Comparing Energy Technologies:

The Many Shades of Green

I am pleased to report that I recently had an article published in Physics World called "How Green is Nuclear Energy?"  I developed this article in response to their request, and it was published as the lead article in their special issue, "Focus on Nuclear Energy."

The online version of the article at the link above attracted a number of interesting comments.  Several of the comments addressed areas that I hadn't covered in the article.  These were valid criticisms, but I was dealing with a strict word limit, and as I have observed many times, energy is a very complex area.  Any analysis of energy alternatives must address multiple dimensions, including economics, health and safety, environmental impacts, resource availability, and reliability.  And each of these areas has multiple dimensions as well.  For example, environmental considerations include impacts on air, water, and land.  To say nothing of the fact that some elements of the picture change over time--new technology developments, new resource discoveries, changing international political alliances, and other factors all affect the comparison of different energy supply alternatives.

So, when I undertook this assignment, the editor and I agreed that I should focus a lot on greenhouse gases (GHGs), since that is a major concern around the world today.  The editor also wanted me to address the issue of waste, as that is an issue that is often regarded as the Achilles heel for nuclear power. 

Even covering those areas proved quite a challenge, and in the end, I would characterize what I wrote as an overview of the topic.  I tried to mention other elements that could affect the comparison of energy technologies, but did not have the space to explain them.

Thus, some of the comments picked up on areas that I had only mentioned in passing.  For example, one comment noted that the impact of nuclear accidents on the environment might trump the benefits of nuclear energy.  This topic alone is a huge one, and to address it properly, one would have to compare region impacts versus global ones, short-term impacts versus long-term ones, the costs and potential for cleaning up from accidents versus dealing with climate change, and much more.  And, while the impacts of an event at a solar or wind farm may be small, one should then consider the whole life cycle of other technologies.  To cite just one recent example that crossed my desk, solar panels and wind farms use materials that are, to date, in limited supply.  However, some people believe that there are large untapped resources at the bottom of the sea--but mining materials for solar panels in the oceans can carry risks to the environment in case of accident that could be widespread and significant.

Other comments legitimately noted areas that I hadn't addressed.  One commenter, for example, spoke to the fact that we should reduce our use of energy.  I agree that conservation should be part of the equation (although the author of the comment may have had more in mind than the type of conservation I am thinking about), but trying to evaluate how much we could save was beyond my mandate.  Furthermore, globally, there are huge numbers of people who live in severe energy poverty, so the calculus of how much energy the world really "needs" quickly becomes very complicated.  My focus was limited to addressing nuclear power as one option to meet whatever energy needs society has, and to assessing nuclear power in terms of its effects on the environment, i.e., it's "greenness."

Another commenter observed that we may not really know how good or bad different pollutants are.  Can increased levels of CO2 be a good thing?  Can radioactivity lead to mostly good genetic changes?  And the author of that comment wonders if mankind will even be around forever, so what difference does it make?  Again, my mandate stopped far short of such apocalyptic musings.  The author of that comment does make a good point that perhaps there may be ways to recycle CO2 and use it, and indeed, there are researchers looking at just such things.  But, unless you feel that the fate of mankind is already determined and there is nothing we can do, I feel that our role is to plan the best we can for the world as we know it.  It is a delicate balance, I know.  You can't totally ignore the fact that we are working on improved ways to store energy, cheaper and more efficient solar cells, advanced nuclear reactors, nuclear fusion, etc.  I do not doubt that, 100 years from now, the conversation about the greenness of one source of energy or another might be very different.  But today, we can only operate on the best knowledge we have, and my comparisons are made in that spirit.

Finally, one commenter noted that I hadn't covered all the materials issues associated with power production.  In particular, that author mentioned the large amount of cement needed for nuclear power plants.  This one was of particular interest to me, because I have seen a lot of discussion of the materials requirements for different energy sources, and while current nuclear power plants are large structures and clearly require a lot of cement, most sources I've read point to wind and solar energy as the major culprits for large use of construction materials.  While a single windmill is, of course, much smaller than a nuclear power plant, the diffuse nature of the wind and sun creates a requirement for many windmills or solar panel structures, and the resulting use of materials is much higher, per unit of energy generated, for solar and wind plants than for nuclear plants.  One example of the comparisons I have seen is provided in a table by Breakthrough, that is based on data from a report by the University of Sydney, in Australia. 

My one brief article was not intended to address all the issues.  Nor was it intended to "prove" that nuclear power is the best of all options.  As I said in the article, there are clearly shades of green.  And there are shades of any other element of energy production we may care to examine.  The whole point of my writing the article is that we need to move away from the simplistic views of energy technology that regard wind and solar as green because it is natural, and everything else as bad.  Wind and solar power do have impacts on the environment, and a fair comparison of energy technologies has to look at multiple dimensions.  Each will excel in some areas and fall short in others, and finding the right balance is, and will remain, a difficult and imperfect process.

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Update May 5, 2017:  The graph below, from a Department of Energy report (Table 10.4, DOE Quadrennial Technology Review 2015), came to my attention after I posted this article.  I add it here as a further example of the materials requirements for different energy technologies:

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Energy, Economics and Correlation versus Causation:

Drawing the Right Conclusions

I recently came across an article that left me scratching my head.  Entitled "Economic development does mean a greater carbon footprint," it reports on a study by Max Koch, a professor in Social Work from Lund University in Sweden, and Martin Fritz from the University of Bonn in Germany, on the connections between growth, prosperity and ecological sustainability in 138 countries.  Professor Koch is quoted as saying that he conducted the study in an effort to test the assumption "that extensive investments in green production and sustainable consumption can increase economic growth without increasing the emissions of greenhouse gases."

That sounded like an interesting idea, so I read on.  They divided the world's countries into four groups based on their gross domestic product (GDP) per capita: poor countries, developing countries, emerging countries, and rich countries.  That's pretty standard, I thought.  But then they identified a category of 8 countries they called "overdeveloped."  These are countries in which the average annual income exceeds $50,000 (US) per person.  Five of the 8 countries in this group are identified:  the United States, Singapore and Switzerland, as well as "rich oil nations, such as Norway and Qatar."  Although the article didn't state the other three countries, it did include an infographic with a map that indicates the other 3 countries are Saudi Arabia, Kuwait and the United Arab Emirates. 

Hmm, I wondered, seeing the word "overdeveloped."  That seems to have a bit of a negative connotation, as in "more developed than they need to be."  Is a bit of bias creeping in?   And given the diversity of these countries, should the same designation really apply to all of them--as opposed to, for example, most of the rest of Western Europe, which merely falls in the category of "rich countries."

But I read on.  They then looked at the prosperity of the different groups of countries according to several metrics: ecological sustainability, social inclusion and quality of life (including life expectancy, literacy rates and subjective well-being).  Their conclusion was that there was greater social inclusion and the quality of life as the countries became increasingly wealthy at the expense of environmental sustainability such as greater emissions and carbon footprint.


While they acknowledged in some sense that the GDP and the environmental emissions might be separable, saying, "We are not saying that it is impossible to separate economic growth from ecological issues," they nevertheless go on to say that there is "a clear connection between economic development and increased greenhouse gas emissions that cannot be ignored."

From this, they conclude that, because of the urgent need to reduce emissions globally, "the possibility of economic degrowth should be seriously considered"--in other words, that economic growth should be given less priority as a policy objective than has been the case.

I had to wonder about this conclusion on several grounds.  In the first place, I don't think that the study ever really made the projections that had been promised.  I could see what the emissions are today, but I could not see an analysis of how different levels of investments in some of the many possible options--nuclear power, renewable energy, biofuels, energy-saving devices, etc.--might affect economic growth--and environmental conditions--in the future.

In the second place, it is likely that that the greatest impact of trying to achieve environment sustainability by curbing economic growth would be to condemn the poorest countries in the world to continued poverty.  Yes, I suppose the conclusion implies that the overdeveloped countries may have to shave their own growth, too, but clearly, the impact on richer countries will be much more modest than the impact on the poorest countries.  In effect, the benefits of an improved global environment will accrue to all countries, but the poorest countries would bear a disproportionate share of the burden. 

Therefore, while the kind of data gathered in this study can be very useful, I believe that the authors have not looked at all the dimensions of the issue.  Given the seriousness and importance of the issue, I think that is a serious shortcoming of the study.  While I do not expect to find a solution that allows the world to "have its cake and eat it, too," I think far more exploration is needed of all the issues and options before we conclude that we need to move civilization backwards. 

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