2022 PC3 California Renewable Portfolio Standard (RPS) Net-Short Out-of-State Study Report
PC3 Out-of-State CA RPS Net-Short Sensitivity
(PC3 Out-of-State CA RPS Net-Short Sensitivity September 19, 2013)
Introduction
The purpose of the 2022 PC3 Out-of-State California RPS Net-Short Sensitivity study is to examine the impact on transmission congestion and generation dispatch of increasing the amount of out-of-state resources assumed in the California (CA) renewable resource portfolio as compared to the 2022 Common Case.
Key Questions
Results from the Out-of-State California RPS Net-Short Sensitivity study are intended to address the following key questions.
1. What impact would additional out-of-state renewable resources have on transmission flows within California?
2. What impact would additional out-of-state renewable resources have on transmission flows across the Western Interconnection?
3. How does the generation dispatch, and particularly that of gas-fired generation, change in CA and across the Western Interconnection with increased out-of-state renewable resources?
4. What benefits are provided by the addition of a transmission line between Idaho and Nevada?
Study Limitations
The amount of out-of-state renewable resources modeled as part of the CA Renewable Portfolio Standard (RPS) resource portfolio may need to be adjusted if it is determined that increasing the out-of-state resources to the levels requested violates restrictions set forth in CAs RPS legislation.
Input Assumptions
All 2022 study cases are constructed from the 2022 Common Case. As such, a number of the assumptions used to construct the 2022 Common Case are carried through to each subsequent study. The following assumptions are those specific to this study and may be in addition to or an alternative of those assumptions used in the Common Case.
Loads No change to 2022 Common Case loads
Transmission System
Initial run PC3a No change to 2022 Common Case transmission
Expansion run PC3b Added the South West Intertie Project (SWIP) North
Generation 11,168 GWh of in-state CA RPS resources were replaced by out-of-state renewables. This is the amount of energy produced by in-state renewable resources assumed to be part of the CA RPS resource portfolio in the 2022 Common Case that were not existing, under-construction, or designated as a California Public Utility Commission (CPUC) discounted core resource needed to create a fifty-fifty split between in-state and out-of-state RPS net-short[footnoteRef:1] resources. [1: The RPS net-short is calculated for purposes of this study as the RPS energy requirement less energy produced by existing renewable resources.]
Repackaging California RPS
The California renewable generation portfolio assumed in the 2022 Common Case was derived from a combination of the Loads and Resources data submittals and the CPUC modified cost-constrained resource stack. The in-state RPS resources that were removed from the generation portfolio and the additional out-of-state resources that were added were selected from the CPUCs modified cost-constrained resource stack. The results of this exercise are summarized in Table 1 and Figure 1.
Table 1: California RPS Adjustments for PC3 Out-of-State California RPS Net-Short Sensitivity
RPS Generation Mix
PC1
PC3
Change
CA RPS Existing Generation (GWh)
42,826
42,826
0
CA RPS Net-short In-state Generation (GWh)
33,889
22,721
-11,168
CA RPS Net-short Out-of-state Generation (GWh)
11,553
22,721
11,168
Total CA RPS (GWh)
88,268
88,268
0
Percent Total CA RPS -- In-state
79%
66%
-13%
-- Out-of-state
21%
34%
+13%
Figure 1: California RPS In/Out of State
Table 2 provides the summary details of where the generation was removed from and added to in order to increase the out-of-state proportion of the California renewable portfolio. Note the shift from geothermal and solar to wind resources. Although the annual energy is the same, several aspects of the generation in the portfolio cases are not, including capacity factor and installed capacity (MW).
Table 2: Renewable Changes for Out-of-State Study
Generation Changes (GWh)
Biomass
Geothermal
Small Hydro
Solar CSP0
Solar PV
Wind
CA RPS Net-short Removed
CA Imperial (IID)
3,821
120
CA San Diego (SDGE)
467
448
CA South (SCE)
14
1,132
3,988
CA North (PG&E)
1,178
>
14
3,821
0
1,132
467
5,734
CA RPS Net-short Added
Oregon
814
17
7,013
Colorado
621
Nevada
250
5
Utah
63
Wyoming
11
2,457
>
814
250
96
0
0
10,091
Study Results
The following study results are organized according to the key questions associated with this study. Additional results of interest are also outlined.
Transmission Flows within California
The majority of in-state renewable resources removed in this study were removed from southern California while the majority of resources added out-of-state were added in Oregon. As a result, more surplus generation was made available in the Northwest which could flow into southern California and replace energy lost from the in-state California renewables resources that were removed. As a result of this generation shift, the utilization of Path 15 Midway-Los Banos (south-to-north flow) and Path 42 Imperial Irrigation District (IID)-Southern California Edison (SCE) decreased while the utilization of Path 26 increased (north-to-south flow).
Figure 2: Duration Plots for Path 15
Flow for Path 26, illustrated in Figure 3, increased from what was observed in the 2022 Common Case. This is mostly due to the resources added in the Northwest trying to reach load in southern California by flowing on this path.
Figure 3: Duration Plots for Path 26
Flow on Path 42 is shown in Figure 4. Flow decreased from the 2022 Common Case levels because geothermal resources in IID assumed in the 2022 Common Case were removed in this sensitivity, thus resulting in lower IID-SCE flow. Figure 5 shows that the flows on Path 43 did not change.
Figure 4: Duration Plots for Path 42
Figure 5: Duration Plots for Path 43
Transmission Impacts Overall
The paths between the Northwest and California were among the most significantly impacted as a result of the shift of renewable resources outside of California. Since the majority of the relocated renewable resources were sited in Oregon, this is not surprising. Figure 6 illustrates the most congested paths observed in the Out-of-State California RPS Net-Short Sensitivity study and Figure 7 provides a comparison of path utilization between the 2022 Common Case and the Out-of-State California RPS Net-Short Sensitivity study.
The decrease in the utilization of Path 8 seen in Figure 7 highlights the effect of must-take resources, such as wind, on the dispatch of other resources. The amount of Colstrip generation that was displaced increased from 1,169 GWh in the 2022 Common Case to 1,501 GWh in the Out-of-State California RPS Net-Short Sensitivity study most likely due to the addition of incremental wind resources in Oregon.
Figure 6: Most Heavily Utilized Paths - PC-3a
Figure 7: Change in Utilization for the Most Utilized Paths
The duration plot for Path 65 Pacific DC Intertie (PDCI) and Path 66 California-Oregon Intertie (COI), combined in Figure 8, shows the extent of the increased flow in the Out-of-State California RPS Net-Short Sensitivity study compared to the 2022 Common Case. The increase is consistent with the 7,844 GWh of renewable energy that was moved to the Northwest, which is equivalent to about 900 aMW/hr.
Figure 8: Duration plot for combined path 65 plus 66
The duration plot for Path 27 Intermountain Power Project (IPP) DC-line in Figure 9 shows part of the impact of moving a portion of the renewable resources from California to out-of-state locations. Doing so removes zero cost energy from inside California. California load still must be satisfied and in this instance, importing power from IPP via Path 27 is an economic alterative, as shown the increased path flows.
Figure 9: Duration plot comparison for path 27
Figure 10 provides a summary of the changes in subregional energy transfers from the 2022 Common Case to the Out-of-State California RPS Net-Short Sensitivity study. Every transfer into California increased as expected. Since a majority of the resources removed from California were previously located in southern California (see Table 2), a substantial amount of the relocated energy was needed to replace the lost generation.
Figure 10: Comparison of Regional Transfers
The flows on Path 8 Montana to Northwest (see Figure 11) decreased slightly due to the influx of new generation in Oregon that displaced some of the coal imports from Montana.
Figure 11: Duration plot comparisons for Path 8
Impact on System Generation
The chart in Figure 12 shows the change in annual generation by resource type between the 2022 Common Case and the Out-of-State California RPS Net-Short Sensitivity study. Most visible is the shift from geothermal and solar generation (removed from California) to wind generation (added outside of California). There is also a change in dispatch from coal resources to combined cycle resources.
Figure 12: Change in Annual Generation by Type
The difference in annual energy by state/province is provided in Figure 13 and Figure 14. The renewable change was omitted from Figure 14 to improve the resolution of the other resource type changes.
Figure 13: Annual Generation by State/Province
Figure 14: Annual Generation (non-renewable) by State/Province
A 10-day plot of the load/generation balance during a period with high-wind output is shown in Figure 15. The priority given to wind and hydro forces curtailments of coal and nuclear resources. Since the added wind resources for the Out-of-State California RPS Net-Short Sensitivity study are not directly assigned to California loads, they are used by PROMOD to serve load in the Northwest. The same plot in economic stack[footnoteRef:2] order (see Figure 16) shows the type of generation that is being exported from the Northwest into California. [2: Generation pricing assumptions in the TEPPC studies do not reflect contract prices, which are often confidential. The assumed price for wind and solar energy, for example, is a negative $1,000/MWh. Actual contract prices for wind and solar are most often in the range of $40 to $120/MWh.]
Figure 15: Example of NWUS Dispatch
Figure 16: Example of NWUS Dispatch (stack order)
In the Northwest U.S. (NWUS) subregion, 3,285 GWh of coal and nuclear generation was displaced by wind and hydro resources during the study year.
A comparison of the daily wind output for all of the hour 4s and hour 14s is provided in Figure 17, both sorted from highest to lowest. This chart shows that over the study year (2022) there was more NWUS wind output at night (hour 4) than during the afternoon (hour 14). The total installed wind capacity in the NWUS subregion for the Out-of-State California RPS Net-Short Sensitivity study is 15,454 MW.
Figure 17: Wind Comparison - NWUS
A 10-day plot of the load/resource balance that includes the peak day for the NWUS subregion is shown in Figure 18. It is interesting to note that there are a number of off peak hours when the NWUS is resource deficient and is likely importing energy.
Figure 18: Sample Dispatch - NWUS with peak
Impact of Adding SWIP-N Transmission Project
The SouthWest Intertie Project (SWIP) consists of two phases a southern phase that was included in the 2022 Common Case as a Common Case Transmission Assumption, and a northern phase that was not included. A map of the planned SWIP North (SWIP-N) project is provided in Figure 19.
Figure 19: Map of SWIP-North
The majority of the relocated energy in the Out-of-State California RPS Net-Short Sensitivity study was placed in the Northwest and Wyoming (see Table 2). It was thus expected that the SWIP-N line would enable the delivery of energy back to California via an alternate, less-constrained, and parallel path to the COI/PDCI. The hourly chronological flow on the SWIP-N transmission line in the expansion case is provided in Figure 20. The average flow was 838 MW north-to-south.
Figure 20: Hourly Flow on SWIP-N
The change in annual generation by type and state/province as a result of adding SWIP-N is provided in Figure 21. There was not a substantial change in annual generation as compared to the Out-of-State California RPS Net-Short Sensitivity study, but the SWIP-N project does appear to provide a means to deliver additional surplus coal resources to Nevada and California in order to lower the overall system variable production cost, which is the goal of the production cost model.
Figure 21: Generation Change by State/Province with SWIP-N
Another measure of the effectiveness of the SWIP-N lines ability to help deliver the out-of-state resources is its impact on the regional transfers. Figure 22 shows that additional energy was delivered from the Northwest to southern California via the Basin and Desert Southwest (AZNMNV) subregions with the addition of the SWIP-N project. Note that SWIP-N is considered a path from Basin to AZNMNV.
Figure 22: Comparison of Regional Transfers
The change in path utilization between the 2022 Common Case and Out-of-State Net Short Sensitivity with SWIP North, and the Out-of-State California RPS Net-Short Sensitivity study are shown in Figure 23 and Figure 24, respectively. Adding the transmission project increased flows from AZNMNV to the California South (CA_S) subregion, and decreased flows from the NWUS to California North (CA_N), and from CA_N to CA_S, as shown on the chart. In all instances flows increased from the levels observed in the 2022 Common Case.
Figure 23: Change in Path Utilization - PC1 to PC3b (with SWIP N)
Figure 24: Change in Path Utilization - PC3a to PC3b (SWIP N)
Other Observations
For the Western Interconnection overall, the hourly load requirements in the Out-of-State California RPS Net-Short Sensitivity study were generally met by dispatchable hydro, combined cycle, and combustion turbine resources as illustrated in Figure 25, a 10-day plot including the Western Interconnection peak on July 21. The plot also shows an example of the occasional curtailment of coal resources. The curtailment of base-load resources is more prevalent during periods of low loads, high hydro and high winds.
Figure 25: Sample Dispatch - WECC
Study Summary
A summary of the key results from both the In-state and Out-of-State California RPS Net-Short Sensitivities is provided in Table 3. The changes observed were not significant and inclusion of the SWIP-N project in the Out-of-State California RPS Net-Short Sensitivity case increased deliverability of the relocated resources.
Table 3: Comparison of Key Results
Input or Result
PC1 Common Case
PC2 In-state Net Short
PC3a Out-of-state Net Short
PC3b Out-of-state Net Short w/ SWIP-N
CO2 Emissions (MMetric Tons)
359
360
359
359
Variable Production Cost (M$)
14,851
14,867
14,913
14,891
Dump Energy (GWh)
397
396
522
470
Coal-fired Gen (GWh)
267,320
267,530
265,870
266,203
Combined Cycle Gen (GWh)
156,646
156,461
158,823
158,142
Biomass Gen (GWh)
13,573
14,453
14,209
14,302
DSM Gen (GWh)
199
195
205
203
Unutilized Coal (GWh)
6,901
6,691
8,350
8,017
In addition to the shift in location of the RPS resources from California to mostly Oregon and Wyoming, there was a significant shift in the type of resources (see Table 2). The out-of-state assumptions added primarily wind resources, which comprised 90 percent of the additions. The changes increased the transmission flows for the interties from Oregon to California, as well as the path between northern and southern California.
The shifts in location and type also impacted the generation results with displacement of coal and nuclear fueled resources in Oregon, Washington, and Wyoming, and increased combined cycle generation in California, Arizona, and Mexico.
It should be noted that the RPS resource assumptions used to develop the 2022 Common Case and both the In-State and Out-of-State California RPS Net-Short Sensitivities were based on the CPUCs modified cost-constrained resource stack finalized in 2011. Since that time, RPS procurement and planning in California have moved towards greater emphasis on in-state resources, especially solar (in part reflecting declining solar Photovoltaic (PV) costs). Therefore, it is the belief of TEPPCs California stakeholders that the RPS resource scenario depicted in the Out-of-State California RPS Net-Short Sensitivity case is not likely to occur over the 10 year horizon considered in the study. However, greater California reliance on imported renewable energy is somewhat more plausible over a longer planning horizon if there is an increase in Californias RPS goal, but only if the present trend towards solar is slowed or reversed, policy and technical barriers to high levels of renewable energy imports are eased, and other states do not substantially increase their own RPS targets and seek to purchase increased wind energy from the Northwest.
California RPS Comparison (GWh)
CA RPS Existing GenPC1PC34282642826CA RPS Net-short In-statePC1PC33388922721CA RPS Net-short Out-of-statePC1PC31155322721
Page 1 of 22
Page 2 of 22
-4000-3000-2000-10000100020003000400050006000
Megawatts
P15 Midway-LosBanos Path Duration Plots
2010PC1_CCPC3a_CA_Outstate
S->N
-4000-3000-2000-1000010002000300040005000
Megawatts
P26 Northern-Southern California Path Duration Plots
2010PC1_CCPC3a_CA_Outstate
N->S
-2000-1500-1000-5000500100015002000
Megawatts
P42 IID-SCE Path Duration Plots
2010PC1_CCPC3a_CA_Outstate
E->W
-3000-2000-10000100020003000
Megawatts
P43 North of San Onofre Path Duration Plots
2010PC1_CCPC3a_CA_Outstate
S->N
0%10%20%30%40%50%60%70%
Most Heavily Utilized Paths -PC3a CA RPS OOS no xmisn
U75U90U99
-10%-5%0%5%10%15%P26 Northern-Southern CaliforniaP45 SDG&E-CFEInterstate WA-BC WestP66 COIP03 Northwest-British ColumbiaP08 Montana to NorthwestP47 Southern New Mexico (NM1)P29 Intermountain-Gonder 230 kVP79 TOT 2B2P27 Intermountain Power Project DC LineP11 West of CrossoverP22 Southwest of Four CornersInterstate WA-BC EastP60 Inyo-Control 115 kV TieP01 Alberta-British Columbia
Change in Utilization -PC1 to PC3a
U75U90U99
-8000-6000-4000-20000200040006000800010000
Megawatts
Interstate COI plus PDCI Path Duration Plots
20082010PC1_CCPC3a_CA_Outstate
N->S
-2000-1500-1000-500050010001500200025003000
Megawatts
P27 Intermountain Power Project DC Line Path Duration Plots
20082010PC1_CCPC3a_CA_Outstate
N->S
(500)0500100015002000250030003500
AZNMNV
To Ca_S
Basin To
AZNMNV
Basin To
Ca_N
Basin To
Ca_S
Ca_N To
Ca_S
Canada
To NWUS
NWUS To
Basin
NWUS To
Ca_N
NWUS To
Ca_S
RMPA To
AZNMNV
RMPA To
Basin
Average Megawatts
Transfers between Sub -Regions (aMW)
PC1 CCPC3a CA-NS OOS
-2000-1500-1000-50005001000150020002500
Megawatts
P08 Montana to Northwest Path Duration Plots
20082010PC1_CCPC3a_CA_Outstate
E->W
(4,000)(2,000)02,0004,0006,000Conventional HydroPumped StorageSteam - CoalSteam - OtherNuclearCombined CycleCombustion TurbineCogenerationICNegative Bus LoadBiomass RPSGeothermalSmall Hydro RPSSolarWind GWh
Annual Energy Difference: 2022 PC1 Common Case vs. 2022 PC3a CA OOS Net-short Sensitivity -No Xmisn Added
-12,000-10,000-8,000-6,000-4,000-2,00002,0004,0006,0008,000
GWh
Annual Energy Difference: 2022 PC1 Common Case vs. 2022 PC3a CA OOS Net -short Sensitivity -No Xmisn Added
Hydro+PSSteam - BoilerCombined CycleCombustion TurbineCogenerationRenewableOther
-50005001,0001,5002,000
GWh
Annual Energy Difference: 2022 PC1 Common Case vs. 2022 PC3a CA OOS Net -short Sensitivity -No Xmisn Added
Hydro+PSSteam - BoilerCombined CycleCombustion TurbineCogenerationOther
Excluding Renewable Generation
05,00010,00015,00020,00025,00030,00035,00011/5/202211/6/202211/7/202211/8/202211/9/202211/10/202211/11/202211/12/202211/13/202211/14/2022
NWUS Load/Gen Balance Snapshot -PC3a -CA OOS Net-short
DSMOther Combustion Turbine Steam - Other Combined Cycle Biomass RPS Geothermal Small Hydro RPSHydro+PS Solar Wind Steam - Coal NuclearDemand Dump
MW
05,00010,00015,00020,00025,00030,00035,00011/5/202211/6/202211/7/202211/8/202211/9/202211/10/202211/11/202211/12/202211/13/202211/14/2022
NWUS Load/Gen Balance Snapshot -PC3a -CA OOS Net-short (stack order)
DSMOther Combustion Turbine Steam - Other Combined Cycle Biomass RPS Steam - Coal Nuclear Geothermal Small Hydro RPSHydro+PS Solar WindDemand Dump
MW
020004000600080001000012000140001600011223344556677889100111122133144155166177188199210221232243254265276287298309320331342353364
Megawatts
Duration Plot -PC3a NWUS Wind Hour 4 vs. Hour 14
Hour 4Hour 14
Daily -Sorted Largest to Smallest
05,00010,00015,00020,00025,00030,00035,00012/8/202212/9/202212/10/202212/11/202212/12/202212/13/202212/14/202212/15/202212/16/202212/17/2022
NWUS Load/Gen Balance Snapshot -PC3a -CA OOS Net-short (stack order)
DSMOther Combustion Turbine Steam - Other Combined Cycle Biomass RPS Steam - Coal Nuclear Geothermal Small Hydro RPSHydro+PS Solar WindDemand Dump
MW
-5000500100015002000
SWIP North Path Flow (MW)
-800-700-600-500-400-300-200-1000100200
GWh
Annual Energy Difference: 2022 PC3a CA OOS Net -short NoTrnsm vs. 2022 PC3b CA OOS Net-short w SWIP N
Hydro+PSSteam - BoilerCombined CycleCombustion TurbineCogenerationRenewableOther
(500)0500100015002000250030003500
AZNMNV
To Ca_S
Basin To
AZNMNV
Basin To
Ca_N
Basin To
Ca_S
Ca_N To
Ca_S
Canada
To NWUS
NWUS To
Basin
NWUS To
Ca_N
NWUS To
Ca_S
RMPA To
AZNMNV
RMPA To
Basin
Average Megawatts
Transfers between Sub -Regions (aMW)
PC1 CCPC3a CA-NS OOSPC3b CA-NS OOSwSWIP-N
-10%-8%-6%-4%-2%0%2%4%6%8%10%12%P26 Northern-Southern CaliforniaP45 SDG&E-CFEP08 Montana to NorthwestInterstate WA-BC WestP03 Northwest-British ColumbiaP66 COIP47 Southern New Mexico (NM1)P79 TOT 2B2P27 Intermountain Power Project DC LineP11 West of CrossoverP22 Southwest of Four CornersInterstate WA-BC EastP60 Inyo-Control 115 kV TieP01 Alberta-British ColumbiaP76 Alturas Project
Change in Utilization -PC1 to PC3b
U75U90U99
-6%-5%-4%-3%-2%-1%0%1%2%3%4%5%P26 Northern-Southern CaliforniaP45 SDG&E-CFEP08 Montana to NorthwestInterstate WA-BC WestP03 Northwest-British ColumbiaP66 COIP47 Southern New Mexico (NM1)P79 TOT 2B2P27 Intermountain Power Project DC LineP11 West of CrossoverP22 Southwest of Four CornersInterstate WA-BC EastP60 Inyo-Control 115 kV TieP01 Alberta-British ColumbiaP76 Alturas Project
Change in Utilization -PC3a to PC3b
U75U90U99
020,00040,00060,00080,000100,000120,000140,000160,000180,000200,0007/14/20227/15/20227/16/20227/17/20227/18/20227/19/20227/20/20227/21/20227/22/20227/23/2022
WECC Load/Gen Balance Snapshot -PC3a CA OOS Net Short
DSMOther Combustion Turbine Steam - Other Combined Cycle Biomass RPS Geothermal Small Hydro RPSHydro+PS Solar Wind Steam - Coal NuclearDemand Dump
MW