Alternative technology, all the fashion some decades ago, has gotten a bad name mostly because of unsustainable fancies. Sometimes the proposals were theoretically valid but problems in large scale application, unsound project economics or unrealistic input requirements, vitiated adoption. Occasionally they were plain crackpot proposals with no basis in physics, chemistry or mechanics, peddled by the naive or the knavish. Unfortunately, in the wake of all this, some pretty sound and proven options were discarded like the proverbial baby who exited with the bathwater.
Two useful technologies which merit close attention and adoption are this week's topics, but let me first hasten to give credit where it is due; it was Tharu not yours faithfully who has brought them to fruition. OK, I admit it, in the title I punned on Star to get your attention; 'Tharu' does not twinkle-twinkle in the night sky, it's the diminutive of V. Tharunaratnam, innovator, entrepreneur, engineer and generally jack of many trades and master of quite a few.
Before getting down to water and gas a few words about Tharu who as a young engineer built that footbridge across the Mahaveli in the campus that many of us have fond memories of - I stopped a now distinguished researcher and Peradeniya Professor of Chemistry, then a lovesick youth, jumping off some forty years ago! Tharu left for the UK in 1964 and then spent 30 years in Nigeria working with water, mines, gems and what have you, getting back home in 1997 to have a go at intelligent technology transfer.
Ground-water and Mini-wells
Experts will tell you that globally there is more fresh water in the soil than in all the world's lakes, glaziers and rivers put together (0.4% versus 0.2% of the world's entire water). Even in the most arid climes once rain water seeps a few feet below the surface it is safely trapped for long periods - people in North Africa and the Middle East have known and exploited the resource for centuries. As for rain drenched Sri Lanka, there is enough ground water between Fort and Dehiwala to meet Colombo's needs. One meter of annual rainfall over a 1000 sq km area amounts to one billion cubic meters per annum, renewable, and if just 10% is captured that's enough for a population of one million people (at a very generous 100 litres per person per day) with nearly twice that amount left for industrial and general use.
The trick is in the collection method known as a collector-well or mini-well system. It's just a network of wells, or a single well in the case of a small installation, no deeper than an ordinary well, but with a few radial horizontal holes (little tunnels) at the bottom leading away in different directions from the well. The ground water seeps into these holes and flows into and collects in the well. So it's like an ordinary well except that it collects water from a larger surrounding area. Naturally, a prior geological investigation seeking the best soil conditions and identifying aquifer paths will enhance collection efficiency.
Tharu is well beyond the experimental stage with 30 to 40 successful schemes already in operation, including one at the University of Moratuwa. An ambitious scheme now nearing completion in Amparai links several collector-wells together and the pooled water will be pumped to neighbouring localities.
This method of water supply can be implemented at a fraction of the cost of conventional reservoir based schemes and with much shorter lead time, so why is there only limited interest? The answer seems to be a lack of interest; the national water board would rather go ahead with its mega projects, local governments are not knowledgeable enough and see it as a leap in the dark, and institutions like the University of Moratuwa had to battle a mountain of red-tape for obtaining government approval to go ahead.
Have you heard the quip that the next world war will be fought over water, not oil? Secret strategic studies have been conducted in centres of world power to assess how to gain access and control global fresh water resources if it comes to a crunch in the long future. Water is of strategic importance and also the commodity with the highest added value in the whole world - tap water sells at about one rupee per cubic meter, bottled water in the shop costs Rs 50 a litre, a mark up of 50,000 times for simple distillation and a plastic container. Ground water extraction deserves a lot more attention than it is getting. And the technology is already here!
Gasification of wood, peat, coal, charcoal and other carboniferous materials is an old hat and as Tharu says he has not reinvented the wheel but only produced a reliable contraption using readily available construction materials which works fine with local fuel inputs such as coconut shells and firewood. A kilo of LPG costs about Rs 80 but an equivalent amount of energy can be obtained by the gasification of three kilos of coconut shell, says Tharu.
The science behind it is quite simple. The energy released in the burning of wood and similar materials is about one third captured as ambient heat and about two- thirds lost in smoke and gas. The idea is to control the burning in such a way that as much as possible of the energy is transferred to the gases and then to impound the gas for later use. The gaseous products are 20% combustible hydrogen (from the breakdown of water vapour in the wood), 20% carbon monoxide and 60% nitrogen from the air. The nitrogen forms a safe conveyance medium while the carbon monoxide is toxic and must be handled sensibly. (If you lock yourself in an unventilated space with a car engine running, well that's one way of shuffling off this mortal coil).
The crux of the technology is to burn the wood with only 30% of the air it needs for normal combustion. In this condition an exothermic reaction raises the temperature very high and this maximises the decomposition of water vapour and the production of hydrogen. A simple gasifier design has been developed and tested and a few units are already in operation around the island.
"Wood-gas" or "producer gas" was widely used in Europe in the nineteenth century before cheap and all-conquering oil, and during World War II 95% of all farm machinery in Denmark and 40% of all motor traffic in Sweden ran on wood-gas. The US Federal Energy Management Unit has commissioned and tested design prototypes in the 1980s and 1990s for introduction in the event of an oil emergency.
Small units using the local design are suitable alternatives to imported kerosene and LPG and in the longer term wood-gas has potential as a vehicle fuel for tractors and heavy machinery. Obviously firewood and coconut shells are not options for the big works like the large scale generation of electricity for the power system.
Now that the basic R&D is done and venture capital for the innovation stage is not need it would be profitable and serve national goals if a private company with financial resources were to step in and bring the product to market. Unfortunately Sri Lanka's trade, commission and tourism oriented private sector has little industrial drive.
The moral of this article is that there are numerous innovative, productive and profitable small scale industrial initiatives which are languishing in the woodwork. They must be understood, evaluated and brought to market sensibly. Those with real commercial potential must be separated from the silly ones that violate the elementary laws of science and economic rationality. Feet firmly planted on the ground technologists and able entrepreneurs, not overzealous nationalists and still wet behind the ear greens, are the best people to involve in these decisions.