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Coconuts - power for the Pacific

Coconut oil extracted from dried coconut flesh known as copra is best known for its use in cooking and skin creams. However, recent innovations in extraction and filtering of the oil, combined with some simple adaptations to diesel engines, are encouraging Pacific island energy ministers to believe that a home grown biofuel could make a major contribution to their energy needs.

Coconuts, power for the Pacific
Coconuts, power for the Pacific

In island nations like Vanuatu, where oil imports cost US$10 million per year, representing about ten per cent of the value of all imports, widespread use of a coconut-based fuel in vehicles and other diesel-powered machinery could bring a significant reduction to balance of payments deficits. Sele Molise, Vanuatu's Minister of Finance, believes that expenditure on foreign diesel could be halved if the energy in the islands' coconut crop was fully utilised.

The use of coconut oil as a fuel in diesel engines is not new; during the Second World War because of oil shortages it was used as fuel in the Philippines. However, it was never widely adopted, partly because of the subsequent availability of diesel and also because raw coconut oil starts to thicken at temperatures below 22°C, becoming close to solid at 14 degrees. Converting coconut oil into an engine-compatible biodiesel through transesterification is possible, but is relatively expensive to set up and requires chemicals and equipment that are hard to source in the Pacific. But in Vanuatu, purified coconut oil is now being used as a fuel in cars and minibuses, thanks to the committed vision of a local mechanical engineer and entrepreneur.

New technologies

Tony Deamer runs a garage and car hire business in Vanuatu's capital Port Vila. Five of his hire cars run on pure coconut oil, which is warmed in a heat exchange unit to reach a viscosity matching that of diesel, before it enters the engine. Deamer has also developed a simple, gravity-feed filtration system which removes water and free fatty acids from the oil, thereby lowering the temperature at which it solidifies. Mixing the purified oil with either diesel or kerosene also prevents it from thickening. In 2002, over 200 minibuses on the island were running on a coconut/diesel mixture, although a change in government excise duty, which raised the price of mixed fuels, has since reduced this number. Coconut oil is also being used to power the generator of COPV Santo, Vanuatu's only industrial copra mill. And there is potential for tractors, pumps and other machinery in regular and sustained use to be run on a coconut-based fuel mix.

New opportunities

As well as reducing trade deficits, the development of coconut oil as a biofuel could also revitalise the agricultural economy in Vanuatu. Copra is the islands' biggest export commodity, making the economy heavily dependent on the world copra price. In recent years this has been falling, largely due to expansion in soya production. As a result, many copra plantations have been abandoned with the workforce migrating to urban areas. The Vanuatu government has supported the local copra price but providing subsidies is a costly option for a small island economy but a new approach to extracting oil from copra could provide a new and rewarding industry for rural communities.

Coconut husks laid out to sun-dry for copra production
Coconut husks laid out to sun-dry for copra production

Conventional extraction of oil from copra uses high pressure presses powered by an engine. However if copra is dried to a precise moisture content, extracting the oil using manual presses is possible. Dan Etherington of the Australian National University, who has conducted research on manual extraction, has also found a simple way of achieving the right moisture content. Using traditional methods, communities can dry their copra before adding the appropriate quantity of water to bring the copra to its required moisture level. Small mills have been set up to test this 'Direct Micro Expelling' process in several island groups, including Fiji, Samoa and Tonga. By-products from the process include animal feed from the pressed copra and charcoal from the coconut shells, including 'activated' charcoal which can be used as a water filter.

On the Fijian island of Taveuni, in the village of Welagi, an electrification system has been established based on a dual-fuel generator which can run on either diesel or coconut oil. Dual-fuel systems generally run on diesel for starting and warming up and the heat from the engine is then used to warm coconut oil, which is stored in separate fuel tank. Once the required temperature is reached, the coconut oil is automatically fed to the engine, with the diesel only coming on stream again in the last moments before the engine is turned off. Modifying diesel engines to run on pure coconut oil is also possible. While Tony Deamer has managed this on a small-scale by meticulous monitoring of his vehicles, the process usually involves the use of adapted fuel injectors, special pumps and extra filters. Long life in such adapted engines depends, however, on having a reliable supply of high quality oil - something which is more difficult to achieve in small-scale production systems.

Fuel with a future?

If coconut-based biofuel is to take off in the Pacific, ensuring a regular supply of coconuts will be another key challenge. A recent report by Jan Cloin of the South Pacific Applied Geoscience Commission states that most island nations in the Pacific would need to carry out significant replanting of coconuts, restoring production to pre-1990 levels, in order to guarantee sufficient supply. While acknowledging that niches exist for the production and use of coconut oil as a biofuel by remote communities large-scale adoption, says Cloin, would depend on rationalising and mechanising coconut production and processing, and shifting control of the coconut industry from government to private companies.

Date published: November 2006

 

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The New Agriculturist is a WRENmedia production.

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