**1.1 Why alcohol used as alternative fuel**

At present, the future of the world ecosystem is obviously the most important issue. Recently, our young researchers improved the awareness on environmental protection and usage of alcohol fuels or non-fossil fuels for internal combustion engines. Generally, lower molecular weight alcohols, particularly ethanol or methanol, comprise one group of alternative fuels which is considered attractive for this

**Figure 1.** *Alcohol fuel bus [5].*

*Alcohol Fuels as an Alternative Fuels - Bringing New Heights in Sustainability DOI: http://dx.doi.org/10.5772/intechopen.86626*

purpose. The alcohol fuel has more advantages compared with fossil fuels, and they are given below:

