4 ms·

"These solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants in s

"These solar cells are used in concentrator photovoltaics (CPV), a technology which achieves more than twice the efficiency of conventional PV power plants in sun-rich locations. The terrestrial use of so-called III-V multi-junction solar cells, which originally came from space technology, has prevailed to realize highest efficiencies for the conversion of sunlight to electricity. In this multi-junction solar cell, several cells made out of different III-V semiconductor materials are stacked on top of each other. The single subcells absorb different wavelength ranges of the solar spectrum." If that isn't a reason to be investing in Space, I don't know what is. "This world record increasing our efficiency level by more than 1 point in less than 4 months..." I think we may start to see Moore's Law starting to be applied to Solar Cells. Which actually reminds of a chart on the waves of innovation[1] on the Stanford Tech Entrepreneurship course where we are now seeing the tail of IT and computing and beginning of renewable technologies. The same thing can be said about energy density of batteries(According to Tesla batteries). [1] Page 5 https://d2d6mu5qcvgbk5.cloudfront.net/documents/original/69bd3725d86ab970f2d9509424bb67ae4c832faa.pdf?1377910658 https://d2d6mu5qcvgbk5.cloudfront.net/documents/original/69b...

killerswan 13y ago
It is indeed interesting, but IIRC most of the funding for satellite launches (R&D for III-V semiconductors) came from intelligence, not NASA. So, um, thank you, NSA! :P
- hrkristian 13y ago
  What with their love for predictability, it's no wonder they're strong supporters of the sun.
- hxc 13y ago
  I would rather dump trillions of dollars into NASA and their tech :D.
- D9u 13y ago
  I thought it was the NRO? http://www.nro.gov/about/ http://www.nro.gov/about/
wyager 13y ago
>I think we may start to see Moore's Law starting to be applied to Solar Cells. It would have to be a kind of inverse Moore's law, given that you can't double beyond 100%.
- TheLegace 13y ago
  I guess what I really mean was exponential increase in gains.
  - markfx 13y ago
    Moore's law describes a polynomial increase, not exponential.
    - ScottBurson 13y ago
      I'm afraid you're mistaken. Doubling every 18 months is an exponential progression.
- gilgoomesh 13y ago
  It's worse than that. There's no room for a single doubling of 44% efficiency. The theoretical maximum for multi-junction concentrator cells is about 86%: https://en.wikipedia.org/wiki/Shockley–Queisser_limit https://en.wikipedia.org/wiki/Shockley–Queisser_limit For single junction cells it's a mere 33%.
  - MikeCapone 13y ago
    Efficiency matters, but price/watt matters more and there's still room for a kind of moore's law there.
    - jnw2 13y ago
      Which of efficiency or price/watt matters more depends on the application. For example, I believe something like 4 m^2, 40% efficient, 8 hours of charging is enough to get electricity to drive a Tesla something like 30-40 miles. (In practice, I assume you'd cover all of the outside of the car with 40% efficient solar panels to make this work (or maybe even 80% if you can figure out how to build them), and then 4 m^2 approximates the effective useful area after you take into account suboptimal sun angle, the side of the car facing away from the sun, etc.) The number of people whose commutes could be entirely covered by 40% efficient solar panels built into the car being used to recharge the battery is a lot more than the number of people whose commutes could be covered entirely by 12-15% efficient solar panels. Current mass produced technology doesn't make any variation on this cost effective today, but it seems clear that in the future, a 12% efficient panel array built into a Tesla is never going to be all that attractive for this application no matter how cheap it might become. I suspect that high rise apartment buildings can cover a much larger percentage of their energy consumption from solar panels mounted on their sides and roof if those solar panels are 40-80% efficient instead of 12-15% efficient. If localized solar right next to the consumer of the power becomes cheaper than paying for electric grid transmission, this may become very relevant in 10 or 20 years. Even for residential suburban solar installation, where finding adequate space for an adequate quantity 12% efficient solar panels is generally not a problem, the really important thing is not the price per watt of the panels themselves, but the price per watt of the system as a whole. The mechanical support of the panels is a part of the system cost, and the cost of that portion will shrink with more efficient solar panels, though of course there is an open question as to whether that will end up lowering the total system cost or not in the long run.
MysticFear 13y ago
There are many reasons to be investing in NASA. They actually have subdomain devoted to highlighting their spinoff technologies. http://spinoff.nasa.gov/ http://spinoff.nasa.gov/
dpatru 13y ago
> If that isn't a reason to be investing in Space, I don't know what is. To justify government research, the results need to be compared to the alternative. Had NASA scientists not been working for the government, they would have been working for private companies engaged doing useful work. The Soviet Union had similar resources to the US, yet their research budget was spent wholly by government, whereas a large portion of the US research during that time was directed by private companies. If you want to restrict the comparison just to the US, ask yourself what would the massive wealth that was dedicated to NASA had produced had it been directed by private interests? What would NASA engineers have produced had they been employed by in Y-Combinator-style startups? (or even big private companies like Google, Apple, Facebook, Amazon, etc.)
- eru 13y ago
  > (or even big private companies like Google, Apple, Facebook, Amazon, etc.) Or IBM, or everyone's favourite, Tesla. A similar argument always crops up with people always looking at how much technology came out of war-time efforts. The opportunity costs are huge.
- nitrogen 13y ago
  While you're considering alternatives, what would the massive wealth dedicated to the DOD have done in the hands of NASA and private non-military researchers?
- scarmig 13y ago
  A couple points: 1) It's not like the Soviet Union was a terrible hellhole for research. It had impressive research output for decades. 2) That's almost beside the point, however. Let's take it as a given that more good research, whatever that is, is a worthy goal for a society, and that the market under-invests in it in favor of short term profits. It's obviously not a binary of either 100% government funding or 100% private; it's not even really a one-dimensional continuum, because for the large capital expenditures typically involved in research, the government always has a heavy involvement, either in tax breaks or grants or collaboration. The question is, how do we allocate money to produce the best research? It's undoubtedly at some value that's somewhere between 0% and 100%. 3) There's a whole lot of money floating around now that makes endeavors like SpaceX practicable. That wasn't the case in, say, the Sixties. Even if the arguments for government spending on research were weak now, they'd be stronger in the 1960's, particularly for things like space exploration that required substantial concentrations of capital.

killerswan 13y ago

It is indeed interesting, but IIRC most of the funding for satellite launches (R&D for III-V semiconductors) came from intelligence, not NASA. So, um, thank you, NSA! :P

hrkristian 13y ago
What with their love for predictability, it's no wonder they're strong supporters of the sun.
hxc 13y ago
I would rather dump trillions of dollars into NASA and their tech :D.
D9u 13y ago
I thought it was the NRO? http://www.nro.gov/about/ http://www.nro.gov/about/

wyager 13y ago

>I think we may start to see Moore's Law starting to be applied to Solar Cells. It would have to be a kind of inverse Moore's law, given that you can't double beyond 100%.

TheLegace 13y ago
I guess what I really mean was exponential increase in gains.
- markfx 13y ago
  Moore's law describes a polynomial increase, not exponential.
  - ScottBurson 13y ago
    I'm afraid you're mistaken. Doubling every 18 months is an exponential progression.
gilgoomesh 13y ago
It's worse than that. There's no room for a single doubling of 44% efficiency. The theoretical maximum for multi-junction concentrator cells is about 86%: https://en.wikipedia.org/wiki/Shockley–Queisser_limit https://en.wikipedia.org/wiki/Shockley–Queisser_limit For single junction cells it's a mere 33%.
- MikeCapone 13y ago
  Efficiency matters, but price/watt matters more and there's still room for a kind of moore's law there.
  - jnw2 13y ago
    Which of efficiency or price/watt matters more depends on the application. For example, I believe something like 4 m^2, 40% efficient, 8 hours of charging is enough to get electricity to drive a Tesla something like 30-40 miles. (In practice, I assume you'd cover all of the outside of the car with 40% efficient solar panels to make this work (or maybe even 80% if you can figure out how to build them), and then 4 m^2 approximates the effective useful area after you take into account suboptimal sun angle, the side of the car facing away from the sun, etc.) The number of people whose commutes could be entirely covered by 40% efficient solar panels built into the car being used to recharge the battery is a lot more than the number of people whose commutes could be covered entirely by 12-15% efficient solar panels. Current mass produced technology doesn't make any variation on this cost effective today, but it seems clear that in the future, a 12% efficient panel array built into a Tesla is never going to be all that attractive for this application no matter how cheap it might become. I suspect that high rise apartment buildings can cover a much larger percentage of their energy consumption from solar panels mounted on their sides and roof if those solar panels are 40-80% efficient instead of 12-15% efficient. If localized solar right next to the consumer of the power becomes cheaper than paying for electric grid transmission, this may become very relevant in 10 or 20 years. Even for residential suburban solar installation, where finding adequate space for an adequate quantity 12% efficient solar panels is generally not a problem, the really important thing is not the price per watt of the panels themselves, but the price per watt of the system as a whole. The mechanical support of the panels is a part of the system cost, and the cost of that portion will shrink with more efficient solar panels, though of course there is an open question as to whether that will end up lowering the total system cost or not in the long run.

MysticFear 13y ago

There are many reasons to be investing in NASA. They actually have subdomain devoted to highlighting their spinoff technologies. http://spinoff.nasa.gov/ http://spinoff.nasa.gov/

dpatru 13y ago

> If that isn't a reason to be investing in Space, I don't know what is. To justify government research, the results need to be compared to the alternative. Had NASA scientists not been working for the government, they would have been working for private companies engaged doing useful work. The Soviet Union had similar resources to the US, yet their research budget was spent wholly by government, whereas a large portion of the US research during that time was directed by private companies. If you want to restrict the comparison just to the US, ask yourself what would the massive wealth that was dedicated to NASA had produced had it been directed by private interests? What would NASA engineers have produced had they been employed by in Y-Combinator-style startups? (or even big private companies like Google, Apple, Facebook, Amazon, etc.)

eru 13y ago
> (or even big private companies like Google, Apple, Facebook, Amazon, etc.) Or IBM, or everyone's favourite, Tesla. A similar argument always crops up with people always looking at how much technology came out of war-time efforts. The opportunity costs are huge.
nitrogen 13y ago
While you're considering alternatives, what would the massive wealth dedicated to the DOD have done in the hands of NASA and private non-military researchers?
scarmig 13y ago
A couple points: 1) It's not like the Soviet Union was a terrible hellhole for research. It had impressive research output for decades. 2) That's almost beside the point, however. Let's take it as a given that more good research, whatever that is, is a worthy goal for a society, and that the market under-invests in it in favor of short term profits. It's obviously not a binary of either 100% government funding or 100% private; it's not even really a one-dimensional continuum, because for the large capital expenditures typically involved in research, the government always has a heavy involvement, either in tax breaks or grants or collaboration. The question is, how do we allocate money to produce the best research? It's undoubtedly at some value that's somewhere between 0% and 100%. 3) There's a whole lot of money floating around now that makes endeavors like SpaceX practicable. That wasn't the case in, say, the Sixties. Even if the arguments for government spending on research were weak now, they'd be stronger in the 1960's, particularly for things like space exploration that required substantial concentrations of capital.