Since you are reading this, I am going to guess that you arepro-photovoltaic. Like me, you are probably hoping for — perhaps evenworking towards — making photovoltaics a ubiquitous, low-cost sourceof clean, reliable, renewable energy. But how do we get there fromhere? Can today’s technologies get the job done or do we still need a"revolutionary" technological breakthrough?

PV industry participants generally believe that the basic elementsof a self-sustaining, large-scale, low-cost PV industry are already inor near mass production today. The only uncertainty is our velocitydown the cost curve, which in turn is seen largely to be a function ofthe size, nature and predictability of government incentive programsthat have already proven to be quite effective in incubating the PVindustry to its current scale.

People in this camp often cite themind-boggling cost reduction achieved in semiconductor manufacturing,and the not-so-mind-boggling-but-still-incredibly-impressive costreduction in LCD manufacturing. Cost reduction and performanceimprovements nearly inconceivable just 10-15 years ago have beenachieved in both industries step by step. No real revolutions. Justevolutionary innovation enabled by large-scale production, extensiveR&D, and a lot of hard work year after year, standing on theshoulders of the poor son-of-a-gun that got burned out and quit lastyear. 

Dramatic cost reductions have already been achieved in PV,and the scale and diversity of efforts in the industry today promise toyield acceleration in cost reduction in the years to come. 

Not everyone shares this faith in our current technologies. A number of prominent academics and venture capitalists, perhaps even our current Secretary of Energy,have argued that existing flat-plate PV technologies are a dead end.According to this group, PV is only relevant if it can meaningfullycontribute to solving global warming, which in turn means solar energymust be able to supplant fossil fuels for large-scale power generationin both developed and developing economies, particularly India andChina.

Framed in this way, the litmus test for any solar energy technologyis its ability in the next 10-20 years to be deployed in hundreds ofgigawatts per year, delivering electricity at $.05-.07/kWh, even inareas that aren’t very sunny. Given the load factors of PVinstallations, not to mention the possible need for storage, we need toconsider a target installed system price of no more than $1/Wp.

Panel prices have indeed come down significantly, but the PV "experience curve" (15% cost reduction for each doubling of production) is too slow, requiring us to get to 40-80GW per year production just to reach sub-$1/Wp panelpricing. And unless we see disruptive improvements in conversionefficiency, the "balance-of-system" costs (i.e., all the system costsother than the solar panel itself) will make it impossible to achieve a$1/Wp system price even if the panels are nearly free.

The logical conclusion to this argument is that we must focusresources on R&D that can potentially deliver a "Nobel-worthy"advancement in the science of solar cells.

Quite honestly, both points of view have merit. Abandoning effortsbased on incremental innovation would be foolhardy given all that hasbeen achieved already and the incredible opportunities that lay justahead. But we cannot assume that current PV technologies willnaturally, and without guidance, improve at a pace sufficient to berelevant in the battle against climate change. In fact, regardless ofyour "PV religion," let’s all agree that more, and more effective,R&D should be among our top priorities.

It may be axiomatic to point out that the future is impossible topredict. But recognition of this fact, coupled with soberacknowledgement of the magnitude of our global warming threat, shouldlead us to embrace and significantly bolster both evolutionary andrevolutionary research efforts in photovoltaics. 

Craig Hunter is the Vice President and General Manager, Energy Technologies at Intermolecular.

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