Wednesday, August 24, 2011

Blythe switches to PV

There have been dramatic, astonishing and significant developments with the 1000 MW Blythe solar project in California, the biggest solar project in the world.  On 18 August 2011, the developer (Solar Trust of America, a joint venture between the German companies Solar Millenium and Ferrostaal) announced that the first 500 MW of the project will now be powered by PV, and not solar thermal as previously announced.

Dramatic news?  Absolutely – the Solar Millenium share price collapsed from around EUR 20, where it had been for around a year, to around EUR 4.

Astonishing?  Absolutely – the foundation stone for this project had already been laid, approvals had been secured, funding was in place, and construction of the solar thermal plant was under way.  A switch at such a late stage in a multi-billion dollar project is truly surprising.  One might well wonder at the quality of the decision-making process in the first place.

Significant?  Some might argue this is proof that PV has decisively triumphed over solar thermal in the mortal struggle for market share.  That would be taking things too far, but it does say that in SE California where water is scarce, at the present, PV gives cheaper power than parabolic troughs with air-cooled condensers and no thermal storage.

I analysed the Blythe installation in Cost of Solar Power (12).  According to my standard assumptions, I found the cost per peak Watt was USD 5.79 and the Levelised Electricity Cost was USD 315/MWhr.  I thought the costs were high and commented at the time that “the LEC for the Blythe project is 25% higher than for another big US project currently under construction – Ivanpah”.  The Ivanpah installation, which I analysed in Cost of Solar Power (10), uses heliostats and towers, and will be able to collect heat at a higher temperature than the parabolic trough technology proposed for Blythe.   That indicates a technological advantage for power towers over troughs when air-cooled condensers are used.

According to Solarbuzz data, the cost of PV modules in the USA has fallen from USD 4.75/Wp in mid 2008 to below USD 3.00/Wp today.  Solarbuzz comments that the “module price is 50-60% of the total installed cost of a solar energy system”.  Presumably this led the decision-makers at the Solar Trust of America to turn away from their tried and tested parabolic trough technology.  It must have been a painful decision.

What does this mean for Solar Millenium and their parabolic trough technology?  Well, that technology still offers the great benefit of thermal storage.  Moreover, where water-cooled condensers are possible, the peak power output will be higher than with air-cooled condensers as proposed for Blythe. 

My view is that there remains a place for solar thermal power with storage.  Several contenders are slugging it out for dominance – troughs, heliostats/towers, Compact Linear Fresnel Reflectors and dishes – without a clear winner in sight yet.  (I might also modestly draw attention to my evaporation engine, see  I also think that costs for solar thermal power station components will continue to fall as more large-scale installations are constructed.

I expect the battle between solar thermal and PV to continue.  It will be a tough fight.

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