Biohydrogen Generation and Other Methods - Hydrogen Generation, Storage, and Utilization - page 50

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Biohydrogen Generation and
Other Methods

4.1 BASICS ABOUT BIOHYDROGEN

An alternative for hydrogen generation is through biological processes,
so-called biohydrogen generation. Biohydrogen produced from biorenew-
ables is a promising alternative for a sustainable energy source. Biohydrogen
is a renewable biofuel produced from biorenewable feedstocks by chemical,
thermochemical, biological, biochemical, and biophotolytical methods [1].
Biohydrogen is particularly attractive for rural areas of the world since it can
potentially be carried out at low cost and with more primitive techniques. In
addition, there are several reasons for biohydrogen to be considered as a
relevant technology by both industrialized and developing countries. First, it
is less energy-intensive compared with other processes for hydrogen genera-
tion, such as steam reforming of natural gas, coal gasification, or electrolysis
of water. Second, less undesired by-products, such as CO 2 , are produced in
the process compared with some of the other techniques. This is because
using biomass instead of fossil fuels to produce hydrogen reduces the net
amount of CO 2 released to the atmosphere, as the CO 2 released when the
biomass is gasified was previously absorbed from the atmosphere and fixed
by photosynthesis in the growing plants [2].
Currently, there are two major approaches for using biological
organisms for hydrogen production. The first is direct production through