The rubber industry and clean practical solutions to Sri Lanka’s energy crisis – III
Posted on June 16th, 2019

by Chandre Dharmawardana

While the country remains mesmerized and  paralysed by revelations of incredible security lapses, the failure to implement long-term plans for energy production, updating of agriculture and industry  to keep pace with climate change, population growth etc.,will cause irrevocable systemic collapse causing more prolonged misery than any sudden Jihadist shocks. Many of us  have written articles pointing the way forward, since many decades, but wonder  if it is all futile, or if there is still room for optimism.

Surely, the biggest single expenditure faced by  most nations  is in meeting energy costs.  The availability of cheap energy is the  determining factor essential to all types of development.  So the strongest effort of the government and the entrepreneur should focus on energy.  When clean energies like solar  and wind power were not competitive, it made sense  for Sri Lanka to include coal power in its energy-mix. So the plans of the 1990s, if executed would have ensured that Sri Lanka today would not be facing a power crisis. Today Lanka would have been ready to mothball the old technologies and move to new sustainable technologies.

Instead, the government has again commissioned new coal plants.  This is a  keen-jerk  long-term commitment to highly polluting fossil energy already undercut by cheaper, cleaner alternatives. To compound the folly, the government continues  in expensive oil and gas explorations in the Palk Straits. It should note how weak but oil-rich countries have become enslaved by powerful nations who rob  their oil using compliant puppet regimes to keep the people under the jack boot. Off-shore oil sources are environmentally far more damaging than land-based oil exploitation.

Apparently,  Sri Lanka’s  ‘Surya Bala Sangraamaya’ program, launched in 2016 is set to collapse. This is despite its great success with some 17,000 installations and a combined output of nearly 200-250 MW added to the grid. This solar energy saves emissions of noxious nitric oxides, acid rain, toxic metal residues, and some 200,000 metric tonnes of CO2 per Annum. And yet, new legislation terminates the purchase of solar power from  small rooftop producers, claiming that the CEB will end up subsidizing”  consumers of 60 units/month  or less at  Rs. 4.68 a unit. Surely, these consumers will necessarily consume more than 60 units before long. While failing to encourage solar  energy, coal power and thermal stations that burn oil at great cost to the consumer and the environment are embraced.

Sri Lanka does NOT  NEED fossil fuels of ANY SORT. In a previous article (Island, 6th May)  I explained how, since 2009, I had advocated the installation of floating solar panel arrays on hydro-electric reservoirs;  the power generated is fed to the grid or used to pump up water back to the reservoir. That is, solar power is stored as reservoir water, and no batteries are needed.  Even pumping up the water can be avoided, by simply RETAINING the equivalent quantity of water instead of sending it into  the hydro-turbines. The solar panels on the water saves some 30% of the  evaporation by wind and sun. That is, merely floating solar arrays on ten  hydro-power reservoirs  adds  three new hydro-power reservoirs at  negligible comparative cost!

Wind power, installed around reservoirs can also be stored as water power using the same concepts.

The average life-cycle cost of solar in Sri Lanka is some 15-20 rupees/unit. Bio-energy is cheaper, and provide more employment. While hydro-energy is cleaner,  biomass offsets climate change, safeguards biodiversity,  pollinating insect species etc., by maintaining habitat. As Dr. Weeraratne, an agricultural scientist,  had documented  (Island, June 15th ) the agriculture sector and the economy are down. Tea, Rubber, coconut or even a staple like paddy are not prospering.

In my second article on the energy crisis (Island, May 23)  I showed how the coconut plantation sector can be revived into an energy giant  using the husk biomass for energy production. There is enough energy in the currently produced coconut husks  to supply Sri Lanka’s energy needs inexpensively and healthily. At present, these husks feed a  polluting  fibre industry with little or no future. Its future is in the energy sector.

However, it is not just the coconut plantation sector that can re-vamped. Sri Lanka’s Rubber Industry Master Plan needs to include its bio-energy potential to further improve its prospects. It is imperative that the rubber plantations move towards greater profitability. If not, these prime lands, often with  road-and-bungalow infrastructure will be rapidly converted to housing or tourist chalets,  asphalt roads, concrete buildings, night clubs, casinos and bars. The enormous loss of green habitat is catastrophic to the biosphere.  Although having plantations is not as good as having virgin forests, they are the next best defense against continued habitat encroachment by humans. Making rubber plantations more profitable  by moving them towards bio-energy production, we are resolving the energy crisis, and also safeguarding the environment.

Seeds produced by rubber trees go waste in most plantations.

How do we convert the rubber plantations to energy-producing power-plants?  Rubber  does not constitute a  rapid-growth biomass, but we exploit the currently wasted rubber seeds.  New hybrids or bio-engineered plants with a  high SEED YIELD should be planted.  Existing trees will  be tapped as usual for the latex since the annual world consumption of natural rubber is increasing at about 3-4% . Seeds of any kind of tree are packets of energy stored for the seed to grow. In all cases, seeds make better fuel than other biomass. That is, if the seeds are burnt, shell and all, the heat produced can be very profitably converted to electricity  using high-efficiency burners which are now a standard part of  bio-electricity technology.

Malaysian researchers Satyanarayana et. al.  [Int. J Green Energy, vol. 7   pp. 84-90, (2010) ] found that rubber seed is a viable option for bio-diesel, and  has  low CO2 and  nitrogen oxide outputs among  potential biofuels. Here we do not examine bio-diesel production, but simply the burning of seeds in high-efficiency generators to produce electricity.

 Elementary calculations show that using rubber seed  to make energy is  profitable and sustainable.  A yield of 100-400 kg of nuts per hectare  per year is typical for the south-Asian region including Sri Lanka, while China has clones which produce 1500-2000 kg/ha/year [Wei-Wei et al. China Oils Fats, vol.30, pp. 63-66, (2005)]. According to Selle et al (1983), Rubber seed  has a total energy value of  about 7000 kcal/kg.

Sri Lanka has some 130,000 hectares of rubber plantations. Hence assuming a yield of 300 kg of nuts/ha and a collection efficiency of 66%, the annual rubbernut output can produce some 200-250 GWh of electricity by burning the seeds, using a Carnot-Rankin efficiency of 25-30%. The use of Chinese clones with high seed yields  boosts  outputs to 400 GWh. In addition,  rubber other biomass from the plantation can be used. Effective, safe herbicides like glypohsate have  been restored to the rubber industry. Hence crops like castor  can be economically inter-cropped in plantations to provide additional high-energy biomass, and hence a target of 400-500 GWh of electricity is realistic.


Since the infra-structure,  raw materials, etc.,  are already in place, the main cost is the installation of the burner-generators which can be amortized over 10-15 years, making it cheap compared to the cheapest coal.  The additional profits from a hitherto wasted resource, namely, rubber seeds should be considered in Lanka’s Master plan of the rubber industry.

The expression of  oil-synthesis genes in  seeds is controlled by known transcription factors like LEC1, LEC2, and WRI-1. Genetically  modifying  plants by including  a mutation in the cgi58 gene results in the accumulation of lipid droplets even in the leaves. Converting the energy in the rubber nuts using fuel-cell technology instead of directly burning them is a method of beating  the Carnot-Rankin energy loss. Then near 95% efficiency can be achieved. But such  technologies are still a matter for the research labs.

What has been said here about rubber or coconut industries can also be adapted for cinnamon and other
Industries. So there is no excuse for our planners  to opt for fossil-fuel  energies.  Solar-  Wind and bio-energy are unequivocally available as cheap, non-polluting,  firm power  implementable within a shorter time scale compared to the commissioning of coal power stations.

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