Tuesday, March 8, 2011

Cost of solar power (5)

Before I launch on the main theme of today’s post, I’ll describe progress of late.  I have a few projects under way:
·         I’ve committed to attend the International Solar Energy Society’s 2011 Solar World Congress to be held in Kassel, Germany from 28 August – 2 September 2011.  I’ve lodged my abstract, and assuming that’s accepted I’ll have a paper to write.  It will be on the performance of my engine-canopy system at Wellington NSW in the case where the canopy slopes at the latitude angle.  To give a preview of the results (which were completed late last year and are as yet unpublished) – compared to the horizontal canopy the sloping case has a lower maximum output, but  larger annual output that is more uniform throughout the year.  Results for the horizontal canopy were presented at the 2010 meeting of the Australian Solar Energy Society (AuSES).
·         I’m excited about the prospects of thermal storage with my heat engine.  Back-of-the-envelope calculations indicate that storage will be feasible and cheap.  What’s required now is a substantial simulation, which I think I know how to do but will take me some months.  That’s a job for the near future.  If successful, I’ll present the work at the 2011 AuSES meeting.
·         I also have another substantial project under way that regrettably must remain confidential for the moment.  That has occupied all my research time since mid January.
And so to the main topic of today’s post – cost of power for the Solar Oasis.

Solar Oasis (www.solaroasis.net.au)

From their web site …

“The Project will use 300 Big Dish solar thermal concentrators to generate 66GWh of electricity each year; enough electricity to power ~9,500 Australian homes and reduce GHG by 60,000 tonnes/year - an equivalent reduction of ~17,000 cars/year. The Project will deliver the first commercial scale concentrating solar thermal plant to dispatch power to the Australian electricity market and will also assist with the commercialisation of Wizard Power's Australian owned and developed Big Dish concentrating solar thermal technologies.”

The ‘Big Dish’ is a concept of the solar thermal research group at the Australian National University, which has been at the forefront of solar thermal research for several decades.  In 2005, the Big Dish technology was licensed to Wizard Power, one of the participants in the Solar Oasis.  Recently, a new Big Dish has been constructed on the ANU campus.  It’s very impressive!

The Solar Oasis project is based at Whyalla in South Australia.  Solar energy will be collected by 300 parabolic dishes, each of approximately 500 m^2 aperture.  The heat energy drives a conventional Rankine-cycle steam turbine, with power sent directly to the grid.  (The ANU team have worked extensively on storage of solar energy by splitting ammonia, but there is no mention of that with the Solar Oasis project.)  Other project details as announced in mid 2010: site area estimated at 0.8-1.0 km2, peak output 40 MW, annual output 66 GWhr, cost AUD 230 million.

To estimate the cost of solar power from Solar Oasis, I make 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), and
·         all projects have the same annual maintenance and operating costs (3% of the total project cost), and
·         government subsidies are neglected.

Cost per peak Watt     AUD 5.75/Wp
LEC                            AUD 432/MWhr

The components of the LEC are:
CAPEX           {0.094× AUD 230×106}/{66×103 MWhr} = AUD 328/MWhr
OPEX             {0.030× AUD 230×106}/{66×103 MWhr} = AUD 105/MWhr

On the numbers above, the Solar Oasis project is not cheap for a project that won’t be operational for a couple of years. Using the same methodology, Andasol 1 (parabolic trough, molten salt storage, online in March 2009) has a LEC of EUR 205/MWhr.  See Cost of Solar Power (3).

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