About this Research Topic
Demands for clean water and energy have been increasing strongly since the industrial revolution and changes in lifestyle. There is a strong water-energy nexus as a large volume of water is needed to produce energy from different sources and simultaneously energy is needed to produce potable water from different sources.
Water for energy:
The production of oil and gas, geothermal energy and mining of coal from subsurface reservoirs requires water. For example, water is flooded with different chemical agents in subsurface oil reservoirs during secondary and tertiary oil recovery. On average the volume of water required is roughly 10 times the volume of oil recovered. Similarly, an Enhanced Geothermal System requires approximately 2 L of water to produce 1 kWh of energy and about 250 L of water is needed to mine 1 tonne of coal. A large amount of water is also needed for hydro-fracking, cooling related to power plants and ash disposal in coal-based plants. During cooling around 3 L of water evaporates to produce 1 kWh of electrical power from thermal power plants.
Energy for water:
While the demand for freshwater is increasing, many surface and ground water bodies in some regions, especially in the Global South, are getting contaminated due to an unsustainable development agenda. Climate change is also having a significant impact. To sustain the growing domestic, agricultural and industrial demand for water, water reclamation and reuse is being thought of as a possible solution. Declining groundwater levels require more energy for pumping. In many coastal cities, seawater desalination appears to be a reliable solution to bridge the demand-supply gap. However, desalination is very energy intensive; the specific energy consumption by reverse osmosis desalination is ≈4 kWh/m 3 of freshwater. New technologies for atmospheric water extraction/generation/harvesting also consume energy at a high rate of approximately 4.7 kWh/m 3 , especially in dry conditions. Presently, energy is mostly taken from the electric power grid or diesel generators. Irrigation and water distributions are also very energy intensive process. Some recent studies have found that the energy requirement can be in the range of 0.34 – 1.56 kWh/m 3 .
Therefore, renewable energy sources are being actively sought for irrigation; water and wastewater treatment, desalination etc. Desalination plants, supported by solar, wind, wave energy plants are becoming popular. Geothermal energy can be used directly for thermal desalination and indirectly for reverse osmosis based desalination.
As the demands of energy, water and the inter-dependency between them are ever-increasing, it is critical to find sustainable solutions where renewable energy can be utilized to obtain clean water without impacting the environment and climate. Research and development needed to harness locally available renewable energy to meet the demand of clean water should be prioritized by Academic Institutes, R&D Labs, Industries and Funding agencies.
In this context, different research areas can cover crucial roles. For example, control systems engineering can be significant at the different layers of the automation hierarchy through Advanced Process Control, Real-Time Optimization, Expert Systems and Decision Support Systems. Monitoring, control, and optimization are fundamental requirements to improve the efficiency and the benefits obtained in the water and energy cyber physical systems.
Proposal for a Research Topic: This article collection in Frontiers in Water aims at publishing fundamental and applied scientific research which may lead to the finding of new sustainable solutions for the following topics: (i) Water treatment, water reuse, desalination of seawater and brackish water by renewable energy and (ii) Technology development to reduce the need for water in energy generation sector.
Water for energy:
The production of oil and gas, geothermal energy and mining of coal from subsurface reservoirs requires water. For example, water is flooded with different chemical agents in subsurface oil reservoirs during secondary and tertiary oil recovery. On average the volume of water required is roughly 10 times the volume of oil recovered. Similarly, an Enhanced Geothermal System requires approximately 2 L of water to produce 1 kWh of energy and about 250 L of water is needed to mine 1 tonne of coal. A large amount of water is also needed for hydro-fracking, cooling related to power plants and ash disposal in coal-based plants. During cooling around 3 L of water evaporates to produce 1 kWh of electrical power from thermal power plants.
Energy for water:
While the demand for freshwater is increasing, many surface and ground water bodies in some regions, especially in the Global South, are getting contaminated due to an unsustainable development agenda. Climate change is also having a significant impact. To sustain the growing domestic, agricultural and industrial demand for water, water reclamation and reuse is being thought of as a possible solution. Declining groundwater levels require more energy for pumping. In many coastal cities, seawater desalination appears to be a reliable solution to bridge the demand-supply gap. However, desalination is very energy intensive; the specific energy consumption by reverse osmosis desalination is ≈4 kWh/m 3 of freshwater. New technologies for atmospheric water extraction/generation/harvesting also consume energy at a high rate of approximately 4.7 kWh/m 3 , especially in dry conditions. Presently, energy is mostly taken from the electric power grid or diesel generators. Irrigation and water distributions are also very energy intensive process. Some recent studies have found that the energy requirement can be in the range of 0.34 – 1.56 kWh/m 3 .
Therefore, renewable energy sources are being actively sought for irrigation; water and wastewater treatment, desalination etc. Desalination plants, supported by solar, wind, wave energy plants are becoming popular. Geothermal energy can be used directly for thermal desalination and indirectly for reverse osmosis based desalination.
As the demands of energy, water and the inter-dependency between them are ever-increasing, it is critical to find sustainable solutions where renewable energy can be utilized to obtain clean water without impacting the environment and climate. Research and development needed to harness locally available renewable energy to meet the demand of clean water should be prioritized by Academic Institutes, R&D Labs, Industries and Funding agencies.
In this context, different research areas can cover crucial roles. For example, control systems engineering can be significant at the different layers of the automation hierarchy through Advanced Process Control, Real-Time Optimization, Expert Systems and Decision Support Systems. Monitoring, control, and optimization are fundamental requirements to improve the efficiency and the benefits obtained in the water and energy cyber physical systems.
Proposal for a Research Topic: This article collection in Frontiers in Water aims at publishing fundamental and applied scientific research which may lead to the finding of new sustainable solutions for the following topics: (i) Water treatment, water reuse, desalination of seawater and brackish water by renewable energy and (ii) Technology development to reduce the need for water in energy generation sector.
Keywords: Rational Usage of Water, Renewable Energy, Advanced Process Control, Real-Time Optimization, Expert Systems, Decision Support Systems, Water Treatment and Distribution, Desalination, Specific Energy
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.
