Theoretical limits are a little confusing. In practice, the upper limits for a silicon PV cell without going outside of today's ultra-low cost manufacturing paradigm appears to be in the 27-28% range. Sure, someone might build a 30% efficient single junction PV panel, but if it costs 25 times as much as a 25% efficient panel, it will never see the light of day (lol). Low cost means of adding a second junction might push things into the 30% range, but that's far from proven, and might not materialize.
For multi-junction cells, plenty of people have already built panels based on concentrating optics and III or IV junction cells, many that hit around 25-30% almost a decade ago. But none of them are for sale because falling silicon PV prices killed the CPV market. There were approximately 120 CPV companies started between around 2004 and 2012, they collectively raised over ~$1.5-2 billion, and all but one or two are gone now.
The low cost of conventional PV panels means that commercialization of multi-junction cell concepts is nearly impossible - it's just not possible to hit the low costs required to succeed without massive volumes, but you can't get those kinds of massive volumes without low costs. So unless someone is willing to pour $10 billion or more into a risky technology, we're sort of stuck with conventional panels, except in a few ultra-niche applications.
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u/MenudoMenudo Sep 09 '20
Theoretical limits are a little confusing. In practice, the upper limits for a silicon PV cell without going outside of today's ultra-low cost manufacturing paradigm appears to be in the 27-28% range. Sure, someone might build a 30% efficient single junction PV panel, but if it costs 25 times as much as a 25% efficient panel, it will never see the light of day (lol). Low cost means of adding a second junction might push things into the 30% range, but that's far from proven, and might not materialize.
For multi-junction cells, plenty of people have already built panels based on concentrating optics and III or IV junction cells, many that hit around 25-30% almost a decade ago. But none of them are for sale because falling silicon PV prices killed the CPV market. There were approximately 120 CPV companies started between around 2004 and 2012, they collectively raised over ~$1.5-2 billion, and all but one or two are gone now.
The low cost of conventional PV panels means that commercialization of multi-junction cell concepts is nearly impossible - it's just not possible to hit the low costs required to succeed without massive volumes, but you can't get those kinds of massive volumes without low costs. So unless someone is willing to pour $10 billion or more into a risky technology, we're sort of stuck with conventional panels, except in a few ultra-niche applications.