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This study assessed the economic sustainability and contribution of tomato farming ventures to Addis Ababa's resilience. Using a project-based evaluation method, the profitability of tomato production was analyzed with and without the cost of water. The results showed that including the cost of water, the venture had a negative net present value (NPV) of 30100 USD/hectare/annum, an internal rate of return (IRR) of 0.2%, a payback period (PBP) of over ten years, and a cost-benefit ratio (CBR) of 0.83. However, without the cost of water, the venture showed a subtle profit, with an NPV of 15100 USD/hectare/annum, an IRR of 21%, a PBP of 2.9 years, and a CBR of 1.02. Sensitivity analysis revealed that an increase in sales price and yield positively affected profitability, while an increase in operating cost had a negative effect. The study concluded that when water costs are considered, the tomato venture in Addis Ababa is not profitable or sustainable, and does not contribute to the city's resilience. However, without water cost accounting, the venture's contribution to the city's resilience is minimal. The study recommends policy interventions to enhance farmers' access to the market, establish agro-industries, and improve their bargaining power.

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Social structure is based on the availability of the Water-Energy-Food Nexus. To cover these needs of society, several solutions of different scales of infrastructures coexist. The construction of infrastructure is capital-intensive; therefore, investment risk is always a consideration. In this paper, we try to evaluate the investment risk by interest rates (IR). We show that IR is a key indicator, which includes multiple parameters of prosperity expressing the political and economic status quo of the society. The selection of a particular scale influences the required capital and is thus one of the most critical decisions. Water supply infrastructure is one of the foundations of society, and the selection of the optimal scale of such infrastructure is often a great challenge in civil engineering. As a case study, we analyse three different scales of water supply infrastructures for the area of West Mani (Greece), i.e., dam, water ponds, and seawater desalination. We evaluate each case by the capital intensity by performing stochastic simulations of interest rates and identify the optimal solution as the one with the smallest median unit cost, in this case, the water ponds. In order to assess the impact of the development level of a country on the resulting unit cost stochastic properties we apply the optimal solution to various countries with different development levels and IR. We show that IR in the least developed countries, being generally higher and more variable, increases the unit cost, including its variability, which ultimately indicates higher investment risk.

Social structure is based on the availability of the Water-Energy-Food Nexus. To cover these needs of society, several solutions of different scales of infrastructures coexist. The construction of infrastructure is capital-intensive; therefore, investment risk is always a consideration. In this paper, we try to evaluate the investment risk by interest rates (IR). We show that IR is a key indicator, which includes multiple parameters of prosperity expressing the political and economic status quo of the society. The selection of a particular scale influences the required capital and is thus one of the most critical decisions. Water supply infrastructure is one of the foundations of society, and the selection of the optimal scale of such infrastructure is often a great challenge in civil engineering. As a case study, we analyse three different scales of water supply infrastructures for the area of West Mani (Greece), i.e., dam, water ponds, and seawater desalination. We evaluate each case by the capital intensity by performing stochastic simulations of interest rates and identify the optimal solution as the one with the smallest median unit cost, in this case, the water ponds. In order to assess the impact of the development level of a country on the resulting unit cost stochastic properties we apply the optimal solution to various countries with different development levels and IR. We show that IR in the least developed countries, being generally higher and more variable, increases the unit cost, including its variability, which ultimately indicates higher investment risk. [ABSTRACT FROM AUTHOR]

Seawater membrane distillation (SWMD) is a promising separation technology due to its ability to operate as a stand-alone desalination unit operation. This paper reviews approaches to improve laboratory-to-pilot-scale MD performance, which comprise operational strategies, module design, and specifically tailored membranes. A detailed comparison of SWMD and sea water reverse osmosis is presented to further analyze the critical shortcomings of SWMD. The unique features of SWMD, namely the ability to operate with extremely high salt rejection and at extreme feed concentration, highlight the SWMD potential to be operated under zero liquid discharge (ZLD) conditions, which results in the production of high-purity water and simultaneous salt recovery, as well as the elimination of the brine disposal cost. However, technical challenges, such as thermal energy requirements, inefficient heat transfer and integration, low water recovery factors, and lack of studies on real-case valuable-salt recovery, are impeding the commercialization of ZLD SWMD. This review highlights the possibility of applying selected strategies to push forward ZLD SWMD commercialization. Suggestions are projected to include intermittent removal of valuable salts, in-depth study on the robustness of novel membranes, module and configuration, utilization of a low-cost heat exchanger, and capital cost reduction in a renewable-energy-integrated SWMD plant. [ABSTRACT FROM AUTHOR]

Thermal power plants use large amounts of water, mainly for cooling purposes. Over a long operational period, power-plant cooling can have a large impact on the water source: elevated temperatures of return flows alter the local physical and chemical properties of the water (i.e., quality impact), while water consumption reduces the available water reserves for future and down-stream uses (i.e., Quantity impact). The vulnerability of the energy sector to water availability is an important problem and measures to confront or mitigate this challenge have not yet been adopted. Here, a novel, straightforward methodology to calculate the cost of water impact caused by coal and natural-gas (combined-cycle) plants with once-through and wet-recirculating cooling systems is developed. The goal is to internalize systemic costs related to water use impacts and thereby incentivize more sustainable energy generation practices. The impact is calculated here as a theoretical feedback on the plant’s operational costs, since altered water properties will eventually lead to malfunction or part-load operation. The main parameter affecting the cost of water impact is found to be the temperature rise of the cooling water in the condenser. In plants with once-through cooling systems, the quantity and quality impacts of water use are of a comparable magnitude. The cost of water impacts in facilities with wet-recirculating cooling systems, on the other hand, is determined only by their quantity impact on water resources. Overall, recirculating systems result in a significantly lower water cost when compared to once-through systems. Furthermore, an approximately three times higher cost of water impact is calculated for coal plants in comparison to natural gas plants, which clearly demonstrates the importance of operational efficiency on the water use of power plants.

The use of renewable energy for desalination started in the 1980s, in order to provide a sustainable water supply in windy/sunny areas with water shortages. Nevertheless, this initiative has been generally limited to the R&D field and prototypes, with few units operating under real conditions. The research tradition in this field carried out by the Canary Islands Institute of Technology, based on pilot facilities, resulted in wide expertise on practical issues, as well as a deep knowledge on the state of the art. This paper deals with the most relevant technical aspects to be considered in the optimal design and operation of wind/photovoltaic (PV)-powered reverse-osmosis (RO) systems, focusing on practical indications: appropriate pre-treatment, the use and selection of the RO energy recovery system (ERD), the selection of an energy storage system, key recommendations for the O&M actions in wind- and PV-powered RO systems (extracted from the experience of operating different units in remote locations (PV and RO) and coastal areas (wind and RO)), and an identification of the pros and cons of hybrid systems. A selection of economic data is given, indicating the main aspects of the minimization of the cost of water. Finally, the paper mentions the latest advances in the involved technologies. [ABSTRACT FROM AUTHOR]

Potable water scarcity is one of the major issues that has been affecting millions of lives. It became serious in underprivileged remote communities that are unable to afford conventional water supply and treatment systems. Passive solar desalination systems as a cost-effective option for water supply are becoming more feasible in remote areas. However, low water yield and poor reliability are the main deficiencies that need improvement. This article reviews recent studies conducted on performance improvement and water cost reduction of passive solar stills associated with new designs and modifications appropriate for remote areas to identify the most effective designs. The individual effect of each component's design on performance parameters (water yield, thermal efficiency, and unit water cost) has been reported and discussed. The design specifications and outcomes of studies were reviewed and presented in tables to give a broad view of activities in the area, and to provide future studies with data for validation purposes. This article shows knowledge gaps and opportunities for future research through a distinct classification of studies to shape a clear roadmap on the development of passive solar stills. The most effective designs of components with respect to their application in remote or disaster-stricken areas with no access to power infrastructure were determined. In addition, issues around the structural design complexity and operational reliability associated with new designs were presented. [ABSTRACT FROM AUTHOR]

In this study, we present a novel methodology to design and optimally operate a standalone winddriven reverse osmosis desalination plant to provide the required water production in face of fluctuating wind power. The methodology is applied to a plant with a capacity of 2,592 m3/h for a rural area in Saudi Arabia. The plant nominal size, operating conditions, and the number of wind turbines are determined through numerical simulations. The performance of the desalination plant is tested under fluctuating wind power using two different operation strategies that allow for better leverage of the generated wind power. It is found that the desalination system can provide the annual production capacity if the feed pressure is optimally adapted in response to the varying wind speed. Another successful strategy involves the optimal use of the plant vessels in face of fluctuating wind power. Both strategies are successful but necessitate the use of a control system to automatically adapt the feed pressure or the plant active vessels during wind power variations. Moreover, the economic analysis signified a water cost as low as 0.45 $/m³ for the studied plant. [ABSTRACT FROM AUTHOR]

Cover crops (CC) are used traditionally to control erosion problems, improve water collection, distribution and storage, reduce compaction, and improve soil carbon and nitrogen balances. This work aimed to provide zonal results regarding the contributions of CC on resource use efficiency and sunflower productivity. During 2017 and 2018, six CCs as sunflower predecessors in Coronel Suárez (Southwest of Buenos Aires) were tested. Soil water and dry matter, nitrogen and vegetable yield were evaluated. The difference in edaphic water content upon drying of the CC with respect to the conventional fallow (BC) varied between -8 and 15 mm. The water use efficiency (EUA) ranged from 5.59 kg MS mm-1 in vetch (V1) and 16.16 kg MS mm-1 in oats (A). The highest yields were obtained with V1 (2379 kg ha-1) and the lowest with A (1561 kg ha-1). [ABSTRACT FROM AUTHOR]

An off-grid multi-generation model (solar photovoltaic, wind power, and diesel) has been used to assess the performance of a low scale (up to 250 m3/d) seawater reverse osmosis desalination plant with four different operating modes: fix, variable (180-250 m3/d), modular-fix (100 + 150 m3/d) and modular-variable operation (100 + 115-150 m3/d). The high-pressure pump and energy recovery system have been selected for each case according to the flow requirements; reverse osmosis membrane simulations have been made to know the power demand, product water flow and quality for the whole operating range of each option. The use of real solar and wind data allows to preliminarily assess the performance of the system. A specific battery charge/discharge strategy has been considered to take maximum advantage of wind and solar available energies. The most relevant technical and economic results have been presented, finding out the pros and cons of the different analyzed cases. A sensitivity analysis complements the study to identify the key parameter values addressed to achieve a minimum water cost under 2.2 €/m3. A new index is proposed to assess the performance of the whole system. [ABSTRACT FROM AUTHOR]

A technical and economic assessment has been made to simulate the operation of a wind energy-driven seawater reverse osmosis (SWRO) desalination plant (10,000 m³/d). Three different generation systems were compared: wind and batteries; wind and diesel; wind and photovoltaic (PV). In each case, two options of the SWRO plant were considered: variable operation high-pressure pump and modular plant consisting of three different trains operated independently. The ranges of power demand of said options are 81%-100% and 20%-100% of the nominal value, respectively. The energy lost, operation time, water production and water costs for each case were calculated, concluding design recommendations with the best technical and economic criteria. Water cost was identified in the range 1-1.35 €/m³, operation time under renewable energy supply can reach 75% of the year for modular reverse osmosis plant. A sensibility study for the water cost, for different parameters (capacity of batteries, diesel price, and PV power) was carried out for the different off-grid generation systems. [ABSTRACT FROM AUTHOR]

A technical and economic assessment of wind-powered seawater reverse osmosis (SWRO) systems is presented to identify the best combination of coupling between wind power and demanded power for a 5,000 m³/d SWRO unit. Three situations have been studied: Reference or Case 0) SWRO plant operating at the nominal point all of the time; Case 1) SWRO plant operating with variable power demand (up to 67% of the nominal point) by reducing the rotation speed of the high pressure pump, and Case 2) use of a modular SWRO plant, able to operate at four different values of power consumption by means of configuring two units of 1,250 m³/d and a unit of 2,500 m³/d. Power and fresh water production are calculated through a year based on experimental data of wind availability with time steps of 1 h. A comparative techno-economic analysis is performed to identify the best configurations along with recommendations on nominal values of desalination capacity and battery capacity in relation to the nominal power of the wind turbine installed. [ABSTRACT FROM AUTHOR]

The analysis of the costs and of the structure of tariffs for operators in the sector of water and sewage system in Romania are a real challenge. Through this analysis we can form an overview of the costs which may involve in the service of providing clean water and the sewage and wastewater treatment. The costs is analysed both in the cost structure at the enterprise level and in comparison with the income made from the activity (supply of drinking water or treatment of wastewater). In the article we study the cost structure at the level of sector of activity and the correlation between the tariff applied to water and sewer services and size of enterprise, number of employees, wage costs, maintenance and repair costs, energy cost and other variables. The correlations results helps us to make the first steps for the realization of an equation of the cost at the level of the sector of water and sewage system. Another correlation study will be between the applied tariff and the size of the investments made with european co-financing in the framework of the SOP Environment. Through this correlation we determine if the size of the tariffs applied in this sector correlate to the size of the investments made in the SOP Environment.

This study assessed the economic sustainability and contribution of tomato farming ventures to Addis Ababa's resilience. Using a project-based evaluation method, the profitability of tomato production was analyzed with and without the cost of water. The results showed that including the cost of water, the venture had a negative net present value (NPV) of 30100 USD/hectare/annum, an internal rate of return (IRR) of 0.2%, a payback period (PBP) of over ten years, and a cost-benefit ratio (CBR) of 0.83. However, without the cost of water, the venture showed a subtle profit, with an NPV of 15100 USD/hectare/annum, an IRR of 21%, a PBP of 2.9 years, and a CBR of 1.02. Sensitivity analysis revealed that an increase in sales price and yield positively affected profitability, while an increase in operating cost had a negative effect. The study concluded that when water costs are considered, the tomato venture in Addis Ababa is not profitable or sustainable, and does not contribute to the city's resilience. However, without water cost accounting, the venture's contribution to the city's resilience is minimal. The study recommends policy interventions to enhance farmers' access to the market, establish agro-industries, and improve their bargaining power., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors. Published by Elsevier Ltd.)

In this paper, nanofiltration (NF) was investigated as a suitable technology for defluoridating brackish groundwater. A comparison between NF and reverse osmosis (RO) was performed to evaluate which method is the best for removing fluorine from groundwater to produce drinking water. Although NF employs a membrane that requires a low amount of energy, both NF and RO have advantages and limitations. NF and RO have similar costs for desalinating brackish water, and thus both the membranes can be used for this aim, but we believe that this will change with the next generation of NF membranes. [ABSTRACT FROM AUTHOR]

This paper is focused on the development of technical and economical prospective of Karachi Nuclear Power Plant (KANUPP) in terms of various desalination technologies. During the first phase, an initial research contingency to desalination technologies already running at KANUPP was discussed and evaluated for economic assessment. In the next phase, mathematical model was developed for calculating various parameters of desalination technologies. During this step, simulation model from IAEA (International Atomic Energy Agency) named as DEEP & DE-TOP were used for calculating various desalination techniques including Reverse osmosis (RO), Multi effect desalination (MED), Multi stage desalination (MSF) and also for coupled technologies i.e., RO+MED and R0+MSF. Different parameters including capital/water cost and thermal desalination parameters were calculated for coupled desalination technologies for KANUPP. Number of stages for coupled KANUPP desalination plant in terms of experimental and computational analysis were carried out. The calculation shows that water cost for each coupled desalination technologies have varying trends. The objective of the research was to developed technical and economical viable model for coupled nuclear reactor desalination system. The research gives an indication to developed experimentally viable KANUPP desalination plant. [ABSTRACT FROM AUTHOR]

Information regarding domestic water consumption is vital, as the Kathmandu Valley will soon be implementing the Melamchi Water Supply Project; however, updated information on the current situation after the 2015 Gorkha Earthquake (GEQ) is still lacking. We investigated the dynamics of domestic water consumption pre- and post-GEQ. The piped water supply was short, and consumption varied widely across the Kathmandu Upatyaka Khanepani Limited (KUKL) branches and altitude. The reduction in piped, ground, and jar water consumption and the increase in tanker water consumption post-GEQ appeared to be due to the impact of the GEQ. However, the impact did not appear to be prominent on per capita water consumption, although it was reduced from 117 to 99 L post-GEQ. Piped, ground, and tanker water use were associated with an increase and jar water use was associated with a decrease in water consumption. Despite improvements in quantity, inequality in water consumption and inequity in affordability across wealth status was well established. This study suggests to KUKL the areas of priority where improvements to supply are required, and recommends an emphasis on resuming performance. Policy planners should consider the existing inequity in affordability, which is a major issue in the United Nations Sustainable Development Goals. [ABSTRACT FROM AUTHOR]

The availability of freshwater supplies to meet future demand is a growing concern. Water availability metrics are needed to inform future water development decisions. With the help of water managers, water availability was mapped for over 1300 watersheds throughout the 31 contiguous states in the eastern US complimenting a prior study of the west. The compiled set of water availability data is unique in that it considers multiple sources of water (fresh surface and groundwater, wastewater and brackish groundwater); accommodates institutional controls placed on water use; is accompanied by cost estimates to access, treat and convey each unique source of water; and is compared to projected future growth in consumptive water use to 2030. Although few administrative limits have been set on water availability in the east, water managers have identified 315 fresh surface water and 398 fresh groundwater basins (with 151 overlapping basins) as areas of concern (AOCs) where water supply challenges exist due to drought related concerns, environmental flows, groundwater overdraft, or salt water intrusion. This highlights a difference in management where AOCs are identified in the east which simply require additional permitting, while in the west strict administrative limits are established. Although the east is generally considered ‘water rich’ roughly a quarter of the basins were identified as AOCs; however, this is still in strong contrast to the west where 78% of the surface water basins are operating at or near their administrative limit. Little effort was noted on the part of eastern or western water managers to quantify non-fresh water resources.

The objective of this study is to include environmental impact in optimization of concentrated solar power plants previously limited to techno-economic analysis only. Performance of solar towers and parabolic trough collectors equipped with dry and wet cooling is numerically investigated at 10 min interval for three climatic zones. Based on electricity generation profiles pertinent to variation of design variables of solar multiple and thermal energy storage, the water usage is quantified techno-economically, considering water scarcity levels. Besides, five different potential impacts over lifecycle of concentrated solar and natural gas-based power plants are compared after unifying them into metric of net environmental impact avoided. Additionally, utilizing techno-economic solutions and eco-friendly solutions, multi-objective 'balanced' solution is proposed. It is found that levelized cost of water increases five-fold for areas with extreme water scarcity and is higher for trough than solar tower. Net environmental impact of troughs is higher and lower electricity generation causes the avoided impact to be higher than solar towers, when compared with natural gas-fired power plants. For eco-friendly solutions, solar multiple varies from 3.5 to 4 with thermal energy storage of 24 h. Dry-cooled solar towers with optimal solar multiple in range of 3–3.2 and thermal energy storage of 18.8–19.9 h are evaluated for pareto-optimality based 'balanced' solutions for all zones. These solutions offer minimum net levelized cost of electricity, alongside maximized electricity generation, huge return on invested capital and energy, and reducing environmental impact by over 94%. Lastly, semi-arid climates are found suitable for concentrated solar power plant installation. [Display omitted] • Dry-cooled systems give better plant output for solar tower and parabolic troughs. • Water footprint of solar tower is 1–1.5 times higher than parabolic troughs. • Water scarcity levels increase the levelized cost of water use manifold. • Global warming is most significant form of environmental impact for both plant types. • Dry-cooled solar towers offer optimality between low-cost and eco-friendly solutions. [ABSTRACT FROM AUTHOR]

This paper presents an overview of using solar energy in running desalination systems, called solar desalination. Solar energy can be converted directly to electric energy, which can operate electrically driven desalting systems such as reverse osmosis (RO), electrodialysis (ED), and mechanical vapor compression systems. Solar energy can also be converted to the thermal energy that can operate the mainly used thermally operated desalination system such as multistage flash (MSF), conventional multieffect (ME), and multieffect thermal vapor compression (ME-TVC), and emerging membrane distillation and humidification–dehumidification desalination systems. The thermal energy converted from solar energy can also be used to produce high-pressure steam running power plant producing electric power to operate mechanically driven desalting systems, and/or extracted steam at relatively low pressure to operate thermally driven desalting system. The main obstacle that hinders the use of solar desalination is the initial investment cost. This paper discusses the use of the solar desalination and calculates the investment cost to install solar desalination plants. These include photovoltaic (PV)-driven RO system, and thermally driven MSF and ME plants by steam directly generated by solar collectors, or by steam extracted from solar steam power plants operated by the concentrated solar collectors. The results revealed that PV-RO desalting system has the highest specific capital cost, among the considered systems, because the expensive storage of the electric energy in batteries, and the fact solar energy supply lasts about one third of the day. It showed also that using the thermally generated energy from concentrated solar collectors operating power plant is much cheaper than using this thermal energy when directly operating the desalination system. [ABSTRACT FROM PUBLISHER]

The treatment of wastewater and its further reuse is an essential part of an efficient rationalization of water within the field of Environmental Management Initiatives. Opting for the regeneration of this resource will lead to an important increase in water supply. Few studies have specifically calculated the economic costs of wastewater treatment and reuse using cost accounting and management techniques. In this paper, a cost management model is designed and adapted to the wastewater treatment process. The model quantifies, in economic terms, the change of water state from treated to regenerated water, favoring more efficient decision making regarding this resource. A practical application of this model was carried out at the Wastewater Treatment Plant of Santa Cruz de Tenerife (Canary Islands – Spain). The costs of the resources consumed by the treatment plant were calculated, as well as the costs for the different activities identified in treatment and reuse processes. As a result of our calculation process, it can be noted that the reuse of wastewater is an interesting option in terms of costs compared to other existing sources of water: surface water, underground water or desalination. [ABSTRACT FROM AUTHOR]

In this paper, research has been conducted on the floating type nuclear power plant named as ABV reactor which is designed for district heating, power, and sea water desalination by OKBM facility at Russia. This reactor was tested under different thermal loads during the designing phase, and three modules have been investigated. Theoretical calculations and simulation studies have been performed on these three modules having specifications as ABV-6M with 47MWth, ABV-6 with 38MWth, and ABV-3 with 18MWth.The results obtained from these modules have been calculated mathematically and verified by simulation. We have compared the originally derived data of ABV desalination system with our theoretical and simulation analysis. The results from two desalination techniques including RO and RO + MED have been calculated and are presented in this paper with details. The results obtained from both analysis show that the efficiency of ABV nuclear reactor desalination system increases with the decrease in corresponding water cost ratio. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Reverse osmosis (RO) has contributed to a large extent in positioning membrane desalination as one of the best available technologies to meet water demand in dry coastal areas. However, membrane desalination may still be perceived as an energy consuming and high cost desalination technology. Seawater Osmotic Dilution (SOD) may lower the energy consumption and the water cost by decreasing the salt content of seawater; and, at the same time SOD can become a sustainable technology that does not impact marine environments considering that less concentrated brines are discharged into the sea. The main objective of this study was the economical evaluation of SOD for the purpose of decreasing desalination costs. The authors have investigated the attractiveness and viability of SOD opportunities compared with standard RO membrane desalination. Three process configurations (desalination, desalination and reuse, SOD) were defined for a coastal area location, where the possibilities of water availability are limited to mainly the ocean. For each configuration, three different water production capacities (1.000, 10.000, and 25.000 m³/day) were studied and evaluated economically in terms of capital expenditure (CAPEX) and operational expenditure (OPEX). The results show that SOD can produce desalinated water with 27% energy reduction compared with seawater reverse osmosis desalination; and that operational costs of desalination can be reduced by 31%. Water volume balances of each configuration demonstrate that SOD has a high potential in dry coastal areas with limited availability of fresh water. For SOD with a commercial price of forward osmosis (FO) membranes at 30–60 US$/m² and a membrane flux of 7–14 L/m²-h, SOD becomes a viable technology for lowering costs of desalination, with payback times of less than 1.5 years when compared with desalination. [ABSTRACT FROM PUBLISHER]

A battery is required in reverse osmosis powered by a photovoltaic system (PV-RO) to prevent inevitable dumping energy and to prolong the operating time of producing water simultaneously. However, the battery is expensive and has a short lifespan. To obtain a competitive water cost, a battery capacity should be as small as possible. This study presents a novel strategy to prevent dumping energy and minimize battery capacity. PV-RO system with battery (PV-RO-Battery) and seasonal water storage tank (SWST) is investigated and its water cost is analyzed. This strategy ensures that all of the daily energy produced by the PV system is used to produce water in less than 24 h, avoiding the accumulation of storing daily excessive energy. Excess daily water production over daily demand is stored in SWST and is supplied to the source of demand when the water production is less than demand. A comparison of a PV-RO-Battery system with and without SWST is also conducted. The reduction of water cost was from 10.21 $/m3 to 2.31 $/m3 and 36.96 $/m3 to 3.06 $/m3 for the constant and variable demand, respectively. It means that the water cost from the system with SWST is only 20.5% and 8.3% of the system without SWST. • Novel strategy in PV-RO-Battery system to fulfill the demand is presented. • The concept of seasonal water storage tank (SWST) is employed. • The resulted water cost is 20.5% of the system without SWST. • The required capacity of PV modules is only 33.2% of the battery-less PV-RO system. • The required capacity of RO unit is only 48.5% of the battery-less PV-RO system. [ABSTRACT FROM AUTHOR]

The present work proposes a stand-alone process for brackish water thermal desalination for the Brazilian semi-arid (BSA) region. The Multi-Effect Distillation (MED) is coupled with solar collectors, a thermal energy storage (TES) system, a biodigester for electricity generation and a brine reject valorization scheme. The TES provides the continuous production of freshwater using solar energy alone, unlike other studies in the literature. The brine recycling affords lower amounts of brine reject than that reported in the literature for MED plants. A detailed cash-flow analysis estimates the economic feasibility of the plant and a water sales price of US$ 4.95/m³ for a plant with a capacity of 72 m3/day. The results indicate that thermal desalination is a cost-effective and sustainable alternative to mitigate the water shortage in the BSA region. • Stand-alone MED plant coupled with thermosolar energy in Brazilian semi-arid. • Thermal energy storage system affords freshwater supply over the whole year. • Economic feasibility analysis estimates freshwater sales price at 4.95 US$/m3. • Brine recycling affords a reject of only 13% of the brackish water inlet. • Brine valorization scheme further provides biomass for electricity generation. [ABSTRACT FROM AUTHOR]