দেশ নিয়ে চিন্তিত Crops are being used as food or raw materials of food for thousands of years. Only cereal grain contributes up to 80% of the world’s food supply. While 10 million people still die for hunger or hunger related diseases each year. The cereal based biofuels production brings up the dispute in the world food supply chain. In recent years land based fuel production has received much policy attention. Because the rate at which conventional oil production can be increased has been reduced due to the lack of refining capacity and the fact that nearly 50% of the worlds provable and proven conventional light crude oil reserves have already been consumed (USGS 2004). This reality as well as the global worming concern in recent decades has stimulated interest in using crops as Biomass for Energy production. In this essay I will discuss the usefulness of crops as a raw material for food and fuel and their economic and environmental impacts. Crops used for biofuel: Rapeseed, sunflower and soybean is mainly used for the biodiesel production while the crops include corn, barley, oat, rice, wheat, sorghum and sugar cane can be used for ethanol production. Sugar cane is used as the major feed stock for ethanol in Brazil and corn grain in USA. On the other hand all these crops are being used as important food source in daily life all over the world. The crops waste during all stage of handling, storage and transportation can also be used for bioethanol production which includes corn stover, crop straws, sugar cane bagasse etc. Biomass: Vegetable species use the solar energy to produce sugar in the form of glucose or starch molecules, cellulose etc from CO2 and H2O by photosynthesis. These photosynthetic matters are called the Biomass. The biomass is being used for the production of electricity and liquid fuels or biofue.4 Bioethanol and Biodiesel are the two major fuels obtained from field crops. In 2004, 14 million hectors of land (1% of global land of crop) has been used for biofuels production. Biomass are the attractive feedstock for three main reasons: 1) it is a renewable source that could be sustainably developed in future 2) It cause the recycling of carbon in the biological process resulting no net release of CO2 and very low Sulpher content and 3) It decrease fossil fuel prices [5]. Biodiesel production process: Pre-treated rapeseed oils or sunflower oil is passed through a reactor with methanol and alkaline catalyst (Na-methylate). Transesterification takes place in the mixing section and produce methyl ester and glycerine. The subsequent settling section separate the methyl esters as light phase and glycerine water as heavy phase. The methyl esters are then passed through a washing column to remove minute by products and gives ready to use biodiesel. The surplus methanol present in the glycerine water is removed in a rectification column and recycles to the process. Additional steps i.e. chemical treatment, evaporation, distillation and blanching are followed to purify the glycerine. Bioethanol production process: Two processes are now exists to produce ethanol from corn, dry milling and wet milling. In wet milling corn kernel is fractionated into starch, fibre, corn germ and protein but it is more costly. Only starch is used for ethanol production. On the other hand, dry milling uses the whole kernel and more cost effective. The biomass first goes through a size reduction process for better handling and facilitating the ethanol production process. The complex carbohydrates, hemicelluloses and cellulose present in biomass are then converted to simple sugar (pentose and glucose) by hydrolysis with sulphuric acid and cellulose enzyme respectively. Yeast or bacteria is then feed on the sugar for fermentation and produce ethanol and CO2, called ethanol broth. The ethanol is then separated from other component in the broth. A final dehydration step removes any remaining water from the ethanol. Lignin is produced as by-products in ethanol production process and can be used to produce electricity for the ethanol production process. Discussion: Using the crops is a dispute between hungers against modernization or socialism against capitalism. Before dedicating the crops for fuel production, I think this will be more wise first to think about the food security and then to produce the biofuels. Again, the question is when the world fossil fuel reservation will be finished then what will be the source of energy for global production and transportation. Many countries have actively encouraged the biofuel production to replace the fossil fuel for transportation and it has lower co2 emission to the environment. But the biofuels are not carbon neutral. The carbon emissions from gasoline take place during combustion while the biofuel only gives the carbon emission during its production stage. Lands that are not suitable for agricultural production, but currently being used for forestry or grassland can be used for biofuel production. Again the conversion of grassland to croplands is estimated to release 134 tons of stored carbon per hector into atmosphere in US and 165 tons in Brazil while conversion of forest could release 600- 1000 tons of carbon per hector. Biofuel production may affect the world food security negatively. As the biofuel production converting the land used for food to fuel, it will increase the food price and also will stimulate the deforestation. So an alternative could be to change the food habit towards dairy and meat. But still this sector requires huge amount of land. For the production of1L of 99.5% ethanol uses 46% more fossil energy than it produces. For example, 1 L of ethanol production consumes 7474 kcal of energy but it gives 5130 kcal of energy. In the US the subsidies for ethanol is $6 billion and for biodiesel $500 million per year which means subsidies per liter of ethanol and biodiesel is 60 and 74 times greater than subsidies per liter of gasoline and diesel fuels. In 2006, 19 billion liters of ethanol were produced using 20% of US corn production which contributes only 1% of total US petroleum use. If the total 100 % of produced in US is being used for ethanol production, It will contribute only 5% of total oil consumption in US. Food and Bio fuels are dependent on the same resources for production: land, water and energy. The resulting decrease in food supply results in widespread malnutrition. The World Health Organization reports more than 3.7 billion people (56% of the global population) are currently malnourished and that number is steadily increasing due to the utilization of crops for fuel production. Fedel Castro says this is a good way to kill the people living in poor countries. They will only produce the food and the people from reach country will take the food from them. On the contrary it is also possible to think that people from poor country could sell their crops at higher price for fuel production and fuel will make the food available and affordable. Using the crop residue (corn Stover, wood cheeps) and high yielding energy crops (switchgrass) could be a possible solution to mitigate the food versus fuel dispute. Conclusion: When a lot of people die every day for food or malnutrition in this world, then using the crop for fuel production brings up the dispute in science and politics at the same time. But when we know that half of the world fossil fuel reservation has already been consumed, then the demand for a sustainable alternative is increasing and biofuel is a step on that way. Using the crop residue (corn Stover, wood cheeps) and high yielding energy crops (switchgrass) could be a possible solution to mitigate the food versus fuel dispute.