Salinity gradient energy: awaking the silent waterfalls at rivers mouths

由于人口增长和工业发展，全球能源需求不断增加。随着气候变化和全球变暖，可再生能源正以迅速加快的速度被采用。然而，许多可再生能源（太阳能、风能、潮汐能、地热能和水能）具有较低的可利用系数和季节性发电变异性。因此，柴油发电仍然是偏远地区（如安大略省北部和世界许多地方）社区的主要能源来源。考虑到柴油发电的高成本和对环境的影响，有一种可再生能源替代品尚未被开发。盐度梯度能（SGE）是在控制过程中混合两种不同盐度的水溶液所能获得的能量。这种能量来自于水溶液渗透压的差异。SGE作为一种极具前景的可再生能源，最近引起了人们越来越多的兴趣。然而，在SGE成为一种实用的能源之前，还有许多科学和工程方面的挑战。

Global energy demand is continuously increasing due to population growth and industrial development. With climate change and global warming, renewable sources of energy are being adopted at rapidly accelerating rates. However, many of the renewable energy sources (solar, wind, wave, geothermal, and hydro) have lower availability factor and seasonal generation variability. Therefore, diesel-generated electricity remains the main source of energy for communities in remote regions such as in Northern Ontario and many parts of the world. Given the high cost and environmental impact of diesel-generated electricity, there is a renewable energy alternative which has not yet been tapped. Salinity gradient energy (SGE) is the energy available from mixing two aqueous solutions of different salinity in a controlled process. This energy arises from the difference in osmotic pressure of the aqueous solutions. SGE has attracted growing interest recently as a highly promising source of renewable energy. However, many scientific and engineering challenges remain before SGE can become a practical energy source. This research program aims to develop SGE technologies and take them from theory to practical application. A long-term research goal is to provide techniques to generate electricity using available aqueous solutions of different salinity as found at river mouths where fresh water from the river meets seawater, or where industrial brine or wastewater is discharged into fresh surface water. The approach to achieve this aim includes: (i) developing theoretical and experimental studies to simulate and validate SGE processes, (ii) investigating membrane fouling, which is not totally understood with the aim of developing models suitable for the prediction of fouling and to mitigate its effect, (iii) applying pore network modeling (PNM) techniques to model the transport of water through the membranes and to suggest preferred membrane structures, (iv) designing and optimizing SGE systems and membrane modules to maximize power generation, and (v) conducting energy and exergy analyses to assess the performance of developed systems and configurations. This research program will contribute new fundamental knowledge in membrane and energy fields. HQP will be trained in thermofluid sciences including modeling, measuring, validating, designing, and analyzing SGE systems. SGE can offer economical and environmental benefits by providing clean energy solutions to communities in remote regions of Canada with a wide-vision for communities on river-ocean regions worldwide. It will also provide social benefits by enabling more sustainable urban development for future generations by providing their energy demands and improving their environmental conditions. In addition, it will impact the economy and many industries, particularly the evolving and expanding Canadian clean energy industry.