1. HMTF Update TAS Nov 3-4, 2015 Kevin Harris, ColumbiaGrid TEPPC\Hydro Modeling Work Group - Chair

2. Outline Background Change in Hydro Operations on Columbia River 2011+ Understanding PLF and developing K Factor Hydro Dispatch Against Load – Wind Summary of Findings 2

3. Background 3

4. Objective of Current Hydro Modeling Review Review the modeling of Core Columbia River projects: – Determine if existing modeling represents current operations? Make recommendations to correct any operational issues Develop tools/method to determine appropriate Hydro modeling parameters/coefficients for in GridView Test Load – Wind for BPA 4

5. The Core Columbia The Core Columbia River is used to evaluate Hydro modeling in GridView The Core Columbia River represents 45% of Western US Hydro generation (2001-12) Upper Columbia: – Coulee- Priest Rapids Lower Columbia – McNary-Bonneville Think of the Snake River as the dividing point between Northern and Southern System 5

6. Example Historic Operations Example operation for January 2010 through 2013 6 Per unit of generation the operating range of Upper Columbia is greater than the Lower Columbia Load Used:= 100% of BPA + 100% of MidC + 6% of CAISO Aggregated and some individual projects Hydro generation are proportional to load

7. Change in Hydro Operations on Columbia River 2011+ 7

8. Operational Change Starting in 2011 Starting in 2011 the annual average daily operating range decrease by 2,224 MW (38%) Any forecast run should reflect this reduction in operational flexibility 8

9. Operational Change Starting in 2011 9 Note the polynomial for 2011, 2012, and 2013 for operational Min and Max rating over-lap Date Points Spring Run-Off: 122/yr Balance of year: 243/yr Just received hourly 2014 data It’s operation overlays on 2011-13

10. Understanding PLF and Developing K Factor 10

11. Proportional Load Following (PLF) How PLF works – The reference frame for PLF is the average monthly load and Hydro generation – Hourly Hydro generation is equal to the hourly percent change in load, from average load, multiplied by K Factor and applied to average monthly Hydro generation – Min and Max rating is enforced on Calc Hydro generation – K=0 results in a flat monthly shape equal to the average monthly Hydro generation 11

12. K Factor - Hourly Shape (PLF) Positive K Factor result in Hydro generation proportional to load – K Factor 0> and < 1, results in a contraction of the daily operating range in Hydro generation relative to the load shape – K Factor > 1, results in expanding the daily operating range in Hydro generation relative to the load shape 12 Negative K Factor result in Hydro generation inversely proportional to load Note: In the example daily average is equal to monthly average

13. Calculating K Factor The reference frame for PLF is the average monthly load and Hydro generation K Factor:= Slope of – Y= Hydro Gen(Hr i)/Avg Mo Hydro Gen – X:= Load(Hr i)/Avg Mo Load – Example K:= 2.4111 13 You only need two data points to calc a slope: Weekday min and max Consider multi hour avg for weekday min & max The avg WKD min/max do not set operational min/max rating

14. If Slope is all we need: = Delta(Y Axis)/Delta(X Axis) Delta(Y Axis) and Delta(X Axis) can be calculated independently K Factor can be split into two components: – Hydro K’ [Delta(Y Axis)]: Is tailored to the desired average weekday operating range – Load K’ [Delta(X Axis)]: Is based on the load Hydro is to be dispatched to Formula: K can be tailed to dispatch to a forecasted load shape Feedback loop: Spreadsheet Calculate - resulting hourly Hydro generation can be compared to actual Hydro generation without simulation run Two Point K Factor 14

15. Calc Operational Min/Max Ratings Calc operational min and max rating based on historic operations – Base min rating on min gen curve at a 15% probability and max on the max gen curve at 85% probability – Use the target average monthly generation for the average – The StDev is based on: Backcast use actual StDev Forecast use calc StDev based on 2011-13 operations 15

16. Summary of Modeling Change Split the 11 projects into upper and lower Columbia River to calculate PLF coefficients and compare to expected operations – Upper Columbia: Coulee through Priest Rapids – Lower Columbia: McNary through Bonneville 16 Use a flat monthly generation shape for previously hourly shapes K:=0 Objective Take a desired operating year and have it’s monthly operation conform to operation from 2011-13

17. Error Check 2010 Backcast 17 Compare calculated hourly weekday generation shape with historic operation for accuracy in duplicating hourly shape (hour ending 1-24) 2010 backcast matches actual operations

18. Error Check 2013 Backcast 18 Compare calculated hourly weekday generation shape with historic operation for accuracy in duplicating hourly shape (hour ending 1-24) 2013 backcast matches actual operations

19. Hydro Dispatch Against Load – Wind 19

20. Hydro Dispatch Load - Wind Relative to load, wind generation serves up to 64% of BPA daily load in 2014 or 20% of annual load Changing from “Load” to “Load – Wind” increases the deviation in daily a factor of 2.7 The expanded daily StDev directly impacts the daily allocation of Hydro generation. This impact can be amplified when K is > 1 20 Installed Wind Capacity in BPA for 2014 4,515 MW

21. Hydro Dispatch Load - Wind The top right chart BPA load vs Core Columbia gen (R^2=0.616) The bottom right chart: BPA Load – Wind vs Core Columbia gen (R^2:= 0.252) Bottom chart show daily Hydro generation tracking BPA load 21

22. Hydro Dispatch Load - Wind Compare backcasting April 2013 Hydro operation: – Against Load: A better match against actual Hydro operation – Against Load-Wind: When wind comes on and off for a couple of days the result Hydro diverges from actual Hydro generation 22

23. Summary of Findings 23

24. Summary of Findings Current modeling does not reflect operational changes on the Columbia River which starting in 2011 – Base Hydro operating on year 2011-2013 for any forecast year K factor can be adjusted to account for different load forecast Dispatching Hydro against “Load – Wind – Solar” – In the Pacific Northwest, K based on: “Load” is more predictable and matches historic operation “Load –Wind” results in increase volatility in daily allocation of monthly Hydro generation which is greater than historic operations Next step working on Hydro Thermal Coordination (HTC) 24

25. Proposed GridView Improvements Load – Wind – Solar: Add two new dimensions that control how Load – Wind – Solar is set: – The ability to set Load – Wind – Solar by area/region – The ability to set a percentage (0% to 100%) of wind and solar that is subtracted from the load – Example: BPA: 10% Wind and 100% Solar CAISO: 100% Wind and 100% Solar 25

26. 26 Kevin Harris Harris@columbiagrid.org (503) 943-4932