (34)

CC 83,535 83,569 (34) 82,211 82,386 (176) 81,109 80,948 161 80,392 80,037 355 79,509 79,194 315 78,032 77,410 621

CT 9,462 9,480 (18) 9,593 9,548 45 9,631 9,620 10 9,689 9,722 (33) 9,768 9,722 45 9,829 9,780 49

DR-EE 3,099 3,099 0 3,409 3,409 - 3,750 3,750 - 4,124 4,124 - 4,537 4,537 - 4,990 4,990 0

ES 1,387 1,449 (62) 1,449 1,502 (53) 1,504 1,552 (48) 1,542 1,589 (47) 1,587 1,616 (29) 1,603 1,645 (42)

Geo 14,476 14,476 0 14,466 14,464 1 14,455 14,454 0 14,443 14,443 (0) 14,441 14,439 1 14,431 14,436 (5)

Small Hydro 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0 4,206 4,206 0

PSH 3,393 3,551 (159) 3,531 3,660 (129) 3,556 3,705 (149) 3,644 3,789 (145) 3,711 3,836 (126) 3,769 3,913 (143)

PV-BTM 12,022 12,022 - 13,147 13,147 - 14,273 14,273 - 15,399 15,399 - 16,524 16,524 - 17,650 17,650 -

Solar 34,361 34,361 0 37,579 37,579 (0) 40,794 40,795 (0) 44,005 44,005 0 47,207 47,207 (0) 50,397 50,398 (1)

Wind 16,203 16,203 (0) 17,721 17,721 - 19,238 19,238 - 20,756 20,756 (0) 22,273 22,273 0 23,790 23,790 -

CA Total Gen 257,212 257,698 (486) 262,231 262,715 (485) 267,128 267,397 (268) 272,503 272,626 (123) 277,825 277,917 (92) 282,530 282,377 154

Net Import 63,018 62,869 149 61,962 61,790 172 60,933 61,003 (70) 59,524 59,774 (250) 58,203 58,470 (266) 57,496 58,060 (564)

Total 320,230 320,566 (336) 324,192 324,505 (313) 328,061 328,399 (338) 332,027 332,400 (373) 336,028 336,386 (358) 340,026 340,437 (411)

Table 5-2 California Generation Changes by Generator Type Due to Utah CAES Project

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5.4 Contributions to Emission Reductions


With the Utah CAES Project, the coal generation in California is increased slight for all years. However, due to the CC and CT generation increase in California in years 2020 and 2021 but reduction in years 2022 to 2025, the CO2 production in California is increased in years 2020 and 2021 but reduced in years 2022 to 2025.

Year


Base CAES

CO2 Reduct

ion


CO2 Cost

Reduction

CO2 Cost

Reduction (%)

2020 370,528 370,378 150 0.04% 1,286,122 1,288,657 (2,535) -0.20%

2021 371,032 370,925 107 0.03% 1,273,065 1,275,707 (2,642) -0.21%

2022 371,566 371,750 (185) -0.05% 1,261,043 1,260,293 750 0.06%

2023 371,979 372,156 (178) -0.05% 1,252,827 1,250,945 1,882 0.15%

2024 372,702 372,723 (21) -0.01% 1,244,758 1,242,042 2,716 0.22%

2025 373,347 373,634 (287) -0.08% 1,229,569 1,224,093 5,476 0.45% Table 5-3 WECC CO2 Reduction and CA CO2 Cost Reduction Due to Utah CAES Project.

5.5 Contribution to Renewable Generation Integration

The pumping mode of the Utah CAES project operation can absorb some of the over-generation from the solar and wind generation. The Utah CAES project helps reduce renewable curtailment from 0 GWh in year 2020 to 5.11 GWh (0.61 GWh Solar generation curtailment reduction and 4.5 GWh wind generation curtailment reduction) in year 2025.

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Figure 5-10 WECC Renewable Generation Curtailment without and with Utah CAES Project

5.6 CAES Storage Cavern Capacity

The Phase I CAES project was assumed to be configured with cavern capacity capable of storage supporting 48 hours of continuous generation at full output. This assumption was provided by the client in anticipation of future (post-2025) applications of the CAES facility integrating large amounts of intermittent wind energy.

At the beginning of the simulation period, the initial volume in the cavern is assumed to be half of the full cavern capacity. At the end of the simulation period, the ending volume in the cavern is half of the full cavern capacity. The PLEXOS results show that compression and generation events would typically extend only about two to four hours in continuous duration during the study period. Additional modeling to dispatch the CAES facility for the storage owner’s own specific needs (rather than the needs of the WECC region as done here) may produce different results. However, although this PLEXOS study did not include examination of capital costs, the size of the storage caverns used for Phase I may be an opportunity for capital cost savings.

5.7 STS Transmission Constraints

Though STS (IPPDC-Tie) flow is always from North (Utah) to South (Southern California), one can observe that, at the hourly level,

1. In the most CAES compressing hours, the flow from North to South is decreased as opposed to the flow in the Base Case. This indicates that some generation

-

10.00

20.00

30.00

40.00

50.00

60.00

2020 2021 2022 2023 2024 2025

WECC Solar and Wind Generation Curtailment (GWh) without and with Utah CAES Project

Solar Curtailment in Base Solar Curtailment in CAES

Wind Curtailment in Base Wind Curtailment in CAES

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flows from Southern California to Utah to provide compressing energy for the Utah CAES project.

2. In the most CAES generating hours, the flow from North to South is increased as opposed to the flow in the Base Case. This indicates that some generation from the Utah CAES flows to Southern California.

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6 References

[0] “Lessons from Iowa: Development of a 270 Megawatt Compressed Air Energy Storage Projecy in Midwest Independent System Operator – A Study for the DOE Energy Storage Systems Program”, Robert H. Schulte, Nicholas Critelli, Hr., Kent Holst, and Georgianne Huff. Sandia Report, SAND2012-0388, January 2012, www.lessonsfromiowa.org

[1] WECC TEPPC, “141120_2024CC-V1.3_ReleaseNotes.pdf”, November 20th, 2014

[2] “Integrated Energy Policy Report”, CEC 2013. http://www.energy.ca.gov/2013publications/CEC-100-2013-001/CEC-100-2013-001-CMF.pdf

[3] T. Guo, G. Liu, L. Yu, V. Koritarov, “Adjustable Speed Pumped-Storage Hydro-Generator (PSH) Evaluation by PLEXOS”, Energy Exemplar LLC, Oct 2013, http://energyexemplar.com/wp-content/uploads/publications/2014_EnergyExemplar/Adjustable%20Speed%20Pumped-Storage%20Hydro-Generator%20(PSH)%20Evaluation%20by%20PLEXOS.pdf

[4] V. Koritarov, et al, “Modeling and Analysis of Value of Advanced Pumped-storage Hydropower in the United States”, Argonne National Laboratory, ANL/DIS-14/7, June 2014, http://www.dis.anl.gov/projects/psh/ANL-DIS-14-7_Advanced_PSH_Final_Report.pdf

[5] Matt Hunsaker, Nader Samaan, Michael Milligan, Tao Guo, Guangjuan Liu, Jake Toolson, “Balancing Authority Cooperation Concepts to Reduce Variable Generation Integration Costs in the Western Interconnection: Intra-Hour Scheduling”, WECC Variable Generation Subcommittee project report, March 29, 2013

[6] Lew, D., Brinkman, G., Ibanez, E., Florita, A., Heaney, M., Hodge, B.-M., Hummon, M., Stark, G., King, J., Lefton, S., Kumar, N., Agan, D., Jordan, G., Venkataraman, S. (2013). “The Western Wind and Solar Integration Study Phase 2”, NREL/TP-5500-55588. Golden, CO: National Renewable Energy Laboratory.

[7] “Aug13_2014_InitialTestimony_ShuchengLiu_Phase1A_LTPP_R13-12-010.pdf”, August 13, 2014. http://www.caiso.com/Documents/Aug13_2014_InitialTestimony_ShuchengLiu_Phase1A_LTPP_R13-12-010.pdf

[8] “Nov20_2014_Liu_StochasticStudyTestimony_LTPP_R13-12-010.pdf” November 20, 2014. http://www.caiso.com/Documents/Nov20_2014_Liu_StochasticStudyTestimony_LTPP_R13-12-010.pdf

[9] “CALIFORNIA ENERGY DEMAND UPDATED FORECAST, 2015-2025” http://www.energy.ca.gov/2014publications/CEC-200-2014-009/CEC-200-2014-009-SD.pdf

http://www.energy.ca.gov/2013publications/CEC-100-2013-001/CEC-100-2013-001-CMF.pdf

http://www.energy.ca.gov/2013publications/CEC-100-2013-001/CEC-100-2013-001-CMF.pdf

http://energyexemplar.com/wp-content/uploads/publications/2014_EnergyExemplar/Adjustable%20Speed%20Pumped-Storage%20Hydro-Generator%20(PSH)%20Evaluation%20by%20PLEXOS.pdf



http://www.dis.anl.gov/projects/psh/ANL-DIS-14-7_Advanced_PSH_Final_Report.pdf

http://www.dis.anl.gov/projects/psh/ANL-DIS-14-7_Advanced_PSH_Final_Report.pdf

http://www.caiso.com/Documents/Aug13_2014_InitialTestimony_ShuchengLiu_Phase1A_LTPP_R13-12-010.pdf

http://www.caiso.com/Documents/Aug13_2014_InitialTestimony_ShuchengLiu_Phase1A_LTPP_R13-12-010.pdf

http://www.caiso.com/Documents/Nov20_2014_Liu_StochasticStudyTestimony_LTPP_R13-12-010.pdf

http://www.caiso.com/Documents/Nov20_2014_Liu_StochasticStudyTestimony_LTPP_R13-12-010.pdf

http://www.energy.ca.gov/2014publications/CEC-200-2014-009/CEC-200-2014-009-SD.pdf

http://www.energy.ca.gov/2014publications/CEC-200-2014-009/CEC-200-2014-009-SD.pdf

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