HMTF UpdateTAS Nov 3-4, 2015

Kevin Harris, ColumbiaGridTEPPC\Hydro Modeling Work Group - Chair

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Outline

• Background• Change in Hydro Operations on Columbia

River 2011+• Understanding PLF and developing K Factor• Hydro Dispatch Against Load – Wind• Summary of Findings

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Background

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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

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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

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Example Historic Operations• Example operation for January 2010 through 2013

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

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Change in Hydro Operations on Columbia River 2011+

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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

Average Weekday Operating Range (MW)2005-10 2011-13 Diff %Diff

Apr-Jul 5,537 1,918 -3,619 -65%Balance of Yr 6,087 4,560 -1,527 -25%Annual 5,904 3,679 -2,224 -38%

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Operational Change Starting in 2011

Note the polynomial for 2011, 2012, and 2013 for operational

Min and Max rating over-lap

Date PointsSpring Run-Off: 122/yrBalance of year: 243/yr

Just received hourly 2014 dataIt’s operation overlays on 2011-13

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Understanding PLF and Developing K Factor

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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

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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• Negative K Factor result in

Hydro generation inversely proportional to load

Note: In the example daily average is equal to monthly

average

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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

• 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

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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

𝑲 (𝑺𝒍𝒐𝒑𝒆)=

𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏(𝒂𝒗𝒈𝒅𝒂𝒊𝒍𝒚 𝒎𝒂𝒙)𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏(𝒂𝒗𝒈)

−𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏(𝒂𝒗𝒈𝒅𝒂𝒊𝒍𝒚𝒎𝒊𝒏)

𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏(𝒂𝒗𝒈)𝑳𝒐𝒂𝒅(𝒂𝒗𝒈𝒅𝒂𝒊𝒍𝒚 𝒎𝒂𝒙)

𝑳𝒐𝒂𝒅 (𝒂𝒗𝒈)−𝑳𝒐𝒂𝒅(𝒂𝒗𝒈𝒅𝒂𝒊𝒍𝒚 𝒎𝒊𝒏)

𝑳𝒐𝒂𝒅 (𝒂𝒗𝒈)

=𝑫𝒆𝒍𝒕𝒂 (𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏)

𝑫𝒆𝒍𝒕𝒂(𝑳𝒐𝒂𝒅)=𝑯𝒚𝒅𝒓𝒐𝑲 ′

𝑳𝒐𝒂𝒅𝑲 ′

Two Point K Factor

𝑳𝒐𝒂𝒅𝑲 ′=𝑳𝒐𝒂𝒅𝑹𝒂𝒏𝒈𝒆¿¿𝑯𝒚𝒅𝒓𝒐𝑲 ′=𝑯𝒚𝒅𝒓𝒐𝑮𝒆𝒏¿ ¿

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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

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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

• Use a flat monthly generation shape for previously hourly shapes K:=0

ObjectiveTake a desired

operating year and have it’s monthly

operation conform to operation from 2011-

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Error Check 2010 BackcastCompare calculated hourly weekday generation shape with historic operation for accuracy in duplicating hourly shape

(hour ending 1-24)

2010 backcast matches actual operations

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Error Check 2013 BackcastCompare calculated hourly weekday generation shape with historic operation for accuracy in duplicating hourly shape

(hour ending 1-24)

2013 backcast matches actual operations

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Hydro Dispatch Against Load – Wind

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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 > 1BPA 2014 BA Load and Wind

Avg StDev StDev/Avg

Load 6,282 646 10%Wind 1,271 1,084 85%Load-Wind 5,011 1,351 27%

Installed Wind Capacity in BPA for 2014 4,515

MW

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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

Op Range (X Axis)BPA 0.9 to 1.1BPA-Wind 0.5 to 1.5

StDevAct HY 0.081HY (Load) 0.063HY (Load-Wind) 0.041

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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

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Summary of Findings

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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)

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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

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Kevin Harris Harris@columbiagrid.org

(503) 943-4932