Hired To Investigate Solar Panels, Here's What We Found
Subscriber hired investigation turns up major issues
Disclaimer: This does not constitute financial advice. Speak with a financial professional.
Correction: The article did not mention that CdTe solar panels make up only roughly 8% of solar panels in the US. This correction has been added to alleviate concerns on prevalence.
As some of you may not be aware, The Daily Beagle started offering their services for hire (details for that will circulate soon) on a private basis.
We were recently hired by a subscriber to conduct a private investigation into Cadmium-Telluride (CdTe) solar panels over possible risks, and with their permission we are republishing the information out of public interest given some surprising discoveries.
Not only did we find alarming market signals on supply chain issues, we also uncovered incorrect chemical risks published by a reputable organisation — and got the information corrected.
What Is A Cadmium-Telluride Solar Panel?
Cadmium-Telluride solar panels are solar panels that make use of Cadmium-Telluride in either their wafers or surface structure as a means of absorbing energy from sunlight.
Sometimes Cadmium-Telluride is colloquially (and inaccurately) used to also mean Cadmium-Zinc-Telluride (CdZnTe) solar panels, however CdZnTe solar panels are not the focus of this discussion, and we are focusing solely on Cadmium-Telluride. CdTe solar panels come in two flavours.
The first is a typical solar panel design, which is reportedly cheaper than a solar panel using conventional materials, but also less efficient (~18% average compared to ~20%), as a result, it is often deployed in large solar panel installations and fields where price point is more important than efficiency of space.
The second flavour is thin-film photovoltiacs (PVs), as a means to take up less space and as a more flexible medium for more novel shapes. Visually CdTe solar panels (shown above) are not too distinct from conventional solar panels.
There are only a limited number of CdTe solar panel manufacturers is the world (18 world wide at time of writing), with only four operating in the US. First Solar are the biggest out of the four by a wide margin.
Where Does Cadmium-Telluride Come From?
Cadmium-Telluride is compound manufactured from Cadmium and Tellurium (not very surprising, we know). Cadmium is a rare earth element, whilst Tellurium is a very rare earth element. This means it is only found in very limited qualities in very select locations.
Tellurium is a byproduct of porphyry copper deposits, and it is estimated about 1000 tons of copper ore will only yield about 1 kilogram, or 2.2 pounds, of Tellurium, meaning it requires very extensive and destructive copper mining in order to ‘sustain’.
Descriptions of what porphyry copper deposits are vary, and where Tellurium deposits are found is not clearly known, however according to USGS, it is associated with areas with volcanic veins and similarly (see page 11).
In plain speak, this means it is only found in very select locations, either along the ‘Ring of Fire’ or near volcanic regions, and isn’t something you can just harvest from ‘any old copper mine’. This means it has serious supply constraints which are geographically restricted (read: national security risk).
Supply Of Tellurium Is Very Constrained
Whilst Cadmium-Telluride does have usage for neutron dosimetry in nuclear systems, and in the detection of X-rays and Gamma rays, it is most significantly used by the solar industry. According to USGS, an estimated 30% of the world’s produced Tellurium is used by First Solar Inc, and 40% is used by the solar industry in total (page 13).
First Solar are an American manufacturer, and in the whole of the US, there is only one recycling plant for Cadmium-Telluride solar panels, operated by First Solar, based in Ohio, and only one Tellurium refinery in Texas, meaning supply bottlenecks are a very real possibility.
It one of the few solar panels that can be produced domestically within the US. That said, copper mining — used to produce Tellurium — produces a lot of pollution and waste, prompting fights over copper mining in a number of States, including Minnesota and Arizona. USGS predicts that Tellurium will be near-critical by 2025 (page 13).
PubChem Makes A Mistake On Toxicity
Whilst investigating the environmental impact of Cadmium, Tellurium, and Cadmium-Telluride, The Daily Beagle uncovered a number of incorrect records regarding the legislation and toxicity of the substances.
The Daily Beagle found that PubChem had incorrectly claimed that Cadmium-Telluride was classified as ‘Substances of Very High Concern’ (along with Cadmium) under EU REACH legislation.
REACH somehow stands for Regulation for Registration, Evaluation, Authorisation and Restriction of Chemicals (wouldn’t that be RREARCH?), and refers to EU legislation that regulates toxic substances.
In attempting to verify PubChem’s claims, The Daily Beagle contacted the ECHA (European Chemicals Agency).
One ECHA Regulatory Support Teammember, Mr Eduardo, responded and stated that Cadmium-Telluride was not on ECHA’s list of ‘Substances of Very High Concern’, referring to the ECHA’s candidate table list for SVHCs, which a cursory search reveals Cadmium-Telluride is not among them.
The email was promptly referred on to PubChem with a request for comment from PubChem, asking if they anticipated other errors in chemical information reporting. They avoided addressing this question, even after follow up.
PubChem spokesperson Mr Evan responded, claiming that PubChem had indicated it was a ‘REACH restricted substance’ and ‘not a Substance of Very High Concern’, however he admitted the giant title in bold letters saying “Substance of Very High Concern (SVHC)” was misleading.
PubChem have since rectified the issue, and have changed the title, so the section now more accurately says “Highly Hazardous Substance”, including on Cadmium and similar pages.
This might seem like a technicality in naming to some, but SVHCs are subject to very stringent regulations within the EU, which do not necessarily apply to non-SVHCs, and reflects heavily on the accuracy of The Daily Beagle’s reporting on Cadmium-Telluride solar panels and the issues they face.
Cadmium Is Extremely Toxic
Used in the earliest nuclear plants to control chain reaction, Cadmium is also found in tobacco plants. Cadmium is a notoriously toxic substance (surprisingly so), with the ECHA registering Cadmium under REACH.
Cadmium is reported by PubChem (post-correction) to cause, among many things:
Spontaneous fires (reacts with air)
Inhalation poisoning (acutely toxic)
Genetic mutations/defects (mutagenic)
Cancer (carcinogenic)
Infertility
Organ damage
Acute toxicity in aquatic environments (including long-lasting effects)
Overall, Cadmium is an extremely nasty substance. It is not classified as a Substance of Very High Concern by the ECHA, it is however registered under REACH (along with various Cadmium compounds), but you already knew that.
This means Cadmium-Telluride solar panel manufacturing brings with it extensive risks and environmental pollution issues with the transport of Cadmium.
Cadmium-Telluride Is Also Very Toxic
PubChem (post-correction) notes that Cadmium-Telluride is toxic to both the liver and reproductive systems, and that it is harmful in many circumstances, including:
Skin contact (can be absorbed through the skin)
Via ingestion
Via inhalation
In aquatic environments where it is very toxic, with long-lasting toxic effects
This makes Cadmium-Telluride waste a risk to the environment. Given there is only one recycling plant in the entirety of the US operated by a private entity, there is a grave risk that if recycling operations shut down, people and businesses will be inclined to dump these toxic materials into landfill sites, causing environmental run-off.
There is also the additional hazard involved if the solar panels get broken and the Cadmium-Telluride materials exposed to the general environment. Solar panels can be easily destroyed during hurricane events, especially in high speed winds, or heavy impact from flying debris.
Cadmium-Telluride Solar Panels Are Difficult To Recycle
First Solar and the EPA (Environmental Protection Agency) both stonewalled queries from The Daily Beagle about which parts of Cadmium-Telluride solar panels cannot currently be recycled. The Daily Beagle suspects First Solar know there are key components they cannot recycle, and have opted instead for rude silence.
The Daily Beagle dug deeper, and 911 metallurgist reported on their site that Cadmium-Telluride solar panels require ‘high quality’ Cadmium-Telluride that is free of defects and impurities in order to work, and thus Cadmium-Telluride wafers cannot currently be directly recycled due to Oxygen contamination:
Extremely high-purity materials are required for semiconductors; thus, direct reuse even of the PV manufacturing scrap is impossible with current technology. For example, cut CdTe wafers cannot be remelted and grown into new crystals because of oxygen and other atmospheric contaminants that accumulate on the wafer surfaces during cutting.
From A Market Standpoint, Seems Unsound
This leads The Daily Beagle to believe that Cadmium-Telluride solar panels, from a market investment and environmental perspective, are a ticking environmental timebomb, as the materials cannot be recycled properly, and pose a major environmental toxicity problem.
This is coupled with the fact that supply constraints and rising costs for Tellurium (sourced from copper), with near-critical thresholds in 2025, will negate any ‘cost saving’ advantage the CdTe solar panels might have over conventional solar panels, meaning that they will either match or exceed costs, but with the downside of lower efficiency.
The inability for solar manufacturers to fully recycle Cadmium-Telluride solar panels, will mean that costs will not remain neutral, and eventually recycling will not be financially sound. This will lead to many people owning Cadmium-Telluride solar panels but with no way to have them properly recycled.
From An Environmental Standpoint, Seems Risky
On top of this, the requirement for very extensive — and thus destructive — copper mining to sustain Telluride in a world becoming more adverse to mining and environmental destruction, is not likely to remain popular or viable long-term. The limited choice of deposits means if mining permits are rejected in those areas, then there aren’t many other alternatives to choose from.
Given Cadmium and Tellurium serve critical interests in other industries, it does not seem sensible to use excessive amounts of a very rare material in bulk manufacturing of solar panels. Especially given that Cadmium is extremely toxic, and Cadmium-Telluride is also very toxic, and pose environmental risks, especially to aquatic life and thus possible water run-off contamination (read: fish and drinking water).
What Does The Daily Beagle Think?
The Daily Beagle, in their humble non-expert opinion, do not advise the adoption of Cadmium-Telluride solar panels.
Unfortunately, given that they are visually indistinguishable from conventional solar panels, the average buyer is not likely to be able to easily identify them from visual inspection alone, especially given most solar panel manufactures do not typically list the raw materials of construction. The only vague hint would be an efficiency test. Even then, there are other types of similarly less efficient solar panels.
A materials test would need to be conducted to know for sure, but given the very toxic nature of the materials, is not recommend for members of the public to conduct by themselves.
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Hence my confusion. We need to know which brands.
Well done. Now i am wondering about my solar panels and the cadmium and copper in my region. I guess I better shut up.