“Electricity Options for the
Future" - where will WA's power
come from…..
GAS
Jason Waters
General Manager Trading & Fuel
Presentation to Australian Engineering Week Public Forum –
5 August 2009

Power Systems 101
Summer Demand Curve

Power Systems 101…
Winter Demand Curve

Power Systems 101…
Ancillary Services…
• Frequency control (maintaining “in vs. out”)
• Spinning reserve (Instant back-up)
• Fast start reserve (Delayed back up – 15 mins)
Other Terminology…
• Capacity (MW)
• Energy (MWh)
• Intermittent Generators

What type of Plant?
Three major forms of gas fired
generating plant…
• Open Cycle Gas Turbines
• Cogeneration
• Combined Cycle

Open Cycle GT

Open Cycle GT
• Efficiency Range 25% - 40%
• Low cost ($1000/kW approx)
• Short construction lead times
(2 years)
• Peaking/mid merit supply
• Excellent ancillary service
provision

Cogeneration

Cogeneration
• Excellent total efficiency (80%)
• Electricity generation efficiency as
per OC GT
• Construction time 2-3 years
• Require steam customer
• Baseload supply - inflexible

Combined Cycle

Combined Cycle
• Efficiency 45% - 55%
• Cost $1500/kW approx
• Construction time 2-3 years
• Baseload supply
• Can provide ancillary services but
expensive

Gas in summary
Generating Efficiencies (HHV)
80
70
60
50
40
30
20
10
0
Coal Fired Ultra- Coal Fired Supercritical Coal fired sub-critical Cogeneration Combined Cycle GT Open Cycle GT
Supercritical

Gas in summary
Carbon Intensity…
• Coal 0.8 – 1.0 tCO2/MWh
• Open Cycle GT’s 0.45 – 0.7 tCO2/MWh
• Combined Cycle – 0.4 tCO2/MWh
Gas is not “clean” but is the best currently
available – clean coal still some years away.

Gas in summary…
The Good…
• Relatively low carbon intensity
• High efficiency – good resource use
• Construction cost ($1000/kW -
$1500/kW)
• Delivery / construction lead times
• Ancillary Service Provision
• Dual fuel capability

Gas in summary…
The not so good…
• Price – not sustainable for power
generation
• Availability
• Security – Varanus Incident 2008

Role in the SWIS

Role in the SWIS…
Current installed capacity
Renewable
4% Coal
34%
Gas
62%

Role in the SWIS…
The opportunity…
• Market requires additional 2000 MW by
2020
• Security issues need addressing through
dual fuel capability and gas storage
• Fuel price/availability and carbon role
• Flexibility – ancillary services
• “Enabler” of intermittent renewable
generation

Role in the SWIS…
What are we likely to see…
• OCGT providing capacity
• Likely to see continued peaking and mid
merit use
• Cogeneration application tied to value of
steam
• Limited combined cycle use until Carbon
>$90/tonne