This paper analyzes energy efficiency of the industrial corn-ethanol cycle and brackets energy efficiency of the switchgrass-cellulosic ethanol cycle. In particular, it critically evaluates the publications by Farrell et al (2006a; 2006c) and Shapouri, Wang, et al. (Wang, 2001; Shapouri et al, 2002; Shapouri et al., 2003; Shapouri and McAloon, 2004).  It is demonstrated that in a net-energy analysis of the industrial corn-ethanol cycle (Farrell et al., 2006a; Farrell et al., 2006c) did not (i) define the system boundaries, (ii) conserve mass, and (iii) conserve energy.