what is the cost of producing 1 metric ton or square meter of float glass?

Answer 1

The answer to your question is indeterminate, for several reasons
1) This is a trade secret that competitors would like to know the answer to. Hire a trade spy.
2) What are the L x W x H dimensions of the product?. Costs will be determined by the size of the "bath" vessel required.
3) The surface area-to-volume ratio will determine the melt-spread time, product cooling time required, etc.
4) Is the production order for 1 ton per day? 2 tons? 10 tons?
5) WHAT Clarity (letter) per WHAT Rating per WHAT GPS Standard (#) ?

Answer 2

You need to know the cost of raw materials and the cost of labor.