4 ms·

Surly it has to outperform a normal solar panels in some way before this has uses? Or am I missing something?

dekhn 4y ago
you're not missing anything. they don't outperform normal solar panels. The difference is that this might be easier to set up and maintain in an area with limited technological development. One of the most extraordinary things today is that solar panels are now so efficient that you can collect light across the whole solar spectrum, then feed that to LEDs that emit in exactly the spectrum that plants want, so you can actually grow more plant yield with less light than they would outside in direct sunlight.
- dwroberts 4y ago
  Actually this is missing an extremely important point, which is that the algae generated current even when there was no light (ie overnight). The paper hypothesises this is because it stores some of energy gained for later use.
  - dekhn 4y ago
    you mean dark respiration? not particularly interesting; again, you'd prefer to have a solar panel and a battery, because their efficiencies are far, far higher. You can make a battery out of a potato.
- sydthrowaway 4y ago
  Cant we build a positive feedback loop with algae and solar, like stimulated emission in lasers?
  - dmos62 4y ago
    What is stimulated emission in lasers, and how might that concept transfer to algae and solar? I googled the definition, but it was way over my head.
    - dekhn 4y ago
      The way lasers work is to have a material (called the "gain material") and put a bunch of energy into it. The energy, in the form of light, bounces around in the material and interacts with it, causing it to line up in very specific ways. Eventually, that light is spit out of the material, typically in a straight line, with all the wavelengths kind of lined up, in phase. An important detail related to the term "stimulated emission" is that when you pump energy into the gain medium, the normal histogram of energy populations (IE, how many molecules are in each energy bucket) is swapped- more counts in the higher energy buckets- and then they release that extra energy in the form of light. Trying to interpret that comment, I assume they're saying that you could use algae as a gain medium, solar as the light-energy input, and the algae would eventually somehow "lase". i don't see how this could happen as algae would make a terrible gain medium, and concentrating the solar that much would progbably cause them to overheat and die. That said, "solar concentrators" do exist for algae photosynthesis: https://link.springer.com/article/10.1007/s10811-008-9324-6 https://link.springer.com/article/10.1007/s10811-008-9324-6 basically, lenses to provide more light to algae to make it grow faster.
thinkcontext 4y ago
From a solar efficiency standard its definitely not. Algae is something like 2% efficient vs ~20% for PV cells. However, it doesn't need a battery like it would with a solar panel. Not convinced it will be useful but maybe there are applications out there for it.

you're not missing anything. they don't outperform normal solar panels. The difference is that this might be easier to set up and maintain in an area with limited technological development. One of the most extraordinary things today is that solar panels are now so efficient that you can collect light across the whole solar spectrum, then feed that to LEDs that emit in exactly the spectrum that plants want, so you can actually grow more plant yield with less light than they would outside in direct sunlight.

dwroberts 4y ago
Actually this is missing an extremely important point, which is that the algae generated current even when there was no light (ie overnight). The paper hypothesises this is because it stores some of energy gained for later use.
- dekhn 4y ago
  you mean dark respiration? not particularly interesting; again, you'd prefer to have a solar panel and a battery, because their efficiencies are far, far higher. You can make a battery out of a potato.
sydthrowaway 4y ago
Cant we build a positive feedback loop with algae and solar, like stimulated emission in lasers?
- dmos62 4y ago
  What is stimulated emission in lasers, and how might that concept transfer to algae and solar? I googled the definition, but it was way over my head.
  - dekhn 4y ago
    The way lasers work is to have a material (called the "gain material") and put a bunch of energy into it. The energy, in the form of light, bounces around in the material and interacts with it, causing it to line up in very specific ways. Eventually, that light is spit out of the material, typically in a straight line, with all the wavelengths kind of lined up, in phase. An important detail related to the term "stimulated emission" is that when you pump energy into the gain medium, the normal histogram of energy populations (IE, how many molecules are in each energy bucket) is swapped- more counts in the higher energy buckets- and then they release that extra energy in the form of light. Trying to interpret that comment, I assume they're saying that you could use algae as a gain medium, solar as the light-energy input, and the algae would eventually somehow "lase". i don't see how this could happen as algae would make a terrible gain medium, and concentrating the solar that much would progbably cause them to overheat and die. That said, "solar concentrators" do exist for algae photosynthesis: https://link.springer.com/article/10.1007/s10811-008-9324-6 https://link.springer.com/article/10.1007/s10811-008-9324-6 basically, lenses to provide more light to algae to make it grow faster.

thinkcontext 4y ago

From a solar efficiency standard its definitely not. Algae is something like 2% efficient vs ~20% for PV cells. However, it doesn't need a battery like it would with a solar panel. Not convinced it will be useful but maybe there are applications out there for it.