The average algal concentration of the growth volume in the Experi­mental Case was 0.26 g/L, the neutral lipid fraction was estimated to be

0. 02, and cultivation required 123 days. The neutral lipid content was determined by HPLC and the lipid composition included hydrocarbons, triglycerides, diglycerides, and monoglycerides. On average, 2 mg of bio­crude and 165 mg of post-extraction biomass were recovered per liter of processed volume. These are not high productivity values as the research focus was on processing rather than growth. It was assumed that the bio­oil refining efficiency was 1 and the biomass fuel refining efficiency (con­verting post-extraction biomass to methane) was 0.25 [14,35].

The grown mass productivity (PGM), estimated bio-oil productivity (PBO), and estimated methane productivity (PBMF) were calculated by com­bining these values, yielding 2.1 g of bio-oil per thousand liters of pro­cessed growth volume (0.0026 L/kLp, 0.00069 gal/kLp where Lp is the liters of processed growth volume) and 41.6 g of methane per kLp (cf. Table 2).

For the Highly Productive Case, the algal concentration was modeled to be 1 g/L (a factor of four improvement over the Experimental Case), requiring 12.5 days of cultivation with a grown mass productivity of 0.08 g/L-d. The neutral lipid fraction was assumed to be 0.3 and the production

efficiencies were specfied as: 9harv = °.9, 9Cellsys = °.95, 9sepBC = 09, 9refBO

= 0.9, 9sepBS = 1, 9refBMF = 0.25 [14]. The grown mass productivity (Pgm), bio-oil productivity (PBO), and methane productivity (PBMF) were calcu­lated from these values and are listed in Table 1. As listed, 210 g (0.26 L,

0. 069 gal) of bio-oil and 150 g of methane are produced for each kLp. The Highly Productive Case yields an energy output that is 7 times greater than that for the Experimental Case, and the energy inputs are described below.