Access to water and water that is cool enough to operate power plants could be an Achilles Heel for some power plants and electric systems, as the massive drought gripping 54.6% of the lower 48 states continues. Most power plants don't operate without continuous access to large quantities of water and cool enough water. Electricity generation cumulatively accounts for more than half of all water usage, so the massive drought could become an obstacle to power production in parts of the USA.
Risks to power generation rise the longer the drought goes and the bigger the drought grows. Already, the current drought is the biggest in 50 years, according to the National Climatic Data Center.
http://www.weather.com/news/drought-disaster-new-data-20120715. The NCDC puts this year's drought among the nation's ten largest of the last century and akin to those of the notorious Dust Bowl.
Power plants can be divided into gulpers and sippers of water. Nuclear and coal power plants, in particular, use enormous quantities of water for cooling purposes, and the drought may hinder operations, if it persists much longer. johnhanger.blogspot.com/2012/07/gulpers-sippers-ranking-gas-coal-nukes_05.html. Hydro production, of course, falls significantly during droughts, while wind and solar PV do not consume water at all.
As the drought continues and the heat smashes records, another fact to watch is the temperature of water used by power plants to cool. Some power plants cannot use water that becomes too warm and have curtailed operations in the USA, France, and elsewhere as a result.
When air-conditioning is maxed during the hottest 100 hours of the year, every possible power plant and demand response resource can be needed to keep air conditioners and lights running. Grid systems are stressed. And during those peak demand hours, the loss of any generation for any reason endangers reliability.
This drought reminds that the water needs of the various power generation types can be an important factor in determining what plants are best operationally, economically, and environmentally. In some locations, the supply of water and cool-enough water are as important as capital costs and fuel costs in judging what to build in the future.