Comment by exar0815

Float glass is a continuous process, so it runs 24/7 and too much product is recycled into the smelter at the start again (Funnily, glass waste is actually a scarce resource). Getting the process dialed in to emit the desired quality is a long winded thing as far as i know (not involved in the process myself). Also, the heating is done with gas (LNG/CNG/H2) and electric in combination.