[attachment=13725]
GREEN FUELS
INTRODUCTION
Green fuel is defined as solid, liquid or gaseous fuel derived from relatively, recently dead biological green material and is distinguished from fossil fuels. Theoretically, green-fuels can be produced from any (biological) carbon source; although, the most common sources are photosynthetic plants. Various plants and plant-derived materials are used for green fuel manufacturing. Globally, green fuels are most commonly used to power vehicles, in heating homes, and cooking. Green fuel industries are expanding in Europe, Asia and the USA.
Types of Green fuels:- 
( A ) First generation green fuels
1 ) Vegetable oil
2 ) Bio alcohols
3 ) Bio ethers
4 ) Biogas
5 ) Solid biofuels
( B ) Second generation green fuels
( C ) Third generation green fuels
First generation green fuels
First-generation green fuels are biofuels made from sugar, starch, vegetable oils using conventional technology . The basic feed stocks for the production of first generation green fuels are often seeds or grains such as wheat, which yields starch that is fermented into bioethanol, or sunflower seeds, which are pressed to yield vegetable oil that can be used in biodiesel. These feed stocks could instead enter the animal or human food chain, and as the global population has risen their use in producing green fuels has been criticized for diverting food away from the human food chain, leading to food shortages and price rises.
Vegetable oil
Edible vegetable oil is generally not used as fuel, but lower quality oil can be used for this purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of water and particulates and used as a fuel. To ensure that the fuel injectors atomize the fuel in the correct pattern for efficient combustion, vegetable oil fuel must be heated to reduce its viscosity to that of diesel, either by electric coils or heat exchangers. This is easier in warm or temperate climates. MAN B&W Diesel, Wartsila and Deutz AG offer engines that are compatible with straight vegetable oil, without the need for after-market modifications.
Bio-alcohols
Biologically produced alcohols, most commonly ethanol, and less commonly propanol and butanol , are produced by the action of micro-organisms and enzymes through the fermentation of sugars or starches (easiest), or cellulose (which is more difficult). Bio-butanol (also called bio-gasoline) is often claimed to provide a direct replacement for gasoline, because it can be used directly in a gasoline engine (in a similar way to biodiesel in diesel engines).
Bio-ethers
Bio ethers (also referred to as fuel ethers or fuel oxygenates) are cost-effective compounds that act as octane enhancers. They also enhance engine performance, whilst significantly reducing engine wear and toxic exhaust emissions. Greatly reducing the amount of ground-level Ozone, they contribute to the quality of the air we breathe.
Solid bio-fuels
When raw biomass is already in a suitable form (such as firewood), it can burn directly in a stove or furnace to provide heat or raise steam. When raw biomass is in an inconvenient form (such as sawdust, wood chips, grass, agricultural wastes), another option is to pelletize the biomass with a pellet mill. The resulting fuel pellets are easier to burn in a pellet stove.
Examples include wood, sawdust, grass cuttings, domestic refuse, charcoal, agricultural waste, non-food energy crops (see picture), and dried manure.
BIO GAS
Biogas is produced by the process of anaerobic digestion of organic material by anaerobes. It can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, Digestate , can be used as a biofuel or a fertilizer. In the UK, the National Coal Board experimented with microorganisms that digested coal in situ converting it directly to gases such as methane.
Second generation Green fuels
Supporters of green fuels claim that a more viable solution is to increase political and industrial support for, and rapidity of, second-generation biofuel implementation from non food crops, including cellulosic biofuels. Second-generation green fuel production processes can use a variety of non food crops. These include waste biomass, the stalks of wheat, corn, wood, and special-energy-or-biomass crops (e.g. Miscanthus). Second generation (2G) green fuels use biomass to liquid technology, including cellulosic biofuels from non food crops . Many second generation green fuels are under development such as bio-hydrogen, bio-methanol, DMF, Bio-DME, Fischer-Tropsch diesel, bio-hydrogen diesel, mixed alcohols and wood diesel.
Third generation biofuels
Algae fuel, also called oilgae or third generation green fuel, is a bio fuel from algae. Algae are low-input, high-yield feed stocks to produce bio fuels. It produces 30 times more energy per acre than land crops such as soybeans. With the higher prices of fossil fuels (petroleum), there is much interest in algaeculture (farming algae). One advantage of many biofuels over most other fuel types is that they are biodegradable, and so relatively harmless to the environment if spilled.
The United States Department of Energy estimates that if algae fuel replaced all the petroleum fuel in the United States, it would require 15,000 square miles (38,849 square kilometers), which is roughly the size of Maryland.
Second and third generation green fuels are also called advanced biofuels.
Algae, such as Botryococcus braunii and Chlorella vulgaris, are relatively easy to grow, but the algal oil is hard to extract. There are several approaches, some of which work better than others.
JATROPHA – A BOON TO GREEN FUELS
Jatropha incentives in India
Jatropha incentives in India is a part of India's goal to achieve energy independence by the year 2012. Jatropha oil is produced from the seeds of the Jatropha curcas, a plant that can grow in wastelands across India, and the oil is considered to be an excellent source of bio-diesel. India is keen on reducing its dependence on coal and petroleum to meet its increasing energy demand and encouraging Jatropha cultivation is a crucial component of its energy policy.
The Government of India has identified 400,000 square kilo-metres (98 million acres) of land where Jatropha can be grown, hoping it will replace 20% of India's diesel consumption by 2011.
Implementation
The former President of India, Dr. Abdul Kalam, is one of the strong advocaters of jatropha cultivation for production of bio-diesel. In his recent speech, the Former President said that , out of the 600,000 km² of wasteland that is available in India over 300,000 km² are suitable for Jatropha cultivation. Once this plant is grown the plant has a useful lifespan of several decades. During its life, Jatropha requires very little water when compared to other cash crops.
Karnataka
Farmers in semi-arid regions of Karnataka are planting Jatropha as it is well suited to those conditions.
Labland Biodiesel is a Mysore based Private Limited Company. Since the year 2002, the Company is active in Biodiesel and Jatropha curcas-based Research and Development activities headed by its Chairman and Managing Director, Dr. Sudheer Shetty.
Issues with green fuel production and use
There are various current issues with green fuel production and use, which are presently being discussed in the popular media and scientific journals. These include:
the effect of moderating oil prices
The "food v/s fuel" debate
The Carbon emissions levels
The Sustainable green fuel production
The Deforestation
The Soil erosion
The Impact on water resources
The Human rights issues
The Poverty reduction potential
The Energy balance and
The Efficiency