Saturday, March 10, 2012

Cost of solar power (19)

In this series of blog posts, I like to analyse the cost of solar power for projects at utility scale, say around 100 MW.  Every now and then, however, a smaller project comes along, which is suitable for my analysis and might have some public interest.

One such case is the University of Queensland’s solar array on the rooftops of four of the largest buildings at UQ.  The whole system is rated at 1.22 MW peak output from 5,004 polycrystalline silicon panels on a total rooftop space of 8,200 square metres.  The panels were supplied by Trina Solar.

This project was officially opened on 15 July 2011.  Engineering, procurement and construction cost AUD 4.85 million, and UQ spent (or I should say invested) a further AUD 2.65 million on a visitor centre, viewing platform, additional ground works, and the development of a public user interface. 

Let’s use the AUD 4.85 million figure for the cost of power generation, and not the combined figure of AUD 7.5 million.

A feature of the project is that Brisbane-based RedFlow has supplied a prototype 200kW zinc bromine battery bank that is connected to a 339kW section of panels.  The outcomes of this installation will be interesting to monitor, since the zinc bromine concept offers the promise of relatively cheap storage of electricity.

At the time of writing, a full year’s output has not been measured, but UQ says the system is on track to deliver 1.75 GWhr per annum and save emissions of 1,600 tonnes of CO2 annually.  (Note that much of the electricity generated in Queensland is from black coal, at around 900 kg CO2 per MWhr.)

I now evaluate the Levelised Electricity Cost (LEC) using my customary 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), which means that the required rate of capital return is 9.4%,
          all projects have the same annual maintenance and operating costs (2% of the total project cost), and
          government subsidies are neglected.

For further commentary on my LEC methodology, see posts on Real cost of coal-fired power, LEC – the accountant’s view and Cost of solar power (10).  Note that I am now using annual maintenance costs of 2% rather than 3% as previously.

The results are:

Cost per peak Watt             AUD 3.98/Wp
LEC                                        AUD 316/MWhr

The components of the LEC are:
Capital           {0.094 × AUD 4.85 × 10^6}/{1,750 MWhr} = AUD 261/MWhr
O&M              {0.020 × AUD 4.85 × 10^6}/{1,750 MWhr} = AUD 55/MWhr

By way of comparison, LEC figures (in appropriate currency per MWhr) for all projects I’ve investigated are given below.  The number in brackets is the reference to the blog post, all of which appear with the title “Cost of solar power ([number])”:

(2)        AUD 183 (Nyngan, Australia, PV)
(3)        EUR 503 (Olmedilla, Spain, PV, 2008)
(3)        EUR 188 (Andasol I, Spain, trough, 2009)
(4)        AUD 236 (Greenough, Australia, PV)
(5)        AUD 397 (Solar Oasis, Australia, dish, 2014?)
(6)        USD 163 (Lazio, Italy, PV)
(7)        AUD 271 (Kogan Creek, Australia, CLFR pre-heat, 2012?)
(8)        USD 228 (New Mexico, CdTe thin film PV, 2011)
(9)        EUR 200 (Ibersol, Spain, trough, 2011)
(10)      USD 231 (Ivanpah, California, tower, 2013?)
(11)      CAD 409 (Stardale, Canada, PV, 2012)
(12)      USD 290 (Blythe, California, trough, 2012?)
(13)      AUD 285 (Solar Dawn, Australia, CLFR, 2013?)
(14)      AUD 263 (Moree Solar Farm, Australia, single-axis PV, 2013?)
(15)      EUR 350 (Lieberose, Germany, thin-film PV, 2009)
(16)      EUR 300 (Gemasolar, Spain, tower, 2011)
(17)      EUR 228 (Meuro, Germany, crystalline PV, 2012)
(18)      USD 204 (Crescent Dunes, USA, tower, 2013)
(19)      AUD 316 (University of Queensland, fixed PV, 2011)

[Note: all estimates made using 2% annual maintenance cost.]

The Capacity Factor for the UQ installation is 1,750 / (1.22 × 24 × 365) = 0.164, about what one would expect from fixed panels in a sunny location that had average daily exposure of 19.3 MJ/m^2 in 2011.

The LEC for the UQ installation is a little high compared to other recent projects such as the recently-opened Meuro project and the yet-to-start Moree Solar Farm (which at last report was having trouble securing finance so that construction could start).  It is, of course, a small project built on top of existing infrastructure, so it could not be expected to deliver the world’s best LEC.

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