Thursday, September 17, 2015

Resource Issues and Energy Supply:

What it Means for Our Energy Future

Initially, this is going to look like another article on renewable energy in a blog that is supposed to be about nuclear issues.  But bear with me, this is actually about an article on the resource issues associated with renewable energy that has sparked some broader thoughts. 

The article (which is a few months old, but I only recently saw) starts off listing some of the same issues regarding renewable energy that many, including yours truly, have commented on.  It says that people assume that the wind and the sun are free and limitless, but they need more land, and lots of raw materials:

  • Wind turbine towers are constructed from steel manufactured in a blast furnace from mined iron ore and modified coal (coke). Turbine blades are composed of oil-derived resins and glass fibre. The nacelle encloses a magnet containing about one third of a tonne of the rare earth metals, neodymium and dysprosium.
The article goes on to talk about the waste generated in mining and processing rare earths, the cement needed to build towers for wind turbines, the coal needed to process silicon solar collectors, and the greenhouse gases other than CO2 generated in the manufacturing process.

So far, I'm with the author.  I have seen reports on all these effects before, and have commented on them myself.  I believe they are true and that they should be a concern to everyone who is interested in our energy future.  (Which should be just about everyone, in one way or another.)

However, the article ends in a single paragraph, that says, by contrast, that there is plenty of uranium and thorium for nuclear reactors, and that, anyway, the future is in fusion.  That is quite a leap.

That got me thinking about a comment I received on a recent post that took issue with me for supporting an "all of the above" scenario because of the added cost.  Addressing that comment fully is a subject for a future discussion, but suffice it to say that the "all of the above" scenario basically arises from the fact that no one energy source can solve all problems and meet all needs.  

The reality is that the author of the article I read didn't treat all resources equally.  You can find other authors who dismiss nuclear fission because the uranium and thorium resources are ultimately limited.  And fusion is not yet a realistic option.

The reality is that all energy resources have some limitations.  It may be true that there is more thorium than rare earths, but I doubt that either resource has been fully identified and explored.  It may be true that mining rare earths generates by-products, but so does mining anything. 

Also neglected in the article is any discussion of whether some of these downsides can be ameliorated.  I always got annoyed when people who opposed nuclear power talked about the coal needed to supply the power to operate gaseous diffusion enrichment plants.  Not only did they grossly exaggerate the amount of energy needed, they never considered that we could move away from using coal for this purpose.  That may be a moot point now, but the same point applies to the issue of coal use for manufacturing solar collectors.

My point is that there is no simplistic answer.  "Renewables bad, nuclear fission and fusion good," is no better than "Nuclear and coal bad, renewables good."  Both views are short-sighted.  They fail to address the benefits and short-comings of all technologies equally, and they fail to consider how current practices might be improved for all technologies, and in some cases--or alternatively, they wave away any concerns by assuming advances that have not yet been demonstrated.

Unfortunately, complexity makes things difficult.  There are no simple answers, no brief soundbites, no quick solutions.  But our energy future depends on understanding and addressing the complexities.  


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.