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Prospecting for `green' diesel

N. Gopal Raj

Apart from reducing a country's dependence on fossil fuels, biofuels are renewable and do not contribute to global warming.

CRUDE OIL prices have been increasing steadily and rising tensions in West Asia, which supplies a sizable part of the world's oil, haven't helped. For their part, oil importing nations are anxiously casting about for alternatives to at least reduce their dependence on the `black gold'.

Before them is the enviable example of Brazil. Brazilian cars — and even apparently its small aircraft — have been shifting to either pure ethanol (also known as ethyl alcohol) or ethanol-petrol blends. The use of ethanol stabilised fuel prices in Brazil, saved the country some $50 billion that it would otherwise have spent importing oil over the last 30 years or so and created an estimated one million rural jobs, points out the Worldwatch Institute in its State of the World 2006 report. Combined with increased domestic oil production, Brazil is expected to become self-sufficient in energy this year.

"Dramatic growth in biofuels is virtually certain in the years ahead," predicts the Worldwatch Institute.

Apart from reducing a country's dependence on fossil fuels, biofuels have other advantages too. As they are derived from plants, they are renewable. Biofuels do not, like fossil fuels such as coal and petroleum, add to carbon dioxide levels in the atmosphere and thereby contribute to global warming. Burning biofuels merely returns the carbon dioxide that plants have drawn from the atmosphere for photosynthesis.

After the first oil shock of the early 1970s, a group at Indian Space Research Organisation's Vikram Sarabhai Space Centre in Thiruvananthapuram came up with a technology to turn non-edible oilseeds into what it called "space crude." The liquid fraction of the crude could be used to produce petrol, kerosene, diesel, and lube oils and the gaseous fraction turned into cooking gas. While the technology appeared promising, large-scale production foundered because of problems of securing large quantities of oilseeds at a reasonable price.

The talk these days in India is of making bio-diesel. The country's demand for diesel is five times greater than for petrol. Rapid economic growth has meant more people travelling than ever before and larger quantities of goods being transported. Demand for petroleum products in India, particularly diesel, was set to increase rapidly, according to Leena Srivastava, executive director of The Energy and Resources Institute (TERI) based in New Delhi. Over 80 per cent of passengers and 60 per cent of the freight were moved by road, she pointed out in a recent TERI publication on biofuels.

The Government estimates that the country's diesel requirements in 2011-12 could be more than 66 million tonnes, one and a half times higher than in 2001-02. TERI estimates that India's diesel needs would cross 100 million tonnes by 2020 and 200 million tonnes by 2030.

Today most diesel is produced by refining petroleum, but it is worth remembering that Rudolf Diesel designed his revolutionary compression engine to run on vegetable oils. Even now, certain types of diesel engines can readily run on vegetable oils, points out Udipi Shrinivasa of the Indian Institute of Science. Prof. Shrinivasa has led efforts to popularise the substitution of oil from seeds of the tree Pongamia pinnata (known as `Honge' and `Karanja') for diesel in village power-generation sets and irrigation pumps.

But the diesel engines used in modern vehicles do not tolerate vegetable oils well. These engines are designed to run on petroleum-derived diesel, which is less thick than unmodified vegetable oils, points out L.M. Das, professor at IIT Delhi's Centre for Energy Studies. Vegetable oils do not burn well in such engines and they also affect various engine components, he adds.

The preferred option is, therefore, to chemically modify vegetable oils and convert them into bio-diesel that more closely resembles conventional diesel. Bio-diesel can be readily produced from a wide variety of vegetable oils and even used cooking oil and animal fat. Europe makes bio-diesel from sunflower and rapeseed oil, U.S. from soybean oil, Thailand from palm oil, and recently a bio-diesel factory opened in the Philippines that would use coconut oil. But since India does not produce enough edible oil for its culinary needs, a Planning Commission committee on development of biofuel, which submitted its report in 2003, noted that bio-diesel in this country would have to be made from non-edible oilseeds.

The Planning Commission committee suggested setting a target of selling 20 per cent blended bio-diesel (that is, a mix that would be 20 per cent bio-diesel and 80 per cent petroleum-based diesel) by 2011-12. Such blending could save over 13 million tonnes of petroleum-derived diesel that year alone.

Several plants found in India, including Pongamia pinnata, neem, rubber, and castor bear seeds with non-edible oils that can be used to produce bio-diesel. But the plant that is arousing great enthusiasm for this purpose is Jatropha curcas. "Jatropha is the first choice since it can be grown in both saline and alkaline soils, arid and semi-arid conditions, low slopes of hilly areas, and degraded and abused soils," notes H.M. Behl, a scientist at the National Botanical Research Institute in Lucknow, in a paper in the TERI publication on biofuels.

Converting vegetable oils into bio-diesel is not particularly complicated, but the efficiency of the process, the ability to use different types of vegetable oils, and maintaining quality are key issues. The Central Salt & Marine Chemicals Research Institute at Bhavnagar in Gujarat has filed an international patent for its process that can accommodate a range of vegetable oils and oilseeds. The process is able to efficiently extract oil from the seeds and convert it into bio-diesel that can meet exacting European quality standards, says P.K. Ghosh, director of the Institute. The Indian Institute of Chemical Technology at Hyderabad, another Central Government laboratory, too is getting ready a technology for turning a wide variety of seeds and oils into high-quality bio-diesel. The Institute was also working on catalysts that would reduce the effluents produced, according to R.B.N. Prasad, head of its Lipid Science & Technology Division.

Several trials have now been undertaken in the country running cars, buses, and even trains on pure as well as blended bio-diesel. Two C-Class Mercedes-Benz cars were driven across India using unblended bio-diesel, travelling over 8,000 km in diverse conditions from the high humidity of the South to the high temperatures of North India and even going to Leh in the Himalayas. "We got very good results in terms of emissions," says Suhas Kadlaskar, DaimlerChrysler India's director for Corporate Affairs and Finance. The soot emissions from these cars were down by almost two-thirds without any perceivable loss of power.

The Tatas are plying 40 company buses in Pune on 10 per cent blends of bio-diesel provided by the Indian Oil Corporation (IOC). Some 20 of the Haryana State Road Transport Corporation's long-distance buses are run on pure bio-diesel supplied by IOC. Southern Railways' Tiruchi division is using a 10 per cent blend of bio-diesel to run six trains daily; the bio-diesel is produced at the Perambur Loco Works in Chennai.

Vehicles can switch more easily from conventional diesel to using blends of bio-diesel rather than to pure bio-diesel. Another reason for promoting blends is that not enough bio-diesel is likely to be available at a reasonable price in the immediate future. The Planning Commission committee on biofuels estimated that producing 20 per cent blends by 2011-12 would require over 13 million tonnes of bio-diesel, which, in turn, would require Jatropha to be cultivated on over 11 million hectares.

Limited availability

At present, the availability of non-edible oils and oilseeds within the country is limited, says Alok Adholeya, director of TERI's Biotechnology and Management of Bioresources Division. Plantations of Jatropha and Pongamia are just being established in States such as Andhra Pradesh, Tamil Nadu, Madhya Pradesh, Chhattisgarh, Uttaranchal, and Gujarat. It would be two to three years before these plantations began yielding sizeable quantities of oilseeds to be turned into bio-diesel, he pointed out.

Even supplying the market with five per cent bio-diesel blends is currently not proving easy. In October 2005, the Union Government gave permission for public sector oil marketing companies to purchase pure bio-diesel that met quality standards. The oil companies could then use this bio-diesel to produce five per cent blends. The Government fixed the purchase price for bio-diesel at Rs.25 per litre.

However, bio-diesel is not currently available at that price, says an oil company official. If Jatropha seeds cost Rs.6 to Rs.7 per kg, then bio-diesel can be produced at Rs.27 to Rs.32 per litre, estimates Dr. Ghosh. But right now, there is a "mad scramble" to purchase Jatropha seeds in order to start plantations and the seeds are expensive, he says.

Bio-diesel can be produced within the country cheaper than the current market price of conventional diesel but not at Rs.25 a litre, insists K. Radhakrishna, a director of Hyderabad-based Southern Online Bio Technologies Limited. The company's German-made bio-diesel plant is expected to go into operation in July this year and produce 10,000 tonnes of bio-diesel annually. The company is setting up networks to collect non-edible oilseeds from farmers and tribals. It is encouraging farmers to plant Jatropha and Pongamia and offering buy-back agreements for the oilseeds. The company has also made arrangements with a Malaysian company to import alternative feedstock such as palm oil if required, he told The Hindu .

How much `green' diesel can India hope to produce in the years to come? TERI estimates that it could potentially be as high as 40 per cent of the country's diesel requirements in 2030. Clearly, there is a long way to go to achieve those sorts of production levels.

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