In this blog post, we will compare the environmental impacts of oil and biomass and explore the potential of biomass as a carbon-neutral and sustainable energy source.
Stop what you’re doing and look around you. Among the countless objects surrounding you, how many are not petrochemical products? The clothes you wear, laptop components, printer ink—most items are either petrochemical products themselves or cannot function properly without them. It’s no exaggeration to say modern society runs entirely on oil. Most products we use daily depend on petrochemicals, significantly impacting our lives and the economy as a whole.
This dependence on oil increases further in the fuel sector. Oil is used not only for transportation like cars, planes, and ships but also as the primary raw material for power generation. However, petroleum poses several problems when used as fuel. A major issue is that its combustion produces substances like carbon dioxide, carbon monoxide, nitrogen oxides, sulfur oxides, and hydrocarbons, which contribute to global warming and cause air pollution. These problems extend beyond mere environmental concerns, posing a direct threat to human survival. Beyond this, numerous other environmental pollution-related problems exist. Furthermore, the inherent issue of petroleum being a finite resource that will eventually deplete also exists. Therefore, we feel the necessity to find resources that can replace petroleum and do not pollute the environment. So, what resources can replace petroleum?
One alternative emerging as a viable option is biomass. Biomass is a resource expected to replace petroleum and is currently used primarily as a transportation fuel. Biomass energy is recognized as a carbon-neutral energy source because it returns the carbon dioxide absorbed during plant growth back into the atmosphere, completing the carbon cycle. This means it is an energy source that does not increase atmospheric carbon dioxide levels, making it a notable alternative for addressing the current energy crisis and environmental problems.
Bioethanol is one form of biomass energy, accounting for 80% of transportation biofuels. Its prominence is growing due to Renewable Fuel Standards (RFS) implemented by numerous countries worldwide, which mandate blending bioethanol into transportation fuels at up to 10%. This bioethanol opens the possibility of replacing fossil fuels, establishing itself as a crucial pillar of environmental protection and sustainable energy policy.
Bioethanol is produced from three main types of feedstocks: sugar-based, starch-based, and lignocellulosic. Additional production processes are required depending on the feedstock. First, sugar-based feedstocks, such as sugarcane and sugar beets, can be used as fuel alcohol after undergoing fermentation and purification processes. The fermentation process involves using microorganisms to ferment the sugar extracted from the feedstock to produce ethanol. The purification process involves evaporating water from an ethanol-water solution to create a high-concentration alcohol. These two processes are relatively simple, making ethanol production from sugar-based feedstocks efficient and economical.
For starch-based feedstocks, such as corn and wheat, a saccharification step is added to the production process used for sugar-based feedstocks. This is necessary because, unlike sugar-based feedstocks where the main component is sugar, the main component of starch-based feedstocks is starch. Starch molecules are too large for microorganisms to consume directly, necessitating conversion into smaller glucose molecules. This saccharification process is catalyzed by enzymes, primarily amylase. Once the saccharification enzyme hydrolyzes the starch into glucose, bioethanol is then produced through fermentation and purification processes, similar to those for sugar-based feedstocks. This process is slightly more complex than for sugar-based feedstocks but remains commercially viable.
Lignocellulosic feedstocks like rice straw or silver grass require an additional pretreatment step before undergoing the starch-based process. Lignocellulosic feedstocks are primarily composed of cellulose, which has a very large molecular structure and cannot be broken down by saccharification alone. They also contain lignin, an insoluble, refractory polymer that hinders polysaccharide breakdown and reduces microbial activity surface area. Therefore, both pretreatment and saccharification processes are required. During pretreatment, the molecular structure is loosened through acid or base treatment at high temperatures. Subsequently, sugars are broken down using enzymes such as cellulase and xylanase. Bioethanol is then produced through fermentation and purification processes. This process is more complex and costly than those for other feedstocks, making commercialization challenging at present.
We have now reviewed the bioethanol production process. As mentioned earlier, the process becomes increasingly complex and requires additional steps as we move from sugar-based to starch-based to lignocellulosic feedstocks. This means higher process costs, and considering economic viability, the lignocellulosic feedstock process still faces challenges for commercialization. However, sugar-based and starch-based feedstocks have limitations as they use food crops as raw materials, making them expensive and economically unviable. Consequently, technological developments are underway to minimize the costs of lignocellulosic processes, and techniques utilizing seaweed as a feedstock—which significantly reduces raw material costs—are also being developed.
Biomass technology still faces technical challenges and has the disadvantage of being more expensive than fossil fuels like petroleum. However, biomass holds the potential to replace petroleum, a finite resource, at a time when oil reserves are increasingly depleted. Furthermore, unlike fossil fuels, it is a renewable fuel with lower environmental pollution concerns, making it an increasingly important issue for the future. The development and utilization of alternative energy resources like biomass are essential for sustainable energy supply, a matter closely tied to the survival of future generations. Alongside this, policies and technological support to enhance energy efficiency and minimize environmental impact are also critically needed.
