Fossil fuel consumption in transportation system and energy-intensive sectors as the principal pillar of civilization is associated with progressive release of greenhouse gases. Hydrogen as a promising energy carrier is a perfect candidate to supply the energy demand of the world and concomitantly reduce toxic emissions. This article gives an overview of the state-of-the-art hydrogen production technologies using renewable and sustainable energy resources. Hydrogen from supercritical water gasification (SCWG) of biomass is the most cost effective thermochemical process. Highly moisturized biomass is utilized directly in SCWG without any high cost drying process. In SCWG, hydrogen is produced at high pressure and small amount of energy is required to pressurize hydrogen in the storage tank. Tar and char formation decreases drastically in biomass SCWG. The low efficiency of solar to hydrogen system as well as expensive photovoltaic cell are the most important barriers for the widespread commercial development of solar-based hydrogen production. Since electricity costs play a crucial role on the final hydrogen price, to generate carbon free hydrogen from solar and wind energy at a competitive price with fossil fuels, the electrical energy cost should be four times less than commercial electricity prices.

Hydrogen production from renewable and sustainable energy resources: Promising green energy carrier for clean development

Factors influencing fermentative hydrogen production: a review

A review on dark fermentative biohydrogen production from organic biomass: Process parameters and use of by-products

https://www.ourenergypolicy.org/wp-content/uploads/2011/12/2010_03_Elsevier_InterJourHydrogenEnergy_Balat_HydrogenFromBiomass.pdf

Hydrogen from biomass – Present scenario and future prospects

Advances in fermentative biohydrogen production: the way forward?

Methodology was evaluated to selectively enrich hydrogen-producing species present in biological sludge produced during organic wastewater treatment. The influence of bacterial stress enrichment on anaerobic hydrogen-producing microorganisms was investigated in batch tests using serum bottles. Enrichment conditions investigated included application of acute physical and chemical stresses: wet heat, dry heat and desiccation, use of a methanogen inhibitor, freezing and thawing, and chemical acidification with and without preacidification of the sludge at pH 3. For each enrichment sample, cultivation pH value was set at an initial value of 7. After application of selective enrichment (by bacterial stress), hydrogen production was significantly higher than that of untreated original sludge. Hydrogen production from the inocula with bacterial stress enrichment was 1.9–9.8 times greater when compared with control sludge. Chemical acidification using perchloric acid showed the best hydrogen production potential, irrespective of preacidification. Enhancement is due to the selective capture of hydrogen-producing sporeformers, which induces altered anaerobic fermentative metabolism.

Bacterial stress enrichment enhances anaerobic hydrogen production in cattle manure sludge

The pH and hydraulic retention time (HRT) of an anaerobic sequencing batch reactor (ASBR) were varied to optimize the conversion of carbohydrate-rich synthetic wastewater into bio-hydrogen. A full factorial design using evolutionary operation (EVOP) was used to determine the effect of the factors and to find the optimum condition of each factor required for high hydrogen production rate. Experimental results from 20 runs indicate that a maximum hydrogen production rate of 4,460–5,540 mL/L/day under the volumetric organic loading rate (VOLR) of 75 g-COD/L/day obtained at an observed design point of HRT = 8 h and pH = 5.7. The hydrogen production rate was strongly dependent on the HRT, and the effect was statistically significant (P   0.05) was found for the pH on the hydrogen production rate. When the ASBR conditions were set for a maximum hydrogen production rate, the hydrogen production yield and specific hydrogen production rate were 60–74 mL/g-COD and 330–360 mL/g-VSS/day, respectively. The hydrogen composition was 43–51%, and no methanogenesis was observed. Acetate, propionate, butyrate, valerate, caproate, and ethanol were major liquid intermediate metabolites during runs of this ASBR. The dominant fermentative types were butyrate-acetate or ethanol-acetate, representing the typical anaerobic pathway of Clostridium species. This hydrogen-producing ASBR had a higher hydrogen production rate, compared with that produced using continuous-flow stirred tank reactors (CSTRs). This study suggests that the hydrogen-producing ASBR is a promising bio-system for prolonged and stable hydrogen production. Biotechnol. Bioeng. 2007;96: 421–432. © 2006 Wiley Periodicals, Inc.

Dae-Yeol Cheong

Papers

Bacterial stress enrichment enhances anaerobic hydrogen production in cattle manure sludge

Production of bio-hydrogen by mesophilic anaerobic fermentation in an acid-phase sequencing batch reactor.

Feasibility of hydrogen production in thermophilic mixed fermentation by natural anaerobes.

Acidogenesis characteristics of natural, mixed anaerobes converting carbohydrate-rich synthetic wastewater to hydrogen

Effect of feeding strategy on the stability of anaerobic sequencing batch reactor responses to organic loading conditions