Thursday, April 14, 2011

Cost of solar power (7)

Yesterday, the Australian media carried details of a new and unusual solar installation to be built in the cutely named town of Chinchilla in the state of Queensland.  This can strictly be classified as Concentrated Solar Thermal, but it’s unusual since the solar energy will be deployed in pre-heating water in an otherwise conventional coal-fired power station.

Here is an extract from a press release issued by the owner of the plant, CS Energy (

“The Commonwealth Government and Queensland Government have given the green light to one of the world’s largest solar projects, announcing today that approval had been given for the $104.7 million Kogan Creek Solar Boost Project.  CS Energy’s 750 megawatt coal-fired Kogan Creek Power Station near Chinchilla in South West Queensland will soon become home to a 44 megawatt solar thermal addition representing the largest solar project in the Southern Hemisphere and the world’s largest solar integration with a coal-fired power station.”

According to Chief Executive, David Brown, the project will

“…  [avoid] production of 35,600 tonnes of greenhouse gases annually …  [and] increase the amount of electricity generated by up to 44 megawatts during peak solar conditions, providing an additional 44,000 megawatt hours of electricity per year.”

“The project will use AREVA Solar’s Australian-pioneered Compact Linear Fresnel Reflector (CLFR) technology to supply additional steam to the power station’s turbine, supplementing the conventional coal-fired steam generation process.”

Normally in Rankine-cycle steam turbines, water pre-heating is achieved using heat energy in steam that would otherwise be used to spin the turbines.  The solar pre-heater makes more steam available for the electricity generation process.  In principle, solar pre-heating should be very effective when used in conjunction with existing Rankine-cycle turbines. 

CS Energy’s web site reports that of the total project cost of AUD 104.7 million, AUD 34.9 million came from the federal government’s Renewable Energy Demonstration Program.  CS Energy also reports that

“CS Energy has received support from the Queensland Government through a contribution of $35.4 million to CS Energy’s Carbon Reduction Program, which has enabled the company to direct funds to the Kogan Creek Solar Boost Project.

So a significant chunk of the project’s cost has come from government support.  But let’s calculate the metrics of peak cost and LEC (Levelised Electricity Cost) under my usual assumptions:
·         there is no inflation,
·         taxation implications are neglected,
·         projects are funded entirely by debt,
·         all projects have the same interest rate (8%) and payback period (25 years),
·         all projects have the same annual maintenance and operating costs (3% of the total project cost), and
·         government subsidies are neglected.

That gives for the Kogan Creek project:

Cost per peak Watt     AUD 2.38/Wp
LEC                            AUD 295/MWhr

The components of the LEC are:
CAPEX           {0.094× AUD 105×106}/{44×103 MWhr} = AUD 224/MWhr
OPEX             {0.030× AUD 105×106}/{44×103 MWhr} = AUD 71/MWhr

The cost of per tonne of CO2 emissions reduced is also of interest.  I make that
{0.094 + 0.03} × AUD 105×106/35600 tonnes = AUD 365 / tonne.

By way of comparison, here are my LEC figures for all projects I’ve investigated:

Cost of solar power (2): AUD 199/MWhr (Nyngan, Australia, PV)
Cost of solar power (3): EUR 547/MWhr (Olmedilla, Spain, PV)
Cost of solar power (3): EUR 205/MWhr (Andasol I, Spain, trough)
Cost of solar power (4): AUD 257/MWhr (Greenough, Australia, PV)
Cost of solar power (5): AUD 432/MWhr (Whyalla, Australia, dish)
Cost of solar power (6): USD 177/MWhr (Lazio, Italy, PV)
Cost of solar power (7): AUD 295/MWhr (Kogan Creek, Australia, CLFR pre-heat)

As a big fan of solar thermal power generation, I’m disappointed by these latest estimates.  I had expected that the LEC for this sort of installation would be better.

The other comment I’d make concerns the cost to be applied to CO2 emissions in any emissions reduction scheme.  Here in Australia the discussions seem to focus on a typical cost of perhaps AUD 25 /tonne.  Because of very difficult political processes, that number might be accurate only within a factor of two.  Whatever, it’s a long way short of the AUD 365/tonne I’ve estimated for the Kogan Creek project.

1 comment:

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