Why ethanol made from ethene is a non-renewable fuel but that made from glucose is a renewable fuel?

Answer 1

Ethanol made from ethene is non-renewable because ethene comes from the fractional distillation and catalytic cracking of crude oil. Crude oil is a mined non-renewable resource. The natural reserves of crude oil will eventually run out. It is a fossil fuel.

Ethanol made from glucose is a renewable resource because glucose is obtained from plants. As plants are harvested to obtained glucose, more plants can be planted, and so more glucose can be harvested. Hence it is a renewable fuel.

Answer 2

Ethene can be synthesizes from scratch, but it's not a cost-efficient process. It also exists in some plants as a hormone, but is not in great enough quantities to be marketable. All commercial ethene comes from burning ethane/propane or naphtha, which are, themselves, non-renewable (they come from natural gas and crude oil extracted from the earth). Ethanol synthesized from glucose comes from plants such a corn which are renewable because they grow annually.