[lambdaone]

That's certainly a hard limit for a cell with a single P-N junction. However, with a bit of ingenuity, we can do much better than that; see https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limi...

[ethn]

Sure there are many novel solar technologies that subvert the SQ assumptions thereby avoiding the conclusion. However, the author of the parent post believes that existing technology today is sufficient.