The Confluence Model. Presentation to Modeling and Forecasting Working Group January 21, 2015

Transcription

1 The Confluence Model Presentation to Modeling and Forecasting Working Group January 21, 2015

2 Introductions Presenter: Gary Fiske Working Group Water Department staff

3 Objective: Penetrate the Black Box What Confluence is (and what it s not) How Confluence fits into Santa Cruz water resources planning Key model input assumptions How Confluence simulates actual system operations What we can learn from Confluence outputs

4 Agenda PowerPoint presentation Q&A Break Inside Confluence Q&A

5 Confluence History and Context Roots in power planning Designed specifically for water resources planning Has been applied to a variety of system types & sizes Used to help address many issues in Santa Cruz

6 Confluence: What it is and isn t Confluence is: Planning model Simulation tool Confluence isn t: Operations model Optimization tool Confluence can compare scenarios Confluence can t find the best scenario

7 Confluence Model Structure Weather & Streamflow Inputs Demands System structure Supplies Conservation Facilities System operations Simulation Parameters Observed Demand Conservation Supply Avail Capacity Limitations System Simulation Operating Constraints Outputs Reliability Costs & rates Demands Supply utilization Lake operations Conservation savings Transmission loadings Scenario comparisons Diagnostic reports

8 Confluence Inputs

9 Confluence input assumptions have been continually updated since the IWP to better simulate actual system operations

10 Key Changes in Modeling Assumptions in Last Year Modeling Parameter Previous Current Demand Shape (Percent of annual demand in peak season) 64% 59% Annual Loch Lomond Withdrawal Limit 3,200 AF No limit N Coast Annual Ag Demands (mg) Tait Street Flow Buffer (cfs) Tait Street Well Capacity (cfs) peak 0.78 off-peak

11 Study Definition: Forecast Years, Flows, Weather

12 Two Ways of Defining the Study Drought Year All Years Fcst Year Hydro Years Sim Fcst Year Hydro Years Sim 1 Sim 2 Sim 3... Sim 72 Sim

13 Study Definition (cont d): Text file linkages

14 Interactive Data Map

15 Defining Supply Sources

16 Defining System Components: Shadow Prices and Pointers

17 Source Dispatch is Driven by Shadow Prices

18 Operating the Lake Lake drawdown must be regulated to ensure that lake doesn t run dry midway through summer season Model does that through shadow prices

19 Lake Content (MG) Reservoir Zones and Shadow Prices Alternative $ Rule Curve $ Zone 1 Zone Unuseable Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 May-10 Jun-10 Jul-10 Aug-10 Sep-10 Oct-10

20 Lake Content (MG) Reservoir Zones and Shadow Prices Alternative $ Rule Curve $1500 Zone 1 Zone 2 Unuseable Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 May-10 Jun-10 Jul-10 Aug-10 Sep-10 Oct-10

21 Shadow Prices of Unserved Demand Blocks Block Shadow Price 1 $800 2 $ $ $ $1600

22 Regulation of Lake Drawdown: An Illustration

23 How to Set Rule Curve/USD Blocks? Smooth landing : Use all usable storage by end of dry season in extremely dry year Usable storage is based on a 1 billion gallon insurance policy

24 Two Things We Don t Want to Happen in Extremely Dry Year

25 What We Do Want to Happen in That Extreme Drought Year

26 What Happens in a Event? (With City Proposed HCP Flows)

27 What Happens in a Event? (with DFG-5 HCP Flows)

28 We Distinguish Between Event and Other Years Under most historical water conditions, rule curves/usd blocks based on 1990 drought year. For event, rule curves/usd blocks based on 1977.

29 Two Ways to Operate Lake in 1990

30 System Demand Demand = Volume customers would consume with no city-imposed curtailment. Demand Usage during curtailment. Curtailment is what we want to avoid.

31 Modeling of Peak-Season vs. Off-Peak Season Demand Peak-Season (May-Oct): Daily per-capita demand determined by temperature and precipitation Calibrated to add up to total seasonal demand Off-Peak-Season (Nov-Apr): Seasonal demand allocated to months. No weather-dependency

32 Defining Unserved Demand Shadow Prices (for 5 blocks)

33 Confluence Outputs

34 Types of Output Confluence charts (Data easily exported) Detail/Diagnostic text files (Data easily exported) Excel tables/charts from exported data

35 Sample Confluence Charts: Water Supply Reliability

36 Sample Confluence Charts: Source Production

37 Sample Confluence Charts: Lake Operations

38 Peak-Season Shortage Sample Excel Chart Using Imported Confluence Data: Peak-Season Shortage Duration Curve Comparison 80% Peak-Season Shortage Duration Curve for All Years: 3500 mg Annual Demand 70% 60% 50% 40% 30% DFG-5 City Prop 20% 10% 0% 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Years >= Y Value

39 Sample Excel Chart: Comparison of Modeled and Historical Lake Operations 3000 End-of-Month Lake Levels (millions of gallons) Model Historic Levels Nov-70 Nov-75 Nov-80 Nov-85 Nov-90 Nov-95 Oct-00 Oct-05 Oct-10

40 Sample Excel Table: Shortage Profile Comparison PROBABILITY OF: PROFILE: 0% Peak-Season Shortage 1-10% Peak- Season Shortage 10-20% Peak- Season Shortage 20-30% Peak- Season Shortage > 30% Peak- Season Shortage Worst-Year Peak-Season Shortage IWP Adopted in 59 (83-88%) 6-9 in 59 (10-15%) 1 in 59 (2%) % City Proposal 69 in 73 (95%) 1 in 73 (1%) 2 in 73 (3%) 0 1 in 73 (1%) 34% DFG-5 65 in 73 (89%) 1 in 73 (1%) 0 4 in 73 (5%) 3 in 73 (4%) 69%

41 Sample Excel Table: Average Monthly Source Production Beltz Desal Felton Laguna Liddell Loch Lomond Majors SL Tait St Beltz Beltz Beltz Beltz Desal Desal Desal DesalFeltonFeltonFeltonFeltonLaguna/ Laguna/ Laguna/ Laguna/LiddellLiddellLiddellLiddell Loch Loch Loch Loch MajorsMajorsMajorsMajors SL SL SL SL Av Med Max Min Av Med Max Min Av Med Max Min Av Med Max Min Av Med Max Min Av Med Max Min Av Med Max Min Av Med Max Min Aug Crit Dry Dry Normal Wet All Sep Crit Dry Dry Normal Wet All Oct Crit Dry Dry Normal Wet All Crit Dry Dry ANNUAL Normal AVERAGE Wet All Crit Dry PEAK- Dry SEASON Normal AVERAGE Wet All

42 Sample Excel Chart: Demand-Production Comparison 450 Monthly Source Production Under 1977 Hydrologic Conditions DFG-5 Flows, Base Infrastructure (millions of gallons per month) Peak-Season Shortage: 1,531 mg Loch Lomond Tait Street North Coast Beltz Wells TOTAL DEMAND Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct

43 Questions Then Inside Confluence...