Cost Of Desalination Research Articles

Water desalination cost literature: review and assessment

As water resources are rapidly being exhausted, more and more interest is paid to the desalination of seawater and brackish water concentrations. Today, current desalination methods require large amounts of energy which is costly both in environmental pollution and in money terms. Many studies of water desalination costs appear regularly in water desalination and renewable energy related publications. Cost estimates seem to be very much site specific and the cost per cubic metre ranges from installation to installation. This variability exists because the water cost depends upon many factors, unique in each case, most important of which are the desalination method, the level of feed water salinity, the energy source, the capacity of the desalting plant, and other site related factors. This paper attempts the taxonomy of a large number of related publications, classified in a systematic method and format, in order to allow meaningful comparisons and facilitate the derivation of useful conclusions.

Cost analysis of seawater desalination with reverse osmosis in Turkey

Economically usable water resources per capita are decreasing due to excessive population increase each year in Turkey. For this reason, new water resources should be found in the near future. The potential water resources are seawater or well water both of which need removal of salinity. The most promising treatment method for salinity is reverse osmosis. While reverse osmosis becomes widespread, the cost of the process will decrease. There is no detailed information about cost of seawater desalination in Turkey. In this study, a cost analysis of seawater desalination in Turkey was performed for reverse osmosis systems. The basic parameters of cost analysis such as capacity, recovery, membrane life, energy, chemical costs and flux were evaluated based on the effects on capital, operating and total production costs.

Optimisation of design and operation of MSF desalination process using MINLP technique in gPROMS

Optimal design and operation of MSF desalination process is considered here using MINLP technique within gPROMS model builder 2.3.4. gPROMS provides an easy and flexible platform to build a process flowsheet graphically and the corresponding master model connecting automatically individual unit model equations during simulation and optimisation. For different freshwater demand throughout the year and with seasonal variation of seawater temperature, the total annualised cost of desalination is minimised. It is found that seasonal variation in seawater temperature results in significant variation in design and some of the operating parameters but with minimum variation in of process temperatures. The results also reveal the possibility of designing stand-alone flash stages which would offer flexible scheduling in terms of the connection of various units (to build up the process) and efficient maintenance of the units throughout the year as the weather condition changes. In addition, operation at low temperatures throughout the year will reduce design and operating costs in terms of low temperature materials of construction and reduced amount of anti-scaling and anti-corrosion agents.

Advances in seawater desalination technologies

A number of seawater desalination technologies have been developed during the last several decades to augment the supply of water in arid regions of the world. Due to the constraints of high desalination costs, many countries are unable to afford these technologies as a fresh water resource. However, the steady increasing usage of seawater desalination has demonstrated that seawater desalination is a feasible water resource free from the variations in rainfall. A seawater desalination process separates saline seawater into two streams: a fresh water stream containing a low concentration of dissolved salts and a concentrated brine stream. The process requires some form of energy to desalinate, and utilizes several different technologies for separation. Two of the most commercially important technologies are based on the multi-stage flash (MSF) distillation and reverse osmosis (RO) processes. Although the desalination technologies are mature enough to be a reliable source for fresh water from the sea, a significant amount of research and development (R&D) has been carried out in order to constantly improve the technologies and reduce the cost of desalination. This paper reviews the current status, practices, and advances that have been made in the realm of seawater desalination technologies. Additionally, this paper provides an overview of R&D activities and outlines future prospects for the state-of-the-art seawater desalination technologies. Overall, the present review is made with special emphasis on the MSF and RO desalination technologies because they are the most successful processes for the commercial production of large quantities of fresh water from seawater.

Review and evaluation of desalination cost and costing methodologies

Recently, desalination is becoming a viable alternative for supplying potable water due to new developments in desalination technologies. At present, the cost of desalinated water is about US$0.5/m³ by RO and US$ 1.0/m³ by thermal processes. But these costs are location dependent. Thus the selection of an appropriate desalination technology for any location needs a reliable and accurate costing methodology. Better costing methodologies are also required for optimal process design and economical operation of desalination plants. There are so many costing methodologies reported in the literature with varying accuracy and details. Most of the publicly available costing methodologies are either black-box type with less details of costing methodology, or use thumb rules that do not sufficiently account local conditions. Therefore, there is a need to develop a more reliable and accurate costing methodology for public use. In this paper, desalinated water costs and costing methodologies with respect to accuracy and reliability are reviewed.

Economic Costs of Desalination in South Texas: A Case Study

In the 1990s, water emerged as a critical issue for the Texas Lower Rio Grande Valley because of rapid population growth, a prolonged drought, and shortfalls in water deliveries from Mexico over many years (Sturdivant et al. 2007). Since that time, opportunities for, and investigations into easing the stress from limited water supplies for municipal, industrial, and agricultural users have taken many paths, with key identifi ed alternatives including:

Green chemistry gets the prize | PBDEs in electronics-recycling workers in China | E-waste recycling spews dioxins into the air | Investing in renewable energy | Mixed reports on EU industrial pollutants | Battling climate change the American way | Nuclear energy: not a climate cure | Shift urged for chemical toxicity testing | Sustainable coal use | Environmental costs

Green chemistry gets the prize | PBDEs in electronics-recycling workers in China | E-waste recycling spews dioxins into the air | Investing in renewable energy | Mixed reports on EU industrial pollutants | Battling climate change the American way | Nuclear energy: not a climate cure | Shift urged for chemical toxicity testing | Sustainable coal use | Environmental costs

UCLA and Virginia Tech develop novel desalination technologies

Research that is being done in the US is aiming to develop improved and enhanced desalination technologies. Scientists at the University of California have developed a reverse osmosis membrane that promises to reduce the cost of sea-water desalination and wastewater reclamation. Researchers at Virginia Tech have created a new polymer membrane for reverse osmosis that is resistant to chlorine. Here, we provide a summary of both technologies.

Economic evaluation of nuclear desalination systems

This paper describes the detailed analyses of power and water costs for several nuclear reactors operating in a cogeneration mode (e.g. the 900 MWe French PWR, the advanced PWR, AP-600, the gas cooled, high temperature reactors, such as the GT-MHR and the PBMR) and coupled to two main desalination processes, e.g. multiple effect distillation (MED) and reverse osmosis (RO). Results for a specific site in a south Mediterranean country, Tunisia, are presented. It is shown in particular how the desalination costs could be further reduced by utilising waste heat from the GT-MHR and the PBMR type of reactors. Comparisons are made with desalination costs from the cheapest of fossil energy based systems, namely the 600 MWe gas turbine, combined cycle plant (CC-600) in various cost scenarios and in conditions specific to the selected site. Calculations are performed using the DEEP-3 software, recently developed by the International Atomic Energy Agency (IAEA). In the light of the results obtained, it is concluded that: a) Compared to the CC-600 system, all nuclear desalination options lead to much lower power production costs, as long as gas prices are ≥150 $/toe, and for discount rates of 5, 8 and 10%. Thus for example, at 8% discount rate and a gas price of 40 $/bbl (291 $/toe) for the CC-600, the kWh cost of the PWR-900 is 56% lower. Under the same conditions, that of the AP-600 is 49% lower; b) If the economic performances of the GTMHR and the PBMR, as announced by their respective developers, are indeed true than the GT-MHR would lead to the lowest kWh costs of all options considered. The kWh cost of the PBMR would be comparable to the large sized PWR-900; c) At 8% discount rate, the MED desalination cost by the PWR-900 and the AP-600 are respectively 46 and 42% lower than the corresponding cost by the CC-600 plant; d) The lowest costs with the MED plants are obtained by the GT-MHR and PBMR, utilising virtually free waste heat. Compared to the cost by the CC-600 + MED system, these reactors give desalination costs which are respectively 62% and 44% lower; e) For all energy sources, the desalination cost with the RO process is lower than with the MED process.

Steam driven large multi effect MVC (SD MVC) desalination process for lower energy consumption and desalination costs

It has been published and demonstrated in operating plants that the low-temperature multi effect desalination process (LT MED) when operated on turbine backpressure steam requires minimal energy consumption yielding specific desalination energy costs approaching values of optimal RO energy costs. However due to variations in electricity demand, the operation of large steam turbines at base load is in most cases impractical. As a result, in order to allow variations in electricity supply and full capacity of the desalination extraction, steam extracted from the turbines at higher pressures than the back pressure is commonly used. The extraction steam pressure of these turbines is in the range of 1.5–4.5 barg. (Typically as required for process steam at refineries and for MSF desalination plants). The LT MED process when utilizing such extraction steam incorporates thermo compressors (steam ejectors) in order to take advantage of the excessive extraction steam pressure, thereby increasing the economy ratio of the MED (decreasing energy consumption). Thermo compressors (ejectors) as a rule have a relatively low adiabatic efficiency, thus limiting the potential of the MED to increase the economy ratio even more. In this paper an approach of using a novel large centrifugal compressor driven by an auxiliary steam turbine utilizing the extraction steam is incorporated instead of the thermo compressor for large LT MED plants. The centrifugal compressor and auxiliary turbine having a much higher efficiency than the thermo compressor results in significant energy savings, thus lowering the desalination costs. This paper will also describe the thermodynamic advantages, the specific investment and desalination costs comparison, and the resulting desalination cost reduction potential of the steam-driven multi effect MVC process.

Overview of the cost of desalinated water and costing methodologies

In the last decade desalination has been considered as a solution for potable water needs only for specific water scarcity countries having cheap fuel. Now, desalination is extensively used, even where it was unthinkable twenty years back, due to reduction in desalination cost. The cost reduction is due to new developments and improvements in desalination technologies, particularly in RO technology. The RO is a well accepted technology due to recent increase in energy prices and takes up a major share in worldwide market. But, it is not able to achieve its proper share in the Arabian Gulf market due to difficult seawater composition and extensive historical use of thermal desalination. But RO still has potential in hybrid systems in the Arabian Gulf to account for seasonal and night to day fluctuations in the demand for power and water. There is a need for an accurate methodology for evaluation of desalination costs to help in selection of appropriate technology suitable for a specific location, for process design and other requirements. However, existing methodologies and software packages do not account for all the parameters that contribute for desalting cost and their accuracy is limited to specific conditions. This paper presents an overview of the trends in desalination costs for major desalination technologies like Multi Stage Flash, Multi Effect Distillation and Reverse Osmosis and review of costing methodologies.

Utilisation of waste heat from GT–MHR and PBMR reactors for nuclear desalination

The gas turbine–modular helium cooled reactor (GT–MHR) is currently being developed by an international consortium; the pebble bed modular reactor (PBMR) is to be constructed in South Africa. In both these reactors, circulating helium that has to be compressed in two successive stages cools the reactor core. For thermodynamic reasons, these compression stages require pre-cooling of the helium to about 26°C through the use of pre-cooler and intercooler helium-water heat exchangers. Considerable thermal power (≈300 MWth) is thus dissipated in the precooler and the intercooler. This thermal power is then evacuated to the heat sink. Depending upon the specific designs, the temperature ranges of the water in these exchangers could be between 80 and 130°C. This is an ideal range for desalination in a multiple-effect distillation (MED) plant, which can be coupled between a mixer (of the flows from the pre-cooler and the intercooler) and the switch- cooling unit, evacuating the heat to the heat sink (sea or river). It is thus interesting to evaluate the desalination costs of such a system, utilising virtually free heat. The usual code for desalination cost evaluation is the DEEP software, developed by the International Atomic Energy Agency. Actual versions of DEEP do not have models for GT–MHR and the PBMR providing heat for desalination. This paper describes the successive steps that led CEA to the development of these models from basic thermodynamic considerations and their integration in the new, CEA version of the DEEP code. The models are then applied to a realistic case study based on the TUNDESAL project [1]. It is shown that the desalination cost of a GT–MHR + MED system is 34% lower than that of a gas turbine, combined cycle plant + MED system, for a fossil fuel price of about 21 $/bbl and a discount rate of 8%. Under the same conditions, this cost is 2% lower for the PBMR + MED systems.

Influence of fuel costs on seawater desalination options

Reference estimates of seawater desalination costs for recent mega projects are all quoted in the range of US$0.50/m 3. This however does not reflect the recent trends of escalating fossil fuel costs. In order to analyze the effect of these trends, a recently updated version of the IAEA Desalination Economic Evaluation Program, DEEP-3, has been used to compare fossil and nuclear seawater desalination options, under varied fuel cost and interest rate scenarios. Results presented for a gas combined-cycle and a modular high-temperature gas-cooled reactor design, show clear cost advantages for the latter, for both Multi-Effect Distillation (MED) and Reverse Osmosis (RO). Water production cost estimates for the Brayton cycle nuclear option are hardly affected by fuel costs, while combined cycle seawater desalination costs show an increase of more than 40% when fuel costs are doubled. For all cases run, the nuclear desalination costs are lower and if the current trend in fossil fuel prices continues as predicted by pessimist scenarios and the carbon tax carried by greenhouse emissions is enforced in the future, the cost advantage for nuclear desalination will be even more pronounced. Increasing the interest rate from 5 to 8% has a smaller effect than fuel cost variations. It translates into a water cost increase in the range of 10–20%, with the nuclear option being the more sensitive.

The real cost of desalted water and how to reduce it further

Freshwater scarcity on a worldwide level is now a burning problem, widely discussed in media interviews and in major newspapers. In this context, the majority of the media are underlining the importance of seawater desalination as an attractive and logical alternative source to fight the freshwater scarcity. Unfortunately the majority of all these discussions are providing a totally wrong picture of the real cost of freshwater production from seawater. Figures for desalted water costs from below 0.25 €/m 3 to over 0.6 €/m 3 for large-scale realisation are frequently quoted. In some media, however, the costs given for desalted water production are too prohibitive for large-scale applications. Many so-called experts are enhancing the confusion with incorrect or in incomplete statements. Even simple considerations, such as water cost ex desalination plant vs. water cost at consumer tap, are neglected. Yet another neglected point is that freshwater of any kind is either highly subsidised or overpriced to finance costs which are not water-related costs. Even in the EU Commission the real cost of seawater desalination is sometimes incorrectly perceived. In principle, the calculation of specific freshwater cost is simple and based on a few clear parameters such as investment cost for a given desalting capacity, energy cost, cost for distribution, amortisation period and concept, financing cost, inflation rate, operation and maintenance cost and, last but not least, plant availability and lifetime. A typical example to illustrate the reigning confusion is the primary energy cost. Today, the barrel of crude oil costs in the world market approximately 70 US$ or more. However, many tenders or BOT projects compare the water and energy cost on a 5 US$/barrel level. With this energy cost level and other unrealistic conditions even oldfashioned, low-GOR MSF plant can produce freshwater for a nominal cost of 0.60 €/m 3. With today's world market prices for crude oil, realistic cost and conditions for financing and all other costs fully covered, the real specific desalted water cost will exceed the 2 €/m 3 level for the same plant. It is clear that the freshwater has to be produced at socially acceptable cost and this would be about 1.0 €/m 3 or below. However, the calculation of the specific water cost has to be compatible with realistic parameters in order to be able to compare them and to draw correct conclusions and decisions. Therefore, in this paper an attempt has been made to calculate a realistic cost of freshwater from seawater for various types and sizes of desalination plants in combination with various energy sources and with comprehensible realistic conditions utilizing as a basis some older studies. The basic conclusion of our investigation is that large thermal and membrane desalination plants may reach in the future the same level of specific water cost and that a water production cost of 1.00 €/m 3, with energy cost of the year 2006 can be achieved with moderate R&D efforts. However, it is difficult (not impossible) to reach 0.50 €/m 3 and it will require time-consuming and intensive R&D work to achieve this goal.

Molecule Tubes May Lower Desalination Costs

Molecule Tubes May Lower Desalination Costs

Memstill membrane distillation – a future desalination technology

Triggered by the worldwide fresh water scarcity problem and the need for low cost water supply, Memstill is a newly developed membrane-based distillation concept, which has the potential to improve the economy and ecology of existing desalination technologies for seawater and brackish water to a large extent. This technology combines multi-stage flash and multieffect distillation modes into one membrane module. Because a Memstill module houses a continuum of evaporation stages in an almost ideal countercurrent flow process, a high recovery of evaporation heat is possible. The process promises to decrease desalination costs to well below 0.5 USD/m, using low grade waste steam or heat as driving force.

The US freshwater supply shortage: Experiences with desalination as part of the solution

Parts of the USA are facing impending shortages of freshwater. One proposed solution is the construction of desalination plants to turn seawater into freshwater. Although seawater desalination plants are widely used in the Middle East, especially Saudi Arabia, there are few desalination plants in the USA. In 2003, Tampa Bay Water built the largest desalination plant in North America. Persistent operating problems and escalating costs have caused the utility to re-evaluate its reliance on the seawater desalination plant as part of a long-term regional water supply strategy. In addition, environmental effects of the plant are uncertain. Advances in reverse osmosis technology have significantly reduced desalination costs. However, desalination of seawater is still more expensive than other freshwater supply sources and demand management measures. With time and research, seawater desalination may prove to be a sustainable, cost-effective source of new freshwater supplies, especially if plants are coupled with renewable energy sources. Until then, the development of small-scale groundwater desalination plants, the re-use of water, water conservation, and a more efficient allocation of water through higher prices and rising block rates will be important strategies in meeting growing water demand. Moreover, it is important to improve the coordination between water supply planning and land use planning as populations continue to increase.

Integrating Membrane Contactors Technology and Pressure-Driven Membrane Operations for Seawater Desalination: Energy, Exergy and Costs Analysis

Membrane science and technology has nowadays become the dominant technology in water desalination. In this context, Reverse Osmosis, in combination with other pressure-driven membrane operations (i.e., microfiltration, ultrafiltration and nanofiltration), represents the most diffuse practice. Despite this success, specific actions are requested in order to solve problems related to water recovery factors, brine disposal, cost and quality of the water. In this paper, a MF–NF–RO membrane system is integrated with membrane distillation/crystallization units. The use of these membrane contactors devices, operated on the NF and/or RO retentate, permits to increase the water recovery factor up to 92.8% without a significant increase of the costs if waste thermal energy is already available to the process. In addition, the sale of salt crystals grown in high concentrated brines might potentially reduce the overall desalination cost, thus confirming the potential interest for the proposed approach. Energy and exergy analysis permitted to individuate the points of higher entropic losses and low thermodynamic efficiency for the systems, and possible solutions based on the use of energy recovery devices have been discussed in detail.

How green is ethanol? | Pretreatment lowers desalination costs | News Briefs: Sick-stream diagnosis ` Cadmium linked to cancer | OMB proposes to harmonize risk assessments

How green is ethanol? | Pretreatment lowers desalination costs | News Briefs: Sick-stream diagnosis ` Cadmium linked to cancer | OMB proposes to harmonize risk assessments

Advanced MED process for most economical sea water desalination

The low temperature horizontal tube multi-effect desalination (MED) process is thermodynamically the most efficient of all thermal distillation processes. A comprehensive multi-disciplinary development and design approach resulted in prevention of corrosion and scale formation on the plant’s heat transfer surfaces. It also allows the successful and most economical use of aluminum alloys for heat transfer tubes, as well as carbon steel epoxy coated shells for the evaporator body. The ability to use economically low grade heat, such as waste heat, exhaust steam from power station turbines as the primary heat source for MED, yields very low specific energy costs for sea water desalination. Recent developments of very economical low temperature deep pool nuclear heat reactors, when acting as the primary energy source for large MED plants, yield very low specific desalination energy costs. The combination of economical specific MED plant costs with low energy cost, together with the inherent durability of low temperature MED avoiding the necessity of comprehensive sea water pretreatment (such as with RO plants) make the MED process one of the best candidates for safe and durable large capacity economical desalination options. This paper describes the design principles and various energy considerations that result in this uniquely economical MED process and plant. It also provides an overview of various cases of waste heat utilization, and cogeneration MED plants operating for many years.