Advantages and disadvantages of biofuels
What is biofuels
Biofuel is essentially an alternative fuel source derived from biomasses. Rapid depletion of fossil fuel reserves and increasing pollution issues have rung an alarm to look for sustainable alternatives such as biofuels namely biogas, biodiesel, bioethanol and biobutanol. Biofuels are believed to be cleaner fuels since they do not add up the carbon content in the atmosphere as the carbon emission from their usage equalizes the amount assimilated during growth of the biomass.
In the current scenario, the biomass energy amounts approximately 50EJ (exajoules) which is about 10% of global energy demand. On the top, that amount covers up 75% of the total renewable energy in use today.
The produced biofuels are available in all the three principal forms of matter, i.e. solid, liquid and gas. However, the latter two forms are predominant owing to the ease of usability and environmental concerns. Liquid ones are the alcoholic biofuels as mentioned earlier and the gaseous ones are predominantly methane (CH4) and hydrogen (H2). Oil refineries produce the petrochemicals and fuels from petroleum crude. Similarly, biorefineries yield biofuels from the biomasses.
The concept of biorefineries:
The biorefinery is essentially a collection of facilities in terms of technology and equipment to process the biomasses and subsequently yield biofuels for transportation and chemicals from them. In a board sense, biorefineries involve three different steps for their functioning namely; pretreatment of biomasses for making them fit for conversion. Conversion step is the one that acts on the pretreated biomass to yield biofuels and assorted chemicals. The final step is nothing but separation and purification which eventually makes the products market worthy. In the current global scenario, the major challenge for biorefinery development process is the efficient production of transportation biofuels.
Generation of biofuels based on biomasses used:
The biomasses for biofuel production are categorized in to various generations namely, first generation, second generation and the third generation of biomasses. Based on the generation of biomass used, the biofuels are also named accordingly. Although first generation biofuel production is not in practice today and the third generation biofuel production still needs lots of research and development for efficiency enhancement.
Generation of biofuels chart
| Generation of biomass | Type of crop | Examples |
| First generation | Food crop | Sweet potato, sugarcane, ground nut |
| Second generation | Non-food crop | Lignocellulosic biomass from agriculture and waste plants |
| Third generation | Non-food crop | Microalgae, photosynthetic bacteria |
Advantages of Biofuels
Renewable energy source
Unlike finite fossil fuels, biofuels are replenishable through continuous biomass production. For instance, sugarcane in Brazil or corn in the U.S. can be harvested annually, ensuring a steady supply. This renewability reduces long-term dependency on geopolitically unstable fossil fuel reserves.
Carbon Neutrality and Emission Reductions
Biofuels are often considered carbon-neutral because the CO₂ released during combustion is theoretically offset by the CO₂ absorbed by plants during growth. Studies by the Intergovernmental Panel on Climate Change (IPCC) suggest that ethanol from sugarcane can reduce greenhouse gas (GHG) emissions by 70–90% compared to gasoline. Similarly, biodiesel from waste cooking oil cuts emissions by 88% relative to diesel.
However, this “neutrality” depends on sustainable farming practices. Deforestation for biofuel crops, for example, can negate carbon benefits by releasing stored carbon in soils and forests.
Biodegradability and Reduced Pollution
Biofuels like biodiesel degrade 4–5 times faster than petroleum diesel, minimizing ecological damage in case of spills. They also produce fewer toxic byproducts, such as sulfur oxides (SOₓ) and particulate matter, improving air quality in urban areas.
Energy Security and Economic Diversification
Biofuels enable countries to reduce oil imports and enhance energy independence. Brazil’s Proálcool program, launched in the 1970s, transformed the nation into a global leader in sugarcane ethanol, displacing 40% of its gasoline demand by 2010. Similarly, the EU’s biodiesel industry supports over 220,000 jobs, fostering rural development.
Agricultural and Rural Development
Biofuel production creates markets for farmers, stabilizes crop prices, and revitalizes rural economies. In India, the National Policy on Biofuels (2018) promotes ethanol production from surplus sugarcane, offering farmers an additional revenue stream.
Engine Compatibility and Infrastructure
Ethanol blends (E10, E85) and biodiesel (B20) are compatible with existing engines, requiring minimal retrofitting. Flex-fuel vehicles (FFVs), which run on any ethanol-gasoline blend, are widespread in Brazil and the U.S., demonstrating the adaptability of biofuels to current infrastructure.
Disadvantages of Biofuels
Food vs. Fuel Debate
First-generation biofuels compete with food production for arable land and resources. The 2007–2008 global food crisis, exacerbated by U.S. corn ethanol subsidies, saw maize prices surge by 70%, sparking ethical concerns. The OECD estimates that biofuel expansion could increase food prices by 20–50% by 2050, disproportionately affecting low-income populations.
Land-Use Change and Deforestation
Indirect land-use change (ILUC) occurs when biofuel crops displace food production to new areas, often triggering deforestation. Indonesia’s palm oil industry, which supplies 40% of global biodiesel feedstock, has driven the destruction of 31 million hectares of rainforest since 1990, threatening biodiversity and indigenous communities.
Water Scarcity and Pollution
Biofuel crops are water-intensive. Producing 1 liter of corn ethanol requires 1,700–2,500 liters of water, compared to 5–20 liters for petroleum refining. In water-stressed regions like India’s Maharashtra, sugarcane ethanol production exacerbates groundwater depletion. Additionally, fertilizer runoff from biofuel farms contributes to eutrophication in water bodies.
Energy Return on Investment (EROI)
The EROI of biofuels—the ratio of energy produced to energy invested—is often marginal. Corn ethanol has an EROI of 1.3:1, meaning it yields only 30% more energy than it consumes. In contrast, fossil fuels have EROIs of 10:1 to 30:1. Poor EROI undermines the viability of biofuels as a large-scale energy solution.
Lower Energy Density
Ethanol contains 30% less energy per gallon than gasoline, reducing vehicle mileage. For example, a car running on E85 (85% ethanol) travels 25–30% fewer miles per tank than on gasoline. This inefficiency increases consumer costs and limits adoption.
Conclusion:
Biofuels production via biorefineries is definitely a sustainable approach to produce alternative transportation fuels, biogas, and thermal energy. Thermochemical processes are being used widely for the biofuel production in the current scenario because of the well-developed technologies.
Biochemical conversion techniques although are eco-friendly but are having limitations in terms of quantity of yield. Physicochemical processes have proved themselves as the most sustainable pathways for biofuel production, but need significant downstream processing before releasing the biofuels to the market. However, a lot of research and development inputs need to be provided in each of the methods for making the processes more efficient.
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