Ohio State has been conducting research on switchgrass. From the switchgrass section of the hempoline article :
Switchgrass is often considered a good candidate for biofuel — especially ethanol fuel — production due to its hardiness against poor soil and climate conditions, rapid growth and low fertilization and herbicide requirements. Switchgrass is also perennial, unlike corn and sugarcane, and has a huge biomass output, the raw plant material used to make biofuel, of 6-10 tons per acre.
Switchgrass has the potential to produce the biomass required for production of up to 100 gallons (380 liters) of ethanol per metric ton. This gives switchgrass the potential to produce 1000 gallons of ethanol per acre, compared to 665 gallons for sugarcane and 400 gallons for corn.
However, there is debate on the viability of switchgrass, and all other biofuels, as an efficient energy source. University of California, Berkeley professor Tad Patzek points out that switchgrass has a negative ethanol fuel energy balance, requiring 45 percent more fossil energy than the fuel produced.
On the other side, David Bransby, professor of energy crops at Auburn University, has found that for every unit of energy input, switchgrass yields four units out.
Based on what Ohio State University soil scientists have seen in three years of switchgrass research, production is feasible. But it will be at least another year before the crop is harvested and data generated to evaluate the crop’s production and economic efficiencies.
Lal attributes the slow establishment to the plant’s small seed, which also gives presents problems with weed competition. “Once switchgrass is established, however, it’s a remarkable species, growing quite successfully, especially in no-till systems,” said Lal. “It also grows well on sloping land and other land areas that may not be suited for field crop production.” Switchgrass reaches full yield only in the third year after planting. When managed for energy production it can be cut once or twice a year with regular hay or silage equipment.