Theoretical Assessment of Algal Biomass Potential for Carbon Mitigation and Biofuel Production

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 alternative for biodiesel production. However its realistic potential is often either over estimated or underestimated. In view of this, a rigorous assessment is carried out to evaluate the realistic potential of micro algal biodiesel based on photosynthesis, 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 is combined to estimate annual biomass production, lipid production and carbon mitigation potential. Maximum possible 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 2 provides a baseline data for theoretical maximum, minimum and best estimates of open pond microalgae production systems. INTRODUCTION structure, fast growth rate and for high oil content. There Microalgae are one of the planet’s most promising different proportion of lipids, carbohydrates and proteins. sources of renewable biomass [1]. Biomass derived Very few species of microalgae namely Spirulina, from seaweed and algae are gaining significance for Dunaliella saliina, Chlorella vulgaris and production of biodiesel [2]. Algae can grow in a wide Haematococcus pluvialis have been invariably exploited variety of conditions from freshwater to extreme commercially [8]. Some algae strains may contain up to 80 salinity [3-5]. They are more efficient converters of solar percent lipids making them very suitable for the energy than terrestrial plants and take carbon dioxide out production of liquid fuels [8, 9, 10]. Biodiesel derived from of the atmosphere as they grow [6]. Algae are the most microalgae were found to have similar properties to that of optimum organisms for sequestration of CO because a standard diesel [11]. 2 of their ability to fix carbon by photosynthesis. The cultivation of algae has been suggested for carbon The site selected for algae cultivation have to meet capture because of its ability to fix CO into biomass the following criteria. 2 and thereby to produce carbon neutral fuels. The prospects of CO mitigation by microalgae is inhibited C Availability of sunlight throughout the year. 2 because of lack of viable technologies at large scale C Favourable climatic conditions, temperature, relative [7]. Macroalgae, on the other hand, such as seaweed, humidity, precipitation and evaporation. are less preferred than microalgae. The preference C Land topography. towards microalgae is due largely to its less complex C Assess to nutrients, carbon sources and water [12]. are many varieties of micro-algae; each species has a