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The Ocean Solution (from Water 21 Jan-Feb 2000 pp 24-260)In the face of undisputed progression towards an era of critical water shortages in many parts of the world many millions of words are written about possible remedies. National and international conferences on the subject abound, exposing the huge concentrations of effort being applied to leakage control, low consumption fittings in households, water re-use, aquifer recharge and every other aspect of conservation and demand management. What all these approaches have in common is their focus on making best use of the water available close to the centres of demand. Very often the objective is to preserve high consumption lifestyles where per capita household demand has little to do with the necessities of life and much to do with filling private swimming pools and watering golf courses. Transporting water across the seas to fulfil those needs may never be justified economically, perhaps explaining why, to date, much less has been said on that subject. But a fundamental problem of water supply is that availability and demand are not always in the same place so, in the more critical situations long distance movements will increasingly come into the picture, including movement across the seas. In an often quoted 1996 comment the World Bank's Water Resources Manager, John Hayward said "One way or another water will be moved around the World as oil is now". When that was said the first commercial movements using tugs and flexible fabric sausage-like containers were little more than a year away, the results of technological developments that had commenced in the early 1990s. Four separate groups had been investigating and developing this new technology for bulk trans-ocean transport. With a World glut in oil tankers more traditional shipping interests with an eye on the potential market were earnestly seeking ways to clean out and extend the life of redundant bulk carriers. That problem remains unsolved but developments in flexible container technology are beginning to prove their worth. One other unconventional method remains on the drawing board. Developed and patented by the Norwegian companies Pickupcat AS and Ugland Marine Services As this concept centres on a catamaran-type propulsion unit which locks into a separate cargo unit, the combination bearing close resemblance to a conventional very large tanker. One propulsion unit would serve two or more cargo units, offering speedy turnarounds by leaving a filled unit at the delivery port for unloading while an empty unit is locked in and propelled back to base. A tentative agreement signed between Pickupcat and the Isbre Holding Corporation of New York in 1997 should have seen the start of spring water deliveries between Norway and Mexico in August 1998. The contract would have involved an initial $27m investment in one propulsion unit and two 10,000tonne cargo units. It did not come to fruition because of 'funding difficulties' at the New York end but other possibilities are being pursued and, given Norway's natural advantages of a strong maritime tradition and ample supplies of clean water from unpopulated mountain catchments, must in the longer term have every chance of success. These assets are neatly combined in an association between the two shipping partners and Aktieselskabet Tyssefaldene, a hydro power company with a plant at the seaward end of the Hardanger fjord in south-western Norway. Tyssefaldene's docking facilities can handle water tankers of over 300,000m3 capacity and they have installed pumps capable of loading 40,000m3 of hydro plant outlet water onto a carrier in 24 hours. The group have their eyes on northern European outlets and say that, with one Pickupcat propulsion unit and three (300,000m3) cargo units, they can deliver 27Mm3 a year and double that with up rated pumps and the carrying fleet extended to two power units and four cargo carriers. Given the stated $27m investment for the much smaller transporters on the proposed Mexico venture the 'up front' investment for an operation on this scale would clearly be considerable; not surprising then that Tyssefaldene Managing Director Karstein Bremnes says they are seeking long-term contracts, 10 years or more. Flexible bag operations are not subject to such contract rigidities because their big advantage is that they are cheap. Only a few years ago paper studies by James Cran of the Canadian-based Medusa Corporation, one of the four groups developing the technology, suggested that a bag with the capacity of five supertankers could be constructed for about 1.25% of the cost. Nor is there anything special about the towing unit. With certain modifications conventional tugs can be used, or the type of vessel used for servicing off-shore oil platforms. One other major consideration in flexible bag transport is the low unit value of water relative to the oil that brought supertankers to the fore. To Cran's mind that means that a supertanker carrying 400,000m3 could never be economic. The aim must be to develop bags of very much greater capacity, in the order, he has suggested, of 0.5 to 3Mm3. Medusa research and development has therefore followed that direction. As a mathematician Cran believes that operational bags will be built to suit a specific application, with mathematical analysis to optimize bag shape according to fabric and towing costs, annual delivery volumes and coastal characteristics at the delivery site. His outline for a unit of 1.75Mm3 suggested a streamline shape with flat top and bottom, 650m long by 150m wide and 22m deep. In the event a bag of that size, although considered feasible, has not been tested but development work continues, albeit on an initially less ambitious prototype. Following lengthy discussions with a UK engineering consultant on the costs and other practicalities of testing it has been decided to develop a 100,000m3 unit and that work is currently under way. The other proponent of bags on the American continent, Terry Spragg of California, is equally convinced of the need to transport very large volumes under one tow, but his idea is for a linked train of 50 or more bags of much smaller individual size, around 17,000m3. Spragg successfully towed an even smaller bag, about 3000m3 capacity, as long ago as 1990 and, with the aid of the Massachusetts Institute of Technology and the engineering consultants CH2M-Hill, has since gone on to develop a unique high strength zipper system that will connect the bags via a non-watertight fabric sleeve that can fill with seawater and gradually express it to ease stresses posed by differential movement between bags under tow. Towing tests over a 160km coastal voyage with two bags connected were made in 1996. Like other bag proponents Spragg sees potential outside the USA but his initial search for contracts has been on home territory, moving water from further north to hard-pressed locations in southern California. To date, despite the demonstrable progress on hardware development, three separate water agencies have declined to take up the system. This may be partly to do with not unreasonable reservations on technical aspects - bag fabric has failed under tow and no fully fault-free tows of units of proposed contract size have ever been made. However, one cannot escape the impression that in this land of the free market the bigger impediments to the first breakthrough come from vested commercial and political interests. In a system in which water rights are bought and sold Spragg has also experienced difficulty in actually getting some water to transport. Since last Summer, in yet another attempt to get things moving Spragg has been embroiled in a state Public Utilities Commission (PUC) hearing on a proposal to supply the Monterey Peninsula where the present incumbent is the California-American Water Company (Cal-Am). In response to a 1995 State Water Board decision that 60% of their abstractions from the environmentally damaged Carmel River were illegal Cal-Am have proposed that their needs be satisfied by constructing a dam on the river at a cost of $107m. As an alternative Spragg proposes bringing water from the site of a disused pulp mill 640km to the north. According to a detailed economic analysis presented to the PUC hearing this can be done at a maximum capital outlay of $29m for bags and ancillary works and, compared to dam-supplied water, will offer end users a saving of between 37% and 45% on water delivered. And, says Spragg, while his imports would otherwise flow unused into the ocean a dam would only inflict more environmental damage on an already much abused river. While the jury remains out on that one the remaining two groups, Nordic Water Supply of Norway and Aquarius from England, have met with more success. Amongst the four developers only Aquarius can claim to have established a satisfactory entry into commercial operations although Nordic Water may be nearly there if current problems can be overcome on a contract to deliver water from southern Turkey to northern Cyprus. In the same region of the eastern Mediterranean Aquarius has exploited a niche market to supply Greek islands using much smaller bags than the other three and over relatively short distances. Whereas Terry Spragg's latest proposals in the Pacific will involve a round trip time of over 9 days Aquarius have, since 1997, been supplying the two islands of Angistri and Aegina in the Saronic Gulf, in an overall journey time of around 8 hours. Director Jean Claude Chalmet likens the operation to 'a milk round' on which he says speeds of up to 5 knots have proved practical, whereas others in the field are generally talking of a maximum of 3 knots or less if towing problems are to be avoided. Based on an original fleet of one 700bhp tug and a mix of 720m3 and 2000m3 bags they have been able to deliver between 1500 and 2000tonnes per day, towing one or two bags. Over the last year a projected expansion in the workload has been addressed with a considerable expansion of the fleet, adding two more 2000m3 bags to bring the total to four at 2000m3 and eight at 720m3, two 1200bhp tugs and a tanker with carrying capacity of 700m3. With these resources to hand Aquarius is currently tendering for a contract in the Peleponnese where the successful tenderer will be required to deliver between 500,000 and 1m tonnes per year, involving a round trip of 130km. Contract award is expected in February 2000. Looking further ahead they are optimistic about another extension of the Greek operation into the Cyclades and Dodecannese islands and are also negotiating in the Middle East for a contract concerned with the transfer and storage of desalinated water. And, like others they are keeping an eye on the water tightrope being trod in Israel and the Palestinian Occupied Territories. In this confident mood there are also plans for two tugs in the 1500/2000bhp range, giving the power to tow three bags together, something not yet attempted. Negotiations are also proceeding for purchase of a 1200m3 capacity tanker and, back in the UK, research and development for a 5000m3 bag is underway. When the specification is ready this will be manufactured, like all the Aquarius bags, by the sail makers, Bruce Banks, in Southampton, southern England. Chalmet says inclusion of a tanker in the fleet gives assurance of deliveries when bad weather prevents tug movements (not, he emphasizes, use of the bags). The existing and in-purchase ships are both fitted with stainless steel tanks, having been previously used for carrying edible oils and wine. Nordic Water too has had to make some resort to traditional methods in a contract to ship water between the Turkish mainland and northern Cyprus. In this case though it has not been a planned backup to guarantee the bag operation but rather a wholesale substitution of steel barges to maintain deliveries while persistent problems with the bags are resolved. With a commitment to deliver 7Mm3 per year Nordic's plan at the contract start in 1998 was to tow with a single bag of either 10000 or 20,000 m3 until operational problems were smoothed out and crew training completed, when they would move up to a more continuous operation using two of the smaller bags and one of the larger size. In the event the problems were enough to stop the operation completely in July and again a few months later when it was found necessary to make a fundamental re-appraisal of the situation and the decision was taken to keep deliveries going by towing barges rather than bags. The principal difficulties are said to centre on bag damage caused as the empty units are winched back onto the flat back of the towing vessel; another area of concern is the towing connection to the bag and there have been some straightforward fabric failures for which a warranty claim is under discussion. Despite these setbacks Nordic have retained a good measure of client confidence. The Turkish government clearly want the technology to succeed - they are willing to re-negotiate the contract rates and have offered a further contract, 'a short distance in sheltered water along the coast', with a 10 year term and a minimum annual delivery of 4Mm3. Contractual discussions and technical preparations are in hand for a start by the middle of the year. By the time that gets under way Nordic will have brought a new tug into operation, better suited to house and operate the upgraded bag retrieval system now in preparation. Elsewhere Nordic are devoting considerable effort into gaining a foothold in the Iranian Gulf and the Caribbean, in the latter case in joint venture with another Norwegian company, Aquatrans AS, and with local partners. At the same time a more permanent 'strategic alliance' is being sought with one or more partners able to strengthen the company's financial standing and aid further development. Six possibilities are said to be under review. Nordic's struggle and persistence well illustrates the approach taken by all the developers of this new technology. Setbacks have been many but they are being overcome and, importantly, governments are taking notice. They should do because from these small beginnings will come the means to offer a reliable lifeline to water starved communities throughout the world. Bill McCann Tel: +44 (0)1286 871664 |