The energy inputs and outputs for all 20 cases are shown in Fig. 2. The
energy impacts assigned to each contribution are listed in TableD-3 of the
SI. Case 1 incorporates inefficient methods that yield high energy requirements
and a low-nitrogen growth setting with lower productivity than
the high-nitrogen cases. Case 2 improves upon Case 1 by usingmore efficient
technologies and Case 3 applies a high-nitrogen growth setting with
higher yields, further improving the EROI with respect to Case 1. Case 4
(Desmodesmus sp.) has a greater oil content than Case 3 (Staurosira sp.)
and no silicon requirement, but the EROI is less than Case 3 because
there is less animal feed produced, which receives a large displacement