Energy cost of solar cells...

[Externet]

Good day.

Read often that manufacturing solar cells (not panels !) is expensive in terms of electrical energy used.  Anyone knows figures ? 

To make cells that produce 1 KW, how many KWh are used at the factory ? (embodied energy)

[Sensei]

1 hour ago, Externet said:

Read often that manufacturing solar cells (not panels !)

Solar panels are made of modules and they are made of solar cells. Unsure why do you want to separate them..

1 hour ago, Externet said:

is expensive in terms of electrical energy used. 

I think so energy is used in mining, extraction of rare Earth metals and regular metals, transport, melting etc. etc. It depends on abundance of metal in ore, distance travelled between factories and mines, and so on. Too many variables to generalise.. 

1 hour ago, Externet said:

To make cells that produce 1 KW,

Typical solar cell is giving 0.5v to 0.6v with low amperage. If you have array of them you have solar panel which can give you more volts, ampers and therefor more power in KW.

1 hour ago, Externet said:

how many KWh are used at the factory ? (embodied energy)

Divide net cost of production of a thing (without any subventions) by (local country) price of energy and you will have theoretical maximum number of KWh per unit. Exceeding this value would make production economically unviable.

The cost of energy is part of product price.

[Externet]

Thank you, Sensei.

Cells alone would give me the perception am after.  In panels, there is cost of glass + frame + assembly labor + transport - I prefer to set aside for the moment.

Yes, I have on my roof an array of panels; 240V -  4.5KW.  Paid ~$450/KW price to public; which should be a manufacturing cost well under half for panels.     And about half for cells alone.  As a guess, cells should be around $100/KW  and a fraction of that, the electrical energy used to manufacture them, but prefer a less guessy figure. 

[Ken Fabian]

This study of Solar in Switzerland (in part a response to another study in support of nuclear that claimed PV used more energy than it produced) came up with 7-10 times more energy produced than energy used, in less than ideal Swiss climate. That includes associated equipment, installation etc, not just solar cells. Other studies have come up with higher than that and lower. Currently home solar is heavily advertised in Australia, with 6kW grid tied systems for around AU$4,000 (maybe US$3000) installed.

I don't see how it would be possible for manufacturing to support costs that low if EROI is low, even given lower power costs for Chinese manufacturers; manufacturers elsewhere, with high power (as well as other) costs are usually more expensive but not by that much.

Edited September 5, 2021 by Ken Fabian
exchange rates

[Peterkin]

You also have to compare the cost in energy of solar equipment to the cost in energy of equipment for whatever system it's replacing. And then figure in the lifetime of the equipment in both cases. Solar panels and batteries are improving all the time: I understand they're lasting 25 years now - during which time, nothing needs to be replaced by men in cherry-pickers. (And you'll have no power outages, or poles or live wires falling on your car during the big storms coming at us more frequently each year. )

Edited September 5, 2021 by Peterkin