Wood for power

By Tharuka Dissanaike

Imagine growing our own electricity. This is exactly what scientist Dr. Ray Wijewardene and engineer P.G. Joseph suggest we do.

Having researched it for decades, Dr. Wijewardene and Mr. Joseph envisage a totally decentralised network of small power plants across the country fuelled by wood, feeding into the main electricity grid. The wood supply would come from homespun plantations but, importantly, only the branches will be periodically lopped off to fuel the power plant.

"Remember, it is the sunshine in the fuel that converts into energy. In oil and coal it is old sunshine, preserved for many years. But in growing trees it is present day sunshine that is converted into energy and this country is blessed with year round sunshine," Mr. Joseph said.

Already Sri Lankans consume a large volume of wood for fuel. Wood is used as an energy source mainly for domestic cooking and certain industrial kilns as well. "It's a large portion of our GNP that goes unmentioned due to lack of record," Mr. Joseph said.

As much as 55 percent of the country's total energy requirement is met through wood today. But to meet this demand entire trees are chopped down and reduced to bundles of fire- wood. Hardly any replanting is done to replenish the destruction.

Termed Dendro power, fuelwood electricity is not a new or radical idea. In fact large fuelwood plantations are feeding massive power plants in the United States, Europe, China and Scandinavia where Dendro is considered a fast growing environment friendly energy source, Mr. Joseph said.

A typical fuelwood plantation would cover several hectares of dense branching trees, preferably several species. The harvested branches would be supplied to a Dendro power plant, where the farmer will be paid by the weight, and the wood fed directly into a kiln that will generate the thermal power. The fast- growing trees would immediately absorb the carbon dioxide emitted in the wood burning, making the plant very environment- friendly. The energy source is constantly regenerating and sustainable. What's more large plantations will add to the much needed forest cover. In western countries, the trend is to build large power plants fed by vast plantations. But in Sri Lanka, we have to work out a system more feasible for the country,Mr. Joseph said.

"For many reasons it is best to keep the plant small and privately managed." He noted that it is important to keep the government out of the project except in encouraging and spreading awareness about the viability of Dendro power.

A smaller plant would mean less initial investment making it feasible for local entrepreneurs. A small plant would emit less carbon dioxide at the location. Also, decentralised power stations across the country will open up certain remote areas that have not been serviced by the grid so far. "As many as 80 per cent of rural households in this country have no access to electricity," said Mr.Joseph. If a number of small plants are operating, electricity supply would be less vulnerable to terrorist threats as well.

It is no secret that the country has effectively run out of sites for hydro stations. Meanwhile energy consumption has increased greedily and projections point to a 10 percent yearly growth in the future. The Ceylon Electricity Board is desperately trying to avoid another power shortage by pushing many thermal power plants and especially the Kalpitiya coal power project.

But continuous dependence on oil or coal based thermal generation, could lead to a huge drain on the economy. Dr. Wijewardene and Joseph have worked out costs for the next 15 years, on the present prices of oil and coal. Their prediction is that by 2008 the money spent on purchasing fossil fuel (coal/oil) to generate the predicted requirement of electricity, would equal the total foreign exchange earnings from tea, rubber and coconut- US $ 700 million. Plus the exchange rate of the dollar against the rupee would keep escalating, draining the country's resources further.

Fuelwood on the other hand is entirely home grown and not subject to exchange rate fluctuations.

But how viable is actual large scale power generation from Dendro? First there is the question of land. Forest Department estimates point out that some 1.7 million hectares exist as scrub and sparsely utilised land. This tract of land is what interests Dr. Wijewardene and Mr. Joseph. This land, which comprises 28 percent of the total land area in the country, while unsuited for food crops, is well suited for the tree species used for fuel.

"Consider just one third of this land," Mr. Joseph said. "Under moderate conditions a hectare plantation would yield 20 tonnes of wood a year. So 500,000 hectares of fuelwood would produce 10 million tonnes. This amount of wood could generate 10,000 GWh (Giga Watt hours) or twice our known hydro potential. The generated power is equal to 1700 Megawatts of power plant capacity while running at 67% of available time. Comparatively, the Kalpitiya coal power plant would generate 300 Mw initially and expand gradually to 900 Mw. The price of a unit of electricity generated from a 10 MW fuel wood station has been calculated at US cents 4.85. This is slightly higher than estimated prices for coal-power generated electricity but certainly lower than for oil-based plants. "What we must remember is that prices of imported fuel are out of our hands and will certainly increase, even if it's due to the exchange rate."

Employment is another crucial factor. Fuel wood plantations can provide self-employment opportunities to a large population, who may presently be engaged in environmentally unsound chena-type cultivation. A three-hectare plantation could provide a family with an income of around Rs. 90,000 annually.

Sri Lanka, being a tropical country has climatic conditions conducive to tree farming. Dr. Wijewardene and Mr. Joseph have experimented with several species of fast growing fuelwood species like gliricidia, acacia, cassia, casuarina, paulonia and even medicinal and spice trees like adathoda and cinnamon to find the most favourable conditions for each species. The trees, planted densely, one metre apart, take roughly a year to mature to harvesting size if sticks are planted. Seeds take a longer time. Branches are lopped off when 1 or 11/2 inches in diameter and the tree simply branches out again and is ready for harvesting in four-to-six months. The leaves and green matter are added to the soil as mulch. Generally a mixed plantation is recommended.

"Multipurpose plantations are also important. Gliricidia is grown in tea estates for shade. The same plant could be used for fuelwood. Cinnamon branches could be used for fuel after the bark is harvested for spice. Many species grow very well in coconut estates," Mr. Joseph said.

But even the most enthusiastic supporters of Dendro power admit that it will take a long time for the concept to catch on. The Ministry of Science and Technology had been very interested in the studies of Dr. Wijewardene and Mr. Joseph. "If the government is giving serious thought to the project, it would require a special authority, a Dendro Forest Fuelwood Authority to monitor and coordinate farmers and intake into power plants. Certainly the government could not make any financial commitment towards Dendro power, but it is essential that a background be prepared for such an endeavour by the state.

"It will take a long time to change people's ideas and perceptions. We have to stop thinking of massive projects and start thinking small and decentralised," Mr. Joseph added.

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