Wednesday, September 24, 2014

Water and Energy:

                       A Close Connection

Several recent items brought home for me the very close linkage between water and energy.  In particular, one study suggests that coal and nuclear power plants are vulnerable to climate change.  The study predicts that rising temperatures could exacerbate the problems we have seen in recent years with plants having to shut down because cooling water temperatures were too high.  Specifically, they predict that electricity production could be reduced by between 4 and 16 percent between the years 2030 and 2060 due to increasing temperatures.

The authors of the study drew the conclusion that this might mean that electricity production might have to shift from coal and nuclear plants to natural gas plants, which use less water.  They appeared to jump to this conclusion without considering other options, including the use of cooling towers and the use of advanced nuclear technologies that don't rely on water for cooling.  I have seen other suggestions that more plants in the future could be sited in coastal areas, thus having access to the oceans, which would not heat up the way confined bodies of water can.

Of course, I have to agree that each of these solutions faces challenges, but so does the greatly increased use of natural gas.  The point is that there is a potential concern in the future and we need to begin to think about ways to address it.

What was even more interesting to me, however, was another article that crossed my desk, this one saying that water is also an issue for some renewables.  The article reports that solar thermal farms that are more "financeable" also potentially use billions of gallons of water.  Since some of these projects are being sited in desert areas, that could become a significant problem.  They mention one project in Nevada that would require about 20 percent of the area's water supply.

Once again, this is not a dire projection of doom and gloom.  The article identified solar technologies that use less water.  These include a technology that places mirrors on towers, producing high-temperature steam, and using a dry cooling method.  They indicated that photovoltaics require water "only" to clean the panels.  However, I understand even that can be significant, as dust can reduce the output of a photovoltaic array significantly.  Further, they say that photovoltaic arrays are typically more expensive and less efficient than solar thermal farms.  For photovoltaics as well, research continues on ways to improve the efficiency and to clean the panels without water.

While the article didn't mention it, wind produces electricity without the need for cooling water.  But as I've indicated in other posts, there are other issues associated with wind.  Therefore, wind has a role in the energy mix, but as with every technology, there are tradeoffs.  

The point of this discussion is not to conclude that we have no options.  The point is to recognize the issues associated with the water needed to produce electricity and the possible trends, and to assure that growing constraints are considered as new technologies are developed. 

On a larger scale, of course, water and energy are linked at a more fundamental level.  Just as it takes a lot of water to produce electricity from most sources, it also takes a lot of energy to produce clean water, more so in places where water for human consumption needs to be extracted from seawater. 


1 comment:

  1. Nuclear and water can also work hand in hand. Some countries use nuclear power plants in conjunction with desalination plants. Lack of potable water is a huge problem in some parts of the world, and desalination uses a lot of energy. In addition, because water can be stored in large quantities, and electricity cannot, desalination can take place during low load times, thus helping balance electric loads.