k Sudhakar - Bioenergy Laboratory, Maulana Azad National Institute of Technology, Bhopal, India
m Premalatha - Biosequestration Laboratory, CEESAT, National Institute of Technology, Tiruchirapalli, India

In view of ever increasing global demand for energy, there has been substantial interest in developing renewable biologically produced fuel. Microalgae are one such emerging resource considered as an alternativefor biodiesel production. However its realistic potential is often either over estimated or underestimated. In viewof this, a rigorous assessment is carried out to evaluate the realistic potential of micro algal biodiesel based onphotosynthesis, thermodynamics and physical assumptions. This paper identifies six best regions in each continent for algal biomass cultivation considering both sunlight and local climatic conditions. The mean hourly meteorological data, sunlight, ambient temperature and rainfall information for the identified potential site iscombined to estimate annual biomass production, lipid production and carbon mitigation potential. Maximumpossible algal biomass yield and oil productivity have been estimated for six global sites at three different scenarios of photosynthetic efficiency 11.42, 6 and 3%. The upper optimistic biomass, oil yield and carbon fixation potential was calculated to be 533 T/ha/yr, 1, 25, 333 L/ha/yr. and 95 Tons CO /ha/yr. This study 2provides a baseline data for theoretical maximum, minimum and best estimates of open pond microalgae production systems.

Microalgae; Biofuel; Carbon-fixation; Photosynthetic efficiency; Biomass productivity;Raceway pond