Abuse of companies and direct sellers in solar PV

Forum solar photovoltaic PV and solar electricity generation from direct radiation solar energy.
Christophe
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View Christophe » 23/11/10, 08:53

bernardd wrote:It ends up in co2, but it first makes methane by fermentation, which has a much greater greenhouse effect than co2.


No, to make methane you need very specific conditions (temperature, pressure, substrate and above all absence of oxygen...). A compost heap does not or very little in proportion to the CO2 because even a very compact heap has oxygen so as not to methanize ... and fortunately! Because knowing the greenhouse power of methane, not sure that life could have developed as we know it!

If this were not the case, the proportion of methane would not be linked to human activity, except it seems to me that it is almost as much as CO2, right?


bernardd wrote:By the way, forests are progressing in France


It's in my (last) answer: have you read it or hovered over it?

dedeleco wrote:It is also necessary to answer him that the wood if not burnt, in much greater quantity abandoned in forests and gardens, rots and produces CO2 inexorably in 10 to 20 years maximum, therefore its position against fuelwood is untenable, because it gives back CO2 !!


Correct, but I am not sure that a proportion of the wood does not remain in solid form, that is to say feeds the humus (same for the leaves).

That is to say that part of the carbon in rotting wood does not "gasify". What is the residual% by mass? No idea. References or necessary studies please.

I think that if 100% of dead wood were to gasify into CO2 the forest soils would be very poor in humus, but it is quite the opposite. We can see that the leaves largely contribute to making vegetable compost on the forest floor.

ps: as he registered he will surely read your answer directly.
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dedeleco
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View dedeleco » 23/11/10, 16:01

That is to say that part of the carbon in rotting wood does not "gasify". What is the residual% by mass? No idea. References or necessary studies please.

Current soils with humus are around 10000 to 12000 years old at most since the last ice age in France (before not a tree, only from the tundra to the south of Spain !!
So easy, you look at the proportion of humus and its depth in the flat forest soil and you divide by 8000 to 10000 to have the deposition rate there !!
A few meters at most often (and much less in an erosion zone) gives a maximum of around a tenth of a mm per year !!
So a few% of the carbon used by plants which recycle almost everything.
In equatorial forests, Amazonia, we say that the soil is very poor and therefore there the forest recycles everything (hot so very alive recycling everything) and it is a disaster to deforest because everything is lost in a few years and impossible to restore before a millennium (see tera preta
http://fr.wikipedia.org/wiki/Terra_preta
).
Only peat bogs accumulate a lot over hundreds of thousands of years in cold zones !!
Another part goes into rivers and oceans to end up deep in oil millions of years later !!
Only 1/1000 is enough to make petroleum to burn several times all the oxygen on the planet renewed every 200 years !!
In this case very variable depending on the location, and therefore extremely difficult to measure, since it is necessary to measure everywhere, apart from an estimate at a factor of ten !!
.
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Christophe
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View Christophe » 23/11/10, 18:32

dedeleco wrote:So easy, you look at the proportion of humus and its depth in the flat forest soil and you divide by 8000 to 10000 to have the deposition rate there !!


Ah ah ah what a tease!

I don't think we have the same definition of the word "easy" ...

dedeleco wrote:A few meters at most often (and much less in an erosion zone) gives a maximum of around a tenth of a mm per year !! So a few% of the carbon used by plants which recycle almost everything.


It's good that you talk about erosion because climatic erosion is still present everywhere! Rainwater drains everything ...

Otherwise on plant recycling, it seems to me that plants do not take carbon via their roots, only in the air ... root = water and some rare nutrients (trace elements)

dedeleco wrote:In equatorial forests, Amazonia, we say that the soil is very poor and therefore there the forest recycles everything (hot so very alive recycling everything) and it is a disaster to deforest because everything is lost in a few years and impossible to restore before a millennium (see tera preta
http://fr.wikipedia.org/wiki/Terra_preta
).
Only peat bogs accumulate a lot over hundreds of thousands of years in cold zones !!
Another part goes into rivers and oceans to end up deep in oil millions of years later !!
Only 1/1000 is enough to make petroleum to burn several times all the oxygen on the planet renewed every 200 years !!
In this case very variable depending on the location, and therefore extremely difficult to measure, since it is necessary to measure everywhere, apart from an estimate at a factor of ten !!
.


It's not wrong, it deserves to look into it ...
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dedeleco
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View dedeleco » 23/11/10, 19:50

To see the difference in the speed of growth of plants with (or without) carbon (terra preta charcoal) and humus in the soil, they really need carbon through and the symbiosis with fungi, molds, bacteria, etc of the soil which give it back to them by complex molecules !!
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