Analysis by Peter Rees
There is a great deal of false information circulating about the South Australian solar-thermal plant that is been approved for construction.
The cost is $650 million and for this you could build a combined cycle gas plant dispatching around 500MW.
Now let’s look at what South Australians are getting for their money. The technical data I use comes from the following reneweconomy article.
The plant is estimated to generate 495000MWh(495GWh) of electricity per annum and if we divide by 365 we get 1350MWh being generated every day on average.(To put things in perspective, Hazelwood power plant could generate 38,400MWh/day when it could generate 1600MW. )
What happens in a thermal-solar plant is that the sun’s heat is used to heat up molten salt which is stored in a large insulated tank. It the SA case, the tank has the capacity” to store heat that will later generate 1100MWh of electricity.
The molten salt is then passed through heat exchangers to turn water into steam and this steam then drives an electric generator.
But what size generator to use? Remember there is only 1100MWh of stored electric energy available.
So we could have an 1100MW turbine and it could run at max for 1 hour before the stored energy is expended or we could have a 45MW generator which would in theory give us 24/7 despatchable power. In reality, cloudy days would make this impossible.
So the 1100MW turbine would have a capacity factor of 4.1% (1 / 24) and the 45MW turbine would have a capacity factor of 100%, but both process the same amount of energy.
For this reason, capacity factor for a solar-thermal is totally meaningless despite what the reneweconomy article says.
The project is actually installing a 150MW generator but about 10% of that is lost in conversion and plant operating requirements so only 135MW is delivered to the grid.
However, the steam needs to drive the 150MW generator and 1100/150 = 7.3 hours. Renewenergy says about 8 hours. So we get 8 hours of generation at 135MW per day. Hardly despatchable!
So let’s recap…..
For $650 million we could get
- A 500MW combined cycle gas plant that can deliver the 500MW for probably 95% of the time(12,000MWh/day). It receives no ARENA subsidies or LREC’s for each MWh produced.
- A 150MW solar-thermal plant that can deliver 135MW for 8 hours a day(1100MWh/day) on average. It receives a $110 million dollar concessional loan from ARENA and LREC’s (currently about $80/MWh) for each MWh produced.
Tom (energy minister) tweeted.
So somehow, option “2” above was better than option “1” above.
The inmates are running the asylum!
But there’s more……
From the article….
“The full energy output of the Aurora facility is contracted to the South Australian Government under a ‘Generation Project Agreement’ (GPA) designed by Danny Price of Frontier Economics, and will provide a benefit in favour of the SA government”
The SA government has signed a contract to buy 20 years output from the facility at around $78 which is around $39 million a year. But what about the LREC’s?
From the article…
“One quarter of the renewable energy certificates (LGCs) created will be bundled with the energy, which will be voluntarily surrendered by the SA Government, ensuring that 25% of the Government’s power is carbon neutral, which will go towards the state’s Carbon Neutral Adelaide targets. The remaining 75% of certificates will stay with SolarReserve, who will presumably market them as they please.”
Pardon my ignorance but why is the SA government not picking up 100% of the LREC’s? They are only taking 25% so someone else has to fork out the other 75% which will be SA businesses and householders. What a slimebag act.
At $80/MWh, the full annual cost of the solar-thermal generated electricity LREC’s is $40 million and the SA government are paying only $10 million of it and duckshoving the rest onto SA businesses and households.
I despair for this country.
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Warwick Hughes reports
Record daily wholesale electricity price for Victoria in Adelaide-Melbourne heat