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'The new design converts direct sunlight to electricity with 44.5 percent efficiency, giving it the potential to become the most efficient solar cell in the wor

by Gys 9y ago

'The new design converts direct sunlight to electricity with 44.5 percent efficiency, giving it the potential to become the most efficient solar cell in the world.'

sbierwagen 9y ago
Note careful use of "potential" there. Fraunhofer hit 46% two years ago with a four-junction cell: https://www.nrel.gov/pv/assets/images/efficiency-chart.png https://www.nrel.gov/pv/assets/images/efficiency-chart.png
- londons_explore 9y ago
  it's sad that nothing more has been published on that architecture for 2+ years... One would imagine most of the research dollars being into how to make multi-junction cells cheaply, rather than into other much lower efficiency cells.
  - sbierwagen 9y ago
    "The only figure of merit in a PV system is cost per kilowatt-hour installed". Multijunction cells require concentrating panels and two-axis tracking. In order for them to make economic sense, both the panels and the tracking have to have lower lifetime costs than standard untracked panels. So far, they don't. Plus, concentrating panels don't work under cloudy skies, so...
    - ZenoArrow 9y ago
      > "In order for them to make economic sense, both the panels and the tracking have to have lower lifetime costs than standard untracked panels." Is this the problem that Insolight have a potential solution for? https://insolight.ch/ https://insolight.ch/
      - sbierwagen 9y ago
        We'll know as soon as they put product pricing on their site.
        ZenoArrow 9y ago
        Fair point, but it does seem to be a solution worth tracking the progress of.
    - logicallee 9y ago
      >"The only figure of merit in a PV system is cost per kilowatt-hour installed". This doesn't make intuitive sense to me. If you could pay $50 for a bucket of goop you can slather on your roof that would capture 1% of the incident light energy hitting it forever, would everyone do so? by your standard "hell yeah" as that means the equivalent of $2.5k per roof (I multiplied the $50 for 1% by 50 to conpare apples to apples) to capture 50% of the energy which is far better $ per KWh than offered by anyone else! The issue is that for many people they would prefer to capture more than 1% and they are willing to pay more per kwh in exchange for getting more kilowatt hrs. So they would prefer to pay a large premium, thereby showing that it really doesn't just come down to cost per KW-hr installed. there are other factors.
      - sbierwagen 9y ago
        I'm a little confused by your argument, so I'll go through it one clause at a time. If you could pay $50 for a bucket of goop you can slather on your roof that would capture 1% of the incident light energy hitting it forever, would everyone do so? Sure? If you postulate a PV system that has much lower cost per KWh installed than has ever been achieved, then of course it'll make economic sense. by your standard "hell yeah" as that means the equivalent of $2.5k per roof (I multiplied the $50 for 1% by 50 to conpare apples to apples) to capture 50% of the energy which is far better $ per KWh than offered by anyone else! Sure? You made the fictional system way, way better, so it's an even better deal now. The issue is that for many people they would prefer to capture more than 1% and they are willing to pay more per kwh in exchange for getting more kilowatt hrs. So they would prefer to pay a large premium, thereby showing that it really doesn't just come down to cost per KW-hr installed. You are now talking about something completely different. Homeowners demonstrably don't care about the power conversion efficiency of their roof-- the penetration rate of rooftop solar is pathetic. People care about how much their electricity costs, and only install rooftop solar if gives them cheaper electricity. If grid power costs $0.10/KWh, and solar costs $0.50/KWh, then they won't buy it. Look out the window! Look at all the solar panels you don't see. That's the argument from economics. The argument from product availability: regular planar unconcentrated multijunction cells for terrestrial use don't exist. You can't buy them, because there's no market for a $10,000 500 watt cell when $200 300 watt cells are sold. https://www.wholesalesolar.com/solar-panels https://www.wholesalesolar.com/solar-panels You can get them for space applications, presumably at incredible expense: http://www.spectrolab.com/DataSheets/Panel/panels.pdf http://www.spectrolab.com/DataSheets/Panel/panels.pdf Concentrated multijunction panels for terrestrial use exist, but are only used in utility-scale installations, since you don't do two-axis tracking with rooftop solar. (Dual tracked solar panels cast shadows on each other, so they have to be spaced much farther apart, and consequently have bad space utilization) The only figure of merit in a PV system is cost per kilowatt-hour installed. Right now, all rooftop solar installations are single-junction. If multijunction cells resulted in a lower cost per kilowatt-hour installed, then they would be used, but they don't, so they aren't.

by Gys 9y ago

'The new design converts direct sunlight to electricity with 44.5 percent efficiency, giving it the potential to become the most efficient solar cell in the world.'

sbierwagen 9y ago

Note careful use of "potential" there. Fraunhofer hit 46% two years ago with a four-junction cell: https://www.nrel.gov/pv/assets/images/efficiency-chart.png https://www.nrel.gov/pv/assets/images/efficiency-chart.png

londons_explore 9y ago
it's sad that nothing more has been published on that architecture for 2+ years... One would imagine most of the research dollars being into how to make multi-junction cells cheaply, rather than into other much lower efficiency cells.
- sbierwagen 9y ago
  "The only figure of merit in a PV system is cost per kilowatt-hour installed". Multijunction cells require concentrating panels and two-axis tracking. In order for them to make economic sense, both the panels and the tracking have to have lower lifetime costs than standard untracked panels. So far, they don't. Plus, concentrating panels don't work under cloudy skies, so...
  - ZenoArrow 9y ago
    > "In order for them to make economic sense, both the panels and the tracking have to have lower lifetime costs than standard untracked panels." Is this the problem that Insolight have a potential solution for? https://insolight.ch/ https://insolight.ch/
    - sbierwagen 9y ago
      We'll know as soon as they put product pricing on their site.
      - ZenoArrow 9y ago
        Fair point, but it does seem to be a solution worth tracking the progress of.
  - logicallee 9y ago
    >"The only figure of merit in a PV system is cost per kilowatt-hour installed". This doesn't make intuitive sense to me. If you could pay $50 for a bucket of goop you can slather on your roof that would capture 1% of the incident light energy hitting it forever, would everyone do so? by your standard "hell yeah" as that means the equivalent of $2.5k per roof (I multiplied the $50 for 1% by 50 to conpare apples to apples) to capture 50% of the energy which is far better $ per KWh than offered by anyone else! The issue is that for many people they would prefer to capture more than 1% and they are willing to pay more per kwh in exchange for getting more kilowatt hrs. So they would prefer to pay a large premium, thereby showing that it really doesn't just come down to cost per KW-hr installed. there are other factors.
    - sbierwagen 9y ago
      I'm a little confused by your argument, so I'll go through it one clause at a time. If you could pay $50 for a bucket of goop you can slather on your roof that would capture 1% of the incident light energy hitting it forever, would everyone do so? Sure? If you postulate a PV system that has much lower cost per KWh installed than has ever been achieved, then of course it'll make economic sense. by your standard "hell yeah" as that means the equivalent of $2.5k per roof (I multiplied the $50 for 1% by 50 to conpare apples to apples) to capture 50% of the energy which is far better $ per KWh than offered by anyone else! Sure? You made the fictional system way, way better, so it's an even better deal now. The issue is that for many people they would prefer to capture more than 1% and they are willing to pay more per kwh in exchange for getting more kilowatt hrs. So they would prefer to pay a large premium, thereby showing that it really doesn't just come down to cost per KW-hr installed. You are now talking about something completely different. Homeowners demonstrably don't care about the power conversion efficiency of their roof-- the penetration rate of rooftop solar is pathetic. People care about how much their electricity costs, and only install rooftop solar if gives them cheaper electricity. If grid power costs $0.10/KWh, and solar costs $0.50/KWh, then they won't buy it. Look out the window! Look at all the solar panels you don't see. That's the argument from economics. The argument from product availability: regular planar unconcentrated multijunction cells for terrestrial use don't exist. You can't buy them, because there's no market for a $10,000 500 watt cell when $200 300 watt cells are sold. https://www.wholesalesolar.com/solar-panels https://www.wholesalesolar.com/solar-panels You can get them for space applications, presumably at incredible expense: http://www.spectrolab.com/DataSheets/Panel/panels.pdf http://www.spectrolab.com/DataSheets/Panel/panels.pdf Concentrated multijunction panels for terrestrial use exist, but are only used in utility-scale installations, since you don't do two-axis tracking with rooftop solar. (Dual tracked solar panels cast shadows on each other, so they have to be spaced much farther apart, and consequently have bad space utilization) The only figure of merit in a PV system is cost per kilowatt-hour installed. Right now, all rooftop solar installations are single-junction. If multijunction cells resulted in a lower cost per kilowatt-hour installed, then they would be used, but they don't, so they aren't.