The buried lede in a story about Tesla defects in solar, which started a school fire, is the question of what is an acceptable rate.

…representatives told the Unit school board the U.S. Department of Energy estimates only one in 10,000 solar arrays have a malfunction of the nature seen at Olympia. Halo’s staff told the school board they couldn’t speak to that particular system, they said the technology has improved despite there being no recalls issued for the defective connectors.

Henkes just shakes his head when it comes to the one in 10,000 figure being used to say solar panel fires are rare. He calls it voodoo that one in 10,000 is a low risk and would like to find out who at the Department of Energy is spreading that around. One in 10,000 would be 0.01%. Henkes says that’s arson.

Henkes points out that if we go to six sigma, an industry standard used to reduce defects, reduce errors, minimize variation, increase quality and increase efficiency, “We are looking at the target rate for industry is 0.0000034 percent.”

That’s a truly huge difference. And a 0.01% rate would be like 10 schools on fire when you think about 100,000 or more units (number of school buildings in the US).