4. Future application of bio-fuel
As we mentioned before, the renewable energy source, especially, the biomass energy
source would be promising for global warming protection. Using the biomass feedstock,
there are many fuels which can be converted through the gasification, the fermentation or
another process. Here, we concentrated to the biomass gasification process by which
electricity and thermal energy or Bio-H2 fuel are produced. Also, the CO2 emission due to
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Energy Paths due to Blue Tower Process 599
LCA methodology, which is estimated in order to understand the impact of Global warming
numerically, was estimated. As a next step, we have to create the countermeasure
for promotion of our proposed system. However, there is not example in which the
relationship between the supply and the demand is argued enough. Based on the sequential
and entire system, we have to judge the effects and/or the benefits such as CO2 emission etc.
(See Fig. 1).
Here, as a good example, we introduce the following system. However, that might be
difficult to promote our proposed system due to the cost barrier against a conventional
system at the present time. The combined system in which the renewable energy such as
Bio-H2 can be available would have a significant meaning in the future utilization for Global
warming protection. Simultaneously, we have to create the new business model which
would be suitable for the end users.
Now, there is the proposal to install an advanced cell phone (a smart phone) with a PEFC
unit so as to get CO2 benefit. A smart phone is an electronic device used for two-way radio
telecommunication over a cellular network of base stations known as cell sites. The sale of
mobile phones has been one of the fastest growing markets in the world today. For instance,
the cell phone users of Japan were approximately 107 million in 2005 (Infoplease, 2005). At
present, around 85% people in America have used cell phone. In addition, new technology
of a mobile communication is being developed very quickly. A few years ago, people used
their cell phone just for making a call or sending a short mail through a SMS function.
However, at the current time, there are a lot of features of a smart phone such as music
player, video player, game, chatting, internet browsing and email, etc. These factors should
increase energy consumption and increase CO2 emission.
The current power supply system in a smart phone is dominated by a Li-ion battery, which
has some advantage such as wide variety of shapes/sizes without a memory effect. In
addition, the rapidly advancing needs for mobile communication are increasing the
consumer demand for portable application with even higher power output, longer
operation time, smaller size, and lighter weight. A Li-ion and other rechargeable battery
system might not be suitable for high power and long time span portable devices due to
their lower energy density, shorter operational time, and safety. Li-ion batteries are well
established as a power supply for portable devices. Recently, since the power demand has
been increasing faster than battery capabilities, the fuel cells might become a promising
alternate for niche applications. A fuel cell is an electrochemical device which continuously
converts chemical energy into electricity and thermal energy by feeding H2 fuel and oxygen
into it. A fuel cell power supply can be higher energy per a unit mass than conventional
batteries. Also, the using of fuel cell system is not harmful to the environment, if compared
with a Li-ion battery (Hoogers, 2003). Also, there are the following two types of fuel cell: 1)
Polymer Electrolyte Fuel Cell (PEFC) and 2) Direct Methanol Fuel Cell (DMFC), which are
operated in low temperature. These two systems are almost same, the difference is only in
fuel, that is, the PEFC is operated by H2 (gas) and DMFC is done by methanol (liquid). Here,
we focused on the PEFC into which H2 fuel is fed. The reason why we concentrate the
system is that the fuel for a PEFC can be produced by the renewable resources such as
biomass feedstock with a lower CO2 emission in comparison to the conventional production
system. In the area where there is plenty of biomass feedstock (e.g. Indonesia and Malaysia
etc.), there is a good potential to install that. A PEFC is applied to replace a Li-ion battery. A
comparison of CO2 emission between a Li-ion battery cell phone and a PEFC cell phone was
calculated using Life Cycle Assessment (LCA) methodology, in consideration of the user's
behaviour.
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600 Biofuel's Engineering Process Technology
4.1 A case study on a smart phone due to LCA methodology
The goal of this study is to compare the CO2 emission of the conventional Li-ion cell phone
and the PEFC cell phone. The functional unit is the specific CO2 emission per a life cycle
(LC) of kg-CO2/LC. Fig. 6 shows the life cycle stage on the schematic design of system
boundary, in which a pre-processing of raw materials, a manufacture, a transportation and
distribution, an energy consumption of end users and a disposal process are included. Also,
in this study, we referred to the duration time of each operation of cell phone (Dowaki et al.,
2010a).