Friday, August 19, 2011

The opportunity cost of cheap photovoltaic cells

Climate Progress has just published a news story, "The World’s Largest Planned Solar Plant Switching 500 MW from Concentrated Solar Thermal to Photovoltaics".

The ever lower cost of photovoltaic solar cells is great news, in so many ways – but paradoxically, it could delay the transition to completely renewable electricity.

Storing electricity is difficult and expensive. To do it with batteries in an isolated rural home is easy (and common) enough, but if you tried to roll out batteries on a large scale, the amount of materials needed would cause an ecological disaster in itself – if you don’t believe me, read this article by Tom Murphy, an associate professor of physics at the University of California, San Diego.

Tom Blakers has recently argued for using pumped hydro storage, which certainly works – but on this dry continent there are going to be a lot of questions before we decide how much of that we can use.
Photovoltaic cells produce electricity directly. On the other hand, solar thermal power plants can easily build storage, because heat is quite easy to store. As you can read here, the Torresol Gemasolar plant has successfully achieved 24 hours round-the-clock electricity production.

But if solar companies turn in a big way to photovoltaics, which only generate electricity while the sun shines, we can generate a lot of clean electricity (and cut some emissions) – without making the necessary preparations to completely abandon our reliance on fossil fuel energy.

Solar thermal plants continue to be built in countries that have put in place some of the necessary assistance to renewable energy, but as the article below indicates, if bottom line cost considerations are our only guide then we may fall to the old maxim: “if you don’t know where you are going, any road will take you there.”

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