Gray photovoltaic solar energy? Profitable?

[Christophe]

difficult to say until we have an objective study on the subject.

Absolutely ... so there are 2 options:

a) find one
b) make it one (one of the 1st mission of the association?)

[Remundo]

B) Not stupid the CO2 method ... it indirectly allows to recover the gray energy ...

So if we have 100 gr / kWh PV produced and we suppose that 100% of the CO2 emissions of PV are produced during its production / installation then we can arrive at another estimate of the gray energy.

By cons I do not understand your method 25 / 4.6 = 5.5 years ???

I considered that the life cycle of PV panels is 25 years (pessimistic), and that over this life cycle, I admit that they required 100 g CO2 / kWh elec products (pessimistic also because apparently, the SFEN says between 60 and 150 g CO2 / kWh

I also admitted that the kWh elec requires 460 g CO2, produced in Europe on the basis of the European electricity mix.

Well, that being said ...
1) each kWh elec PV over 25 years elec PV required the investment of 100 g CO2

2) to produce each of these kWh, the European electricity mix over the same 25 years requires 460 g / kWh

This amounts to saying that PV produces 4,6 times less CO2 for 25 years for a given electrical production.

3) But as for PV, the CO2 investment is made for almost all from the manufacturing (but the "official values" are reduced in g / kWh produced over the lifetime ...), this can be reformulated approximately so:
"PV gives a CO2 benefit from 25 / 4,6 = 5,5 years."

It is a personal calculation method which gives an idea because I have not found reliable theses / studies describing precisely the life cycle of PV panels, in particular their carbon footprint.

[recyclinage]

Recy, do you know that there is a form of pollution which is bad grammar / spelling ...

I've always heard that the silicon industry is one of the most polluting in the world.
It may be a little exaggerated, but to have a colleague who worked in an integrated circuit "foundry" in the Paris region, given what he tells us on this subject, I want to believe that it is far from 'be clean!
Now, should we really condemn photovoltaics so far? difficult to say until we have an objective study on the subject.

false I am the most polluting industry

[Remundo]

Hi Recy, so you make 23 dictation mistakes

Otherwise, I had already given this link on Econo
http://www.oilcrisis.com/netEnergy/Ener ... V_NREL.pdf
from NREL in the USA, 3,5 years of CO2 payback time

Christophe, if you have time, you should strip the results of this google search ...

Anglo-Saxon research seems more dynamic than Ademe ... There are even university articles

[Remundo]

I found this study in my archives.
https://www.econologie.info/share/partag ... HnbtJP.pdf

it was not bad, but did not give any information on the CO2 cost of recycling.

[Christophe]

Yep we are going to search and unravel all this ...

Here is a first honorable "task" for the association!

[Remundo]

Ah yes ... The asso will become better than the Ademe

This amounts to saying that PV produces 4,6 times less CO2 for 25 years for a given electrical production.

3) But as for PV, the CO2 investment is made for almost all from the manufacturing (but the "official values" are reduced in g / kWh produced over the lifetime ...), this can be reformulated approximately so:
"PV gives a CO2 benefit from 25 / 4,6 = 5,5 years."

It is a personal calculation method which gives an idea because I have not found reliable theses / studies describing precisely the life cycle of PV panels, in particular their carbon footprint.

that is to say that there is a profit from PV after N years such that, by producing 1 kWh / year
25 x CO2 cost 1kWhmix = N x cost of CO2 1kWhPV

[dirk pitt]

Concerning Photowatt, I know that they leave blocks of raw silicon but I don't know if they melt them (I don't think so.)
I can tell you to have visited the factory that the process is made up of an enormous number of successive operations to go from the block of raw silicon to the panel. and some operations use not very nice products ....

[bernardd]

Following https://www.econologie.com/forums/post211496.html#211496 after traffic lane change ordered by the traffic police ;-)

The gray energy deconstruction is important in this case because of the molded concrete structure which supports the panels.
Well seen bernardd.

In this case, when 12kg of panel replace 45kg of concrete or terracotta tile, the advantage must also be on the panel, right?

Edit by Christophe. Uh, am I the traffic police?

Edit by bernardd: yes, the channel reorganizer forum when they become impenetrable, the lord of these virtual places ...

I copy / paste the important message of the original subject:

3 years of photovoltaic production compensate for the gray energy of manufacturing the panels and the dismantling of the panels currently represents 1 additional year of gray energy.

An energy production system that spares the planet for 20 years (the lifetime of a PV exceeds 25 years) is a worthwhile investment for the planet.

Okay, all the more so as you have to compare to other roofing materials replaced by panels.

With tiles, we are around 40kg / m2, concrete or terracotta.

see for example http://www.toitulor.com/tuiles.htm

With panels, we are less than 12kg / m2, mainly glass.

How long does it take to return to the gray energy of a roof without panels?

PS: Could you quote your sources for the times of return quoted? I do not believe at all in the figure for the destruction, it seems to me largely exaggerated, because once removed the facade glass, the frame in aluminum profile and the plastic back, whose carbon energy can be burned, which in makes a gain, the remaining mass of silicon must be able to be recovered like glass, it is almost pure silica with a metal hair for the connections.

[Did67]

I do not know if this is the right place and I am afraid that this little animation will stay online for a very long time at this address (but I do not know how to "copy" it; perhaps it is elsewhere than on the site of the newspaper Le Monde?):

http://www.lemonde.fr/sciences/video/20 ... 50684.html

Superb animation that makes everything understandable for ordinary people! Well I think...