By Frederik Groeman / Published on Tue, 2007-10-23 16:43
Frederik Groeman & Kees van den Ende, KEMA
When a river runs into the ocean and fresh water mixes with saltwater, huge amounts of energy are unleashed. Unlike violent torrents in a waterfall or steaming hot geysers, the energy released cannot easily be seen from the banks of the estuary. Nevertheless, the energy is there, and everyone who has tried to separate salt from seawater knows that large amounts of energy are needed.
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By Sergio Ferreira / Published on Fri, 2007-09-21 16:16
An increase in fossil fuel prices and geopolitical development will force the search for new energy sources. Because of global warming and the CO2 price this search will be for CO2 free energy sources. Breakthroughs in membrane technology started for desalination will open the route for salinity gradient power generation. Further development is needed, but a membrane market for power production will also significantly reduce membrane prices because of the scale. Blue Energy seems to be the most realistic salinity gradient choice for the use of the river-sea interface potential.
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By Sergio Ferreira / Published on Fri, 2007-09-21 13:36
The two membrane processes for energy production based on salinity gradients, pressure-retarded osmosis and reverse electrodialysis, have the following different characteristics:
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By Sergio Ferreira / Published on Fri, 2007-09-21 13:31
The main drawback of these membrane-based energy conversion techniques was the high price of membranes. The price of membranes was by far the main factor in the final high kWh price estimated in the eighties. The increasing price of fossil fuels and the added “negative price” for the CO2 emitted by fossil power plants made reconsideration of the available membrane-based processes for the production of sustainable power from salinity-gradient worthwhile.
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By Sergio Ferreira / Published on Fri, 2007-09-21 13:03
The vapor pressure of a salt solution is lower than that of pure water at the same temperature. This results in a higher boiling point for salt water. People have known this for centuries.
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By Sergio Ferreira / Published on Fri, 2007-09-21 13:01
From thermodynamics and the formulas of Gibbs free energy, ΔG including the chemical potential µ, it is known that a solution represents a lower chemical potential than the pure solvent. Nature tries to equalize the chemical potentials of two different solutions in contact which each other in order to create maximum entropy. So the driving force for the transport of a component, for example across a membrane between two solutions, is such a gradient in ΔG.
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By Bruno De Wachter / Published on Mon, 2007-08-13 07:30
Desalination by either evaporation (EV) or reverse osmosis (RO) is very energy intensive. However certain methods have been developed for reducing energy usage and greenhouse gas (GHG) emissions, as well as for powering installations where it is not feasible or is impractical to connect to the electricity grid.
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By Bruno De Wachter / Published on Thu, 2007-08-09 12:26
Closely linked to energy issues
Accessible fresh water resources around the world are severely limited. In fact they represent only 1 per cent of all water on earth. Desalination of abundantly available seawater is one solution for producing fresh water for drinking, cooking, sanitation, agricultural irrigation, and industrial applications. However, desalination is a very energy intensive process and its potential is therefore limited by the availability of cheap energy. Consequently, the global fresh water problem is directly coupled to global energy issues.
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By Hans De Keulenaer / Published on Sat, 2006-10-07 21:24
The Gulf states are preparing for the post oil boom era. Given their excellent strategic location between the West and Asia, the countries of Bahrain, Qatar and the United Arab Emirates are aiming to become a commercial hub and center of tourism. As a supplier of infrastructure, Siemens is involved in a number of projects in the region. Special examples include Shuweihat (photo), the most efficient power station and desalinization facility in the world.
Copyright Siemens
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