Bigger, Cheaper Solar Cells

Phenombecile800 writes "First Solar, a start-up from Arizona, is making photovoltaic cells at a fraction of the usual cost. Their secret: increasing the light-catching area 'from postage-stamp to traffic-sign dimensions,' reducing the manufacturing time to 1/10th of the competition's, and thinning the active element to 1/100th the usual thickness over a glass substrate, which enables the production of large panels. IEEE Spectrum provides some technical details about the production process. 'Glass is placed on rollers and fed into the first chamber, where it is heated to 600 C. Then it is transferred into the second chamber, which is full of cadmium sulfide vapor, formed by heating solid CdS to 700 C. The vapor forms a submicrometer deposit on the glass as it moves through this cloud, after which a similar process in a third chamber adds a layer of micrometers-thick CdTe in about 40 seconds. Then a gust of nitrogen gas rapidly cools the panels to 300 C in a fourth chamber, strengthening the material so that it can withstand hail and high winds.'"

Comments

The old green question

[gilgongo]

It's probably unanswerable, but I wonder how much energy it takes to make these cells, and how long it takes for them to offset that?

Re:The old green question

[Anonymous Coward]

It's probably unanswerable, but I wonder how much energy it takes to make these cells, and how long it takes for them to offset that?

We can answer anyway without even RTFA. The summary says that the cells are made out of glass (not hewn out of a crystalline ingot of silicon). Assuming 10% efficiency and 20% availability of sunlight (due to weather and geometry), you get approx 20W/m^2, or 1 kWh every two days.

Given that glass beer bottles cost a few cents each, a square meter of glass probably takes no more than a few dozen kWh of energy to produce. Even if the vapor deposition doubles or triples that, you still would end up with an energy surplus after just a couple of months of operation.

Re:The old black question

[dubbayu_d_40]

What's a better use of oil, making persistent sources of energy, or driving to 7-11 for nachos?

Arizona!

[copponex]

Well, a smart idea would be to move all of our high tech manufacturing to the hottest deserts we have. You can build earth sheltered factories to save on A/C, cover the roof and surrounding area with solar panels for virtually unlimited electrical supply, bury some flywheel energy storage to keep necessities going at night. If solar panels turn out to be unsustainable, simpler thermal power plants could be used.

You have an endless supply of sand for glass and silicon. You make non-perishable goods that can be moved out slowly and efficiently (solar/thermal powered electric rail or whatever). To make it really sustainable you could use the same transportation to import recycled or recyclable plastics for the rest.

Our current answer is using fuel that's guaranteed to run out. We should shop direct for our energy.

No objection to a solar powered solar panel plant.

[Firethorn]

Actually, the biggest portion of glass manufacturing is, of course, heat. You wouldn't want to use 10% efficient cells to produce electricity that goes directly to an electric resistance element to make that heat.

Instead, you'd want to build a solar furnace - using mirrors and lenses and such you can get 90% efficiency, and using panels even cheaper than this.

The trick would be the substantial start-up time in the mornings. Due to the heat levels involved, you'd be wasting a lot of energy each day heating the equipment up again.

So either you have to find a solution for this, or use natural gas or whatever during the night to keep production up. This isn't bad as long as you still get more energy out of the resultant panels, etc...

Mojave Desert

[falconwolf]

Forbes mentions that Mojave Desert real estate is becoming more valuable because many companies want to build solar facilities there.

It's not just solar farms that are sprouting up in the Mojave, wind farms are as well. Actually there's one wind farm that virtually sat there silent back when CA had those rolling blackouts because the transmission capability wasn't there.

Falcon