Transcript Hydro Tasmania Vision and Goals

Hydro Tasmania
Drought and Climate Change
Andrew Scanlon
Environment and Sustainability Manager
Tasmania, Australia
Hydro Tasmania Business Position
•
Australia’s largest renewable
energy generator.
•
Australia’s largest dam owner.
•
Australia’s largest water
manager.
•
One of Australia’s largest
renewable energy developers.
Hydro Tasmania’s Generating System
 29 small to medium size
hydropower stations (2300 MW);
 70 MW of wind power with another
200 MW under construction or
planned;
 Two diesel-wind systems on each
of two offshore islands; and
 A gas-fired thermal power station
(120 MW) and 3 gas turbines (105
MW).
Two Very Large Storages
Great Lake
Storage Capacity
= 3000 GL
Lake Gordon
Storage Capacity
= 11000 GL or
22 Sydney
Harbours
Large Seasonal Storages Above Cascades
Lake King William - Central Tasmania
Small-to-Medium
Run-of-River Power Stations
Cluny Dam – South-eastern Tasmania
Coping with Drought (1)
• A major drought occurred in the late
1960s – power rationing and low
lake levels.
• Decision to provide thermal support
– 240 MW thermal station
commissioned in the early 1970s.
• Continued development of hydro
system till fully developed in the
1990s.
Coping with Drought (2)
• Connection to the mainland power
grid in 2005 (600 MW DC link).
• Diversification into wind power.
• Conversion of thermal station to gas
and addition of three gas turbines.
• Drought conditions have persisted
since the late 1990s.
Environmental and Social Issues
Low lake levels, diminished
downstream flows, and water quality
problems present a range of
environmental and social issues.
These include:
• Lake and river ecosystem stress;
• Economic and social impacts on
other users.
Great Lake (1)
Great Lake (2)
Risk Bands and Monitoring
1040
1035
1030
1025
1020
NMOL
1015
Lagoon of Islands and Ouse River
Environmental Management Lagoon of Islands
• Alternative water source for downstream
users.
• Biomanipulation pilot study – early 2007.
• Remediation of Ripple Canal – 2007-2009.
• Full-scale biomanipulation commences
summer 2007-08.
• Investigation of options for new storages.
Climate Change and Water
Supply – Adaptation Options
Supply Side
Demand Side
More reservoir capacity.
Water use efficiency.
More groundwater use.
Changed water use,
e.g., different
agricultural crops.
Desalination.
Water transfer.
Water recycling.
Price signal and water
markets.
Climate Change – Hydro Tasmania
• Hydro Tasmania is reliant on water inflows
and meets a customer demand that is, in
part, dependent on climate.
• Hydro Tasmania has a multiple-use water
resource with requirements additional to
generating electricity.
• Hydro Tasmania has significant fixed
assets including 44 large dams.
• Sustainable management requires an
ability to predict likely future trends.
-50.0%
time
Oct-06
Jul-06
Apr-06
Jan-06
Oct-05
Jul-05
Apr-05
Jan-05
Oct-04
Jul-04
Apr-04
Jan-04
Oct-03
Jul-03
Apr-03
Jan-03
Oct-02
Jul-02
Apr-02
Jan-02
Oct-01
Jul-01
Apr-01
Jan-01
Oct-00
Jul-00
Apr-00
Jan-00
Oct-99
Jul-99
Apr-99
Jan-99
Oct-98
Jul-98
Apr-98
Jan-98
% of Monthly Average Inflow
High Variability in Inflow
Monthly Inflow Variation 1999-2006
300.0%
250.0%
200.0%
150.0%
100.0%
50.0%
0.0%
Climate Change – Looking Back
Climate Factor
Climate Factor (Post 1950 / Pre 1950)
1.60
1.40
1.20
1.00
0.80
Total
Central
Western
Queenstown rf
Carrick rf
King sf
Hellyer sf
0.60
0.40
0.20
0.00
1
2
3
4
5
6
7
Month
8
9
10
11
12
Climate Change – Looking Forward
• Climate change modelling study – CSIRO.
• Focus on impact of climate change on
Hydro Tasmania and Tasmania.
• Better representation of Tasmania in
modelling.
• Identifying trends in rainfall, temperature,
evaporation and wind.
• Plan to implement outcomes into Hydro
Tasmania models to estimate impacts to
business.
Conformal Cubic Atmospheric Model
(CCAM) Grid (+topography)
40°S
1100
1000
41°S
800
700
Latitude
• Time step = 4
minutes
• Grid size– 11km
• 70 year simulation
– 10 million time
steps
– 50 days on
supercomputer
– 110 Gb storage
900
600
42°S
500
400
300
43°S
200
100
44°S
144°E
145°E
146°E
147°E
Longitude
148°E
149°E
0
High Resolution Model Results
• Tasmania is in a region of reduced climate
change compared to the global average.
• Climate change might be relatively moderate
in Tasmania out to 2040; some warming and
some change in rainfall patterns and winds.
• Result uncertainty due to the use of a single
emission scenario, but the scenarios do not
diverge very much by 2040.
• Some uncertainty from using a single rather
than an ensemble of different global models.
High Resolution Model Results - Rainfall
On a seasonal
basis there is
increased winter
and early spring
rainfall in all
catchments.
There is a drying
trend in the north
east in the first
half of the year,
only partly
compensated by
increased rainfall
later in the year.
South Esk
Annual
rainfall is
projected to
increase by
7-11% in all
catchments
except in the
South Esk,
which
decreases by
around 8%.
Hydro Tasmania Inflow Prediction
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
•Factor of 1.0
represents no change
in inflows.
Arthur's Lake
Great Lake
Trevallyn Dam
•Factors <1.0
represents drying.
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
•Factors >1.0
represents wetter.
Jan
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Lake Burbury
Lake Rowallan
Feb
Mar
Apr
•Great Lake factors well
below 1.0 and thus
drying predicted.
•Others have drier
summers/autumns and
wetter winters.
Lake Mackintosh
Jan
Dec
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Climate Change Conclusions
• Strong evidence for a shift in inflows to drier
summer/autumns and wetter winter/springs.
• Future predictions are showing similar trends.
• Potential significant reduction in annual/seasonal
inflows in the central and easterly catchments.
• These shifts in inflows will result in a change to
future operations of Hydro Tasmania.
• Probable Maximum Precipitation not examined
(spillway capacity – dam safety issue).
Climate Change -- Future work
• Future work with Antarctic CRC:
– Multiple emissions scenario.
– Multiple climate models.
• Outputs of future work:
– Rainfall trend estimates for modelling impact on
Hydro generation.
– Temperature variations for electricity and
agricultural sectors.
– Wind variability for wind farms and transmission
authorities.
– Extreme weather events for flooding and planning
considerations.