What is the main biomass-derived-fuel used in the US?

Answer 1

Corn grown for alcohol. This is because alcohol production is artificially stimulated by tax subsidies. Without the subsidies, alcohol from corn would not be economical, and even WITH the subsidies, is only marginally economical.

The problem is that it takes almost as much oil to grow and harvest the corn and turn it into alcohol as the energy from the alcohol itself produces. Diverting corn from food to fuel causes its own economic inefficiencies, by (for example) raising the cost of beef or pork, or raising the cost of the corn itself which is a dietary staple for many people.

Hamburgers and tortillas are both more expensive than they ought to be because we're putting corn in our gas tanks rather than our mouths.