1. Hydro Modeling Improvement for TAS Approval May 4, 2017
Kevin Harris, ColumbiaGrid
TEPPC\Model Work Group - Chair

2. Overview Clean up Item Convert Select Fixed Hourly Shape to PLF
Correct HTC p Factor for use in Triangle Method
Castaic PS
Thermalito Duplicate units
Convert Select Fixed Hourly Shape to PLF
Modeling of the Core Columbia River
Consolidate Assumption on the Core Columbia River
Eliminate Multi Region for Core Columbia River
Lowering HTC on the Columbia River

3. For TAS Approval

4. HTC p Factor Review of the 2026CC results show an input error
GridView support two methods for evaluating HTC: Rectangle and Triangle method
Rectangle Method divides by 4
Triangle Method divides by 2
Aggregate Hydro by Plant
Issue: P factor in the 2026CC are divided by 4. This reduces the HTC dispatch range by 50%
Propose WECC: Correction all “p” factors to correspond to ‘Triangle Method’ by multiplying by 2

5. Castaic PS Current PS efficiency 85%, 75% and 65%
Notes from CEC the average operational PS efficiency is 70%
Proposed WECC lowering PS efficiency of Castaic to 71%, 66% and 61% (and adj the benefit cost ratio to 1.0)

6. Thermalito Duplicate Units
Duplicate units exist for Thermalito 2-4. It is modeled as a hourly shape and PLF
Propose WECC consolidate modeling as Thermalito as PLF only

7. Aggregate Hydro Units by Plant
Aggregates Hydro units by plant simplifies the process of maintaining and processing Hydro data
ABB is no issues with this aggregation in the PCM or the round-trip process
For the Core Columbia River and lower Snake this eliminates 197 units from the dataset
Propose WECC apply scenario that aggregate Hydro by plant when they become available or when WECC staff has time to create them
ColumbiaGrid will provide a scenario to aggregate the Core Columbia and Lower Snake River

8. Hourly Shape Hydro Dispatch
Converting Hydro unit that support daily peak from fixed hourly shape to Proportional Load Following (PLF) will allows them to support a changing load curve
The primary advantage is when Hydro is dispatching against “Load – Solar” the daily peak generation shifts in response to the net load
This feature will be evaluated in a WECC scenario

9. Hourly Shape Hydro Dispatch
Propose the following:
Convert the listed units in “Convert Fixed to PLF 2026CC1.7 v02.xlsx” from fixed hourly shapes to PLF
For any plant the owner/operator disagrees with will not be converted

10. Modeling Changes for Columbia River

11. Consolidate Assumption on Core Columbia River
Mismatch assumption are currently used in the 2026CC
Consolidate modeling assumption on the Core Columbia River
Propose WECC completing the modeling change on the Core Columbia by changing the fixed hourly shapes to PLF

12. Hydro Dispatch to Multi Regions
Hydro dispatch to multi regions scales the Hydro unit and dispatched it against the region load
This makes it difficult to calc an appropriate K when load factor of the regions are not similar
A clean relationship exist of historic Hydro operation to BPA load. See posted file ‘ Columbia Riv Gen HTC PLF Compare v01’ posted DWG 4/11/17
Propose WECC eliminate multi regions assignment for NW entities with regions outside of the NW

13. Core Columbia with 50/50 PLF/HTC
From posted spreadsheet ‘ Columbia Riv Gen HTC PLF Compare v01’ DWG 4/11/17
50% HTC shifts morning ramp energy to afternoon ramp in most months
PLF only misses the afternoon ramp in when NW peaks in the morning (Mar)
20% HTC is a reasonable compromise that balances 50% HTC with 0% HTC (100% PLF)

14. Core Columbia with 50/50 PLF/HTC
Posted spreadsheet (DWG 4/11/17) ‘ Columbia Riv Gen HTC PLF Compare v01’ compares average weekday Hydro generation shape vs. historic Hydro operation and load
For both absolute and unitized values
Overall the 50/50 PLF/HTC results in a significate shift from historic avg hourly generation shape
Propose WECC lowers PLF/HTC modeling assumption on the Core Columbia River from 50/50 to 80/20
Long term: Work with BPA to determine what an appropriate Hydro flexibility exist and provide to the HMTF with updates when new information becomes available

15. Other Questions
(503)