Can bioenergy really be a sustainable alternative?

Bioenergy is gaining traction as an alternative to fossil fuels, but its production process still causes environmental problems and food resource shortages. We need to find a more environmentally friendly and sustainable way.

 

Modern industrial civilization has its roots in the Industrial Revolution of the 19th century. One of the driving forces of the Industrial Revolution was the use of fossil fuels. During the First Industrial Revolution, fossil fuels were simply used as fuel to heat boilers in steam engines, but as internal combustion engines became more widespread during and after the Second Industrial Revolution, they became even more important. Later, fossil fuels were also used to generate electricity as electricity became widely used in industry and in homes. In the 20th century, fossil fuels were also used to make various organic chemicals and plastics. Today is the age of oil and coal.
However, this reliance on fossil fuels presented problems before the 20th century came to an end. Limited reserves of fossil fuels, air pollution caused by carbon dioxide, sulfur oxides, and nitrogen oxides from fossil fuel use, and marine pollution from oil spills have caused direct environmental damage. In addition, it is difficult to estimate the scale of additional damage such as global warming and global extreme weather events caused by increased carbon dioxide concentrations.
Therefore, in order to reduce the use of fossil fuels, governments and international organizations such as the United Nations have tried to curb carbon emissions by developing various alternative energies. As a result, alternative energies such as solar and solar thermal energy, hydroelectric energy, wind energy, tidal energy, geothermal energy, nuclear energy, and hydrogen energy have been developed, most of which emit very little carbon. However, there is a fundamental problem that these alternative energies cannot be used as fuel for internal combustion engines. In addition, most alternative energies are difficult to store, and the amount of energy they produce is small relative to the investment cost and generation time.
Bioenergy, such as bioethanol and biodiesel, has emerged as a new energy source to solve these problems. Bioenergy is an alternative energy source that produces hydrogen and organic carbon by decomposing biomass, which refers to organic carbon sources such as wood, crops, and food waste. This process can yield a variety of hydrocarbons, biodiesel, methane, ethanol, and more. The key to bioenergy is that the amount of carbon dioxide produced when the energy is used is zero or negative. In particular, when using plant products, the carbon dioxide emissions are zero because the carbon dioxide fixed during photosynthesis is only released again. The same is true for hydrogen or methane, which is obtained by decomposing organic waste. Bioenergy is therefore a fuel that can run an internal combustion engine, and its carbon footprint is consequently zero. It has the best of both worlds: the advantages of traditional alternative energy and the advantages of fossil fuels.
But does bioenergy really have a rosy future? Does bioenergy have a zero carbon footprint? So far, various academic papers have emphasized the importance of the bioenergy industry and highlighted its advantages. However, bioenergy has a fundamental problem. Bioenergy is still organic energy based on a carbon skeleton, which means it emits carbon dioxide when burned. More importantly, it’s the actual causes of the bioenergy production process.
To obtain bioenergy, especially biodiesel and bioethanol, which are used for transportation, fermentation of mainly food crops is required. In the United States and Brazil, the world’s first and second largest producers of bioethanol, corn and sugarcane are grown in large quantities for fuel. Fossil fuels or bioenergy are needed to harvest the feedstock crops and transport them to the bioenergy production plant. Harvesting and fermenting corn and sugarcane emit carbon dioxide. In Brazil, sugarcane, the feedstock for bioethanol, is harvested in a traditional way, releasing large amounts of carbon dioxide by burning unwanted leaves and stalks. Bioethanol made from fermented corn in the U.S. requires the extraction of sugars, which inevitably results in additional costs and carbon dioxide, which is released during transportation and production. Furthermore, to meet current fossil fuel demand, astronomically large areas of land must be planted with crops like corn for fuel. Growing these crops for fuel requires not only more farmland, but also large amounts of fertilizer and water, which contribute to environmental pollution.
Biodiesel and bioethanol are also derived from food crops. Sugarcane in Brazil and corn in the United States are representative crops for bioethanol, while biodiesel is obtained from rapeseed, soybean, sunflower, and palm oil. Corn, in particular, is a widely used staple food grain along with wheat and rice, and sugarcane is a crop that produces sugar, an important food resource. When large amounts of food crops are used to produce bioenergy, there is a shortage of food crops. These food crops are important food resources that are mainly imported by third world countries. Therefore, when multinational energy companies purchase large quantities of these crops to produce bioenergy, they are actually causing food shortages in countries that need food. Furthermore, the law of supply and demand dictates that there is a limit to how much supply can be increased, so as demand continues to increase, the price of supply will increase. Therefore, mass production of bioenergy can lead to higher prices for many food crops.
The impact of bioenergy on rainforest degradation is even greater. The main bioenergy crops – corn, sugarcane, and oil palm – thrive best in tropical climates. In addition to the United States, the largest producer of corn for fuel, and Brazil, the largest producer of sugarcane, palm oil, the raw material for biodiesel, is produced in Indonesia and Malaysia. In Indonesia, in particular, significant areas of rainforest and wetlands are cleared to grow oil palm for palm oil production, and uncontrolled human-caused fires to burn uneconomical residual wood often damage the surrounding rainforest. Furthermore, if various African countries that are potential bioenergy producers jump into the bioenergy industry in earnest, they will significantly degrade the central African rainforests that are suitable for growing crops for bioenergy. Not only does this upset the balance of the carbon cycle and increase carbon dioxide emissions, but it also harms the biodiversity of the rainforests, which are endangered. Turning a blind eye to rainforest deforestation for bioenergy is blinded by immediate gains and unable to deal with future losses, and is essentially no different from the current indiscriminate use of fossil fuels.
Of course, bioenergy production from food crops and wood has its own problems, and more carbon-neutral methods of bioenergy production have been devised. These include methane and hydrogen from organic waste, ethanol and various hydrocarbon gases from industrial byproducts such as waste paper and straw, and agricultural byproducts. The former is positive in that it reduces the environmental impact of direct waste dumping, landfilling, or incineration, and it provides a useful fuel rather than decomposing into unusable carbon dioxide. The use of methanol or bioethanol from wood is also being actively researched. Bioethanol derived from woody biomass is not only more economical than bioethanol derived from corn, but it also provides about 40% more carbon dioxide savings and is a better quality fuel. But fundamentally, even these alternatives have some limitations. It’s very difficult to secure enough supply to replace fossil fuels. Woody bioethanol also requires the use of a limited resource – wood – to produce the fuel, so there’s a lot of room for conflict with existing wood-using industries. Furthermore, wood is slower to grow, mature, and turn over than annual crops.
Recognizing these problems, bioenergy has recently shifted from land to sea. The ocean covers about 71% of the Earth’s surface area, and photosynthetic algae in the ocean account for 90% of the Earth’s total carbon fixation. Korea is surrounded by the sea on three sides and is one of the world’s top three seafood farming countries, along with Japan and China. Therefore, growing algae for bioenergy in large quantities by expanding existing algae farms could economically produce more bioenergy than crops. However, this is still a long way off, and technical limitations and process inefficiencies need to be addressed before it can be commercialized.
Of course, it’s not wise to stop developing and producing bioenergy just because it has these limitations. Fossil fuels are rapidly depleting, and there is no clear alternative energy source to replace them. Even the rapidly emerging hydrogen energy system, a bioenergy alternative, currently relies heavily on the petrochemical industry. Moreover, even if carbon-neutral electric vehicles, hydrogen-oxygen fuel cells, and nuclear fusion power, which can dramatically reduce the use of fossil fuels, become practical, fossil fuels and bioenergy will continue to be used. Hydrocarbons are needed to produce the petrochemicals that support human life, namely plastics. Therefore, the bioenergy industry is essential for sustainable development to produce fuels and petrochemicals.
The environmental concerns of the bioenergy industry have also been exaggerated. In the United States and Brazil, the world’s two largest producers of bioethanol, the cultivation of bioenergy crops is not associated with deforestation. In Brazil, sugarcane is grown in the south-central region of the country, far from the Amazon and other rainforests, and is planted on existing wastelands or on land that has already been cleared. The same is true for the bioenergy industry using microalgae. These industries use microalgae that are grown and harvested collectively in coastal farms, so they don’t have a negative impact on marine ecosystems. While bioenergy may not be environmentally friendly, it doesn’t mean that bioenergy development is indiscriminately destroying the environment. The increase in corn prices due to bioethanol production is also inflated. The increase in corn prices due to increased cultivation of corn for fuel was predicted to be modest, at $3.6 per bushel, only a 50% increase over pre-2008 prices, and the increase in corn consumption and supply was predicted to be balanced.
However, the fundamental limitations of bioenergy must be clearly recognized and not overproduced to the detriment of ecosystems and global food resources. Instead, bioenergy should be used as an intermediate step in the fuel sector until carbon-neutral, sustainable, and efficient energy resources such as nuclear fusion energy and hydrogen energy are commercially available. For the production of synthetic resins and synthetic fibers, such as plastics, ongoing research is needed to minimize the burden on the environment and innovate technologies to produce bioenergy efficiently in small areas. Korea’s bioenergy industry is currently underdeveloped as its competitiveness is very low compared to the United States, Brazil, Malaysia, and Indonesia. If oil becomes scarce in the future, this situation could lead to energy dependence again, so it is necessary to develop a national bioenergy industry. However, scientists and technologists should clearly recognize the limitations of bioenergy and mention not only its advantages but also its disadvantages, so that the public does not blindly believe that bioenergy is clean energy.
The bioenergy industry needs continuous development, and even if humanity stops using fossil fuels, the use of bioenergy will continue. Currently, bioethanol and biodiesel, which are the main forms of bioenergy, cause environmental damage such as deforestation in their production and directly affect the demand for food crops and the expansion of agricultural land. Therefore, it is necessary to develop and commercialize bioenergy that is as free from these constraints as possible, and Korea, which currently imports the largest amount of fossil fuels from abroad, should increase its energy independence through bioenergy development. To this end, scientists and technologists should clearly recognize the limitations of existing bioenergy technologies and work to develop bioenergy that is more environmentally friendly and free from food resources.