Does solar energy have a future?

[jmarc3]

The hourly energy received by the earth from the sun is 3200 billion kWh.
The consumption annual global energy (128 billion kwh) therefore only represents 000 hours of sunshine on our planet.

In other words, it suffice to convert 0,5% of energy received from the sun to cover the loan of global energy consumption.
Certainly easier said than done, but who can still claim that solar energy has no future?

[Did67]

Without opening a big debate, just remember that all vegetation, all biomass, is solar energy "concentrated" thanks to chlorophyll ...

So harnessing all the solar energy to make energy would be like not eating anymore ...

Now it is true that with "deserts", there is room, although there is life in any desert and I cannot get used to the idea of ​​obscuring whole "plates" of Sahara or Gobi or Atacama ... just to continue to agitate us ... I would prefer that we be a little more contemplative (go and see a sunset over the Assekrem from the hermitage from Foucault's father near Tamanrasset) and a little less restless (and therefore energy intensive) ...

[jmarc3]

Absolutely agree, all energy on earth, except nuclear, comes from the sun. My purpose was just to show the potential of solar energy.
With regard to photosynthesis, nature is not very efficient. Its efficiency is barely 1%, against 15% for photovoltaics and significantly more (80% I believe, to be checked) for solar thermal.

ps: how much CO2 emitted to go see a sunset in Tamanrasset?

[Did67]

how much CO2 emitted to go see a sunset in Tamanrasset?

Oh my God !

1) It is an image, not to be taken literally!

2) It is, for me, a memory. I was there (in Algeria). After that, it was only a "detour" of 3 or 4 km, in 000 CV ... Not much in the million km that I traveled then ...

So "nostalgia sequence", don't shoot me !!!

I have no idea if today I would do it again ...

3) That said, the question I am evoking deserves further study: with much less agitation, addictive consumption, etc ... (in short, all that we can put in "agitation of this world ", meaningless) everyone could not afford a trip to any" Tamanrasset "and the results would still be positive ???? (I was talking about contemplation - I should have written "meditation" as opposed to "addiction" - to consumption) ... I was not talking about consumer tourism!

All of this is, I agree, extremely confusing ...

Anyway, I agree with you too!

[Ahmed]

Did67, I don't find it confusing, but rather very consistent!
Jmarc3 wrote :

With regard to photosynthesis, nature is not very efficient.

The comparison between natural processes and our products is misleading because it is not very relevant: nature does not aim for isolated performance, but for the overall optimum. If we consider it from this point of view, its effectiveness is incommensurate with ours.

I specify : 1- what seems lost in one action will allow another to function more easily. 2- moreover, there is, so to speak, neither creation nor destruction, but a balanced cyclic process which can therefore be repeated endlessly.

I insist : in human production, there is destruction of nature, both during manufacture and in use, then accumulation of waste (part of which can be recycled, at the cost of other destruction).

Admittedly, the use of direct solar energy would limit the extent of the destruction, but that would not fundamentally change things since it would have no effect on the other factors that are the uses of energy.
It is showing little imagination to consider only this energy aspect and not to understand that the addiction to petroleum has taken us in a bad way and that it is not the exhaustion of petroleum resources But addiction which is the real problem.

[sensei64]

does solar energy have a future?

tomorrow or the day after tomorrow when oil is 6 € it will be present.

so as much

do what is necessary today and keep the black gold which will really become so for needs that have not yet been adapted (technological evolution) or not yet replaced (political reason, remains of elected officials of the twentieth century who would not have did not understand everything)

ditto for all renewable from mother nature

[oiseautempete]

With regard to photosynthesis, nature is not very efficient. Its efficiency is barely 1%, against 15% for photovoltaics and significantly more (80% I believe, to be checked) for solar thermal.

It is a bit presumptuous to reduce the efficiency of nature to any number: a tree that lives 5000 years in harsh conditions by barely reaching 2-3m, does not necessarily have the same quantifiable efficiency as bamboo or laminar algae that grow 1M per day in good conditions, nor the enormous productivity of miscantus ...

[jmarc3]

With regard to photosynthesis, nature is not very efficient. Its efficiency is barely 1%, against 15% for photovoltaics and significantly more (80% I believe, to be checked) for solar thermal.

It is a bit presumptuous to reduce the efficiency of nature to any number: a tree that lives 5000 years in harsh conditions by barely reaching 2-3m, does not necessarily have the same quantifiable efficiency as bamboo or laminar algae that grow 1M per day in good conditions, nor the enormous productivity of miscantus ...

This is just one observation: when it comes to converting solar energy into "usable" energy, photosynthesis is not an efficient process overall.
What would be presumptuous is to generalize by claiming that man does better than nature.

[Remundo]

Hello everybody,

"efficient" does not mean anything in itself ...

If you want to make electricity, photovoltaics are more efficient than photosynthesis, thermodynamic solar more than photovoltaics (and again ... depending on the latitude, that is debatable).

If you want to have plants, milk and meat, then Nature is unbeatable.

Otherwise, solar energy already has a past which combines with the present ... petroleum is nothing other than a photosynthesis stored millions of years ago.

For the present, almost nothing is done without solar energy (wind, weather, clouds, fauna and flora are the result of solar influence). This energy is prodigious and has a future for human activities, for sure.

@+

[minguinhirigue]

jmarc3 I have already seen the argument very often:
"Nature is less efficient than technology. Look at solar panels, look at a tree, with the same energy received, there is one of the two that produces much more usable energy than the other ..."

Except that :
1) the figures taken are generally for the production of oil or synthetic fuel from biomass: therefore lower than all of the energy present in adult plants, and very variable depending on the species as specified oiseautempête

2) you can still try to make a solar panel that:
- grows spontaneously during its life,
- self-replicates,
- self-repairs,
- decreases the concentration of CO2 in the atmosphere,
- participates in the water cycle and the formation of ecosystems essential for our survival (unless you have already traded your body for a cyborg?)
- provides 15% solar-electric efficiency (just for fun).

However, I remain in agreement on the general idea that you defend: photosynthesis is not a powerful mechanism for converting solar energy to another form of energy. But mother nature didn't want it as such, it's just us, energy-hungry humans, who will soon see in the tree only a fuel with roots!