Reserch Institute for Photobiological Hydrogen Production -A Grand design for large-scale renewable energy production-

Our need for the explotation of renewable energy

The Amount of Solar Energy is Huge

The amount of solar energy is huge (2.7 × 1024 J/year) But low in intensity ( about 1,500 kWhm -2yr-1 )

 Quantity
(1018J/year)		  Ratio
(vs. fossil f.)
World
Fossil fuel consumption		 417 1
 (Social primary energy use)  (513)  (1.23)
 Photosynthesis
(net production)		  4,200  10.4
Solar energy
(received on Earth's surface)		 2,700,000 6,500
Human digestive energy intake 20 0.05
Given the amount of energy in foods (about 5% of the world's primary energy use ),it seems rather unrealistic to expect large amounts of additional energy (e.g.bioethanol,biodiesel) from crops grown on land.

We are consuming a huge amount of energy !

Digestive energy intake 2000kcal/day/capita
Social energy from fuels world 20 times
US 100 times
Japan 50 times
China 15 times
(2010)
The amount of energy in foods:
about 5% of the world's energy use from fossil fuels.