Summary:
According to “Liquid Biofuels” by Greg Pahl, in the Citizen Powered Energy Handbook (2007), because oil has been reducing by transportation, liquid biofuels will be more and more important in future. The author showed the history of using liquid biofuels, which started form a design named “an early version” which used alcohol by Nikolaus August Otto in the middle of 1800s (Pahl, 2007, p186), and the modern ethanol industry was founded after the oil shocks.
The writer stated that ethanol was better than gasoline, because the oxygen in ethanol could help “combustion process” and reduce the emissions of CO and NO (Pahl, 2007, p189); therefore, ethanol is used more widely than another liquid biofuels. Pahl said that there was a problem of growing ethanol, because of “new coal- fired ethanol refineries” (Pahl, 2007, p191). The author noted that producing ethanol should keep the balance of energy, and a new ethanol named “cellulosic ethanol” was better than ethanol which is produced from corn (Pahl, 2007, p192). The writer described that producing also had a limit, because the land on the earth is not only for ethanol, as a result, many plants were made to use the whole materials to produce ethanol. The author explained that the backyard ethanol is different from the process of ethanol production.
Pahl reported that biodiesel was also widely used in recent year, and Germany, who produced “1.6 million metric tons” every year, was the leader in producing biodiesel (Pahl, 2007, p200). The author stated that people could use “recycled cooking oil” and the fat from animals, and when biodiesel was produced, people should put water to mix (Pahl, 2007, p202). The writer demonstrated that using biodiesel has some benefit, because biodiesel is fit for any engine and have more oxygen; however, biodiese could be used in cold weather.