FreeWord – Biofuel
Hello folks! It’s FreeWord time. This is a continuation of my previous Biomass, the carbon-neutral energy source article. Now we are going to dig deeper into biofuels which have been investigated as a highly potential alternative source for renewable energy. Biofuels raw-materials vary remarkably geologically and can be more evenly distributed than fossil fuels, which allow for autonomous and secure energy supply.
Rising gasoline prices during 2005–2008 exploded the use of biofuels, and a renewable fuel standard of 36 billion gallons of biofuel by 2022 was set. This generated incentives for a massive investment in U.S. corn-based bioethanol plants, which are currently the most produced biofuel. The US dominance of biofuel production as seen below, is a result of fuel targets and incentives put in place by the US government.
Global bioethanol production by country, 2018
Bioethanol And Gasoline (today)
The use of bioethanol in internal combustion engines has many advantages compared to gasoline. It has a higher oxygen content, which promotes better combustion and lowers exhaust emissions, and a higher octane number, which allows engines to operate at a higher compression ratio. This leads to reduced carbon monoxide (CO) emissions produced by older machinery. Also, integrating bioethanol with the existing road transport fuel system is easy – it can be blended with conventional fuels up to 15% without any need for engine modifications. Some car manufacturers are also introducing new FlexiFuel cars, which can be used almost entirely with ethanol 85% (E85).
Improving the quality of air is one of the most essential functions of bioethanol. When mixed with fuel, bioethanol reduces the use of cancer-causing gasoline compounds such as ethylbenzene, toluene, xylene, and benzene. It also reduces the emissions of small particulates and soot from motor fuels and greenhouse gas emissions.
The disadvantage is that bioethanol provides 34 percent less energy per liter than ordinary petrol. This increases the vehicle’s fuel consumption slightly. An E10 mixture increases fuel consumption by only approximately 3 percent, while E85 increases it by about 25 percent. The positives still easily outnumber the negatives, and for example, China has made an announcement of its goal to move to a 10% ethanol blend in all automobile gasoline by 2020.
Biofuel Production Today
The first generation and second generation bioethanol can be produced from primary sources. These feedstocks support food sustainability, have a low and stable price, and do not require extra land. Among these feedstocks are lignocellulosic biomass (LCB) that comprises different types of biomass, such as energy crops, agricultural residues, and forest materials.
First generation bioethanol still dominates the majority of bioethanol production worldwide, with the United States and Brazil accounting for more than 75% of the global output, predominantly based on corn and sugarcane. However, concerns over the long-term sustainability of first-generation bioethanol, such as impacts on land use, water resource, the potential contamination of soils with the distillation residues, and the competition between food and fuel are frequent.
The second generation biofuels are produced from lignocellulosic biomass, but a costly and challenging pre-treatment is required. The pulp and paper industry has the highest income of biomass for non-food-chain production and simultaneously generates a high amount of residues. According to the circular economy model, these residues which are rich in monosaccharides, or even in polysaccharides besides lignin, can be utilized as a proper feedstock for second-generation bioethanol production.
With the second-generation model, the most significant cost component is the processing, not the feedstock. Cost reductions are therefore achieved through the learning curve on processing costs, mostly in developed countries. 2nd generation biofuels are supposed to have much better GHG reduction potential.
Since first-generation biofuels have several inherent limitations, researchers have focused more on the second-generation. However, the second-generation biofuel production process requires expensive and sophisticated technologies. For now, biofuel production from the second generation has not been found profitable for commercial production. Therefore, the researchers have started to focus on third-generation biofuels.
Microalgae are currently being promoted as an ideal third-generation biofuel feedstock because it has many advantages over land-based feedstock. When seaweed grows, it absorbs CO2 and releases O2 (greenhouse-gas fixation ability). Furthermore, seaweed cultivation does not require fertilizers, and it increases plankton in the area, which in turn supports the local fishing industry and preservation of marine life. It grows in saltwater and thrives in harsh environmental conditions and produces energy-dense oil content. The oil content in microalgae varies remarkably. Several discovered species of microalgae can have an oil content of up to 80% of their dry body weight.
Microalgae cultivation still faces many uncertainties and challenges, including variation in composition due to sources, infrastructure, weather conditions, etc. This leads us to the 4th generation.
Fourth-generation biofuel is the result of developments in plant biology and biotechnology of carbon capture and storage techniques. Fourth-generation uses genetically modified (GM) algae to increase biofuel production. Extensive research has been carried out on genetic modification and other technologies that aim to increase the productivity of algae strains. Only a handful of them deals with the legislative limitations imposed on exploiting and processing GM algae. Although GM algae biofuel is a well-known alternative to fossil fuels, the potential environmental and health-related risks are still of great concern.
Other sources for biofuel improvement
Optimizing international trade policies should improve the import of biomass from developing countries to the developed countries who can process and convert the raw materials to next-generation biodiesels in the most cost-effective way. The next step could be achieved by transferring technologies from the developed countries to the developing countries, who have the necessary supplies of raw materials, but could also learn to produce the final goods themselves. This would ultimately lead to a global price reduction.
It is a fact that biofuels have many positive effects. It reduces exhaust emissions and improves energy safety and operation of transport facilities. However, the first-generation biofuel production possesses notable economic, environmental, and political concern as the mass production of biofuel requires more agricultural lands resulting in reduced areas for human and animal food production. Advanced biofuels are still far from commercial scale, but possess endless opportunities since they can be sourced from a much wider variety of non-edible feedstock, and thereby limiting the direct ‘food versus fuel’ competition associated with most first-generation biofuels.
Picture credit: https://www.cagle.com/gatis-sluka/2018/02/grain-and-biofuel