Paper #1: An Assessment of Water Desalination Technologies

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1 Paper #1: An Assessment of Water Desalination Technologies Prepared for course # Technology and Strategy at the Massachusetts Institute of Technology Introduction Water desalination is a technology with both a long history and a rapidly developing future. The rapid development is due to the increasing worldwide demand for water in agricultural, industrial and private use. This rapid development in technology is being pulled by the ever increasing worldwide demand for freshwater. This demand is being amplified by the countless organizations and scientists forecasting dire circumstances in the near future due to current water consumption trends. It is estimated that by 2020, only 11 years from now, we will need 17% more freshwater than is currently available, to support our agricultural needs alone. 1 A water shortage thus will have serious implications not only in terms of thirst but in terms of global hunger, especially in the developing world. Water is also an important input into many manufacturing processes as well as a staple consumable used in daily living, most heavily in developed nations. As water prices rise, standard of living declines in developed nations as consumers are made to pay higher prices for a myriad of goods and services that depend on water in some portion of the value creation process. Key Parameters There are many key parameters that characterize water desalinization processes, some of which are specific to certain methods of water desalinization. As this paper is intended to address the technology as a whole, key parameters have been chosen to be the high level characteristics that are common amongst all methods of water desalination. A summary of the key parameters is shown in figure 1 on the following page. As with nearly all emerging technologies cost is a critical parameter in water desalination. However it is important to note that cost is the primary driver of innovation for water desalination technology today. Water 1 (Kirby, 2000)

2 desalination as a practiced technology has been around for millennia, the recent pull for this technology is focused on cost effective methods (measured in terms of $/m³) to meet the demand and quality requirements of a growing worldwide population. Fig. 1: Key Parameters of Desalination Capital Cost Operating Cost Cost per unit Capacity/Throughput Uptime Service Life Size / Spatial Needs Portability Electricity/Power consumption Resulting Water Quality Seawater Temperature Waste / Byproducts and Handling Secondary to cost, perhaps the next most critical parameters are system capacity, system waste, and system power consumption. Though power consumption would seem to be closely aligned with cost, it is worth mentioning independently because many of the concerns regarding water desalination technology are environmental and consumers are favoring desalination technology with minimal carbon foot prints. This can be seen in Australia where a desalinization project in Perth is powered entirely by wind power and is processing 143,000 m³ of water per day. 2 Waste is another primary environmental concern due to the effect of the effluent stream (commonly called brine) on the surrounding ocean environment. The brine that is returned to the ocean is super-concentrated and thus more dense than ocean water. For this reason, the brine will fall directly to the bottom of the ocean and has a disruptive effect on the marine life of the ocean floor. Trade-offs When designing a desalination system the key trade-off is cost vs. non-renewable energy consumption. At the moment the most cost efficient systems are dependent upon the existing energy grid, which is typically either made up of nuclear or fossil fuel non-renewable energies. Though the use of renewable energies is preferred, it is more costly due to the capital costs of creating a renewable energy system to support the desalination process. Additionally depending upon the surrounding ecosystem and the capacity of the desalination project, there may be tradeoffs between capacity, price, and waste generation/handling. To achieve desired capacities but 2 (Sanz & Stover, 2007)

3 stay within environmental viability, developers of desalination projects may need to add cost to their projects to manage the waste appropriately. The Performance Envelope and Natural Limit The performance envelope can be thought of as the current limits of the critical process performance parameters, wherein many of the process performance parameters are one level of detail greater than the key parameters above. The process parameters that make up the performance envelope relate specifically to the cost, capacity and detailed water quality characteristics. The performance envelope is summarized in figure 3, which due to its length is shown in the appendix. The cost benchmark of the performance envelope ($.49/m³) is the current best performance which is being realized by Singapore-Tuas Seawater Desalination plant. 3 Academic research has demonstrated cost models far lower than this price, however the performance envelope remains at $.49/m³ because these developmental methods have yet to be placed into practical use. The capacity benchmark is also the current best performance (300,000,000 m³/year) and is being achieved by Jebel Ali Desalination facility in the United Arab Emirates 4. The water quality parameters are identified by the European Union in Council Directive 98/83/EC. Though even superior water quality performance could be achieved, the directive can be thought of as a natural limit, or better yet as a point of diminishing returns in terms of desalination. Innovation Trajectory It has been stated earlier that desalination technology has existed for thousands of years. Given its long history and the recent explosion of interest in this technology, desalination has been placed on a steeply inclined innovation trajectory. Figure 2 on the following page shows the evolution of desalination technologies through time and overlays this evolution on a technology S-curve so that the current and previous rates of innovation may be better understood. It can be seen that improvements in existing technologies (Reverse Osmosis) as well as many new technologies are advancing innovations in water desalination along an increasing slope. The effect of this rapid development in desalination on the key parameters 3 (Kolesnikov-Jessop, 2006) 4 (Bowman, 2008)

4 Fig. 2: Desalination Technology S-curve Fusion Desalination Sand and Wool Filters Land Based Multi- Stage Flash Distillation Simple Distillation -Reverse Osmosis -Electrodialysis Forward Osmosis Nanotube Desalination Geothermal Desalination Desalination through Evaporation Clay Filters 400 BC 100AD Present Future of the technology has been dramatic improvements for nearly all parameters: increases in throughput, reductions in cost, and improvements in water quality. However as the scale of the technology has increased, so too has the scale of waste discharge and energy consumption with both serving as the primary negative aspects of water desalination processes. Competing Technologies Though desalination would seem to be an obvious choice for meeting the water needs of ever-increasing human populations, it is by no means the only method of doing so. The primary competing technologies are transportation, deep water aquifer drilling, the capture of rainwater runoff, and recycling/reuse strategies. These technologies are also being employed in massive scales to meet the growing water demand. A practical example of the implementation of these technologies is the $100 million dollar project being championed by T Boone Pickens to transport water from rural areas in Texas to city of Dallas 5. The main advantage of these technologies are three-fold, in some cases they are less expensive than desalination, they have a much smaller carbon footprint (transportation is achieved via pipeline), and they typically have a 5 (Berfeld, 2008)

5 much smaller environmental impact as well. The main disadvantage of the above technologies is the perception that each is able to provide only a limited supply due to the source of the water and will be unable to scale up to meet rising water demands. Forward Looking Conclusions In the years to come, we will likely see advances in all water supply technologies. However desalination is likely to see the largest advances due to the essentially limitless supply of salt water, the existing successful desalination projects, and the research dollars from both public and private sources that are fostering improvements in this technology. In the near term we are likely to see continued reductions in cost and energy consumption for water desalination, specifically for reverse osmosis technologies. In the long term it is difficult to predict which of the many competing technologies will dominate the desalination market, however it is almost certain that the technology will move past reverse osmosis to more cost effective and energy efficient systems.

6 Appendix Fig. 3 Process Performance Envelope A. Cost: $49/m³ B. Capacity: 300,000,000 m³/annum C. Water Quality as shown:

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9 Bibliography Berfeld, S. (2008, June 12). There will be water. Business Week. Bowman, J. (2008, March 26). Desalination Risk to Marine Life. Arabian Business.com. Kirby, A. (2000, June 2). Dawn of a Thirsty Century. BBC News, p. 2. Kolesnikov-Jessop, S. (2006, September 12). Singapore Taps Ocean for Water and Income. International Heral Tribune / New York Times. Sanz, M. A., & Stover, R. L. (2007). Low Energy Consumption in the Perth Seawater Desalination Plant. IDA World Congress, (p. 1). Maspalomas, Spain.