Friday, September 11, 2015

Impacts of Renewable Energy Sources:

More Unexpected Consequences

This is getting to be somewhat of a theme with me, but everywhere I turn, I find reports of new and unexpected consequences associated with the greater use of renewable energy sources.  This week, I I learned of two new potential impacts on the same day, so I just had to return to the topic. 

The two reports apply to different areas:  One calculates that more wind turbines may offer diminishing returns--that is, as wind farms are expanded, the energy generated will not go up proportionately with the number of wind turbines installed.  The other pertains to hydroelectric plants, raising the surprising (to me) concern that hydroelectric plants may create conditions that generate an environmental poison called methyl-mercury. 

The first issue, the impacts of wind turbines, arises from the fact that large numbers of wind turbines may affect wind patterns.  I had heard this before, and while it isn't my area of expertise, it seems plausible.  It also initially seems unimportant.  So what if the gain isn't linear?  Just build more windmills, right?  Wrong.  More windmills require more land, and getting less bang for the buck increases the cost of wind energy.

The second issue is more complex, and is way out of my area of expertise.  The argument is that the flooding associated with hydroelectric dams (at least in the Arctic) creates areas where fresh and salt water merge.  The differing densities cause them to stratify, which creates a feeding zone for marine plankton.  The bacteria in this zone turn naturally occurring mercury into methyl-mercury, which then accumulates in the food chain.  (The article also notes that the melting of Arctic ice due to climate change has a similar effect.)

I must admit that I have a lot of questions about both studies.  How thorough and complete are the studies?  How pronounced is the non-linearity of the windmill effect?  Can the design and layout of the windmills make a difference?  Can anything be done to reduce the stratification of the fresh and salt water?  Can the methyl-mercury be removed? 

The point of mentioning these studies is not to imply that we have to stop building windmills or hydroelectric dams.  Rather, it is to point out that ALL energy sources have effects on the environment.  As we use more and more of any resource, these impacts become more apparent.  The response should not be to ban the use of the resource.  Rather, it should be to continually improve our understanding of the impacts, to design ways of reducing or ameliorating the impacts, and to look at the big picture--both supply and demand.

So, why am I covering these issues in a blog on nuclear power?  It is because I see some parallels to the way some people view nuclear power...or coal, or anything else.  The first time early hominids rubbed two sticks together and created fire, they probably burned themselves.  The point is that every form of energy--in fact, every agricultural or industrial activity--has impacts on the world around us. 

The first, and seemingly easiest, response is to ban the activity.  That is a short-sighted reaction.  The mindset we need to develop is to figure out how to manage the resource and its impacts.  This applies equally to every energy resource, and to every other human activity as well.


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