Page 89 - agl036_D9

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Environment
Sustainability Performance Report 2012 87
Watermanagement
Consumed water
Water is an essential resource for AGL’s operations.
AGL operates in regions where water restrictions are
common, and seeks to minimise water consumption
where possible.
Approach
AGL consumes water for a variety of purposes as outlined below:
>> AGL’s largest consumer of water is the Torrens Island Power
Station, where water is consumed in the production of steam.
Around 90% of the water used at this power station is sourced
from an aquifer located approximately 130 metres below the
site. This saline water is passed through a reverse osmosis unit
and a demineralisation process to remove salts prior to use in
the power generation process;
>> cooling water is required at the Hydrocarbon Extractions Plant
to cool the process that takes Caltex Refinery waste fuel gas
to extract LPG and Naphtha;
>> at Somerton Power Station, water is injected into the combustion
chamber to reduce emissions of nitrogen oxides from the plant;
>> at Upstream Gas exploration and production project sites, water is
used to lubricate and cool drill bits during drilling operations; and
>> water is essential at all of AGL’s offices for provision of
basic amenities.
The acquisition of the Loy Yang A power station and associated
coal mine by AGL in June 2012 will greatly increase AGL’s future
water consumption and the power station will account for the
vast majority of AGL’s water use in the coming years. The most
significant water consumption at AGL Loy Yang is related to the
cooling tower system; each day the cooling system evaporates
approximately 80ML of water drawn from the La Trobe River
and local government reserves.
Performance
In FY2012, over 70% of the water consumed at AGL’s sites
comprised groundwater drawn from beneath the Torrens Island
Power Station, while the majority of the remaining consumed water
consisted of potable water purchased from retail water suppliers.
A small portion of water was derived from other sources, such as
harvested rainwater.
In addition, AGL makes important non-consumptive use of water
resources. This is discussed separately under ‘Managed Water’
on page 90.
In general, for power generation assets, the amount of water
consumed is proportional to the amount of power generated over
a particular time period. As Torrens Island Power Station consumes
the largest amount of water of all AGL’s operated assets, total water
use is strongly influenced by the power generated by this asset in
a given year.
Power output at Torrens Island Power Station in FY2012 was up
slightly compared to FY2011, although water consumption reduced
following works to fix town water pipe leaks and improve water
use efficiency for the generating units. Power output at Somerton
Power Station during FY2012 was significantly down compared to
previous years and this is reflected in the water consumption data.
In recognition of the need to use water sustainably across coal
seam gas operations, AGL will finalise water management strategies
during FY2013 for drill water, and fracture stimulation/flowback
water as well as conventional produced water. These strategies
will sit alongside AGL’s PWM Strategy and, together with a Brine
Water Management Strategy, will form AGL’s overarching water
management framework for unconventional and conventional oil
and gas projects.
Water use
0
50000
100000
150000
200000
250000
300000
350000
Major
AGL offices
Cooper Basin
Oil and
Gas Project
Silver Springs
Oil and
Gas Project
Galilee
Gas Project
Hunter
Gas
Project
Gloucester
Basin Gas
Project
Camden
Gas Project
Hydrocarbon
Extractions
Somerton
Power Station
Torrens Island
Power Station
kL
Legend
FY09
FY10
1
FY11
2
FY12
3
Notes
1 FY2010 was the first full year that the Gloucester, Hunter and Galilee CSG exploration projects have been owned and operated by AGL and so there is no water
consumption data available for preceding years.
2 AGL took ownership of Silver Springs and Cooper Basin assets in October 2010 therefore the first full year of data is FY2011.
3 In FY2012, major AGL offices included North Sydney (NSW), Canberra (ACT), Brisbane (QLD), Spencer Street and Bourke Street offices in Melbourne and East
Burwood (VIC) and Eastwood (SA).
4 Where office buildings are occupied by multiple tenants, AGL’s water consumption has typically been estimated based on property management data for the building,
pro rated to reflect the amount of building floor space occupied by AGL.