On Earth, there is a wide variety of organisms, or biomass, both on land and in the oceans. In the oceans, the biomass accumulation is not as large due to the relatively short life cycle of marine organisms. On the other hand, terrestrial organisms, mainly in forests (more than 90% of the total), take in about 1/10 of the atmospheric CO2 each year through photosynthesis. Some of the biomass dies and falls to the ground, where it is decomposed into CO2 and released into the atmosphere. This carbon cycle between the atmosphere and forest ecosystems is very important for our energy and environmental issues.
Solar energy is the driving force behind photosynthesis. Therefore, the accumulation of biomass is considered to be a storage of solar energy. The annual accumulation of biomass is equivalent to about four to five times the world’s primary energy demand. Biomass use is considered “carbon neutral” because the CO2 emitted from biomass originates from atmospheric CO2 and the net CO2 emissions are considered to be zero.
Biomass energy currently accounts for about 10% of the world’s primary energy demand, which is a staggeringly large proportion. This is only 1/40 to 1/50 of the aforementioned biomass potential. Doubling the use of biomass would cover 20% of the world’s energy needs. Of course, it must be used without affecting the carbon balance. The main use of biomass energy is as firewood in developing countries. In developed countries, on the other hand, biomass is not used much because it is not an advanced energy source for us, despite the abundance of biomass waste such as paper wastes, construction wastes and food wastes.
Biomass conversion technologies are attracting attention under these situations. Particularly in developed countries, it is important to convert biomass into advanced energy sources such as liquid automotive fuels and electricity. However, the technology is still not yet established. In our lab, we are working on efficient production of energy and chemicals from biomass.
Competition with food is a concern for the use of biomass. Bioethanol production from edible raw materials such as corn and syrup will compete with food demand and lead to higher prices for food crops. While non-edible resources such as trees, branches, and stems are the main inedible resources on Earth, edible resources are minor biomass. Therefore, there is a need for efficient use of biomass from non-edible resources. Lignocellulose, such as wood and grasses, is inedible, consisting mainly of cellulose, hemicellulose and lignin. Lignocellulose has gained a strong body during evolution to protect itself from attacks by other organisms, so the technology to convert lignocellulose has not yet been perfected. These characteristics of lignocellulose make it difficult to use biomass. This is a brain war between nature and us.
Young power will create the future of biomass. Let’s build a sustainable biomass-based society to save the planet.