Biohidrogeno

International Journal of Hydrogen Energy 33 (2008) 258 – 263 www.elsevier.com/locate/ijhydene

Biohydrogen as a renewable energy resource—Prospects and potentials
Shireen Meher Kotay, Debabrata Das ∗
Department of Biotechnology, Indian Institute of Technology, Kharagpur 721302, INDIA Received 18 June 2007; accepted 9 July 2007 Available online 4 September 2007

Abstract Biohydrogen holdsthe promise for a substantial contribution to the future renewable energy demands. It seems particularly suitable for relatively small-scale, decentralized systems, integrated with agricultural and industrial activities or waste processing facilities. Biohydrogen is considered as an important key to a sustainable world power supply and is currently being seen as the versatile fuel of the future,with the potential to replace fossil fuels. It has the key prospective to become the ideal means among the range of renewable H2 production technologies presently existing. This review attempts to delineate the prospects and potentials of biohydrogen as renewable energy resource. 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Keywords:Biohydrogen; Renewable energy; Waste-to-energy; Bioremediation

1. Introduction Hydrogen holds the promise as a dream fuel of the future with many social, economic and environmental benefits to its credit. It has the long-term potential to reduce the dependence on foreign oil and lower the carbon and criteria emissions from the transportation sector. Only in the last decade that the idea of a post-fossilfuel hydrogen-based economy started to gain mainstream interest. Molecular H2 has the highest energy content per unit weight among the known gaseous fuels (143 GJ ton−1 ) [1] and is the only carbon-free fuel which ultimately oxidizes to water as a combustion product. Therefore burning hydrogen not only has the potential to meet a wide variety of end use applications but also does not contribute togreenhouse emission, acid rain or ozone depletion. The use of hydrogen will contribute to significant reduction of these energy-linked environmental impacts. H2 can be used either as the fuel for direct combustion in an internal combustion engine or as the fuel for a fuel cell. The largest users of H2 , however, are the fertilizer and petroleum industries with, respectively, 50% and 37%. Sales ofhydrogen have increased by 6% annually in the last five years, which is
∗ Corresponding author. Tel.: +91 3222 278053, +91 3222 283758; fax: +91 3222 255303. E-mail address: ddas@hijli.iitkgp.ernet.in (D. Das).

closely related to the increased use of hydrogen in refineries as a result of stricter standards for fuel quality [2]. The Global Hydrogen Vision envisions hydrogen as a flexible, safe,affordable, domestic energy resource to be used in all sectors of the economy and all regions of the world. Hydrogen will become world’s “clean energy choice”, joining electricity as a primary energy carrier and providing the foundation for a globally sustainable energy system [3]. It has a wide variety of applications, including fuel for automobiles; distributed and central electricity and thermalenergy generation (Fig. 1). 2. Barriers for biohydrogen production Technical challenges in achieving a hydrogen economy include lowering the cost of hydrogen production, delivery, storage, conversion, and end use applications. Although hydrogen is the most abundant element in the universe, it must be produced from other hydrogen-containing compounds such as fossil fuels, biomass, or water. Eachmethod of production requires a source of energy, i.e., thermal (heat), electrolytic (electricity), or photolytic (light) energy (Table 1). In other words they are highly energy intensive and not always environmentally benign [4]. Moreover, there is a growing concern arising out of the projection of fossil fuel shortfall towards the middle of twentyfirst century. Under this perspective, biological...