> Making glass from scratch is incredibly energy intensive Not much more than melting existing glass. It's not like aluminum, where melting is much cheaper tha

> Making glass from scratch is incredibly energy intensive Not much more than melting existing glass. It's not like aluminum, where melting is much cheaper than refining in the first place. > glass impurities can be handled (purified) It's much easier to handle impurities when you start with clean sand.