For sustainable society


Biomass power generation from tequila

Few people may be convinced of the fact that biomass power generation is renewable energy. Since the farm crops used as fuel absorb CO2 as they grow, it is considered that the total amount of CO2 in the whole earth comes out zero even if they are burned to make energy. This is based on the concept of carbon neutral and is regarded as the evidence that biomass power generation is renewable energy. To think it more simply, it can be said that it is renewable energy because crops produced by natural blessings such as the sun, water, and air are used as energy.

Such biomass power generation has various power generation methods. One of them is biogasoline in which bioethanol is made from farm crops and mixed with gasoline. Currently, while corns and sugar canes are mainly used, a research team at the University of Sydney reported this spring that the crop called agave, which is known as a raw material for tequila, has a smaller environmental impact.

However, it is not so easy to explain it. That is because there is a slightly more complicated reason why agave is better than corn and sugar cane. First, there is no need to build irrigation facility for cultivation. Since the origin of the agave is Mexico in Latin America, it has resistance to heat and drought and does not require much fresh water and fertilizer. A research finding has shown that agave can grow with 69% less water than sugar cane and 46% less than corn.

Second, it can be produced also in low-rainfall Australia, which means that Australia does not have to import from overseas. Today, as a raw material of bioethanol, Brazil is the largest exporter of sugar cane and the United States is that of corn. If what had to be imported comes to be able to be produced in own country, CO2 emissions related to transportation can be reduced. This is the complication mentioned above, and since countries that cannot grow agave in their own countries need to import it, it cannot be said that it has a small impact on the environment.

Third, the advantage of agave is that it does not compete against food crops. Corn and sugar cane are not only human foods but also livestock feeds as forage crops. There might be possibilities that crops supposed to be used for biomass power generation will be distributed to the consumption as human foods because of the growing population in Asian countries and poor harvest of farm crops due to abnormal weather. In other words, the market becomes unstable. On the other hand, since agave is basically not used for food although it is a raw material for tequila, it can be said that the market is stable.

Finally, agave produces 7,414 liters of ethanol per hectare. In comparison, 9,900 liters are produced from sugar cane and 3,800 liters from corn. Considering yield alone, sugarcane is the most efficient. However, from the environmental impact assessment of all processes from crop cultivation to ethanol production, it was found that agave is more suitable for biomass power generation. The environmental impact assessment of the production process is called lifecycle assessment, which also includes other assessment items such as eutrophication of fresh water and marine pollution.

Then, will agave production begin in Australia soon? ― It doesn’t seem so. A researcher at the University of Sydney said: “It will not be commercially viable without government support.” However, since demand for rubbing alcohol is increasing as a countermeasure against the coronavirus that is currently pandemic, there also is information that the situation may change. The pandemic of coronavirus has brought about considerable changes in cities around the world, and the changes may also be reaching the energy industry.


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