See: http://www.nrel.gov/ncpv_prm/pdfs/papers/64.pdf
This paper describes incremental improvements at a PV production factory. I have not read any Japanese documents, but I expect it was steps like these that reduced the cost of PVs in Japan by 69% over the last 10 years. Incremental improvements, rather than dramatic breakthroughs, have generated most of the progress in integrated circuits and hard disks.
One of the biggest problems with PVs has been the embodied energy in the silicon. By some estimates, it takes 10 years of PV operation to make up for this. However, this problem has been addressed in recent years by two methods: 1. Reducing the amount of silicon needed per cell, and 2. Recycling silicon from used PVs. (Recycling silicon takes less energy than making virgin material. That is not always the case with other materials.)
- Jed
