The diesel generators being rushed to South Australia in a desperate bid to save the state from summer blackouts can’t run at full power when the temperature goes over 40C.
The Advertiser can reveal that the nine “state-of-the-art” dual-fuel turbines that Premier Jay Weatherill has promised to have in place by December will lose about 25 per cent of their promised 276MW capacity in sweltering heat — exactly when they are most needed to stop forced blackouts.
Mr Weatherill on Tuesday announced the turbines would be split between Holden’s Elizabeth factory after the car industry shuts down, and adjacent to the mothballed Adelaide desalination plant.
After running on diesel for two years, the turbines are expected to combine at a single unknown site and be flicked over to gas, becoming the promised state-owned power station.
This week, Mr Weatherill boasted he was delivering more power with this new off-the-shelf turbine plan than the 250MW that was first imagined in the energy policy he released in March.
However, technical documents seen by The Advertiser show the maximum combined output from the GE TM2500 turbines collapses from 276MW to just 205MW on days of 40C or more.
The reduced capacity applies when the turbines run on diesel or gas. It is due to a phenomenon known as the “heat degradation curve”, an in-built limitation of the technology.
However, the Government insists that its generators will still provide enough power to help stave off the risk of more load-shedding, even when they are cut back to lower output levels.
The forced blackouts endured by SA in February came on a day of 41C temperatures and in a prolonged heatwave.
Official reports into the event found that the blackouts followed a sharp drop in wind and solar power, and a privately owned gas station also remained turned off.
SA’s peak energy demand on the hottest days of the year hits more than 3000MW. In February, 90,000 customers were blacked out when SA Power Networks shed 300MW of electricity.
The surge in SA’s power use typically comes as people return home from work and turn on airconditioners, often coinciding with lower wind and solar output at sunset.
AEMO has also emphasised that market responses, which could include delays in repair work or the opening up of new generation, could further reduce the risk of forced blackouts in summer.
The worst low energy reserve conditions for SA are forecast to occur in February, when a deficit of 337MW is predicted.
Victoria is the only other state facing similar problems this summer.
Its blackout risk sharply increased following closure of the Hazelwood coal-fired power station in March.