Lean for the Solar Industry
Pilots had the sound barrier.
Runners had the four-minute mile.
Now solar manufacturers want to make a panel that costs less than $1 per watt.
It’s a pretty audacious goal: the current number stands between $3 and $4 per watt, but the DOE has set a goal of $1 by 2017 including the modules, electronics and other components.
Leading solar innovator Dick Swanson thinks he has the answer: diamond wire saws.
“I think it will have a huge impact,” he said. Right now, solar cell makers saw wafers from silicon ingots with highly accurate saws capable of cutting off rounds 160 to 180 microns thick. Still, the process turns a lot of pure silicon into expensive dust.
In a few years, diamond sawing could help get that down to 135 and less microns thick. More wafers per ingot directly leads to a lower price for solar power.
Making significant efficiency gains by squeezing fractions of a millimeter out of a silicon ingot sounds a lot like another innovator from about a century ago. Today, we’d call this waste elimination “Lean,” but back then, it was just good business.
No change was too small if it reduced waste. [Henry] Ford saved nearly 300,000 pounds of steel a year by cutting the fan-drive pulley out of the scrap from the hand door stock rather than out of new stock. He originally made eighteen pieces of one part from a metal bar 143 inches long but was able to save “more than two inches per bar” when he found he could get the same number of pieces out of a bar 140 and 9/32 inches long. Two inches saved out of 143 — again, for Ford, no change that reduced waste was too small.
This excerpt, from Cool Companies, by Joseph J. Romm, is just one of many examples of Henry Ford’s relentless pursuit of waste elimination. In his own 1926 book Today and Tomorrow, Ford states:
We treat each tree as wood until nothing remains which is serviceable as wood, and then we treat what remains as a chemical compound to be broken down into other chemical compounds which we can use in our business… Why should not crating be done with the smallest instead of the largest amount of lumber?… Why should a crate or a packing box once used be considered only as so much waste to be smashed and burned?… We are cutting farther into wood by using wherever possible burlap bags and carboard boxes — the latter made from waste and in our own paper mill…. All scrap wood eventually gets back to the wood salvage department.
Romm elaborates:
With his techniques, Ford was able to reduce his use of wood by two-thirds, even as he doubled production. Ford distilled all of the wood waste, including sawdust, shavings, chips, and bark: “Each ton of waste wood yields 135 pounds of acetate of lime; 61 gallons of 82 percent methyl alcohol; 610 pounds of charcoal; 15 gallons of tar, heavy oil, light oils, and creosote; and 600 cubic feet of fuel gas.”

That type of continuous improvement is what drove Ford Motor Company to dominance at the beginning of the last century, and it’s just the type of thinking solar (and other) manufacturers need to embrace to compete in the global market.
The companies that conserve resources will not only produce more competitive products, but will be able to survive in tough economic times. Lean and sustainability are two lanes on the same road.





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