Biofuels – the renewable resource: Potential & Technology Prospects
The concept of biofuels was used in the later part of the previous century unlike the use of renewable energy such as solar energy, hydropower, wind etc. That can be traced back to the beginning of the modern civilization. Biomass is a biological material obtained from living plant matter such as trees or crops that can be processed into fuel and heat. Biomass is a carbon neutral fuel, takes carbon out of the atmosphere while it is growing and returns the same amount back when it is burned. Managed on sustainable basis biomass is replenished with new growth as it is harvested, this maintains a closed carbon cycle with no net increase in atmospheric increase in carbon dioxide levels that contributes to global warming. Using wood and wood products to substitute for fossil fuels means that sustainably managed woodland can provide an ongoing contribution to climate change mitigation. Biomass can be sourced locally from within the UK on an indefinite basis and help support the rural economy. It can satisfy heating and hot water needs for both domestic and commercial properties, used in a distinct mechanical scheme it can enable many homes or properties to be heated from just one boiler. For commercial systems or those heating more than one domestic property biomass can generate a significant income from phase one of the renewable heat incentive. Wood is the most common type of biomass fuel and three main types are used in biomass boilers logs, wood pallets and wood chip. The main advantage to using logs in a biomass boiler is that they are easily available; a fully loaded burn chamber can burn for up to 18 hours when the system is in low demand and keep the hot water and heat ticking over. Automatic controls manage the ferocity of the burn and make the fuel last longer. Wood pallets are generally manufactured from by-products like sawmills and other wood processing industries. They need less storage than logs or chips as they have a higher calorific value for the same volume. Wood pallets boilers are generally fully automated with the pallets sucked by vacuum straight into the boiler from the store so are easier to run the log boilers. Wood chip is timber that has been shredded in a chipper like wood pallets it is an easy fuel for automation with screw feet taking the chips straight from the store in to the boiler. Chip systems are inexpensive to run whether initial capital outlay is greater than other technologies due to the additional path required to make the boiler fully automated. Biomass is a clean and sustainable fuel source; it can supply 100 percent of your heating and hot water demand which makes it a viable and preferable alternative to fossil fuel.
Biofuel & its production techniques
Biofuels are among the most promising replacement for non-renewable fossil fuels such as petroleum, coal that are derived from living organisms or from metabolic by-products such as food-waste products. Unlike other renewable energy resources biomass organic material can be converted directly into burnable fuel, which becomes biofuel. Biofuels can be liquid or gases made from sugars, starch or vegetable oils. Biofuels can also be solid like wood, sawdust, agricultural waste, grass cuttings, domestic refuse, charcoal or dried manure. The two most widely used biofuels are ethanol and biodiesel and both are found in liquid forms. Others liquid biofuels include butane, methane, Fischer-Tropsch diesel and gasoline. Gaseous biofuels produced are hydrogen and methane. Ethanol is an alcohol fuel produced by Fermentation of sugars found in sugarcane, rice, potato and is commonly made from wheat, corn and sorghum. Biodiesel is made from algae, animal fats or vegetable oils or recycled cooking grease. The biofuels can be produced in a number of ways for instance ethanol is produced using a process similar to brewing beer where starch crops are converted in to sugars, the sugars are fermented to ethanol and the ethanol is then distilled in to its final form which can be used as a fuel. Apart from fermentation, ethanol is also produced by the process called hydrolysis, where materials such as lignocelluloses, found in the tissue of plants and other organic materials are used. Biodiesel is made through a chemical process named transesterification whereby the glycerine is separated from the fat or the vegetable oil. This process leaves behind two products – methyl ester which acts as biodiesel and glycerine a valuable by-product. Another process used to extract biofuel is called fast or flash pyrolysis. It occurs by heating compact solid fuels at 350-500 degrees Celsius for a very short period of time(less than 2 seconds). Biomass can also be gasified to produce biogas. Hydrogen is recovered from it and catalytically converted to methanol or ethanol. The gas can also be run through a biological reactor to produce ethanol.
History of Biofuels
Biofuels have been around as long as cars have at the start of the 20th century. Henry Ford has planned to fuel his Model T’s with ethanol and early diesel engines were shown to run on peanut oil. Discovery of huge petroleum deposits kept gasoline and diesel cheap for decades while biofuels were largely forgotten. However, with a recent rise in oil prices along with growing concern about global warming caused by carbon dioxide emissions, biofuels have been regaining popularity. Ethanol fuel is the most common biofuel worldwide. It is the same kind of alcohol found in alcoholic beverages. Though ethanol can be used as a fuel for vehicles in its pure form it is usually used as a gasoline additive to increase octane and control vehicle emissions. Most transportation fuels are liquids because they are easiest to burn cleanly. Liquids meet the requirements of being both portable and clean burning. Also it can be pumped which means handling is easily mechanised, and thus less laborious. Ethanol is most commonly used to power automobiles, though it may be used to power other vehicles such as farm tractors, boats or airplanes. It is generally seen that ethanol only engines are tuned to give slightly better power than gasoline-powered engines. Ethanol has smaller energy density than gasoline, this means that ethanol fuel tanks require more fuel stops than the gasoline tanks to travel the same distance. The largest national use of ethanol biofuel exists in Brazil. It is also widely used in United States. Together both these countries amounted to 88% world’s ethanol fuel production in 2010. It is getting popular day by day in India as well as in other foreign countries. Major reason behind this rise is the limited amount of petroleum product reservoirs. Biodiesels is a renewable, cleaner-burning alternative for petroleum-based diesel fuel. In its pure form it is the lowest emission diesel fuel. It is safe to handle and transport because it is as biodegradable as sugar. When mixed with petroleum diesel, biodiesel is compatible with unmodified engines – be it car, trucks, bus, boat, construction equipment, generator or oil home heating units. It also decreases toxic emissions. Biodiesel is the most commonly used in Europe and since it is primarily derived from plants and animals, the supply can be replenished by means of farming and recycling. Biodiesel and ethanol can be produced on-site in local villages or communities from locally available, renewable resources thus, making biofuels an accessible option to fossil fuels, both socially and economically.
Apart from being used as an alternative to fossil fuels in power generation biofuels have several other applications like for cooking purpose and as an automobile fuel. Biofuels may be of special interest in many developing countries for several reasons. Many countries have the suitable climates to grow biomass. Biomass production is inherently rural and labour-intensive, and thus may offer the prospects for new employment in regions where the majority of populations typically reside. Degraded lands are restored due to biomass production. The rural income is increased by production the of high value products like liquid fuels. The expansion of biofuels production and use also raises some concerns, as well as added pressure on water resources for growing biofuel feed-stocks, is also of concern in many areas. Bio-fuel generated from oil seed crops is another well known first generation bio-fuel. Germany led the world in production, mainly from rapeseed and sunflower, with about 2.3 billion litres produced during 2005. Since then production worldwide is growing rapidly. In India, Jatropha biodiesel is being pursued as part of a wasteland reclamation strategy. From the perspective of petroleum substitution or carbon emissions reductions potential, biodiesel derived from oil-bearing seeds are – like starch-based alcohol fuels.