E50 is a designation used for a specific type of chemical compound known as E50, which is a blend of 50% ethanol and 50% gasoline. This mixture is often used as a fuel alternative in vehicles designed to run on ethanol blends. It can help reduce greenhouse gas emissions compared to traditional gasoline. E50 is part of a broader category of ethanol fuel blends, which includes other mixtures like E10 (10% ethanol) and E85 (85% ethanol). These blends are popular in many countries as a way to promote renewable energy sources and decrease reliance on fossil fuels.