Recommendations for Energy Water Nexus Problems

Abstract

The chronic water problems in parts of India are probably due mainly to mismanagement. The rolling blackout and brownout problems in the larger Indian cities are due to lack of generation capacity. Since about ninety percent of the world's electricity is generated based on the steam Rankine cycle, environmental water is necessary for cooling, and freshwater is used as the working fluid. Furthermore, electricity is tied to water as part of the bigger water energy nexus phenomena occurring worldwide. China has started and continued with many initiatives to correct problems with water management. Projects do exist where the climatically dry north is being fed water from the wet south. China has water energy nexus conditions occurring too. The review of the scientific literature on studies about the sources of the Ganges, the Yangtze, the Yellow river, the Indus and the Mekong (the drinking water source of about forty percent of the World's population), the glaciers that feed these sources and how they are shrinking with global warming, has yielded a simple policy decision. Mass balance considerations provide the answer that the logical solution of the recent accelerated water changing from solid to liquid on mountain tops, requires dams and storage areas (lakes) to prevent all that freshwater from escaping to the lowlands, and ultimately being discharged into the oceans. One of the other major contributions in this work is to suggest conversion of (old) Rankine cycle generation of electricity to (new) combined gas cycle generation and/or simple gas cycle generation. The combined gas cycle generation can achieve efficiencies of 55–60%, while that of the Rankine cycle power generation languishes around 30%. Less water is required per MW electric power generated for condenser cooling in the combined cycle. The simple gas cycle generation can achieve 40% thermal efficiency on the average and use no water for cooling. There is also the suggestion to upgrade to supercritical power plants due to the advances in power plant technologies. The improved thermal efficiencies gained from this upgrade generate other benefits as well. Another contribution is the suggestion to use seawater for closed system condenser cooling in power plants that are not near the sea or ocean or any large body of freshwater. The open system seawater condenser cooling has been practiced for years throughout the world. This will definitely reduce the demand for freshwater, which could otherwise be used for human consumption or agriculture. Additionally, the rising seas problem locally may be reduced somewhat if enough of the seawater is used.