Briefing on the duck curve and current system conditions

Clyde Loutan, Senior Advisor

Market Surveillance Committee MeetingGeneral SessionJuly 15, 2015

Original estimate of net-load as more renewables are integrated into the grid

Typical Spring Day

Net Load 14,160 MW on April 5, 2015

at 15:46

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Distribution of Negative Prices - March, April & May2012, 2013, 2014 & 2015

2012 2013 2014 2015

Negative energy prices indicating over-generation risk start to appear in the middle of the day

Slide 3

Increasing real-time negative energy price frequency indicates over-generation risk in the middle of the day

Average hourly hydro production for high, low and average hydro years --- April

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 242005 3,759 3,598 3,466 3,419 3,470 3,686 3,651 4,065 4,301 4,543 4,690 4,747 4,774 4,826 4,744 4,607 4,565 4,523 4,635 4,988 5,246 4,769 4,445 4,0972006 5,479 5,471 5,347 5,295 5,378 5,439 5,625 5,804 6,000 6,180 6,287 6,288 6,234 6,248 6,120 6,052 5,965 5,939 6,045 6,478 6,602 6,223 6,068 5,7292007 1,579 1,400 1,312 1,282 1,357 1,725 2,116 2,449 2,672 2,962 3,173 3,302 3,297 3,358 3,290 3,151 2,952 2,886 2,838 3,549 3,802 3,083 2,450 1,9182014 1,110 999 960 950 1,038 1,171 1,627 1,797 1,725 1,653 1,597 1,622 1,600 1,662 1,697 1,759 1,841 2,180 2,431 2,856 2,974 2,503 1,810 1,3432015 724 649 601 587 643 857 1,404 1,476 1,112 856 757 651 582 591 655 712 899 1,223 1,777 2,290 2,346 2,121 1,528 1,032

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Average Hourly Hydro Production --- April

2005 - Normal2006 - High2007 - Dry2014 - 3rd year Drought2015 - 4th year Drought

The assessment of a Balancing Authority control performance is based on three components

• Control Performance Standard (CPS1) - measures how well a BA’s ACE performs in conjunction with the frequency error of the Interconnection measured as a 12 month rolling average

• Balancing Authority Ace Limit (BAAL) - is a real-time measure of area control error and system frequency which cannot exceed predefined limits for more than 30-minutes

• Disturbance Control Standard (DCS) - is the responsibility of a BA to recover its ACE to zero if its ACE just prior to the disturbance was greater than zero or to its pre-disturbance level if ACE was less than zero within 15 minutes

• New NERC operating standard (BAL-003-1 to be implemented in 2017)

– All BAs to support the interconnection frequency within 30 seconds following a disturbance greater than 500 MW anywhere in the interconnection

Control Performance AssessmentPass is when CPS1 ≥ 100%; BAALLimit ≤ 30 minutes & DCS = 100%

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Minimum on-line generation expected in a normal hydro year

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Minimum on-line resources expected in a normal hydro year

Nuclear Non_Dis_QF Geothermal Biomas Biogas Normal_Hydro

Reg_Down Min_CCYC_Prod LF_Down Net_Load Min_Net_Load Max_Net_Load

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Assumptions for base-loaded/non-dispatchable resources and minimum system reliability needs

Slide 7

• Base Load & Non-Dispatchable ResourcesDiablo 1 & 2: 2,243 MWNon-dispatchable QFs: 1,900 MWGeothermal 880 MWBiomas 320 MWBioGas 190 MWSmall Hydro 250 MWTotal Non-dispatchable resources 5,783 MW

• Reliability Needs from non-hydro resources

Regulation Down 600 MWLoad-following Down (varies by hour – 3/2015 actual needs) 2,000 MWPmin of CCYC providing Frequency Response (4,844 * .33%) 1,600 MWMinimum Generation on CCYC Resources 4,200 MW

• Minimum Hydro for Dry Year (Avg. HE7 to HE16) 3,000 MW

• Other Assumptions- Hydro resources can provide contingency reserve, regulation up and load-following and 50% of the ISO’s

Frequency Response Obligation (FRO)

- No generation requirement for local constraints

- Zero net imports (assumes the ISO can export approximately 3,600 MW of dedicated dynamic imports i.e. Palo Verde, Hoover, MUNI imports from LADWP and Geothermal from IID)

Approx. 4,844 MW* of capacity on CCYC is

needed to provide about 387.5 MW of frequency response within 30 sec.(i.e. 387.5 / .08 = 4,844)

Based on actual hourly average production for March 2015

*WECC FRO is 907 MW/.1 Hz of which the ISO’s share is about 30% or 272 MW/.1 Hz. This equates to about 775 MWbased on the loss of two Palo Verde units. Typically, a conventional resource on governor control can provideabout 5% to 10% of its Pmax as FR within 30 seconds. Assume CCYC resources can provide 8% of Frequency Response.

RP

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CCYC – Combined Cycle

Classic Frequency Excursion RecoveryTypical frequency response recovery and potentialneed for ancillary services or capacity products

Source: NERC

Slide 8

As the grid transforms, existing ancillary service markets may not ensure the right resources with the right capabilities are available at the right time from all possible sources

• Inertia• Frequency Response

– Fast Frequency Response– Primary Frequency Response

• Regulation• Contingency Reserve

– Operating Reserve – Spinning (Replaced Spinning Reserve in WECC)– Non Spinning Reserve

• Flexible Resources (dispatchable conventional resources including VERs, energy storage devices and dispatchable loads). Attributes include but not limited to:

– Fast Ramping capability for defined periods– Change ramp direction quickly– Store energy or modify use– Multiple Stop/Start Capability– Low Pmin

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RPS Curtailment in 2024 – 40% RPS Scenario

Solutions

Retrofit existing power plants

Enable economic dispatch of renewables

Decarbonize transportation fuels

Increase storage and demand response

Align time-of-use rates with system conditions

Deeper Regional Coordination (EIM)

Targeted Energy Efficiency

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5-Minute energy price distribution for Jan, Mar, Apr & Jun

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Distribution of RTD Energy Prices --- January, 2015

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Distribution of RTD Energy Prices --- March, 2015

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Distribution of RTD Energy Prices --- April, 2015

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Distribution of RTD Energy Prices --- June, 2015

Distribution of RTD Energy Prices vs. Average Net Load --- March 2015

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Distribution of RTD Energy Prices --- March, 2015

March med-2*stdev min max med+2*stdev

Distribution of RTD Energy Prices vs. Average Net Load --- April 2015

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Distribution of RTD Energy Prices --- April, 2015

April med-2*stdev min max med+2*stdev

Distribution of RTD Energy Prices vs. Average Net Load --- June 2015

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Distribution of RTD Energy Prices --- June, 2015

June med-2*stdev min max med+2*stdev

Load, wind and solar 1-minute variability for June 28, 2015

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Load, Wind, solar and Net Load --- 6/28/2015

Load NetLoad Wind Solar

When the RTD run does not pick-up load, wind or solar variability at least 7.5 minutes before the dispatch interval, ramp deficiencies are not reflected in the 5-minute energy prices

5-minute energy prices reflect 5-minute forecast ramping condition but may not reflect all actual intra-hour variability

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RTD 5-Minute Energy Prices --- 6/28/2015

5-Minute RTD load forecast vs. actual load ---6/28/2015

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RTD 5-Minute Load Forecast vs. Actual Load --- 6/28/2015

Diff RTD Load forecast Actrual Load (Exc. Pumps)

5-Minute RTD solar forecast vs. actual solar production --- 6/28/2015

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RTD 5-Minute Solar Forecast vs. Actual Solar Production --- 6/28/2015

5-Min Errors RTD_Forecast Actual Solar Production

5-Minute RTD wind forecast vs. actual wind production --- 6/28/2015

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RTD 5-Minute Wind Forecast vs. Actual Production --- 6/28/2015

diff forecast actual

Generally when the total wind, solar and wind forecast errors are in the same direction as frequency deviations, affects on control performance are not reflected in 5-minute energy prices

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Total Load, Wind and Solar Forecast Errors vs. ACE and Frequency --- 6/28/2015

max_min_ACE Total Errors Actual Frequency Sch_Freq

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