How to Make Fuel From Switchgrass

Some of the most promising recent advances in fuel technology center on the creation of biofuels. These compounds refine the natural sugars contained in plants into ethanol, which you can burn as an additive in gasoline in many newer car engines. Although most biofuel comes from sugarcane or corn, these crops are both less efficient stores of energy than the cellulosic ethanol in switchgrass. It grows on marginal land with little attention---making it much more environmentally friendly than corn---and has a much higher energy density. Making ethanol from switchgrass constitutes a complex and expensive process, however.

• 1

  Plant switchgrass seeds during the early spring. As a North American native grass, it doesn't need much attention, watering or fertilizer. Its ability to grow on marginal land eliminates the necessity of crowding out food crops.

• 2

  Harvest the switchgrass in the autumn after the first frost. Cut it down and bale it for processing. Since producing useful quantities of ethanol involves a large amount of of switchgrass, this process involves towing a mower behind a tractor, then baling it using a towed baler attachment or a self-propelled baling machine.

• 3

  Process the switchgrass. Cut each bale into small bits to expose as much surface area as possible to the enzymes that will release the sugars from the switchgrass' cellulose---a process called enzymatic hydrolysis.

• 4

  Dump the switchgrass chunks into a large tank of water, and add cellulosic enzymes to it. These enzymes will transform the cellulose in the switchgrass into fermentable sugars. They are quite expensive---the major obstacle to industrial-scale switchgrass production. According to Harvest Clean Energy, a processing facility must have the ability handle 5,000 to 10,000 tons of switchgrass per day to make economic sense, putting this process essentially out of reach for the home distiller.

• 5

  Drain the water and add yeasts, which will ferment the sugars produced by the cellulosic enzymes into ethanol in a process similar to wine production.

• 6

  Boil the water off to separate the ethanol, and collect it in a separate tank. Add benzene or cyclohexane to the mixture to produce pure ethanol, as these chemicals bind to and remove the last few water molecules. Some large processing plants use microscopic filters instead of these additives. If performing this process on your own, check the local regulations on alcohol distillation, as ethanol is a type of alcohol and may fall under their purview.