David Tilman and colleagues performed a life-cycle analysis to compare the energy return on energy investment (EROEI), or net energy production, for various biofuels. Ethanol made from corn raised in traditional monoculture agriculture has the highest energy output, but it also requires very high energy inputs, significantly reducing its net energy production. Biodiesel and bioethanol made from low-input, high diversity (LIHD) grassland plants offer a much higher net energy production than corn ethanol or soybean diesel.

Compared to gasoline, all biofuels produced less greenhouse gas emissions in an EROEI analysis. In particular, fuels from LIHD grasses grown on marginal land produced significantly lower greenhouse gas emissions than higher-input conventional biofuel crops (corn and soybeans).