Oh. Oh. Finally a discussion of the toxicology of solar cells is appearing in the scientific... [View all]

[NNadir]

...literature.

The solar industry, in my view, is useless. World wide, after the "investment of" - I would choose the words "squandered" on - of trillion dollar scale resources for this industry, it does not produce even two of the five hundred sixty exajoules of energy that humanity consumes each year. Moreover, this industry has done nothing, absolutely nothing, to arrest climate change. Despite the massive investment in solar energy, 2015 was the worst year ever recorded for increases in carbon dioxide - dangerous fossil fuel waste - the first year in which these concentrations rose by more than 3 ppm in a single year, 3.05 ppm exactly as recorded at the Mauna Loa carbon dioxide observatory.

2016 is clearly on track to blow 2015 away as the worst year ever observed.

Solar energy is often referred to as "renewable energy," although this too is a joke, since the industry is entirely dependent on access to increasing rare materials, many of which are highly toxic, and which must be mined at great risk to the miners. As I've pointed out many times, one element utilized in the solar industry, cadmium, is now widely found in rice in large stretches of China.

One sees, occasionally, if one takes the time to look, lots of discussion of heavy metal poisoning associated with some of the elements utilized in the solar industry, although seldom is the linkage explicitly made. One must both know the composition of solar materials, the toxicology of the metals involved, and something about their environmental distribution to understand this relationship, at least generally.

Twice a month, as issues are released, I undertake readings in one of the world's most prominent environmental scientific journals, Environmental Science and Technology, a favorite journal of mine.

I was very pleased to read a paper that explicitly refers to the risks associated with solar cells as solar cells.

The paper is here: Bulk Dissolution Rates of Cadmium and Bismuth Tellurides As a Function of pH, Temperature and Dissolved Oxygen

(Environ. Sci. Technol., 2016, 50 (9), pp 4675–4681) (Full access to the paper may require a subscription, payment, or access in a good scientific library.)

Some excerpts from the text:

Tellurium is an extremely rare element in the earth́s crust with an estimated upper continental crust abundance of 0.027 ppm(1) and its distribution and fate in the environmental compartments have been comparatively little studied. There is considerable uncertainty as to its likely concentration in natural waters.(2) Some 123 tellurium bearing phases are known to occur as natural minerals.(3) None of these are abundant enough for economical exploitation. Tellurium, a chalcophile element, also occurs as an impurity in sulfidic copper and nickel ores, thus the element is extracted from mining and refining residues of the copper and nickel industries. It is only over the last two decades that economically significant technological applications of tellurium compounds have emerged. It has recently been identified as one of the key technologically critical elements.(4) Metal tellurides are semiconducting materials, and CdTe is gaining importance as an absorber in thin-film photovoltaic conversion modules, owing to its band gap of 1.49 eV,(5, 6) which exactly coincides with the mean energy of solar light. The principal advantage of CdTe photovoltaic cells lies in the combination of low cost and high conversion efficiency. CdTe is also used in photoconductors, specifically in the manufacture of gamma and IR radiation detectors.(5) ...

...Cadmium is known to be extremely toxic to all forms of life,(11) the toxicity of tellurium is still little understood,(11) even though clear adverse health effects have been known for nearly a century,(12) whereas bismuth—used for more than a century in medicine in the treatment of disorders of the digestive tract and in dermatology(13)—is generally considered as environmentally benign(11, 14) although there are reports of genotoxicity of Bi2O3 nanoparticles,(15) inhibition of growth of soil microorganisms(16) and the neurotoxic potential of some bismuth compounds has been confirmed.(17, 18)

Thin films of CdTe, as they are employed in solar modules, are believed to be environmentally quite safe, because the compound is thermally extremely stable (melting point 1042 °C)(19) and it is sealed within glass plates and contained in between thin layers of other compounds. Fortunately, CdTe can be recycled from used modules in excellent yield.(20) Nevertheless, the rate of release of problematic elements such as cadmium and tellurium from these important industrial materials ought to be known, as accidental release (due to inadequate handling or disposal of the finished products or the compounds themselves) can never be ruled out...

From the conclusion of the paper:

As neither of the two substances showed any signs of passivation during dissolution, one must assume that they would dissolve completely under environmental conditions, but as the measured rates are slow on an absolute scale, the accidental release of these compounds into the natural environment would hardly pose a threat and would in any case leave ample time to be tackled. From this perspective, and given their good thermal stability, it appears that both CdTe and Bi2Te3 are indeed environmentally safe materials. However, both will readily dissolve under long-term deposition conditions such as in landfills or uncontrolled open dumps, with the corresponding complete release of their potentially noxious elements, that is, cadmium and tellurium.

The way I read this conclusion is that the authors find that the solar cells are "safe" for now, but they may have tragic consequences for future generations.

Don't worry, be happy. The way we now conduct our lives shows that it is socially acceptable, completely consistent with our practice in every aspect of our lives, to not give a rat's ass about future generations. The reason we are having children, and grandchildren, and great grandchildren is because we expect them to clean up our mess, and if they can't do that, that's their problem and not ours.

Screw 'em if they can't take a joke.

I'm not really sanguine about the conclusion that "release of these compounds would hardly pose a threat." Other literature shows that they are a threat already, that they are tracked, and nothing, absolutely nothing can be done to remediate exposure to them. Were it possible to remediate these exposures, hundreds of millions of Chinese wouldn't be eating rice laced with cadmium.

Still, the authors failings aside, it's very clear that at least the topic is coming up. Distributed energy, I have long contended, is nothing more than distributed pollution, for the long term at least, and the fact that the solar industry - a failed industry in terms of environmental goals - is still insanely popular is, um, well, insane, and a full measure about how little we care about what we do.

Have a great evening.