April Runoff Forecasts April Runoff Forecasts for the Columbia Basin for the Columbia Basin

andandPower Supply Power Supply Implications Implications

Jim Ruff and John FazioCouncil MeetingApril 14, 2010

Boise, ID

2

3

4

April 1 Snowpack for April 1 Snowpack for Columbia Basin above The Columbia Basin above The

Dalles, ORDalles, OR

5

6

2010 January-July Runoff 2010 January-July Runoff ForecastForecast

69.7 Million Acre Feet69.7 Million Acre Feet (April Forecast for The Dalles Dam)(April Forecast for The Dalles Dam)

Hydroelectric Fuel Gauge

69.7 Maf is 65% of Average

95% Confidence Range is from 56 to 83 Maf

7

Recent Runoff VolumesRecent Runoff Volumes(January-July Volume at The Dalles)(January-July Volume at The Dalles)

70

8875

104

139

159

104

124

98

58.2

103.8

87.7

114.7

69.783

81.3 90.295.799.2

0

20

40

60

80

100

120

140

160

180

Ru

no

ff (

Ma

f)

8

Lower Granite Flow Lower Granite Flow ForecastForecast

0

20

40

60

80

100

120

Cub

ic F

eet

per

Seco

nd

Apr

1-

15

Apr

16-

30 May

Jun

Jul

Aug

1-

15

Aug

16-

31

2010 Avg70-Yr Avg

9

McNary Flow ForecastMcNary Flow Forecast

0

50

100

150

200

250

300

Cub

ic F

eet

per

Seco

nd

Apr

1-

15

Apr

16-

30 May

Jun

Jul

Aug

1-

15

Aug

16-

31

2010 Avg70-Yr Avg

10

Hydro System GenerationHydro System Generation

0

5

10

15

20

GW

-Per

iods

Apr

1-

15

Apr

16-

30 May

Jun

Jul

Aug

1-

15

Aug

16-

31

2010 Avg70 Yr-Avg

11

2010 Power Supply 2010 Power Supply OutlookOutlook

(Approximate)(Approximate)

Annual Load/Resource

Balance

Summer Sustained-Peak Reserve Margin

Minimum Required

0 MWa 24%

Critical Hydro and Firm Resources Only

300 MWa 26%

With this Year’s Hydro

1,400 MWa 32%

With Available Non-firm Resources

5,300 MWa 35%

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Power Supply ConclusionsPower Supply Conclusions

Very low chance of power outage Revenues will be lower than average

Less non-firm hydro to sell Need to purchase more from the

market BPA is using some of its financial

reserves to get through this year Reservoir elevations at BiOp levels

13

NW Power Pool Analysis NW Power Pool Analysis (March 5)(March 5)

NW Power Pool area (larger than the Council region) has adequate generation

Low flows will decrease hydro flexibility Emergency measures may need to be

implemented in the event of a significant resource loss and/or extreme temperature event (standard caveat)

14

Additional SlidesAdditional Slides

15

16

2010 Add’l. Court-Ordered 2010 Add’l. Court-Ordered SpillSpill

-10000

0

10000

20000

30000

40000

Ap

r1

Ap

r2

Ma

y

Ju

n

Ju

l

Au

g1

Au

g2

Cu

bic

Fe

et

pe

r S

ec

on

d Lr Grn

L Goos

Lr Mon

Ice H

McNary

J Day

Dalles

Bonn

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Generation Loss due toGeneration Loss due toCourt-Ordered SpillCourt-Ordered Spill

0

100

200

300

400

500

600

MW

-Per

iod

s

Apr

1-

15

Apr

16-

30 May

Jun

Jul

Aug

1-

15

Aug

16-

31

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Runoff Distribution UsedRunoff Distribution UsedDistribution for April Early Bird Forecast 2010

Mean 70.0, sigma 5.0

0

5

10

15

20

50 70 90 110 130 150

Jan-Jul Runoff Volume (kaf) at The Dalles

We

igh

t

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Annual Hydro GenerationAnnual Hydro Generation(relative to the driest year)(relative to the driest year)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

54 69 70 82 90 95 97 103 107 107 111 112 114 119 125 131 153

Jan-Jul Runoff Volume (Maf)

Ave

rage

Meg

awat

ts 70 Mafabout 1,100 MWamore than lowest year

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Lower Granite Flow Lower Granite Flow ForecastForecast

(in Kcfs) 2010 Avg 70-Yr Avg

Apr 1-15 58 78

Apr 16-30 57 90

May 73 107

Jun 61 102

Jul 28 52

Aug 1-15 24 30

Aug 16-31 24 28

21

McNary Flow ForecastMcNary Flow Forecast

(in Kcfs) 2010 Avg 70-Yr Avg

Apr 1-15 125 189

Apr 16-30 134 228

May 140 275

Jun 165 298

Jul 124 204

Aug 1-15 124 162

Aug 16-31 104 126

22

System GenerationSystem Generation

(in GW-mo)

2010 Avg

70 Yr-Avg Diff

Apr 1-15 9.7 14.2 4.5

Apr 16-30 9.7 15.1 5.4

May 9.4 17.2 7.8

Jun 11.5 18.7 7.2

Jul 9.4 15.4 6.0

Aug 1-15 9.5 12.2 2.7

Aug 16-31 8.3 10.1 1.8

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Hydro System GenerationHydro System Generationwith and without Court-with and without Court-

ordered spillordered spill

8

9

10

11

12G

W-P

erio

ds

Apr

1-

15

Apr

16-

30 May Jun

Jul

Aug

1-

15

Aug

16-

31

BiOpCourt

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Energy Value of Court-Energy Value of Court-Ordered SpillOrdered Spill

MW-period

Apr 1-15 176

Apr 16-30 304

May 580

Jun 318

Jul 216

Aug 1-15 373

Aug 16-31 347

Season Avg 350 MW-seas

Annual Avg 150 MWa

25

Court-Ordered Spill Court-Ordered Spill (Columbia R.)(Columbia R.)

BONNEVILLE Apr10-Jun20: 100 kcfs all hours Jun21-Jul20: 85 kcfs day/ gas cap night (113 kcfs) Jul21-Aug31: 75 kcfs day/ gas cap night

THE DALLES 40% of flow all hours

JOHN DAY Apr 10-19: 0/60% of flow, all hours Apr 20 - Jul 20: 35% of flow, all hours (testing 30%

vs 40%) Jul 21 - Aug 31: 30% of flow, all hours

MCNARY Apr10-Jun14: 40% of flow Jun15-Aug31: 50% of flow (testing 40% vs. 60%)

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Court-Ordered Spill Court-Ordered Spill (Snake R.)(Snake R.)

ICE HARBOR Apr3 - May1: 45 kcfs/gas cap (88 kcfs) May2 - Jul16: 30% vs. 45 kcfs/gas cap Jul17 - Aug31: 45 kcfs/88 kcfs of flow

LOWER MONUMENTAL Apr3-June 20 : Gas Cap (~24-27 kcfs) all hours Jun21- Aug 31: 17 kcfs all hours

LITTLE GOOSE Apr3-Aug31: 30% of flow all hours Apr24 - May7: 30% day/gas cap night (38 kcfs)

LOWER GRANITE Apr3-Jun20: 20 kcfs all hours Jun21-Aug31: 18 kcfs all hours