Photosynthesis vs Solar Pannels

[Beanbee]

Disregarding all of actual real life processes and so on...

Approximately how much Light is absorbed and used in photosynthesis?
How does this compare to solar panels (which are hitting about 40% of visible light). I'm well aware that they are two very different processes.

Just a rough thought on it, I'm curious how we are measuring up to nature

[Helm]

I don't know but plants trap 7 times more power than the total power consumption of human civilisation on Earth.

[Beanbee]

Interested and hardly unexpected. The sun is rather powerful and we barely tap into that still.

[Francebunkerer]

http://en.wikipedia.org/wiki/Photosynthetic_efficiency
http://www.fao.org/docrep/w7241e/w7241e05.htm
According to these pages, look one even has sources, it's up to 6 percent of solar radiation (not only visible radiation) that is.

Spoiler Alert, click show to read: 

It is bound to be higher for visible because most of the radiation at sea level is visible light. Also, the absorption spectra of photosynthetically active pigments are mostly in visible light, can't find any figures though.

Spoiler Alert, click show to read: 

[Ummon]

Currently, technologies to use biological processes in producing energy for human purposes are under study.

[Simetrical]

It is bound to be higher for visible because most of the radiation at sea level is visible light.

Most of the radiation from the Sun is visible, at sea level or anywhere else. A black body of its temperature emits mainly visible light. (Which is why it's visible to us, of course.)

Photosynthesis is very inefficient. But then, plants use very little power. Even animals don't use much. A human uses about 100 W average, if you figure it out. Say 2,000 kilocalories a day; divide by 86400 seconds per day, and you get about 100 W. So for all the running and jumping and whatever you're doing, that's using the same power as a light bulb or two, at least on average over the day.

[Ummon]

Photosynthesis is very inefficient. But then, plants use very little power. Even animals don't use much. A human uses about 100 W average, if you figure it out. Say 2,000 kilocalories a day; divide by 86400 seconds per day, and you get about 100 W. So for all the running and jumping and whatever you're doing, that's using the same power as a light bulb or two, at least on average over the day.

So infact it is our technology which is very inefficient.

Hey, I though the agricultural revoulution was 10,000 years ago!

Go check Craig Venter, and be enlightened. :wink:

[Simetrical]

So infact it is our technology which is very inefficient.

Sometimes, yes. Some of our technology is very efficient, some not. Stirling engines are relatively practical, almost 100% efficient heat engines, for example. (That is, as efficient as is thermodynamically possible, not that they don't lose some energy to waste heat.) But we seem to not have very good tech right now for storing energy compactly and cheaply. And I doubt any robot could do as much as a human on 100 W.

[Beanbee]

From the graphs I would give a rough estimate of it being about equal absorbtion rate. Obviously plants are not 100% efficient in converting that energy so Solar Pannels are really quite kicking ass these days. Interesting

Currently, technologies to use biological processes in producing energy for human purposes are under study.

Hey, I though the agricultural revoulution was 10,000 years ago!

[Ummon]

I meant in term of energy consumption, as well.

A brain consumes like a light bulb, but is more efficient than any PC...

[Helm]

It's worth pointing out that solar pannels don't really work in overcast conditions they need full sunlight. But plants can still photosyntheise even in low light conditions. So for that reason I'm assuming nature is far more efficient.

[Simetrical]

I meant in term of energy consumption, as well.

A brain consumes like a light bulb, but is more efficient than any PC...

In some ways. There are plenty of things that computers can do but brains can't. I'm pretty sure there are computers that run on under 100 W, too, if you leave out the monitor.

Edit:

It's worth pointing out that solar pannels don't really work in overcast conditions they need full sunlight. But plants can still photosyntheise even in low light conditions. So for that reason I'm assuming nature is far more efficient.

That doesn't follow at all. Both solar panels and plants can produce power in low-light conditions, but both are a lot less efficient (since there's less incident sunlight to use). As has been noted, plants are much less efficient overall than the most efficient solar cells, by close to an order of magnitude.

[Ummon]

Well, no. Processor frequency and ensuing energy dissipation, etc. forbids computer efficiency. And obviously, a computer can't do most things a brain can do, whereas the things a brain can't do a computer can do, could be said to be implicitly less adaptive.

A long argument that would be. Power over adaptability.

[Helm]

Well the tiny little solar powered fountain I have in the back garden only operates in full 100% sunlight, the slightest bit of shade and it stops entirely. But a plant can operate perfectly well all year round, so it's using the energy it does get much more efficiently. There are plants that still thrive several meters below the surface of the sea where it's gloomy all the time.

[Francebunkerer]

Photosynthesis is very inefficient.

I'm wondering why remains it so inefficient. Would it just be bottle necked by lack of available, e.g., nitrogen?

[Simetrical]

Well the tiny little solar powered fountain I have in the back garden only operates in full 100% sunlight, the slightest bit of shade and it stops entirely.

So does that mean all solar cells are unable to work in shade, or your particular solar-powered fountain is unable to work in shade?

I'm wondering why remains it so inefficient. Would it just be bottle necked by lack of available, e.g., nitrogen?

Well, evolution would tend to make it more efficient, all things being equal, but all things usually aren't equal. Possibly it could be made more efficient, but only at unacceptable other costs to the organism.

Evolution also has no foresight and can only make small modifications, so if it hits a local maximum it generally sticks there. It could be that there are no small improvements left to be made in photosynthesis, and the only way to improve it would be to make the kind of sweeping change only artificial selection can handle with any probability.

It works pretty well as is, though.

[Helm]

So does that mean all solar cells are unable to work in shade, or your particular solar-powered fountain is unable to work in shade?

As far as I know no direct sunlight means no power. Unless they've made some kind of new super duper solar panel I'm unaware about.

[Ummon]

I'm wondering why remains it so inefficient. Would it just be bottle necked by lack of available, e.g., nitrogen?

It's actually perfect for its purposes. You have to consider that the light passes through a living cell.

[Simetrical]

Shade does not mean no sunlight. It means less sunlight. There's only "no sunlight" if you actually can't see anything without artificial light, like in the middle of the night.

[chamaeleo]

Shade does not mean no sunlight. It means less sunlight. There's only "no sunlight" if you actually can't see anything without artificial light, like in the middle of the night.

...unless the moon is reflecting light down upon you.

Are we talkin about the utility/practicality of humans: using plants to collect & store E, vs designing/building/maintaining/improving solar collectors? In this case, it really depends on your specific needs and local conditions.

Why install solar panels and use them to power your AC during the summer, when you can plant shade-trees on your south side? Leaves fall before every winter, so you get the sun when you need it.

I'm currently designing a greenhouse that incorporates a large vermicompost bin that'll serve as thermal mass, provide thousands of worms to sell to bait stores and top-quality plant fertilizer, and will assist in maintaining optimal winter T's as the veggie matter decomposes. The greenhouse will also buffer the S side of my adobe house from the NM summer sun, as well as trap thermal E during the winter. Win-win!