Hydrowatch - 30 October 2014

Energy Link Ltd
Hydro Watch
31/10/2014
Issue: 915
Date: Thursday, 30 October 2014
A weekly summary relating to New Zealand hydro storage and inflows.
Compiled by Energy Link Ltd.
Storage Summary
South Island South Island
Controlled
Uncontrolled
South Island North Island
Total
Taupo
Total Storage
Current Storage (GWh)
1178
507
1685
363
2047
Storage Change (GWh)
8
-55
-47
23
-24
Note: SI Controlled; Tekapo, Pukaki and Hawea: SI Uncontrolled; Manapouri, Te Anau, Wanaka, Wakatipu
Transpower Security of Supply
South Island North Island
New Zealand
Current Storage (GWh)
1585
363
1947
Note: These figures are provided to align with Transpower's Security of Supply information. However due
to variances in generation efficiencies and timing, storage may not exactly match Transpower's figures.
New Zealand Summary
Total storage decreased 23.8 GWh over the last week. South Island controlled
storage increased 0.7% to 1178 GWh; South Island uncontrolled storage
decreased 9.8% to 507 GWh; with Taupo storage increasing 6.7% to 363 GWh.
New Zealand Storage and Inflow Summary
4500
2000
4000
1750
G
1500
3000
1250
2500
1000
2000
750
1500
Inflows (GWh)
Storage (GWh)
3500
500
1000
250
500
0
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Taupo Inflows (2014/15)
South Island 2013/14
Waikato 2013/14
New Zealand Storage (2014/15)
Average SI Storage (9/10-13/14)
Date: Thursday, 30 October 2014
Manapouri
Storage (GWh)
This Week
407
Last Week
442
% Change
-8.1%
Inflow (GWh)
This Week
Last Week
% Change
Ph 03-479 2475
68
162
-58.0%
South Island inflows (2014/15)
South Island 2014/15
Waikato 2014/15
New Zealand Storage (2013/14)
Clutha
Waitaki
Waikato
NZ
207
222
-6.8%
1071
1067
0.4%
363
340
6.7%
2047
2071
-1.1%
46
106
-56.8%
105
154
-31.7%
64
64
-0.4%
283
487
-41.8%
1
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin
Operat
Energy Link Ltd
Hydro Watch
31/10/2014
Lake Levels and Outflows
Catchment
Manapouri
Clutha
Waitaki
Waikato
Lake
Level
Storage
Outflow
Manapouri
Te Anau
Wakatipu
Wanaka
Hawea
Tekapo
Pukaki
Taupo
(m. asl)
178.15
202.67
309.85
277.18
340.96
705.10
524.53
356.74
(GWh)
135
271
45
55
107
286
785
363
(cumecs)
17
177
196
18
Outflow
Change
-91
-8
-17
1
Inflow Summary
The two charts below represent where current inflows are in relation to historic inflow patterns. The
percentile values have been calculated using all inflows since 1931.
South Island Inflows - The past four weeks of S. I. inflows rank as the 35th driest on record.
South Island Inflow Percentile Data
4 week running average
1000
99%ile
900
95%ile
GWh
800
700
75%ile
600
Median
500
25%ile
400
5%ile
300
200
1%ile
100
4week
inflow
0
Month
North Island Inflows - The past four weeks of N. I. inflows rank as the 20th driest on record.
North Island Inflow Percentile Data
4 week running average
140
99%ile
GWh
120
95%ile
100
75%ile
80
Median
25%ile
60
5%ile
40
1%ile
20
4week
inflow
0
Month
Waikato System
Ph 03-479 2475
2
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin
Energy Link Ltd
Hydro Watch
31/10/2014
Waikato System
Lake Taupo Levels and Inflows
357.50
250
357.00
200
356.50
150
356.00
100
Minimum Lake
355.50
50
355.00
Inflows (GWh)
Lake level (m)
Maximum Lake
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Taupo Inflows (2014/15)
2011/12
2014/15
2009/10
2012/13
Average
2010/11
2013/14
Maximum Lake Levels
Lake Levels - Lake Taupo storage increased to 63.5% of nominal full at 363 GWh.
Inflows - Inflows remained steady at 64 GWh.
Generation - Average generation decreased 2.5% to 296.1 MW.
Tekapo
Lake Tekapo Levels and Inflows
712
220
200
Maximum Lake level
710
180
160
140
120
706
100
80
704
60
40
702
Minimum Lake level
Inflows (GWh)
Lake Level (m)
708
20
700
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Tekapo Inflows (2014/15)
2011/12
2014/15
Minimum Lake Levels
2009/10
2012/13
Average (Last 5 Years)
2010/11
2013/14
Maximum Lake Levels
Lake Levels - Lake Tekapo ended the week 39.6% nominally full with storage increasing to 286 GWh.
Inflows - Inflows into tekapo decreased 11% to 49 GWh.
Generation - Average Tekapo generation increased 10.9% to 63.1 MW.
Hydro Spill - Lake Tekapo did not spill.
Waitaki System
Ph 03-479 2475
3
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin
Energy Link Ltd
Hydro Watch
31/10/2014
Waitaki System
Lake Pukaki Levels and Pukaki/Ohau Inflows
535
240
533
220
Maximum Lake level
200
531
180
160
527
140
525
120
523
100
80
521
60
519
Inflows (GWh)
Lake Level (m)
529
40
Minimum Lake level
517
20
515
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Month
2009/10
2012/13
Average (Last 5 Years)
Pukaki/Ohau Inflows (2014/15)
2011/12
2014/15
Minimum Lake Levels
Mar
Apr
2010/11
2013/14
Maximum Lake Levels
Lake Levels - Lake Pukaki ended the week 44.1% nominally full with storage falling to 785 GWh.
Inflows - Inflows into the Waitaki System decreased 43.4% to 56 GWh.
Generation - Average Waikati generation decreased 19.3% to 636.3 MW.
Hydro Spill - Lake Pukaki did not spill.
River Flows - Flows from the Ahuriri River fell to 22.89 cumecs while Waitaki River flows were
lower than last week averaging 280.16 cumecs.
Clutha System
347
and
Inflows
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
Maximum Lake level
345
Lake Level (m)
343
341
339
Normal Minimum Lake
337
Emergency Minimum Lake Level
335
333
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Inflows (GWh)
Lake Hawea Levels
Apr
Month
Hawea Inflows (2014/15)
2011/12
2014/15
Ph 03-479 2475
2009/10
2012/13
Average (Last 5 Years)
4
2010/11
2013/14
Maximum Lake Levels
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin
Energy Link Ltd
Hydro Watch
31/10/2014
Lake Levels - Total storage for the Clutha System decreased 6.8% to 207 GWh. Lakes Hawea, Wanaka
and Wakatipu ended the week 36.1%, 47.7% and 42.9% nominally full respectively.
Inflows - Total Inflows into the Clutha System 56.8% lower at 46 GWh.
Generation - Average generation was 11.5% lower at 436 MW.
Hydro Spill - The was no estimated spill
River Flows - Total outflows from the lakes and Shotover River fell to 436.7 cumecs. This
comprised of 18 cumecs from Lake Hawea, 196 cumecs from Lake Wanaka,
177 cumecs from Lake Wakatipu and 46 cumecs from the Shotover River.
Lake Wanaka Levels and Inflows
279
100
90
80
70
60
277
50
40
30
276
Inflows (GWh)
Lake Level (m)
278
20
10
275
0
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Wanaka Inflows (2014/15)
2011/12
2009/10
2012/13
2010/11
2013/14
Lake Wakatipu Levels
and
Inflows
311
100
90
80
70
310.2
60
50
309.8
40
30
309.4
Inflows (GWh)
Lake Level (m)
310.6
20
10
309
0
Apr
May
Jun
Jul
Wakatipu Inflows (2014/15)
2011/12
2014/15
Ph 03-479 2475
Aug
Sep
Oct
Nov
Month
2009/10
2012/13
Average (Last 5 Years)
5
Dec
Jan
Feb
Mar
Apr
2010/11
2013/14
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin
Energy Link Ltd
Hydro Watch
31/10/2014
Manapouri System
Lake Manapouri Levels and Manapouri/Te Anau Inflows
ober 2014
180
400
179.5
360
320
179
178.5
280
178
240
177.5
200
160
177
Lower Operating Level
176.5
120
176
80
175.5
40
Inflows (GWh)
Lake Level (m)
Upper Operating Level
0
175
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
Manapouri/Te Anau Inflows(2014/15)
2011/12
2014/15
Lower Operating Level
2009/10
2012/13
Average
2010/11
2013/14
Upper Operating Level
Lake Levels - Total storage for the Manapouri System decreased 8.1% to 407 GWh with Lake
Manapouri ending the week 83.3% nominally full and Lake Te Anau ending the
week 98.5% nominally full.
Inflows - Total inflows into the Manapouri System decreased 58% to 68 GWh.
Generation - Average generation was 6% higher at 614 MW.
Hydro Spill - Estimated spill at the Mararoa Weir was 17.3 cumecs.
Operating Range - Lakes Manapouri and Te Anau are operating in the upper end of their repective
'Main operating range'.
Lake Te Anau Levels
204
203
Lake Level (m)
Upper Operating Level
202
Lower Operating
201
200
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
Month
2009/10
2012/13
Average
Ph 03-479 2475
2010/11
2013/14
Upper Operating Level
6
2011/12
2014/15
Lower Operating Level
Level 4, Consultancy House,
7 Bond Street, P.O.Box 478, Dunedin

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