Also see, conversely, '<i>Out with the silver, in with the copper: A new boost for solar cell production</i>' - <a href="https://news.ycombinator.com/item?id=32688307" rel="nofollow">https://news.ycombinator.com/item?id=32688307</a> - about new technologies allowing the replacement of silver with copper, replacement sought for reason of price and scarcity. Paradoxically, /minor/ price and scarcity.