While ethanol production from corn is viable, the question is can we sustain the current 13-plus billion gallons and expand a couple billion more gallons by 2025? The profit margins for ethanol production are incredibly low and perhaps of equal concern the difference between production and use is too low to allow the industry much wiggle room.

It seems fairly clear that alternative biofuel from corn has about maxed out, unless there are new economic subsidies made available to ethanol production. With ethanol from corn maxed out, the next option is biomass crops. The question, Lee contends, is which one will be most efficient to produce, distribute and use.

Sweet sorghum

Sweet sorghum production has been going on in limited acreage for more than 50 years. Unfortunately, we are still using most of the same varieties now that we used in production for livestock feed 50 years ago.

Even using older varieties, we can produce about the same amount of fuel per acre from sweet sorghum as we can from corn, according to Lee.

Sweet stem, or sweet sorghum has been grown for more than a century in the Southeastern United States in small plantings for making sweet syrup. It has several advantages over sugarcane, such as the ability to withstand dry conditions, requires less fertilizer, rapid growth rate, ease of planting, and lower cost of total fermentable sugars.

Crop residue

In the Southeast there is no doubt the vast amount of crop residue from cotton, peanuts and grain crops is huge. However, the value of crop residue as cover crops, for livestock feed and in building organic matter in the soil is too valuable to use them for alternative fuel.

If you add in the cost of harvesting crop residues and solving the technical problems associated with making fuel from them, it’s difficult to see how this is going to be a popular source of a base to make fuel, Lee contends.

Miscanthus

Miscanthus can be established by rhizomes, plugs, or even seeded. In many parts of the Carolinas miscanthus grows wild along the roadsides. No one wants to plant a perennial crop for fuel that will become an invasive species.

Miscanthus is a tall perennial grass that has been evaluated in Europe during the past 5-10 years as a new bioenergy crop. It is sometimes confused with elephant grass (Pennisetum purpureum) and has been called both "elephant grass" and "E-grass".