Renewable Water Research Articles

High-Performance Janus Solar Evaporator for Water Purification with Broad Spectrum Absorption and Ultralow Heat Loss

Interfacial solar vapor generation offers a promising zero-CO2-consuming energy conversion technology for the production of renewable clean water. The key for boosting solar vapor efficiency relies on the rational design of materials composition and structure at the micro/nanoscale to improve light utilization. Here, we demonstrate a Janus evaporator based on a hydrophilic carbon-black-decorated copper oxide (C@CuO) membrane as the light-absorbing layer and an opposite hydrophobic polymer nanofibers as the thermal insulation layer, which enables efficient energy utilization and vapor generation through a synergistic light absorption and thermal confinement strategy. In addition, the hydrated C@CuO surface reduces vaporization enthalpy that accelerates the efficient evaporation of water. A high evaporation rate of 1.88 kg m–2 h–1 is achieved by the Janus evaporator under 1 sun irradiation. This high photothermal conversion rate and ultralow heat loss synergistic engineering offers a bright future for high-efficiency solar water purification applications.

Sustainable city concept based on green hydrogen energy

The current study investigates the green hydrogen production from renewable energy sources for the metropolitan city of Istanbul by using electrolysers. The main idea is to create a hydrogen map for every district in Istanbul, based on renewable energy sources and water splitting technology. The potentially available renewable sources, such as solar (including offshore), wind (including offshore), biomass, geothermal and underwater current are used for calculating the total hydrogen production potential. Istanbul's potential for producing green hydrogen is estimated to be 7.96 Mt. The study results show that Catalca, Şile, Silivri, Arnavutköy, and Beykoz come out as the districts with the highest green hydrogen potential with 1.49 Mt, 1.19 Mt, 1.12 Mt, 0.57 Mt, and 0.46 Mt, respectively. After supplying the necessary power demand for the city, the remaining power is used to produce green hydrogen which may contribute an economic value of over 100 billion US$ with a current price of $13/kg of hydrogen and 23.88 billion US$ with a targeted price of $3/kg of hydrogen, respectively. The available potentials for each district are also specifically studied and discussed. It is more importantly expected to reduce the greenhouse gas emissions by about 90% which will ve very important to achieve a carbon-neutral city and hence country due its dominated role. Furthermore, the results provide a clear guidance to enable policymakers and private sectors to use renewable energy potentials for their investment purposes or promote clean energy programs, tackling carbon-based energy consumption, pollution, and greenhouse effect. This, later on, can be used by policymakers and energy providers to help the city and local communities for achieving the United Nation's sustainable development goals.

Water and climate: Global environmental sustainability and the current state in a developing country, Nicaragua

Environmental sustainability means taking steps to secure adequate management of natural resources in all human productive and livelihood activities. These steps involve a strategy of rational sustainable exploitation and the introduction of effective conservation measures which means integral management on all levels, national, regional and global. The specific situation of Nicaragua, as a prime example of a country in development with a vast richness in natural resources is analyzed. To name a few, in total renewable water resources the country has the 14th highest total yearly internal renewable water resources per capita (24,161/capita/year) in the Americas and as a tropical country has a large variety of biodiversity and ecosystems such as tropical dry and humid forests and 910 km of coastal area in the Caribbean and Pacific coast. These natural resources and more could bring potential to promote its own development. In spite of this, the country is on an unsustainable path as many parts of the world but with even greater challenges due to limited economic sustainability, high vulnerability to climate change and the lack of institutional capacity to establish better management. Unsustainable practices ranging from over-exploitation of resources to drastic land use changes have created environmental problems which consequently affect human wellbeing and health. Additionally, ecosystems and the quality of resources are under pressure which lead to a reduction in quality of water, forests and biodiversity. For example, the dry tropical forests have been reduced in 90% from 2000 to 2011 in the Pacific and Central areas and humid tropical forests are constantly being invaded and converted to agricultural and pasture lands. Water quality has been affected from contamination from agriculture, industries and the natural volcanic geology (arsenic) in groundwater as well as eutrophication and increased sedimentation from the watersheds of both lakes and rivers. Climate change is exacerbating these problems and causing new ones. After illustrating the present state of resources in Nicaragua, strategic suggestions of needed components to introduce an integral and improved management of the water resources have been laid out as a proposal for the future that include improvement in institutional capacity and governance to promote better management.

Overcoming coke formation in high-temperature CO2 electrolysis

AbstractHigh-temperature CO2 reduction reaction (HT-CO2RR) in solid oxide electrochemical cells (SOECs) features near-unity selectivity, high energy efficiency, and industrial relevant current density for the production of CO, a widely-utilized “building block” in today’s chemical industry. Thus, it offers an intriguing and promising means to radically change the way of chemical manufacturing and achieve carbon neutrality using renewable energy sources, CO2, and water. Albeit with the great potential of HT-CO2RR, this carbon utilization approach, unfortunately, has been suffering coke formation that is seriously detrimental to its energy efficiency and operating lifetime. In recent years, much effort has been added to understanding the mechanism of coke formation, managing reaction conditions to mitigate coke formation, and devising coke-formation-free electrode materials. These investigations have substantially advanced the HT-CO2RR toward a practical industrial technology, but the resulting coke formation prevention strategies compromise activity and energy efficiency. Future research may target exploiting the control over both catalyst design and system design to gain selectivity, energy efficiency, and stability synchronously. Therefore, this perspective overviews the progress of research on coke formation in HT-CO2RR, and elaborates on possible future directions that may accelerate its practical implementation at a large scale.

Water Context in Latin America and the Caribbean: Distribution, Regulations and Prospects for Water Reuse and Reclamation

Water scarcity is a problem of global relevance that is affecting more and more people in the world. Latin America and the Caribbean (LAC) have around 35% of the world’s renewable water resources. However, the management of water resources and inequality in access to water has made water scarcity a problem of growing interest in the region. The reuse of water could be an efficient measure to reduce the demand for water resources in the area. In particular, the reuse of greywater is a simple and decentralized method of water reuse, which would mitigate the impact of the lack of water in isolated or difficult-to-access areas. Using the Aquastat database, water consumption in the world and water availability in LAC were studied. In addition, the regulatory framework for water in LAC countries was studied, with an emphasis on water reuse and greywater legislation. Agriculture is one of the most demanding of water in the world, particularly, in LAC, which demands around 70% of renewable water resources. Furthermore, in LAC, the availability of drinking water in rural areas is lacking, with seven countries having less than 80% access to healthy drinking water. The water regulation in LAC is quite heterogeneous. The most general regulation around water is found in the political constitutions of each country. Some constitutions explicitly indicate access to water as a human right, while other constitutions do not include information in this regard. Although some countries have specific regulations on the reuse of wastewater, there is a general lack of regulations related to the reuse of greywater. In most cases, the term “greywater” is not even defined in the general water and wastewater laws. As of the date of this article, only Chile, Peru, and Brazil have bills to regulate the reuse of greywater, of which only the Chilean is approved. The reuse of greywater could help reduce water demand for non-drinking uses. However, the implementation of greywater treatment systems represents a cost that is difficult to cover, especially in the poorest countries of the region. Countries must improve their public policies to improve the management, use and reuse of water to mitigate water scarcity that severely affects human consumption in the region. The relevance of this study lies in providing a general framework of the water situation in LAC for studies and public policies focused on promoting water reuse as a measure to mitigate water scarcity.

Carp Breeding in the Carpathian Basin with a Sustainable Utilization of Renewable Natural Resources.

In the Central European region, there is a long tradition of breeding fish in artificially constructed ponds. As the area belongs to the temperate zone, farmed fish need to survive cold winter periods. Common carp (Cyprinus carpio L.), which is an omnivorous, bioturbating species, is well adapted to warm and cold periods and the alluvial water environment. Since the Middle Ages, a large scale, efficient carp farming methodology has been developed in the region, where production is based on natural resources (protein and fatty acid sources) of renewable water ecosystems. This summary aims to present this well-developed breedi:ng method through discussing aspects of hydrobiology and energy transfer through the food chain as well. Capabilities and effects of agro-technical treatments such as liming and organic manuring, zooplankton management and possible supplementary feedings are also reviewed. Analysing chemical processes of waters uncovers that biological production has no carbon footprint; no carbon dioxide is released into the atmosphere. In contrast, gaseous carbon dioxide diffuses into pond water containing calcium and/or magnesium, then it accumulates in algae production and, through energy migration to upper trophic levels, increases carp production. Thus, it can be declared that pond-farmed carp provides an environmentally friendly, delicious meat among products of animal origin.

A review of solar and air-source renewable water heating systems, under the energy management scheme

Although traditional electric storage tank water heaters (ESTWHs) are the most frequently used systems in the world, they are known to be among the highest energy consumers, due to their inefficiency in converting electrical energy to thermal energy. These systems have grown increasingly hostile to consumers, as power prices have risen. Therefore, the need to reduce energy consumption of hot water production, while maintaining the users’ thermal comfort level, has led to the development of more energy-efficient technologies. In this paper, a review of renewable energy water heating systems, particularly air-source heat pump water heaters (ASHPWHs), solar water heaters (SWHs) and solar-assisted heat pump water heaters (SAHPWHs), as well as the background literature of the studies on these systems, carried out in South Africa, under the energy management schemes, is presented.

PGM-Free AEM Electrolyzer Cell Development for Solar Power Integration

The increasing availability of renewable energy sources, especially solar power, coupled with the desire to reduce greenhouse gas emissions, has led to an increased interest in using renewables to satisfy global energy demand. Hydrogen is an attractive alternative to fossil fuels due to its potential for emissions reductions and advantages in storage and transportation. Direct solar-to-hydrogen generation would enable the conversion of renewable energy and water into a storable fuel, thereby drastically reducing carbon emissions. However, current hydrogen production from commercial PEM electrolysis systems requires acidic environment which necessitates the use of expensive platinum group metal (PGM) catalysts and corrosion resistant cell stack components. Thus, a stable, robust, and inexpensive anion exchange membrane and PGM-free catalysts are needed to make alkaline solar water splitting commercially viable as a replacement for the expensive PEM system.We have developed a fully PGM-free electrolyzer using anion exchange membrane (AEM) in an alkaline environment that operates at 80 °C. Using carbon supported NiMo as hydrogen evolution reaction (HER) catalyst and NiFe as oxygen evolution reaction (OER) catalyst, in combination with commercially available AEM from Versogen, we were able to achieve a stable performance of 1.504 V at 100 mA/cm2, compared with baseline PGM cell at 1.508 V, in alkaline environment. At 2 A/cm2, the fully PGM-free cell demonstrated 200 mV higher potential compared to the PGM baseline cell at 2.009 V. Furthermore, we were able to run more than 200-hour at constant current density 2 A/cm2, with 85 mV performance loss. Further developments in catalyst performance and membrane stability, as well as integration with photovoltaics to enable hydrogen production from water, are underway. Acknowledgement: The project is financially supported by the Department of Energy’s Office of Science under the Grant DE-SC0020576

Understanding Gas Permeation during High Pressure Operation of PEM Water Electrolyzers

Governments and industries across the world have initiated implementation of clean hydrogen (H2) to achieve zero emissions, yet significant challenges remain for large scale adoption. With the decreasing renewable electricity cost PEM water electrolyzers (PEMWEs) show significant potential for at scale deployment due to their high faradaic efficiency and high operating current density. To reduce the per kilogram price of hydrogen and increase the overall energy efficiency, PEMWEs need to be operated at high differential pressures (30 to 50 bar) to eliminate the need for compression during storage and transportation1. To achieve high faradaic efficiency, thinner membranes are required to reduce voltage losses within the cell. However, thinner membranes exhibit a higher gas permeation rate which leads to increased crossover of hydrogen from the cathode through the membrane to the anode. Such increased crossover of H2 not only reduces the efficiency but can also result in flammable gas mixtures (lower flammability limit for H2 in O2 is 4 %) as Iridium/Iridium oxide (anode catalyst) is inefficient in oxidizing H2 1. The addition of a gas recombination catalyst (GRC) to the membrane is an useful strategy to oxidize permeating H2 and minimize the H2:O2 ratio at the anode.In this study, a high pressure (up to 30 bar) electrolyzer setup is coupled with online gas chromatography-mass spectrometry to understand the H2 gas permeation in membranes as a function of H2 partial pressure and operating current density (simulated by varying the flow rates) as shown in Figure 1 . Effect of the GRC, its loading, and its location on the H2 permeation will be elucidated. Differences induced by the addition of anode and cathode catalyst layers on H2 permeation rates will also be presented.Figure 1. Ex-situ H2 permeation rate at different cathode operating pressure at 80 °C. The anode was maintained at 1 bar of O2 partial pressure Acknowledgement This research is supported by the U.S. Department of Energy (DOE) through the Hydrogen and Fuel Cell Technologies Office, program manager Dave Peterson Reference Bernt, M., Schröter, J., Möckl, M. & Gasteiger, H. A. Analysis of Gas Permeation Phenomena in a PEM Water Electrolyzer Operated at High Pressure and High Current Density. J. Electrochem. Soc. 167, 124502 (2020). Figure 1

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Rising agricultural water scarcity in China is driven by expansion of irrigated cropland in water scarce regions

Balancing water scarcity, food production, and trade imperatives in the Caribbean: Could virtual water analysis help?

The food system of the Caribbean Community (CARICOM) transitioned from plantation-based agriculture to one based on small-scale production and high food imports. Through the ‘25 in 5 Plan’, the CARICOM hopes to reduce its US$ 5 billion annual food import bill by 25% in the next five years, mainly by import substitution. Virtual water analysis has the potential to reveal water consumption and fluxes in food production and trade in the CARICOM to highlight hydro-concerns for the anticipated food import substitution. This study, therefore, analysed the virtual water flows associated with maize production and trade in the Caribbean to explore the implications of import substitution for sustainable water use and food security. Maize production and trade matrix data for the period 2010–2019 were obtained from FAO databases, and virtual water content was obtained from the Water Footprint Network database. Virtual water flow was estimated as the product of the virtual water content of maize and quantity traded between any two trading partners. Net virtual water flows were estimated as the difference between virtual water of imported commodities and that of exported commodities for each Caribbean country and its trading partners. Additionally, the equivalent water demand for full import substitution was estimated. The results showed that maize import to the Caribbean was about twice the regional production and both intra- and extra-Caribbean trade were highly concentrated in few countries. The equivalent volume of water required to support full import substitution, at current yields and consumption, was larger than the total internal renewable water resources for some countries. It is concluded that, while there is room for import substitution and diversification to reduce both cost and risk, water scarcity considerations are necessary and can limit the scale of import substitution for key commodities such as maize. A regional approach that takes advantage of national differences in water endowments and production potential, while enhancing intra-regional trade and diversifying extra-regional sources of supply, should be given urgent attention.

Comparison between organic and conventional farming systems using Life Cycle Assessment (LCA): A case study with an ancient wheat variety

Assessing the environmental impact of agriculture is a key factor towards reducing human impacts on the food production chain. Because of the growing consumer interest in healthy foods cultivated with low-impact approach, a study assessing the impacts of ancient wheat variety in organic and conventional farming appears to be of great importance. Thus, this study was aimed at assessing and comparing the environmental impacts and resources consumptions of organic and conventional farming practices on an ancient soft wheat variety (var. Verna) in Tuscany, Italy. The fact that Verna wheat falls within the PDO bread specification, one of the few at the European level, increases the importance of this work. A cradle-to-grave life cycle assessment (LCA) from raw material extraction, through to industrial processing, field utilization, grain harvesting and finally transportation to storage centres was carried out. This study analysed data sampled over a five-year period (2014/2015 to 2018/2019) derived from five organic and conventional farms, respectively. The impact categories considered included: global warming, freshwater ecotoxicity, seawater ecotoxicity, terrestrial ecotoxicity, human toxicity, acidification, eutrophication, photo-oxidant formation, non-renewable energy resource consumption, renewable energy resource consumption, water consumption and land use. In almost all the impact categories, organic farming was shown to have lower environmental impacts, while conventional farming had a lower impact on land use. Results relating to acidification, photo-oxidant formation, ozone layer depletion and non-renewable energy resource consumption were considered similar for the two cultivation systems. Normalization of the results showed that seawater ecotoxicity had the greatest impact among all impact categories (> 99%) for both cultivation systems. Moreover, major environmental problems in conventional farming and organic farming were the use of synthetic N fertilizers and low yields, respectively. Results showed that 192 ×106 hectares of organic farming would be needed to maintain current wheat production in the EU, compared to just 99 ×106 hectares cultivated with the conventional farming. Accordingly, yield increase in organic farming, and reduction of nutrient losses/emissions from conventional farming, are the two most promising strategies towards maintaining a high agricultural production with concomitant reductions in the related environmental impact.

Design and Analysis of a Micro-Hydro Distributed Power System

The purpose of this study is to improve the standard way of producing electricity in a hydropower plant through the introduction of a more effective method. The aim of installing this Micro-hydro Distributed Power System is to achieve greater results in comparison to those attained with a standard micro-hydro power plant, without depending upon rainfall but upon two stored natural resources, air and water. This air supply will come from solar compressors and the water will be drawn from existing dams or runoff from rivers into storage tanks, which will generate electricity throughout the year at the same rate as the existing micro-hydropower that depends upon rainfall. The Micro-hydro Distributed Power System is a working pressure hydropower plant that generates electricity by compressing fluid into the system, using compressed air and is designed and analyzed in CAD design software and results are calculated to ensure the design is sufficiently durable to withstand the pressure, since the entire power system is dependent upon working pressure and how the power is generated using two major renewable sources, water and air. The Micro-hydro Distributed Power System’s working principle has been adapted from hydropower plants, the system converts H-Head(m) into pressure which is then used in the formula in (P=ρgh) to determine the power of the system. Theoretically, the findings of this study prove that the power to be generated, based upon the calculations, is much higher than expected before commencing the research, the power input needed for the Micro-hydro Distributed Power System based upon the compressor system’s rated power is 11KW to produce the 13 bars of pressure needed to compress fluid for maximum power output. At 13 bars the compressor system is found to be producing 398.3MW of power but at a high rate of flow of water which is found to be 391.907 L/s. A major advantage of the Micro-hydro Distributed Power System is that this water is pumped back into the tank from which it is re-used over and over again. This system depends entirely upon compressed air which is used to compress fluid through pipes, without this compressed air the water does not flow and cannot be pumped back into the system

Scaling-up Green Hydrogen Development with Effective Policy Interventions

Discussions around hydrogen as a future energy source have taken center stage in the last few years. Countries have recognized the benefits of hydrogen as an effective energy carrier and consider it a promising transition pathway to achieve net-zero objectives. Several countries support the development of green hydrogen as part of a long-term strategy. Among various hydrogen generation options (Green, Blue, Grey), green hydrogen generated from renewable electricity and water electrolysis is considered sustainable and climate safe. However, green hydrogen development is still at a niche stage and faces various technical challenges and economic viability issues. This paper discusses how effective policy interventions focused on addressing technical and commercial challenges can help scale-up green hydrogen generation. The paper discussed policy interventions by countries like France, Germany, Japan, the UK, the US, and other EU nations leading green hydrogen development and proposed a push-pull policy model. The proposed policy model combines demand-side policy interventions with supply-side policies to scale-up green hydrogen development.

Circular Water Economy in the EU: Findings from Demonstrator Projects

Circular economy (CE) for water aims to maximise value derived from water, processes, and practices. As a result, the recovery of wastewater and renewable water resources is used to offset the exploitation and impact of abstracting new water resources. New regulations such as the new circular economy action plan by the European Commission are emerging to promote circularity within the Green Deal agenda. However, there is still a need for research and practical insights into the interaction and integration of CE for water within existing policies and regulations, and its practical application specifically at the project level. This paper presents findings from demonstrator cases used to explore the opportunities and constraints in the policy, process, and procedural frameworks that govern water circularity in important sectors in Europe. Desk reviews are used to examine and compare European legislation against national and regional legislative frameworks within the different member states. Interviews and demonstrator project feedback enabled the exploration of the policy and value constraints at the project level. The findings provide unique insights into the policy and legislative enablers for and barriers to implementing CE for water in key sectors and specifically at the project level. The paper concludes with a five-point route map for new and revised policies and regulations targeting improved uptake of circular water technologies in Europe.

Revisiting Proportionality in Investment Arbitration: Theory, Methodology, and Interpretation

Abstract The increasing tensions between a government’s right to regulate and investment protection are fueling the constantly increasing number of international environmental disputes and human rights disputes, in particular with respect to renewable energies, water services, and waste management. As a result, investor-State arbitration is facing greater criticism than ever before because of its potential to contradict international environmental agreements and international human rights agreements. Concerns about State sovereignty are on the rise; particularly the perception that investment tribunals have failed to strike a proper balance between investors’ economic interests and general interests of host States to further their environmental policies and interests. Against this background, this Article investigates the methodological justification for the application of proportionality analysis while discussing potential channels in investment law to crystallize such application which would have deep practical ramifications for the global energy market. At a more conceptual level, this Article proposes an alternative viewpoint in understanding constitutionalization of international investment law and argues proportionality is indispensable discourse in investor-State arbitration.

Riboflavin synthesis from gaseous nitrogen and carbon dioxide by a hybrid inorganic-biological system

Microbes can provide a more sustainable and energy-efficient method of food and nutrient production compared to plant and animal sources, but energy-intensive carbon (e.g., sugars) and nitrogen (e.g., ammonia) inputs are required. Gas-fixing microorganisms that can grow on H2 from renewable water splitting and gaseous CO2 and N2 offer a renewable path to overcoming these limitations but confront challenges owing to the scarcity of genetic engineering in such organisms. Here, we demonstrate that the hydrogen-oxidizing carbon- and nitrogen-fixing microorganism Xanthobacter autotrophicus grown on a CO2/N2/H2 gas mixture can overproduce the vitamin riboflavin (vitamin B2). We identify plasmids and promoters for use in this bacterium and employ a constitutive promoter to overexpress riboflavin pathway enzymes. Riboflavin production is quantified at 15 times that of the wild-type organism. We demonstrate that riboflavin overproduction is maintained when the bacterium is grown under hybrid inorganic-biological conditions, in which H2 from water splitting, along with CO2 and N2, is fed to the bacterium, establishing the viability of the approach to sustainably produce food and nutrients.

Exploration of public stereotypes of supply-and-demand characteristics of recycled water infrastructure - Evidence from an event-related potential experiment in Xi'an, China

There is a growing consensus that recycled water, as an alternative and renewable water source, can serve as a vital water supply to alleviate water scarcity problem and in support of water resilience. Accordingly, recycled water infrastructure investment has seen a significant growth in recent years in many regions of the world. However, previous studies found the perceptions of public, the main end user, toward using recycled water for potable or non-potable purposes remain negatively stereotyped. The negative stereotypes led to public rejections to the construction and operation of recycled water infrastructure. Traditionally, public perceptions of recycled water uses are captured through self-reporting interview or survey techniques. To gain a more accurate measurement of the implicit public stereotypes toward recycled water uses, this study employed an event-related potential (ERPs) technique to collect neurophysiological responses with participants and presented a few research findings. Firstly, the negative stereotypes of recycled water still exist. Secondly, the degree of human contact impacts the negative stereotypes of participants toward recycled water uses more significantly on the supply side (referring to the whole supply chain of recycled water) rather than on the demand side (referring to the potential consumers of recycled water) Third, knowledge level significantly impacts the negative stereotypes of participants toward recycled water uses that have close human contact, at both supply and demand sides, and shows a more significant impact on the supply side. The findings of study contributed to the literature through creatively dividing the negative stereotypes of recycled water into the “supply-side” and the “demand-side” ones, and meanwhile have managerial implication for policymaking and scheme implementation in the area.

Analysis of water security and its worldwide context, 2000-2019

The water security (WS) approach must be practical and measurable to address water-related challenges. Since 2000, the term Water Security has been regularly mentioned worldwide. However, nowadays, there is still not an accepted definition either for a country or for a region. This research conducted a meta-analysis in the context of renewable water and global water stress, evaluating 873 scientific papers and 26 definitions of WS, using bibliometric network analysis, geographic information systems, and data mining to analyze the state of the art of WS. The results indicate that the definitions of WS have an anthropocentric character. The term economic in the context of WS definitions is the most relevant, and the term ecosystems are the least relevant. Less than 30 % of the definitions analyzed are operationalized through some measurement instrument. The most researched topics on WS are evaluation, management, and impact. On the frontier of study are the issues of water footprint, operation of springs, and awareness. In the world, countries such as the United States, China, and the United Kingdom, with little renewable water in their respective continents, are the ones that publish the most and try to define the concept of WS. Therefore, it is concluded that the main problem of WS definitions worldwide is that they cannot be operationalized in some local indexes, hindering their implementation. In addition, the environment has not been relevant in WS research and definitions.

A centralized stochastic optimal dispatching strategy of networked multi-carrier microgrids considering transactive energy and integrated demand response: Application to water–energy nexus

Over a few decades, energy system operators have sought to achieve appropriate frameworks based on the water–energy nexus issues due to energy crises and the rapid growth of water demand. In this regard, multi-carrier microgrids (MCMGs) have been widely welcomed to implement water–energy nexus-related strategies to meet local energy and water demands. This paper presents a centralized stochastic optimization strategy for energy transactions in networked MCMGs to exploit the potential capabilities of the promoted energy conversion facilities in meeting electricity, thermal, and water demands at the lowest operating cost. To enhance the flexibility and operational cost of the system under severe uncertainties, the day-ahead scheduling of all individual MCMGs is carried out by a central operator with the consideration of transactive energy management (TEM) strategy and integrated demand response program (DRP). The MCMGs can purchase energy from the electricity and gas markets to supply demands and energize local generation resources, and also exchange electrical energy with each other under the TEM strategy. The uncertainties arising from the renewable power generation, energy demands, water demand, and electricity market prices are applied to the optimization model using a scenario-based method. The proposed strategy is formulated as the mixed-integer nonlinear programming problem and is solved under GAMS software. The effectiveness of the proposed strategy is validated using a test system consisting of three networked MCMGs. According to the obtained results, the central operator can reduce the total operating cost of the networked MCMGs considerably if employing the TEM strategy and integrated DRP.