Net energy calculations for production of biodiesel and biogas from haematococcus pluvialis and nannochloropsis sp

Microalgae have been proposed as possible alternative feedstock for the production of biodiesel because of their high photosynthetic efficiency. However, the high energy input required for microalgal culture and oil extraction may negate this advantage. There is a need to determine whether microalgal biodiesel can deliver more energy than is required to produce it. Using the Cumulative Energy Demand method in Simapro®, net energy calculations were done on systems to produce biodiesel and biogas from two microalgae species: Haematococcus pluvialis and Nannochloropsis sp. In spite of very optimistic assumptions, the results show a large energy deficit for both systems. Largest contributions came from the energy required to culture the microalgae and the energy required to either dry the microalgae or to disrupt the cell wall. Recommendations are made to develop wet extraction and transesterification technology to make microalgal biodiesel systems viable from an energy standpoint. © Springer 2011