ABSTRACT
With severe environmental degradation in the last half-century, decrease in reserves of fossil fuels, significant rise in air pollution levels and dire need for an alternative renewable and sustainable energy alternative, microalgae-based biofuels have emerged as one of the most promising third-generation biofuel technologies. With all the feel-good factors it brings and all the promise it holds for the reversal of environmental degradation, it must be stated that there is very slow progress towards commercialization. Even now no biofuel company in the world is operating commercial-size algae cultivation farms, processing algae to make bio-crude fuel, refining and finally selling the various cuts as either algae-based transportation fuel or as other algae-based petrochemicals. With so much buzz around algal biofuels, how is that there is almost no commercialization? The answer to this situation is that various unit operations that make up the typical algae biofuels process flow may not be fully optimized at scales that are commercially relevant. With a long list of benefits propagated by various research groups and policymakers about algae-based biofuels, biorefinery and bio-economy, how is the technology still not commercially deployable? The answer to this is that very few research groups have actually conducted an integrated end-to-end mass and energy conservation balance and in-depth life cycle analysis to understand overall process economics and energy dynamics. Even when attempts have been made, sufficient data are neither generated nor available to cover the entire gamut of possibilities because this field is so new. This has resulted in inadequate assessment of sustainability of industrial-scale operation of algae. To have the full complement of data, it is very important to have a serious investment of funds and R&D efforts to understand the various facets of the algae industry, including but not limited to strain selection, genetic modification (strain improvement), media optimization, cultivation, vessel design, light, CO2 and nutrient management, contamination control, algae harvesting, concentrating, dewatering, drying, conversion of algae biomass to fuel and fuel upgradation. Although significant advances have been made recently, with several research groups making path-breaking claims in algal technology, not all of these achievements are translatable to field scenarios or are robust under outdoor conditions. This chapter thus focusses on a discussion of the current state of technical feasibility and economic viability of different processes in industrial-scale operation of microalgae and hopefully illustrate to the reader avenues where opportunity exists for further improvement to make the operation practically and industrially applicable at large scale under the realistic environmental scenarios expected to be encountered at actual plant sites.
