Don't start hording your grass clippings just yet. Switchgrass, a promising source for making cellulosic ethanol -- a type of fuel derived from plants -- probably isn't carpeting your backyard, although the perennial is found in the Americas and parts of Africa. The tall grass looks more at home billowing in the prairie, maybe alongside a field of corn, another source of ethanol for your car. Its stature isn't the only thing that sets switchgrass apart. Its energy ratio is what gets alternative fuel proponents really excited.
Unlike corn-based ethanol or regular gas, for every one unit of energy put into cellulosic ethanol made from switchgrass, you create 10 times the energy output. Those numbers easily beat corn-based ethanol and gasoline, which takes more energy to produce than it yields.
The thing is though, scientists haven't figured out how to easily and inexpensively extract cellulose from switchgrass, and that's a big part of the process. Until that happens, you won't be gassing up with grassoline, so if you're bent on biofuel, look for the 10-90 ethanol mix at your local gas station. And before you fill up, read the full article: Grassoline: Can we fuel cars with grass?