Page - 131 - in Water, Energy, and Environment - A Primer

cost– thelignocellulosicbiomassthatconstitutesthebulkofplant matter.Governments andmanyprivate sector firmsare attacking thisproblem,giventhelargepotentialmarketandthepotential for reducing CO2, and a number of second-generation biofuels are being actively explored. Ethanol,which isusuallymixedwithgasoline toproduceE-10 (90% gasoline and 10% ethanol) can also be produced by gasification of biomass such as corn. Gasificationprocesses usehigh temperatures in a low-oxygen environment to convert biomass into synthesis (‘syn’) gas, a mixture of hydrogen and carbon monoxide. This gas can then be chemically converted into ethanol and a wide variety of otherC-H-Omolecules and fuels. 8.5.4 Algae Anemergingandpotentiallymajorbiomassfieldistheproduction of alternative fuels using algae (algaculture). Algae (Latin for ‘seaweed’) are photosynthetic organisms that occur in most habitats. They range from single-celled organisms to much more complex forms, such as giant kelps that can reach lengths of more than 60m. ‘Photosynthetic’ refers to algae’s ability to capture light energy to power the production of sugars, carbohydrates that can then be converted to other C-H-O molecules.Algaedifferfromplantsinthattheyareprimarilyaquatic. Interest in algaewas triggered by the need for alternatives to petroleum fuels and theworld food crisis. Algae produce lipids (a variety of organic compounds) that can be used for making biodiesel, bioethanol, biogasoline, biojetfuel, biomethanol, biobutanol, and other biofuels. They can be grown on land that is not suitable for agriculture – for example, land with saline soil. They can be produced using seawater, brackishwater, and wastewater, and are biodegradeable. An important, and perhaps critical, aspect of algaculture is that it is claimed that algae farming can yield 10–100 times more fuel per unit area than Renewableenergy 131