63
© The Author(s) 2018
H. Komiyama, K. Yamada, New Vision 2050, Science for Sustainable Societies,
https://doi.org/10.1007/978-4-431-56623-6_4
Chapter 4
Technology to Support Low-Carbon
Society (Utilizing Energy)
4.1 Future Image of Renewable Energy
4.1.1 Rethinking the Value of Renewable Energy
In the previous chapters, we have discussed technologies that increase energy efficiency, while minimizing energy consumption and maximizing the obtainable benefits. However, regardless of how much effort is made to improve efficiency, energy
consumption does not become zero, so energy resources with low environmental
impact must somehow be secured.
Firstly, energy resources represent an original source of energy that you do not
have to get energy from anything else. They must be available from nature, such as
buried underground, growing on land, or fallen from the sky.
According to this definition, fossil resources, sunlight, hydropower, wind power,
geothermal power, and biomass are all energy resources. However, hydrogen and
electricity are not energy resources, since hydrogen and electricity cannot be
obtained from nature.
However, hydrogen is often misunderstood. It has been said that “hydrogen will
solve the energy problem”; “hydrogen is obtained by electrolyzing inexhaustible
water, so if we can obtain energy with hydrogen, energy problems will be solved”;
and there has been discussion of a “Hydrogen nation”. Certainly, water is inexhaustible and hydrogen can also be used for power generation. Hydrogen can be used for
both thermal power generation and fuel cells, and it can be regarded as a resource
because it becomes the source of electricity. However, to make hydrogen, we need
another resource. Therefore, hydrogen cannot be considered an energy resource of
itself.
Looking at the amount of energy resources used, the fossil resource usage rate is
still so overwhelmingly large that non-fossil resources account for 24% worldwide
and 7% in Japan. However, in order to realize a low-carbon society while maintaining the economy for mankind, we must increase the proportion of non-fossil
© The Author(s) 2018
H. Komiyama, K. Yamada, New Vision 2050, Science for Sustainable Societies,
https://doi.org/10.1007/978-4-431-56623-6_4
Chapter 4
Technology to Support Low-Carbon
Society (Utilizing Energy)
4.1 Future Image of Renewable Energy
4.1.1 Rethinking the Value of Renewable Energy
In the previous chapters, we have discussed technologies that increase energy efficiency, while minimizing energy consumption and maximizing the obtainable benefits. However, regardless of how much effort is made to improve efficiency, energy
consumption does not become zero, so energy resources with low environmental
impact must somehow be secured.
Firstly, energy resources represent an original source of energy that you do not
have to get energy from anything else. They must be available from nature, such as
buried underground, growing on land, or fallen from the sky.
According to this definition, fossil resources, sunlight, hydropower, wind power,
geothermal power, and biomass are all energy resources. However, hydrogen and
electricity are not energy resources, since hydrogen and electricity cannot be
obtained from nature.
However, hydrogen is often misunderstood. It has been said that “hydrogen will
solve the energy problem”; “hydrogen is obtained by electrolyzing inexhaustible
water, so if we can obtain energy with hydrogen, energy problems will be solved”;
and there has been discussion of a “Hydrogen nation”. Certainly, water is inexhaustible and hydrogen can also be used for power generation. Hydrogen can be used for
both thermal power generation and fuel cells, and it can be regarded as a resource
because it becomes the source of electricity. However, to make hydrogen, we need
another resource. Therefore, hydrogen cannot be considered an energy resource of
itself.
Looking at the amount of energy resources used, the fossil resource usage rate is
still so overwhelmingly large that non-fossil resources account for 24% worldwide
and 7% in Japan. However, in order to realize a low-carbon society while maintaining the economy for mankind, we must increase the proportion of non-fossil