[Science World] The Alternative for Earth is ‘Biofuel’

It is well known that global warming is caused by the massive use of fossil fuels. However, it is not possible to simply stop using coal or oil. Is there any other solution? The answer may lie in a surprisingly simple place. If fossil fuels extracted from underground cause global warming, why not create and utilize plants or other fuel sources above ground? This method, which mainly uses biological processes to cultivate plants or microorganisms, is called "biofuel."

In fact, biofuels are also made using biological processes and therefore contain carbon. In other words, using biofuels also emits carbon dioxide. So what is the difference from fossil fuels? The significance of biofuels lies in their production process. For example, the simplest biofuel is probably firewood. You can grow trees and cut them down to use as firewood. While burning firewood certainly emits carbon dioxide, the trees absorb carbon dioxide from the atmosphere as they grow. When you consider the entire process of tree growth and fuel use, the net carbon dioxide emissions are close to "zero." This is why biofuels are sometimes called carbon-neutral fuels. Some people point out that additional energy is consumed in processes such as reprocessing and transportation. However, it is an undeniable fact that biofuels are more environmentally friendly compared to extracting and using fossil fuels from underground. Currently, the "biomass" that can be used as raw material for biofuels is generated at 200 billion tons annually, which is eight times the global energy consumption.

Biofuel technology has evolved over time. First-generation biofuels mainly use food crops such as sugarcane or corn because they contain a lot of sugars, making it easy to extract alcohol. Second-generation biofuels are produced by breaking down waste wood or sawdust into alcohol, but their efficiency is low, making commercialization difficult. Therefore, microalgae, including green and red algae, are being considered as one of the next-generation biomasses. The oil extracted from these can be refined to become substances similar to conventional petroleum, allowing immediate use in vehicles. Moreover, if desired, plastics and other products can also be produced. Saying that petroleum can be extracted means that by further adjusting its components, the production of petrochemicals is also possible.

Even waste can be used as raw material for biofuels. Since the related law was amended in 2019 to exclude "energy produced from non-renewable waste" from renewable energy, there has been some misunderstanding that waste energy is not necessarily recyclable energy. However, renewable waste containing carbon derived from forests or agriculture, such as paper and food waste, can be classified as biomass.

Recently, technologies that process such renewable waste into biofuels have gained significant attention. This is because they can solve the troublesome waste problem while simultaneously producing environmentally friendly energy. For example, food waste can produce gas through fermentation and other processes, and after refining, it can replace natural gas and other fuels.

Currently, first-generation biofuel technologies are mainly used, with second-generation technologies being applied to a limited extent. If related technologies continue to develop, we can expect a future where concerns about waste are greatly reduced, and we move one step closer to a carbon-neutral society, creating a better world to live in.

Jeon Seung-min, Science and Technology Writer