Table 4 shows the values used to calculate the specific energy demand and the results of the economic estimation of biodiesel production based on the experimental results for the following extraction conditions: 60 min, 2:1 sludge to hexane volume ratio. As shown in Table 4, the energy demand and the price per litre of FAMEs depend on the number of extraction stages, varying between 60.95 MJ/kgFAMEs, 1.88 €/LFAMEs (1 stage) and 290.15 MJ/kgFAMEs, 8.94 €/LFAMEs(9 stages). In a continuous process, no more than three extraction stages should be used to gain 99% of lipids. In addition, the scaling-up of the process from lab-scale to industrial plant should reduce the price.