Switchgrass is a major source of cellulosic ethanol, which has much greater theoretical potential as a biofuel replacement for gasoline than corn-based ethanol, which is a subsidy scheme for politicians to drum up votes in farm country.
The trick is that while a lot of people are working on it, nobody’s come up with a commercializable system for turning switchgrass and other high-cellulose plants into a (relatively) clean, pumpable liquid fuel you could run a car on.
Here’s a step in the right direction, though:
Previous studies on switchgrass plots suggested that ethanol made from the plant would yield anywhere from 343% to 700% of the energy put into growing the crop and processing it into biofuel. But these studies were based on lab-scale plots of about 5 square meters. So 6 years ago, Kenneth Vogel, a geneticist with the U.S. Department of Agriculture in Lincoln, Nebraska, and colleagues set out to enlist farmers for a much larger evaluation. Farmers planted switchgrass on 10 farms, each of which was between 3 and 9 hectares. They then tracked the inputs they used–diesel for farm equipment and transporting the harvested grasses, for example–as well as the amount of grass they raised over a 5-year period. After crunching the numbers, Vogel and his colleagues found that ethanol produced from switchgrass yields 540% of the energy used to grow, harvest, and process it into ethanol. Equally important, the researchers found that the switchgrass is carbon neutral, as it absorbs essentially the same amount of greenhouse gases while it’s growing as it emits when burned as fuel.
Still just a sandbox example, but a good one.