In this blog post, we’ll examine why bioenergy is considered eco-friendly even though it emits carbon dioxide, explore the Earth’s carbon cycle, and discuss the advantages of bioenergy.
One of the biggest issues of the 21st century is environmental pollution. Among these, carbon dioxide emissions are a particularly contentious issue. While the development of petroleum has enabled humanity to lead extremely prosperous lives, the resulting environmental pollution has also become a major problem. A prime example of the environmental problems caused by petroleum use is the greenhouse effect caused by carbon dioxide. The greenhouse effect refers to the phenomenon in which certain gases are released into the atmosphere, absorb heat, and prevent it from escaping, thereby raising the Earth’s temperature; carbon dioxide is considered one of the primary gases responsible for this effect.
The greenhouse effect can cause rapid changes in the Earth’s temperature, leading to extreme weather events and the destruction of ecosystems. Furthermore, the melting of glaciers leading to rising sea levels—and the consequent gradual submersion of continents—is also a major problem. To address these issues, significant efforts are being made to reduce carbon dioxide emissions. A prime example is the development of renewable energy sources to replace petroleum.
Renewable energy refers to energy that can be used sustainably while minimizing environmental impact. Here, we will focus specifically on bioenergy. Bioenergy refers to the production of energy using resources created by living organisms; ethanol fuel made from corn or sugarcane is a prime example. Ethanol is the main component of alcohol; it has the molecular formula C₂H₅OH and, because it contains carbon and hydrogen, produces carbon dioxide and water when burned. This is where many people have a misunderstanding. Since bioenergy is used to prevent carbon dioxide emissions, it might seem pointless if carbon dioxide is actually emitted during the combustion process.
Let’s clear up this misunderstanding by explaining why the amount of carbon dioxide in the atmosphere is increasing. The reason the concentration of carbon dioxide in the atmosphere remained stable for a long time was that, as carbon dioxide entered the atmosphere, it was converted into other forms or absorbed, maintaining an overall balance. Carbon on Earth exists in various forms—not only as carbon dioxide in the atmosphere but also as part of living organisms or dissolved in water. Carbon continuously cycles through the Earth via processes such as plants absorbing carbon dioxide, animals consuming plants, and animal carcasses decomposing and being converted back into carbon dioxide. However, as humanity began extracting and using oil that had been buried deep underground, the total amount of carbon circulating on Earth increased. In other words, if 100 units of carbon were normally circulating and the total amount of carbon increased to 200 due to oil use, the amount of carbon dioxide in the atmosphere would inevitably increase by the same amount. Although bioenergy emits carbon dioxide during the combustion of ethanol, it can be considered an environmentally friendly energy source because it does not involve extracting additional carbon from fossil fuels—such as oil buried underground—but rather utilizes carbon that was already part of the existing carbon cycle; thus, it does not significantly alter the carbon cycle. However, even though there are methods—such as wind and solar power—that do not directly emit carbon dioxide during the power generation process, the reason for developing bioenergy lies in its commercial viability: it allows for the continued use of existing facilities and equipment that were previously used to burn carbon to produce energy. In fact, in the United States, Canada, and Brazil, the supply of bioenergy has reached a level comparable to that of nuclear power. It would be a tremendous loss to neglect the development of such a useful renewable energy source simply due to a misunderstanding.
