Calculating the Energy Cost of Manufacturing Solar Cells: Factors to Consider

[Phrak]

How much electrical energy does it take to manufacture a solar cell?

I'm curious about the break-even time. Silicon boules are grown in an over--probably electric. More machining follows. If the frame is aluminum, it's smelted in an electric arc furnace. This is really an oversimplifed question, but a start. The energy cost of the electrical gear and storage batteries are additional considerations, as well as transportation and installation of all the gear.

I've been suspicious of the value of these things for a long time, where every few years, someone is going to have a break through in a few years that doesn't seem to happen, that would make them more than a novelty item with a government kick-back.

 

[berkeman]

How much electrical energy does it take to manufacture a solar cell?

I'm curious about the break-even time. Silicon boules are grown in an over--probably electric. More machining follows. If the frame is aluminum, it's smelted in an electric arc furnace. This is really an oversimplifed question, but a start. The energy cost of the electrical gear and storage batteries are additional considerations, as well as transportation and installation.

I've been suspicious of the value of these things for a long time, where every few years, someone is going to have a break through in a few years that doesn't seem to happen, that would make them more of a novelty item with a government kick-back.

I'd take a guess that about half the cost of manufacturing the cell is energy cost. Just a guess, but seems ballpark right given the processes that are used. Especially the melting part like you mention.

Found an interestiong page while googling "solar cell economics" to reply to your question:

http://www.solarbuzz.com/Plants.htm

 

[Phrak]

I'd take a guess that about half the cost of manufacturing the cell is energy cost. Just a guess, but seems ballpark right given the processes that are used. Especially the melting part like you mention.

Found an interestiong page while googling "solar cell economics" to reply to your question:

http://www.solarbuzz.com/Plants.htm

Based on that I was tempted estimate the energy cost at half the so called "packback time", the years of operation needed to pay for the solar panel investment. But, to my surprise Wikipedia has a reference to "energy returned on energy invested".

http://en.wikipedia.org/wiki/Photovoltaic"

"Life-cycle analyses show that the energy intensity of typical solar photovoltaic technologies is rapidly evolving. In 2000 the energy payback time was estimated as 8 to 11 years[74], but more recent studies suggest that technological progress has reduced this to 1.5 to 3.5 years for crystalline silicon PV systems [73]."

It's probably safe to ignore the hopeful expectations you can't or shouldn't buy, but costs you only 1.5 to 3.5 years or energy investment. It looks like about 8 years worth of electricity.