Abstract

Sustainable development seems to be the phrase of the 1990's. The phrase is a hopeful one in the sense that it implies humankind has the capacity to achieve a state of development that leaves the natural resource endowment intact. In actuality opportunities to achieve ‘sustainable development’ are rare, and inasmuch as they do exist, population pressure or simply greed, usually preclude their attainment. Although relatively unused to date, deep ocean water (DOW) represents an unparalleled opportunity for sustainable development in the 21st Century. This means major economic and other quality of life benefits can be made available to millions of people located in coastal desert areas in close proximity to the deep ocean. A number of basic technologies to use DOW have been developed, tested and are available for application. To the extent these technologies are applied wisely benefits can be sustainable and without insult to natural environments.

Benefits to be derived from use of cold deep ocean water use resources include: air conditioning and industrial cooling, fresh water production, cool and cold water aquaculture and production of a wide assortment of temperate agricultural crops. Recent discoveries indicate growth of subtropical and tropical crops can also be accelerated through use of DOW. Ocean Thermal Energy (OTEC), the initial interest in cold deep ocean water, is technically feasible but still a stage away from being economical in most locations. This paper briefly summarizes the prominent events leading to the achievement of a transferable DOW technology, reviews these technologies and their stage of development and speculates on their 21st century potential.

Events Leading to Present Stage of Development of DOW Technologies

The single most important factor in the development of current deep ocean water use technologies was the establishment in 1974 of The Natural Energy Laboratory of Hawaii (NELH) at Ke-ahole Point Hawaii by Governor John Burns of the State of Hawaii and John P. Craven, Marine Affairs Coordinator of the State. The first major experiment with DOW water was the successful demonstration of ocean based closed cycle OTEC in Mini-OTEC at NELH in the early seventies, a joint venture of Lockheed, Alfa Laval and the State of Hawaii. The net power was approximately 40 kilowatts. U.S. government interest in alternative energy waned by the mid-1970's and ambitious plans to follow up Mini-OTEC with larger offshore OTEC installations were dropped.

In 1982 the first 12" deep ocean water pipe to shore was placed in operation at NELH. The first pipeline delivered 4.2 cubic meters per minute. In 1997 there are two deep sea water polyethylene pipelines in operation with a total capacity of 64 cubic meters per minute and three surface sea water pipelines with a distribution capacity of 53 cubic meters per minute. A new seawater system is presently being developed will have a capacity of 102 cubic meters per minute of cold deep seawater, and 156 cubic meters per minute of warm surface water (http://www.ilhawaii.com/~nelha/pipeline.html). The initial motivation for developing the 12" pipe was to continue OTEC research. However it was soon learned that electrical energy was, at best, only one of the major products to be derived from deep ocean water. Proof of concept experiments financed by the University of Hawaii Sea Grant College Program and the State Marine Affairs Coordinator’s office soon established plant and animal aquaculture as viable uses of DOW. This work set the stage for the development of a number of aquaculture enterprises at NELH with each entrepreneur concentrating his/her efforts on a particular aquaculture innovation. A number of these entrepreneurs have already demonstrated economic viability based on their product alone. NELHA (in 1990 NELH was converted from an independent State Corporation into an Authority) also found DOW the ideal way to cool it’s offices and laboratory buildings at substantially lower electricity costs.

In 1990, Dr. John Craven took partial retirement from the University of Hawaii and established the Common Heritage Corporation (CHC). The mission of the CHC is to establish self-sufficient environmentally, economically and culturally sustainable communities in coastal zones and islands for the benefit of the Common Heritage of mankind (http://www.aloha.com/~craven/allabout.html) As President of CHC Dr. Craven has continued in his role as premier innovator of new DOW technologies outside of the field of aquaculture, e.g. DOW agriculture and the Hurricane Tower. Today, although a ‘transferable’ DOW technology has been developed and the potential benefits for mankind are enormous, Hawaii remains the sole user of DOW for three reasons. First the U.S. government’s almost complete withdrawal from DOW research and development. The second is the failure of the State of Hawaii to recognize the unique value of what was being achieved and to develop an aggressive program to make Hawaii and NELHA the base for launching these technologies world wide. The third reason is a generic problem with innovation. This was recognized by Machiavelli early as the 16th century, “There is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in introduction of a new order of things, because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new.”

Stage of Development of Deep Ocean Water Technologies.

Deep Cold Water Systems

To date little attention has been given to the uses of the DOW in a riparian sense and few of the contractors at NELHA take a 'systems' approach to use deep ocean water as a resource. However it is clear that in most localities, large economies can be realized in optimizing the systems use of the unique qualities of DOW i.e., cold, nutrient richness, and purity.

The DOW system has three major sub systems a) the electrical power and electrical by-product system, b) the cold utilization system and c) the nutrient utilization system. Since there will be a riparian use of the deep ocean water by these three systems it is convenient to discuss them separately. Most small coastal desert communities should focus on the more affordable cold and nutrient utilization subsystems for a sustainable self sufficiency system that could be immediately implemented.

The Electrical Power Subsystem

Attention has been given to Closed and Open Cycle OTEC. Closed cycle OTEC was first demonstrated in Mini-OTEC. Following Mini-OTEC, a project was initiated with Aluminum Company of Canada (AlCan) for the development of Aluminum heat exchangers. Shortly thereafter a project was initiated with Dr. Alastair Johnson of General Electric of Britain to develop a one megawatt closed cycle plant. These developments were technically successful and construction of a demonstration plant was undertaken at NELHA. A series of administrative delays caused AlCan and GE to abandon their participation in the project which was taken over by Pacific Center for High Technology Research (PICHTR) and a newly formed Aluminum Company (AlGoods). The turbine generator of Mini-OTEC was successfully refurbished but the installation of the aluminum heat exchangers have encountered several expensive and time consuming delays and the demonstration is not operable at this stage.

A technically successful open cycle plant of about 100 kilowatts net power has been built at NELHA by PICHTR. Although it is an engineering feat of some magnitude, the cost of more than ten million dollars and the inability of anyone to conceive of technically feasible ways to scale up on land probably eliminates Open Cycle OTEC as a contender in the foreseeable future.

Cold Utilization Subsystem

Air conditioning and industrial cooling--The most economically valuable use of deep ocean water appears in the form of air conditioning and industrial cooling. Conventional means of cooling are, in fact, forms of reverse OTEC. As a consequence they pay a heavy Carnot efficiency penalty. On the average these systems generate ten times as much heat as they remove in terms of cold. For this reason it is inefficient to generate electricity by Ocean Thermal Energy Conversion and to use that electricity for air conditioning or industrial cooling. As a rule of thumb the amount of water required to generate one megawatt of electrical energy will provide the equilivant of 10 megawatts of air conditioning or industrial cooling (http://www.aloha.com/~craven/coolair.html). A study by Makai Ocean Engineering, Waimanalo, Oahu has indicated that for Guam, 10,000 hotel rooms could be air conditioned with cold seawater and that the capital payback period for installing this system, for air conditioning use alone, would be approximately five to six years (Van Ryzin and Leraand)

Fresh water from condensation and desalinization--Everywhere deep ocean water flows through pipes above the ground or near the surface, condensation is generated. It has been estimated that condensate can be generated at a rate which is about 5% of the flow of cold water. Thus a flow of deep water of about 20,000 gallons per minute should be able to generate 1,000 gallons per minute of fresh water through simple condensation. These estimates have not yet been confirmed in an application or experiment designed to concentrate the condensate. Tests with swimming pool heat exchangers suggest that the engineering will be straight forward. The CHC is experimenting with a number of ways of generating and capturing this condensate. These include condensate in the cold bed agriculture demonstration garden, from a cooling facility (chill house) associated with the garden and from simple room air conditioning units that can be developed and used in third world desert island communities comprised of a cold water supply, an automobile radiator and an inexpensive household fan.

CHC and Oceanit Laboratories have a patent pending for a desalinization device called a Hurricane Tower (http://www.aloha.com/~craven/hcane.html). A model, installed at the CHC facility at NELHA in 1996, demonstrated the validity of the fundamental principle. Additional tests will take place in 1997-98 to determine more optimum configurations of the tower and its water supply at which time it will be possible to make predictions on production and price.

Coldwater Agriculture

Condensation techniques coupled with biophysical applications of cold have produced a surprising result in terms of agriculture in coastal desert areas. Quite simply, black plastic irrigation pipe is embedded in agricultural soil at a depth which corresponds to the root depth of the species to be cultivated. For deep rooted plants, e.g. carrots two sets pipes are desirable. Deep ocean water is passed through these pipes and heavy condensation is induced. A thermal gradient between root and fruit is produced which pumps nutrients into the plant at a rate which is probably three times greater than that produced by nature in the spring or fall in temperate climate areas. The more than 100 temperate climate fruits, vegetables and herbs that have been grown in the CHC demonstration garden all show rapid growth, high yield with high sugar and aromatic content.

CHC has also demonstrated that DOW can be used to induce and break dormancy in temperate climate fruits at frequent intervals. More recent experiments indicate accelerated growth of subtropical and tropical crops through use of DOW. For example, pineapples and papaya have been brought to maturity much faster than under conventional methods (http://www.aloha.com/~craven/cldgrdn.html). These results combine to offer opportunity to use what is often marginal agriculture land in coastal desert areas for a wide variety of crops, temperate and tropical and to optimize production in ways heretofore unavailable. The economics of ColdAg have not been analyzed to date. The experiments have been small and undertaken mostly to demonstrate the feasibility of producing a wide variety of crops. However the cost for DOW at NELHA runs about 10 cents for 1000 gallons and the cost for the half acre demonstration farm is negligible. Of greater significance is the fact that once chilled, the ground loses very little heat and the water flow required to maintain its temperature is small. At the same time the cool surface causes fresh water condensate to form and irrigate the plants.

Nutrient and Purity Utilization Subsystems

After the deep ocean water has been employed in one or more cold utilization applications it can be utilized again for the nutrients, residual cold, (about 13 degrees C) and purity. The cold seawater contains 200 times more nitrates and 20 times more phosphates than surface seawater. (Intergovermental Agency White Paper) The purity or lack of surface pathogens has proven especially important in the production of marine algae such as spirulina and the microalgae, astaxanthin. Examples of current aquaculture operations at NELHA follow: (http://www.ilhawaii.com/~nelha/aqua.html)

•The Cyanotech Corporation is a highly profitable commercial operation for the production of spirulina. The use of cold water to recover carbon dixode from the butane that is used to dry the algae and make it available for plant food also virtually eliminates the release of carbon dioxide to the atmosphere during the production process.

•Royal Hawaiian Sea Farms have produced and marketed a variety of tasty and nutritious "sea vegetables" using DOW since 1987.

•The Kona Bay Oyster And Shrimp Co. produces blue shrimp and American and Pacific oysters in a symbiotic system. The company also produces the marine algae Chaetoceros, from which unique compounds are to be extracted for pharmaceutical products to combat bacteria infection.

•Taylor United Inc. a shellfish company headquartered in Shelton, Washington maintains a Manila clam and Pacific oyster nursery. Larvae are raised in Washington, sent to NELHA as they settle out of their swimming cycle (250 microns), raised at NELHA to a 5 mm size and shipped back to the Pacific Northwest for growout.

•Uwajima Fisheries produces and markets Hirame a flounder highly prized for sushi for the upscale hotel and restaurant trade in Hawaii.

Salmon, steelhead trout, abalone, oysters, kelp, salmon and black pearl oysters have also been successfully cultured at NELHA some in poly culture systems. Although the above demonstrate a wide scope of aquacultural undertakings, it is apparent the entrepreneurs have only scratched the surface of possibilities for DOW aquaculture.

Economics

Costs of installation of a DOW system is difficult to estimate and may vary by a factor of ten or more depending upon the manner in which the development and procurement are carried out. Until a site is chosen and a study is made to identify contractors, subcontractors and construction techniques only the most tentative estimates can be made. Most uncertain is the cost of the deep ocean pipe and pump installation and this again depends on the site. Experience at NELHA has indicated that (under proper design) a pipe and pump system can be built and installed for as little as a half million. The basic cost of pipe and pump is about $125,000.00. Two alternatives exist for the pipes for remote locations a) construction at a remote shipyard and tow to the site or b) transportation of pipe segments by conventional shipping and construction at the site. The former is much cheaper if it is carried out under the supervision of personnel who have had extensive experience with submerged towing. For insurance a two pipe line installation is mandatory. Thus a starter set (pipe and pump and shoreline distribution system) could conceivably be carried out for as little as 3 million dollars but more probably 5 million dollars. The additional cost and the amortization of the pipe and pump depends on the utilization of the water.

If air conditioning and industrial cooling is to be the sole use of the DOW installation, Van Ryzin and Leraand’s study shows that the installation costs for the scenario they develop (similar to Keahole) can be paid back in less than two years depending on the demand for air conditioning and industrial cooling with a more likely final pay back period of about 3.75 years (Van Ryzin and Leraand)

If agriculture is the sole function, available evidence suggests that it too would be profitable but on a slightly longer amortization schedule. Thus the combination of the two systems would provide more economic benefits than either one. For cold bed agriculture, development and improvement in terms of soil and pipe installation based on experience to date, will be somewhere between $1,000.00 to $2,000.00`per acre. Once the site is determined and crops and market potential assessed, agricultural economics analysis can provide the necessary information for decision-making information.

If aquaculture is the sole function, our evidence suggests that it could be profitable on its own but an economic analysis would be required depending upon the species chosen and local market conditions and fluctuations in fishing. Again a site-specific economic analysis is needed. Depending on the species the triad of air conditioning-cooling, agriculture and aquaculture can be highly profitable.

If desalinization is the sole function, the technology is not ready for an economic stand alone system (i.e. the hurricane tower). But fresh water is an inevitable by-product of all of the other systems and thus a free resource except for the cost of collection and distribution. Thus for limited quantities the addition of freshwater generation by atmospheric condensation or by atmospheric distillation of solar heated surface water could improve profitability. For many coastal desert areas the fresh water potential may be critical to development. As more systems are installed rapid advancement and poliferation of technologies to maximum the potential of the fresh water resource can be expected.

If electrical power is included there is no way that it can be competitive with oil or gasoline fired motor generator sets for smaller coastal areas at the present. This is particularly true for the small mass produced generators from Japan, Korea or Malaysia. Thus electrical power may be an economic drag on the system at this time and should not be implemented unless it is desired to advertise and demonstrate a full environmentally sustainable enterprise.

To summarize the economics and the risks: an investment of only $5,000,000.00 could prove highly profitable in terms of return on investment but there is a substantial risk of loss of the entire investment due to unforeseen circumstances (e.g. unrecoverable loss of the pipes at sea prior to or during installation). An investment of $10 million would allow for contingencies and/or a larger system or set of systems is almost certain to eliminate risk of loss and be at least acceptably profitable. This figure would allow a strong probability of being highly profitable in terms of return on investment. Similar profitability should exist for larger investments for system development through CHC of up to about $30 million dollars. Beyond this level the risk of loss and reduced profitability begins to return. This is due to the scale of the project and the greater likelihood that large conventional corporate contracting practices and involvement of government agencies in central management will impose unsustainable levels of overhead costs.

A Basic System for Desert Island Communities

A preliminary survey of coastal desert localities by the CHC has produced a list of 22 sites with attributes amenable to early and successful installation and use of DOW technologies. Successful use of these technologies implies the potential for a wide array of benefits to the local community (http://aloha.com/~craven/okam.html). For such localities, CHC recommends a basic system consisting of a) two 24 inch diameter pipes (and pumps) for DOW recovery and distribution. b) capability for use of ten megawatts of air conditioning and industrial cooling; c) one hundred acres for agriculture and sixteen acres for aquaculture ponds or some combination of these. d) reservation of space and allowance for DOW supply for a one megawatt OTEC electricity plant to be built within the decade.

The size of this system is predicated on capacity for installation by local engineering and construction companies and for operation and maintenance by local people. Since installation costs dominate, the basic small deepwater system may not be less costly than larger systems. Larger systems will require the use of imported barges, construction equipment and imported technologists and specialized personnel for operation and maintenance. Such systems may be beyond the social and structural capabilities of coastal island communities to absorb without a major change in the culture and life style of the island community.

CHC is prepared to suggest a preliminary basic system for interested parties for a number of localities that is both economically viable and environmentally sustainable based in part on the literature, information provided by clients and the experience of the CHC staff and CHC Board. However a recommended system will require specialized modification and tailoring to be culturally compatible and to meet the marketing needs.

The 21st Century Potential of DOW Systems

DOW and Agricultural Business

One of the early and perhaps most significant developments in the use of DOW technologies will be the discovery of DOW by agricultural business. The significance of virtually unlimited opportunities to study and experiment with the effects of cold on dormancy, genetics, continuous cropping, etc., will not escape this sector. But until agricultural business discovers DOW we will see little involvement on the part of university agricultural scientists, who are intellectually confined to the existing agricultural science paradigm.

In any case, the early 21st century should see more high technology agricultural business ventures building and looking for space to build facilities at NELHA (and new DOW sites) than by the aquaculture entrepreneurs . Modern aquaculture is in its infancy while agriculture both in terms of business activity, size of the sector and depth of the science support system is enormous by comparison. Agriculture is coming under ever greater pressure to produce more food and to do so under environmentally sustainable conditions. Some larger agricultural businesses and universities will find it to their advantage to develop their own DOW systems, as will advantageously located agricultural industries with large expenditures for cooling and holding fresh farm produce for distribution and marketing..

Fresh Water for Community Growth

For coastal desert communities requiring larger amounts of fresh water development than presently exist, condensate from DOW systems can utilized to meet these needs. Technologies to collect this condensate should develop rapidly at the systems poliferate. The Hurricane Tower should also be available within two years at which time the primary questions will be what type and size(s) of installations will best work in a given coastal desert community; larger vs. smaller sizes replicated, electric powered or wind driven, etc. These questions will require innovative engineering solutions but are straightforward.

Another option would simply be pipes within the deep water pipes equipped with a Reverse Osmosis membrane at the deep end. Pressure will force (fresh) deep ocean water through the membrane and to the surface. The process would use very little energy as opposed to the prohibitive expense of producing fresh water from surface supplies by this process. Since fresh water has not been a focus in the installation of the present pipelines at NELHA no attempt has been made to date to wed the membrane to a DOW pipe. Again, since the primary technologies are in place this is a straightforward challenge for creative ocean engineers.

A third DOW option is available for larger supplies of cool fresh water for air conditioning and consumption for a number of coastal desert cities . Many coastal deserts are the lee fringe of coastal mountain ranges e.g. the Kona Coast of Hawaii. These mountains often have abundant rainfall and surplus water that is too expensive to import and chill under normal circumstance. Water could be carried from the windward side of these mountain ranges by tunnels and by gravity down and across the desert and offshore to an underwater dome (of what ever size will optimize the water flow) at the 2000 ft depth, where it would chilled by deep ocean water and carried back to the surface by the water pressure. Such a process could provide a continual supply of fresh, chilled water on tap for a growing desert city.

Ocean Thermal Energy

In 1990 the ‘Interlaboratory” study suggested that one megawatt (MW) to 100 MW standalone OTEC plants should be a strong development option for Pacific and Asian islands in the 1990's as a result of a combination of unstable oil prices, growing environmental concern, need for fresh water, and drive for economic self sufficiency. This study estimated at least 350 MW could have been provided by OTEC by 2005 and 2100 MW by 2010 most likely for Hawaii, the U.S. Island Territories, the U.S. Gulf Coast Region and producers of energy-intensive products as the most likely market. In the longer term the study suggested higher energy prices and expanded applications of OTEC could result in large systems for processing seabed ores, producing fertilizer and transportation fuel, developing fisheries and generating baseload electricity. Finally they foresaw markets for military installations in the Caribbean and Pacific and in hotel/resort development

With the advantage of hindsight it appears that these estimates were extremely optimistic. However they were also based on an intensified (six-fold increase) R&D effort with an accompanied lowering of energy costs. Because support for R&D did not materialize, OTEC is still too expensive for low income coastal desert communities as compared to the other technologies. However this situation may change rapidly as costs of fossil fuels continue to rise and their continued supply grows more uncertain. As closed cycle OTEC plants are demonstrated and built, the costs will decrease and many of these communities will see the merits of having their growth and welfare dependent on their natural resources base rather than on foreign sources. Adding Closed Cycle OTEC to the system menu could enable a community to establish eventual energy independence as well as a wide array of the other system benefits described in this paper.

Immediate feasibility for Closed Cycle OTEC will probably be limited to individual units in the range of from 500 kilowatts (KW) to 1 megawatts (MW) with plant sizes employing multiple units being somewhere in the neighborhood of 5 MW. However the size required to meet electrical energy requirements for energy self sufficiency for island and coastal communities is in this size range. The output interface for these power plants is for baseload electricity for pumps and machinery within the immediate vicinity of the generators, or for addition to some sort of power grid. The limitation in range will be eventually resolvable through mating with the fuel generation system allowing realization of virtual energy independence.

Although three OTEC fuel generation alternatives are under investigation (methanol, ammonia, and hydrogen) early commercial feasibility appears to be limited to ammonia. This is simply because of the ease of modification of gasoline powered equipment to operate on ammonia and because the hydrogen carrier in ammonia is readily available nitrogen. A number of commercial processes are available for electrolysis of water into hydrogen and oxygen and a number of catalytic processes are available for synthesis of ammonia. It is not immediately obvious which process or equipment will be most economical but this is mostly a component review process which requires little if any innovative product development. The output of this subsystem will be of little utility with out modification of the fuel distribution and automotive equipment systems.

The existence of transportable fuels suggests that the community need not install expensive power grids providing that adequate numbers of motor-generators are available which can burn ammonia. Similarly kits must be provided for modifying the carburetion systems of automotive equipment. Initially these modification kits will result in excess amounts of NOx. The lead time for development of pre-burning separation of the nitrogen and hydrogen is probably in phase with the growth of these systems to the level that the NOx emissions are significant.

Epilogue

Mankind has been slow to recognize the value of DOW, the earth’s most abundant and least used resource. And even slow to support the development and even adoption of technology to use it. In a sense this is a shame as countries with coastal deserts adjacent to deep ocean water struggle with population pressure and poverty. In another sense it is good because earlier development would almost surely have been done badly. The growing of recognition that for development to be efficient it must also be sustainable, gives hope that we may do it right.

It has been just a little over 25 years since DOW R&D was initiated at NELHA. The CHC begin its private experiments with DOW agriculture a little over 5 years ago. It now appears that four or five DOW systems will be started and perhaps some completed by the turn of the 21st Century. The success of some of these ventures will result in several hundred DOW systems in the operational, in the construction or in the planning stage by 2005. This would include one or more per developing country with coastal deserts and adjacent deep ocean water, and an increasing number of private commercial ventures. By 2020 these desert coastal zones, formerly capable of supporting only small isolated and often poor communities will be looked upon as great assets for and often the only assets for a country’s sustainable development.


REFERENCES

1. Common Heritage Corporation Web Page, (http://aloha.com/~craven/)

2. Natural Energy Laboratory of Hawaii Web Page, (http://www.ilhawaii.com/~nelha/)

3.Van Ryzin, J.C. and Leraand T.K. “Air Conditioning With Deep SeaWater; a Reliable Cost Effective Technology,” Prepared for Presentation at the IEEE Oceans '91 Conference, 12/91, Honolulu, HI. (http://aloha.com/~craven/coolair.html)

4.. Idaho National Engineering Laboratory, Los Alamos National Laboratory, Oak Ridge National Laboratory, Sandai National Laboratories, Solar Research Institute, “The Potential of Renewable Energy, An Interlaboratory White Paper”, Published by the Solar Energy Research Institute, 1990, Appendix D

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