Time Topic Presenter. Rao Konidena, MISO Daniel Brooks, EPRI

Transcription

1 Tuesday October 4, AM-2:45 PM (CT) Time Topic Presenter 8:00 a.m. Welcome, introduction, key points from Monday discussion on energy storage applications by utilities and treatment in energy markets. 8:10 a.m. Consultants insights on key challenges modeling and studies of energy storage for ancillary services Electric System Modeling Overview Status of Modeling Methods Used Recent Studies Rao Konidena, MISO Daniel Brooks, EPRI Facilitator: Daniel Brooks EPRI Daniel Brooks, EPRI Sidart Deb, LCG Consulting Eric Toolson, PLEXOS Solutions 10:00 a.m. Break 10:15 a.m. Discussion: Needs for Modeling in the Future For Utility Planning For System Operations Facilitator: Abraham Ellis, SNL Greg Brownell, SMUD Sidart Deb, LCG Consulting Eric Toolson, PLEXOS Solutions Vladimir Koritarov, Argonne National Lab 11:30 a.m. Wrap-Up/ Adjourn Daniel Brooks, EPRI 12:00 p.m. Lunch All 12:30 MISO Technical Review Group (TRG) for current Rao Konidena, MISO studies of Energy Storage - Introductions 12:45 Detailed EGEAS results David Van Beek 1:45 PLEXOS Model runs plan Jordan Bakke 2:15 Phase 1 report outline Rao Konidena 2:30 Re-cap and Next steps Rao Konidena, MISO 3:00 Adjourn

2 EPRI/MISO Energy Storage Modeling Workshop Power System Modeling Overview Daniel Brooks Grid Ops & Planning Program Manager October 4, 2011

3 Energy Storage Models for System Studies Drivers of Renewed Storage Evaluation More Variable Gen EPA regulations impact on fleet Need for Sources of Flexibility Electric Power Research Institute, Inc. All rights reserved. 2

4 Operations Control & Planning Time Frames Time Resolution of Service/ Control seconds to minutes Regulation tens of minutes to hours Load Following days Daily/Hourly Scheduling Unit Govenor Response LFC Real-Time Operator Actions Economic Dispatch Unit Commitment How does energy storage contribute? 2011 Electric Power Research Institute, Inc. All rights reserved. 3

5 NERC IVGTF Task 1-5 Reliability/Flexibility Functions Assessed Inertial Response. (cycles to 1-2 sec) constrains rate of change of frequency following a disturbance. Primary Frequency Response. (cycles to 5-10 sec), adjusts MW output as a function of frequency to arrest frequency deviations following a disturbance. Regulation. (10 sec to several min) Continuous response of reserves under AGC deployed to correct minto-min deviations frequency or restore desired frequency following a disturbance Load Following/Ramping. (mins to hrs) Slower response whereby available resources are dispatched to follow system ramping requirements. Dispatchable Energy. Related to load following, but focused on energy consumption at times of peak capacity requirements and minimum load Contingency Spinning Reserve. Generation (or load) that responds immediately to a contingency and is fully deployed within ten minutes. Contingency Non-Spinning Reserve. Similar to spinning reserve except that response does not need to be immediate, but still fully deployable within 10 minutes. Replacement or Supplemental Reserve. Additional reserve that begins responding in 30 to 60 minutes, which is required in some regions. VG Tail Event Reserves. Similar to contingency reserves, but maintained to cover large, infrequent ramps of VG that are typically slower Voltage Support. Resources that can provide voltage control to maintain system voltage levels within specified criteria Electric Power Research Institute, Inc. All rights reserved. 4

6 NERC IVGTF Task 1-5 Reliability Contribution of Emerging Resources Qualitative estimates not supported by rigorous analysis Alum. Smelter Shale Oil Ext. Res. AC Comm. AC Industrial Pump. Hydro CAES Solid Batteries Flow Batteries PEV Flywheels Potential [1] Aggregate Benefit Potential Risks to Achievement Inertial Response T A E T T E T Low Storage penetration; Inverter inertia control Primary Freq. Response T T A A E T T E T Low Storage/PEV penetration; Comm. & Control Regulation (AGC) E T A E E T A E Moderate Reg. Storage/Load penetration; Comm. & Cont Load Following/Ramping T T T A E T T T Moderate Disp./Resp. Load/PEV penetration; Comm & C Dispatchable Energy T A A A E E T T Moderate Disp./Resp. Load/PEV penetration; Comm & C Spinning Reserve A T T T A A E E T T Significant Market rules for load; Comm. & Control Non-Spinning Reserve A T T T A A E T T T Significant Market rules for load; Comm. & Control Supplemental Reserve T T T A A E T T T Significant Market rules for load; Comm. & Control VG Tail Event Reserve T A A A A E T T T Significant Market rules for load; Comm. & Control Voltage Support A E T T T T Low Penetration of storage; Comm & Control Reliability Capability Designations A Available commercially E Emerging capability in demonstration phase Appropriate T Technically feasible, but not system currently being pursued studies required to determine actual expected benefits [1] Note that Potential Aggregate Benefits depends more on market incentives and commercial considerations than on technology capabilities. Stated Potential Aggregate Benefit values based on expected incentives Electric Power Research Institute, Inc. All rights reserved. 5

7 Tools/Models for Different Timeframes Power Flow/Stability (msec Sec) Long-Term Dynamics (AGC) (Sec Hr) Resource Adequacy Planning (Yrs) How do we model storage for these analyses? Production Cost Models (Min Wk) 2011 Electric Power Research Institute, Inc. All rights reserved. 6

8 Questions & Answers Contact: Daniel Brooks Program Manager Electric Power Research Institute, Inc. All rights reserved. 7

9 Together Shaping the Future of Electricity 2011 Electric Power Research Institute, Inc. All rights reserved. 8

10 Key Challenges: Modeling Ancillary Services Eric Toolson Regional Director, Energy Exemplar LLC EPRI / MISO Pumped Storage Workshop Oct. 4, 2011

11 Modeling AS in PLEXOS Simultaneous optimization (MIP) Arbitrages all market opportunities 5, 10, 15, 30 minute or hourly time step available Modeled as a system requirement or a market commodity with price Generally dispatch against prices

12 Modeling of AS in PLEXOS (cont.) Four requirements: System or zonal requirement Resources that contribute (demand or supply side) Range of contribution (dead zone) Applicable ramp rate

13 Simulation Challenges Straight-forward Defining AS requirements Modeling resource AS contribution More challenging Import / exports Regional hydro Bid behavior / market power Incorporating uncertainty / volatility

14 Simulation Challenges (cont.) Import / export AS Transfer of AS between balancing areas What is protocal? Regional hydro Energy production relatively easy compared to AS production Bid behavior / market power No easier to forecast than energy bids Preferably are dynamic, tied to changing conditions

15 Scheduling Horizons Forecast Error Day-ahead unit commitment Hour-ahead unit commitment Real-time unit dispatch

16 Modeling Challenges Perfect foresight i. Can be overcome by "locking-down" commitment Sufficient low-probability, high-impact events i. Enough Monte Carlo events to pick up tail-end distributions ii. Employ some type of smart Monte Carlo

17 Modeling Challenges (cont.) Multiple uncertain events i. Each uncertain variables requires distribution and correlation to other uncertain variables Commonly modeled uncertain variables can include: i. Load ii. Market price (energy and AS) iii. Generation and transmission outages iv. VER (Variable Energy Resources, such as wind, solar PV, demand response, etc.)

18 SMUD/PLEXOS Pumped Storage Evaluation Putting it together Pumped Generator Storages Other features Multiple A/S Either in gen mode or pump mode True optimization of gen/pump/as MIP for accurate simulation Can specify multiple constraints Headpond Pumped Gen 1 Tailpond Reprinted with SMUD s approval for the 10/11 MISO storage meeting

19 Pumped Storage Plant Design Adjustable speed system (new in U.S.) Improved Overall efficiency Capable to provide regulation service while pumping Wider range of pumping or generating operation Capable to provide all types of reserves Configuration of an adjustable speed pumped storage system (right) Reprinted with SMUD s approval for the 10/11 MISO storage meeting

20 Pumped Storage Simulation Setting Market Place Consider selling ancillary services (A/S) to market (Regulation and Spinning reserve) Use CA ISO market prices Pump Storage (P/S) configuration Stand alone inside the market Price taker in energy and A/S markets Objective To maximize net revenue by hourly dispatch in generation, pumping in combination with all possible A/S Reprinted with SMUD s approval for the 10/11 MISO storage meeting

21 Pumped Storage Simulation Overview Gen or Pump? Buy low and sell high Reg-up, Reg-down, or Spin? Either in gen or pump mode Follow the money while keep an eye on cost Cost is in the form of: Value of water (pumping cost) while generating Lost opportunity of pumping Need to meet many constraints Max/min gen or pump Max reserve provision (separately and combined) Storage size and weekly target Reprinted with SMUD s approval for the 10/11 MISO storage meeting

22 Pumped Storage Simulation Results Hourly dispatch illustration Annual revenue Gain in A/S provision Effects of market size Effects of trading cost Reprinted with SMUD s approval for the 10/11 MISO storage meeting

23 P/S Hourly Dispatch Generation (MW) Pump Load (MW) Reg Down Reg Up Spin Reserve Price Received ($/MWh) MW, MWh Hours Oct 21, 2009 Pump Storage, SMUD 14

24 Study Observations 1. AS revenue averaged about 30 percent of the total gross revenue Range for AS revenue was 25 to 35 percent 2. The percent of total AS sold to the market: Reg-down 35% Reg-up 45% Spin 20% Reprinted with SMUD s approval for the 10/11 MISO storage meeting

25 Questions?

26 EPRI/MISO Pumped Storage Workshop Insights on Key Modeling Challenges and Studies of Energy Storage for Ancillary Services October 4, 2011 Sidart Deb

27 Storage Modeling Challenges Fundamental Modeling A fundamental approach to analysis captures the financial and physical operations of each element of the network over time. Detailed Representation of Network Components Generation Markets & Physics Transmission Detailed Financial and Physical Operations Temporal Constraints 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 2

28 Storage Modeling Challenges Optimization Time Frames Market clearing is geared towards hourly operations Big storage might need to be optimized at the daily, weekly, monthly or even annual level Limited energy storage might need to be optimized at the sub-hourly level 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 3

29 Storage Modeling Challenges Developing Bids and Offers Market clearing operation requires that generator offers and demand bids be optimized For thermal units, offers can be connected to the marginal cost of operating the unit For storage units, the marginal cost may be close to zero 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 4

30 Storage Modeling Challenges Prices: Chicken and Egg Problems The best input to the pump/generate decision would be the prices In a comprehensive modeling system, the output would be the prices When prices are low, plants want to pump, but the fact that they are pumping raises the prices When prices are high, plants want to generate, but the fact that they are generating reduces the prices 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 5

31 Storage Modeling Challenges Effectively Considering Ancillary Services Storage Unit Generating Size 100MW Pumping Size 100MW Rountrip Efficiency 0.75% Spinning Reserve Capability 25MW Time = 1 Market Prices Energy Price $ Spin Price $ Energy-Based Decision Energy and Ancillary Service Decision Pump 100 $ (3,000.00) Pump 100 $ (3,000.00) Time = 2 Energy Price $ Spin Price $ Generate 75 $ 2, Generate 75 $ 2, Capacity 25 $ Profit $ (187.50) $ Becomes much more complicated when incorporating other factors Multiple Time Steps Inventories The fact that these prices are not known in advance 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 6

32 Recent Studies 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 7

33 Recent Studies Impacts of Storage in Addressing Regional Wind Penetration Client s objective Evaluate the ISO system benefits of energy storage system deployment wind penetration scenarios Client EPRI Energy Storage Program Regions ERCOT, NYISO and PJM Approach Benefits The ERCOT, NYISO and PJM systems were chosen for the energy storage system assessments. A single study year was selected for the market simulations of energy storage portfolios which included compressed air energy storage, bulk batteries and distributed battery systems. Market simulations were conducted using the UPLAN market simulation model and its underlying suite of databases as the analytical platform. EPRI provided estimates of cost and performance of the energy storage options. Study assumptions included inputs of wind penetration and location and the transmission grid configuration for the study year. The research findings will help define more clearly the technical, performance, operational and functional characteristics of storage systems to support renewable integration EPRI members such as electric utility strategic planners, resource planers, R&D managers and Independent System Operators can use the results of this work to best estimate how much storage and what type of storage systems are optimal and what locations are most promising. Further the understanding of critical variables that influence the role of storage - market rules, generation mix, T&D robustness, types and sizes of loads, location of wind relative to load, etc LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 8

34 Recent Studies Compressed Air Energy Storage Cost Benefit Analysis Client s objective Acquire an independent view of the economic viability of CAES within the generation portfolio Client type Utility Region ERCOT Approach Benefits Provide the final specification of the physical and cost characteristics of the storage (cavern or reservoir) including one or more locations, as well as the engineering, performance and cost characteristics of the CAES facility itself (compression, turbine/generator, and balance of plant) in collaboration with the Engineering Group Perform an independent analysis to forecast the economic value of developing and operating a CAES facility in conjunction with the procurement of wind power that would help meet renewable energy goals Use UPLAN to simultaneously simulate both (i) the ERCOT market including the transmission system - and (ii) the CAES and wind facilities to forecast energy and ancillary service prices and the CAES facility operations, costs and revenues Conduct sensitivity/volatility analysis to determine the changes in revenues and value of entire portfolio due to uncertainties in the market fundamentals such as fuel prices and demand Acquisition of detailed analysis of the costs, benefits, risks, and transmission congestion impacts associated with the incorporation of CAES into the generation portfolio Ability to evaluate investment performance of specific facilities such as transmission, storage systems or wind Societal benefits in terms of avoided transmission upgrades and lower energy prices to load 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 9

35 Recent Studies Quantifying the Value of Hydropower in the Transmission Grid Client s objective Develop and demonstrate an innovative approach for quantifying and maximizing the benefits provided by conventional and pumped-storage hydroelectric projects to transmission grids Client Department of Energy Region WECC Approach Develop references cases for 2010 and 2020 including existing and planned transmission, power plants. Apply detailed modeling. Evaluate modeling assumptions, plant operations with project stakeholders incorporate feedback as well as input from other tasks within the project Develop and compute scenario sensitivities including variations on energy futures, system conditions and technological advancement Benefits A series of scenario analyses to quantify the benefits of conventional and pumped hydro power A comprehensive set of plant operations under varying conditions Quantification of expected plant participation in energy and ancillary markets as well as revenues for each of the services provided Insight into the flexibility of plants and their contribution to renewable integration Value of advanced technologies (e.g. variable speed pumps) 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 10

36 DOE Valuing Hydropower Footprint and Transmission For this analysis, the entire Western Interconnect is being modeled, covering 1.8 million square miles of territory. Transmission 16,120 Buses 20,945 Lines and Transformers Latest WECC path ratings Hurdle Rates Functions and Services Energy Regulation Up Regulation Down Spin Non-spin 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 11

37 Preliminary Results Annual Energy Generation Differences Renewable energy in California displaces fossil fuel based generation Pumped storage and renewables are up 50,000 40,000 30,000 20,000 10,000 - (10,000) (20,000) (30,000) (40,000) TEPPC Future 1 Vs Baseline 2010 AZ-NM-SNV CA-MX US NWPP RMPA WECC Biomass Coal Combined Cycle CT+CT Oil+Steam+IC Geothermal Hydro Nuclear Pumped Storage Solar Wind Generation by sub-region and technology (2020 less 2010) 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 12

38 DOE Valuing Hydropower Installed Capacity CC and CT technology additions to compensate for increasing demand and renewables 120,000 MW 100,000 80,000 60,000 40,000 20, AZ-NM-SNV CA-MX US NWPP RMPA Hydro Solar Wind Pumped Storage Geothermal Biomass Nuclear Steam IC CT Oil CT Combined Cycle Coal WECC Total Category Diff (MW) Diff % Biomass % Coal 460 1% Combined Cycle 4,430 9% CT 5,131 25% CT Oil 2 0% Geothermal 2,253 76% Hydro 741 1% IC - 0% Nuclear - 0% Pumped Storage - 0% Solar 11, % Steam (1,812) -9% Wind 11, % WECC sub-region Figure: Installed Capacity in 2010 and 2020 by WECC sub-region (MW) 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 13

39 DOE Valuing Hydropower Pumped Storage Ancillary Service Participation Pumped Storage participation in markets other than non-spin exhibit a fairly consistent pattern and favor peak hours when the unit is spinning LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 14

40 Simulation & Results Pumped Storage Regulation Capability Variable speed pumps would greatly increase hydro s ability to participate in ancillary services. Synchronous Services Provided Capacity (MW) With Variable Speed Pumping Without Variable Speed Pumping Hour 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 15

41 DOE Valuing Hydropower Preliminary Results Preliminary results show pumped storage value increasing over time thanks to increased variable generation and higher gas prices. BaseLine 2010 Future Future Region Unit Size(MW) Generation (GWh) Energy Revenue ($1000) Reserve Revenue ($1000) Net Income ($1000) Average Revenue ($/kw) AZ-NM-SNV ,305 2,908 4, CA-MX US 3,375 4, ,097 6,714 11, NWPP ,096 2,511 4, RMPA 560 1,137 62,265 2,615 11, ,447 6, ,763 14,748 32, AZ-NM-SNV ,322 2,342 6, CA-MX US 3,375 6, ,976 7,321 19, NWPP ,764 5,348 12, RMPA 560 1,173 88,973 1,337 11, ,447 8, ,036 16,348 49, AZ-NM-SNV , , CA-MX US 3,375 6, ,404 4,588 4, NWPP ,175 2,926 5, RMPA 560 1,171 73, , ,447 8, ,778 8,079 20, LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 16

42 Questions? 2011 LCG Consulting. All rights reserved. Do not copy or distribute without express written consent. 17

43 Incorporating Storage into SMUD Planning Processes Greg Brownell Supervisor, Resource Planning, SMUD

44 SMUD Profile SMUD s IRP Process Overview Policy drivers Evaluation framework Outline Future Resource Needs Reliability Energy and Goals Balancing Other Studies and Issues

45 SMUD Profile Service territory area: 900 sq mi Population: 1.4 million Board Members: 7 members elected by voters Revenues: $1.3 Billion Employees: 2,100+ Summer Peak: 3299 MW in July nd largest muni in California, 6 th in nation

46 SMUD Profile 2009 Statistics Customers GWh Revenues Residential 525,100 4,707 $514 M Commercial 70,000 5,985 $631 M Subtotal 595,100 10,692 $1.15 B Sale of Surplus Power 2,133 $ 59 M Sale of Surplus Natural Gas $ 61 M Total 12,825 $1.27 B Average Annual Consumption Residential 8,955 kwh Commercial 85,500 kwh

47 IRP Process Overview: Financial: Competitive rates, capital markets Reliability: T&D, Supply, NERC mandatory reliability standards compliance Environment: Local, State and Federal policies Sustainability: Carbon, renewable, EE, solar and clean DG Staff s IRP establishes strategies that balance and meet or exceed minimum expectations SMUD s Board establishes in Strategic Directives set for each of the areas above. The process tests strategy performance across numerous future uncertainties such as electric, gas, and carbon markets, addresses risks such as project execution and performance risks, changing legislative and regulatory policy mandates, emerging technologies, and economic and load growth scenarios.

48 IRP Evaluation Framework Primary and Secondary Objectives and Relationship to SDs IRP Evaluation Framework (Weighing Strategies) METRICS AND RELATED SDS FOR COMPARING RESOURCE PORTFOLIOS/STRATEGIES SD2 Competitive Rates SD3 Access to Capital Markets SD4 - Reliability SD9 - Resources SD7 Environmental Leadership Risk Measures Renewable Premium Cents per kwh Average System Rates % Rate chg : Total Avg. per Year Fixed Charge Ratio Capital Requirements ($000,000s) Debt per Customer NERC Compliance LSC, base/high growth, surplus (deficit) Renewable Energy Goals (GWh) Cust. Energy Savings/ Energy per Cust. Cust. Demand Savings, Demand per Cust. Clean DG and Solar Leadership (innovation) Sustainable Capacity Carbon Footprint, (000s metric tons) Local and Regional Leadership Exposure to Markets Operation & Flexibility Project Risks Reliability Emphasis Market Emphasis Balanced Emphasis Regulatory Risks

49 Future Needs and Resources Customer Capacity/Energy Needs, Goals Balancing Needs Enabling Technologies and More Renewable Emerging New Technologies EE and Solar EV PHEV,s & Smart Grid

50 Future Needs Load Duration Curve Hours of System Load Duration System Peak (MW) 3,000 2,900 2,800 2,700 2,600 2,500 2,400 2,300 2,200 2,100 2,000 Critical peak: 400 MW for < 50 hrs/year Hours per year

51 Balancing Needs with High Penetration of Wind and Solar Preliminary Results Intermittency Work Group 10/20/2010

52 Balancing Needs - Issues What is the reserve need and flexibility to balance intermittent resources Fast changing variation and regulation need Variation inside an hour and load following need Hour Ahead Forecast Error and load following need

53 Data Compiled 1 minute interval data from a 100 MW wind plant. One full year of data from 2008 Data is at minute interval for all hours of 2008 (527,040 observations) Prior studies show that multiple turbines and turbine inertia minimize the spikes inside a minute.

54 Future Needs and Resources Balancing Needs - Divide and conquer methodology Divide each hour into 12 5-minute intervals Examines three types of variations: 1. Minute by minute deviation from interval average (Fast Regulation need) 2. Deviation of Interval average from hourly average (load following need) 3. Hour Ahead Forecast Error (additional load following need)

55 Wind Data Example minute by minute deviation 90 Wind MW 4/

56 Statistics: Variance from Interval Mean Upward Variance 99 th percentile. By month and hour Variance of Minute Wind MW from Interval Average (5 min intervals) (SAS Output 10/12) Average of 99th Pctl olumn Labe Row Labels Grand Total Grand Total About +/- 3MW regulation maybe sufficient

57 Wind Data Interval Deviation from Hourly Mean Wind MW 4/

58 Statistics: Interval Variance from Hourly Mean Upward Variance 95 th percentile. By month and hour Average of 95th Pctl Column Labe Row Labels Grand Total Grand Total Downward Variance 5 th percentile (Similar to the chart above and not shown here) From 5 th percentile to 95 th percentile, the range covers 90% of all deviations

59 Statistics: Interval Variance by Wind Level Wind output levels are grouped into 11 levels relative to the installed capacity: 0, 0 to 5%, 1, 5 to 15%,, 10, 95 to 100%. Upward Variance (95 percentile) May- Dec-Jan Sep Others ALL Upward Variance (95%) y = x x R² = y = x x R² = y = x x R² = Dec-Jan May-Sep Others ALL Poly. (Dec-Jan) Poly. (May-Sep) Poly. (Others) Dec and Jan are most volatile. May to Sept are half as volatile. Other months are in between

60 Balancing Needs - Hour Ahead Forecast Error Last but not the least. Error is larger than Minute and Interval variances Data-based simple forecast not incorporating meteorological forecast model Used to estimate the upper bound of reserve need Persistence forecast use MW from t-70min to t-60min to forecast MW for hour beginning at t Modified persistence forecast considers season wind profile t- 120 t-70 t-60 t t+60 Forecast Base Operating Hour

61 Hour Ahead Forecast Error Results MW_LAG_LVL % Std Dev 5th Ptcl 95th Pctl 0 0-5% 6.1 (5.4) % 11.2 (10.3) % 12.5 (15.6) % 13.8 (18.1) % 15.4 (20.7) % 14.5 (21.0) % 14.1 (22.9) % 12.9 (24.2) % 11.7 (24.7) % 10.9 (19.8) %? (32.3) th percentile corresponds to downward error (actual is lower than forecast). It is larger at higher output level. Needs upward load following reserve. 95 th percentile corresponds to upward error (actual is higher). It is smaller at higher output level. Needs downward load following reserve. As large as - 21MW to +28MW for certain hours (for a 102MW of wind plant )

62 Conclusions : Balancing and Storage Needs Conclusions Need about +/-25% of wind plant nameplate for balancing and regulation services (may differ at other sites and different amounts at study site) 90% of this is slow balancing resource (1 to 2 MW/min) 10% is faster response resource (5 MW or higher) Expect less when combined load changes studied Similar analysis for PV (preliminary results) Roughly same total as wind but 90% balancing reserve is fast regulation need Combining with load may increase interval to interval need Balancing need has greater seasonal variation

63 Other Issues Combine Wind, PV with Load to study net load, wind at other sites Energy/arbitrage opportunity Maintenance impacts of activating reserves and sub-hourly energy costs Capacity Credit/Unit Commitment costs Need to review larger periods of records more sites

64 2-Pass Simulation Approach for Day-Ahead to Day-Of Resource Scheduling Perform Intermittent Resource / Load Forecast Error Study Hourly DA intermittent resource profiles, Regulation need, load forecast Pass #1 [1] Input DA Data into Plexos DA, Pass #1 data DA Production cost Hourly Day-Of intermittent resource profiles, Regulation need, load forecast [2] Run Plexos (DA Simulation) DA Hourly gen schedules (DA Energy Markets, DA Contracts) A [3] Pass #2 A Frozen DA Hourly gen schedules Allow thermal and hydro resource to adjust within day Limited +- day-of interchange Input Day-Of Data into Plexos Storage resources can provide regulation and reduce inefficient day-of resource dispatch [4] Day-Of, Pass #2 data Run Plexos (Day-Of Simulation) [5] Day-Of Production cost Different Day-Of hourly gen schedules for hydro, thermal, and day-of interchange 22 10/3/2011

65 Storage and Balancing Needs Ongoing studies Under review and evaluation Quantity (several studies underway) Day ahead balancing needs Availability and value of frequency regulation/reserves, load leveling and ramping services in CA electricity markets Future role of demand side programs and distributed storage Hydro Pumped Storage Project (Iowa Hill) Other utility scale storage alternatives (CAES, CSP with molten) Long-term needs and value of utility scale enabling resources Dependent on renewable resource mix, role of demand side and distributed resources such as battery technology, smart grid applications, new game changing innovations. All of the above are inter-related and complex issues