Evaluating the Cleanliness of Solar Photovoltaics Can Be Complicated
I am a frustrating individual who likes to delve deeply into decision making computations and hates easy answers that sound like sales pitches. One of the best compliments I ever received came from one of my division officers when I was serving as the Engineer Officer on a submarine - he told me “Eng, you ask hard questions.”
As vocal advocate for nuclear fission power I recognize that it has many associated questions, but I after 30 years of study, I have determined to my own satisfaction that most of the important questions have reasonably good answers. In contrast, I have not yet found reasonable answers for many of my questions related to other renewable energy sources. (Yes, I - perhaps controversially - classify fission as renewable, but that is a discussion for a different post.)
Solar photovoltaic (PV) cells are a popular and often discussed (see, for example Atlantic City Convention Center Plans Largest Solar Roof in U.S., 10% of U.S. Electricity From Solar by 2025, SF Passes Largest City Solar Program in U.S. (Finally), all of which were published within the past week) form of “renewable” or “green” energy, but a casual scratching of the surface knowledge that many people have about the technology reveals some troubling details.
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Not only are the panels expensive sources of electricity, but they do not last as long as advertised, they do not provide as much energy as the nameplate capacity implies, they consume significant quantities of energy in their production, installation and transportation, and they often use some very nasty materials in their manufacturing process.
The longevity of a solar panel will vary greatly depending on where it is installed, but any customer should remember that they are buying a product that will inherently need to spend as much time as possible fully exposed to the sun and weather. Though there are no visibly moving parts in a solar PV panel, there are many parts of the system where continuous chemical and physical reactions take place that can eventually lead to system degradation and failure.
Take a good look at panels that have been installed for several years and you will notice discontinuities and shiny areas where the components have been damaged and where the power production is reduced. If you have any panels, might want keep a record of the current production so that you can see this effect - or perhaps you will not want to find out just how fast that long term investment is decaying.
The literature accompanying most solar panels provide customers with numbers related to their peak capacity - what I call “noon on a clear day at the Equator”. That quantity of power is only available when the sun is directly overhead, when the panel is perfectly clean and when there are no clouds shading the cells. The cleaning part is important, any panel owner that wants maximum performance needs to set up a routine for cleaning and clearing the panels of any debris.
Leaves and snow are particular nuisances for rooftop solar panels, but sand and bird droppings can be important in some areas as well. Not that the article was specifically discussing PV panels, but I recently read about the 4,000 gallon water tanker trucks that are part of the maintenance equipment at some desert solar power plants.
Some of the most energy efficient solar panels, in terms of both the energy required to produce the panel and the panel operating efficiency are made of a semiconductor material called CdTe (Cadmium Telluride). Companies that make CdTe cells like to brag about the quality of their products, but they have also recently had to warn their investors that they may not be able to sell their panels in the EU for much longer because of rules about using toxic heavy metals in electronics. What they have not made clear yet is what their long term liability is for the panels that they have already sold. What will happen in 5, 10 or 20 years when the panel output is no longer useful and the materials need disposal? Can they be recycled without releasing the heavy metals? Will their customers be able to return the panels to the original producer? Will they make the effort or simply take the systems to the dump like many consumers do with batteries made of similar materials? (Those are the kinds of questions that my former division officer was talking about.)
There are definitely answers to some of the questions that I have about solar PV, but that does not mean that the issues are fully solved. If you are in the market for solar PV systems, please ask the hard questions and realize that anyone who wants you to buy the systems without good answers is just a salesman who is not much different from any other salesman.
Photo credit - The Sun Works (photos to be shared)
Finally someone asks the hard questions! I’ve watched all of the alternative energy solutions quickly loose their luster under the glare of real time use. We have an energy solution in nuclear power but vocal scare mongers without any formal nuclear education are regularly spouting off half-truths and manufactured “facts” to support their cause. In this website we have an educated person who has lived with nuclear power for 30 years. Just maybe we should listen to what he has to say. We are running out of time and we don’t have time to pin our future on the energy fad of the moment.
BOBG wrote:”In this website we have an educated person who has lived with nuclear power for 30 years.Just maybe we should listen to what he has to say.”
What does “educated” mean? Working for the International Atomic Energy Agency (IAEA) or the nuclear industry?
This text is pure bad faith. Of course solar photovoltaic devices require technologies which are not completely “green” but actually which electric device is completely green today? As far as I know no solar device will produce waste which will remain dangerous for centuries just as nuclear power does (and not only in power plants but also during extraction and enrichment). But just think about this: if solar energy had been backed by governements as much as nuclear has been, who knows how much more efficient and “clean” solar devices could be?
And about cleanliness, just ask people in Belarus and Ukraine how clean it is to live in the neighborhood of a nuclear power plant which has exploded more than 20 years ago? How many dead people in the neighborhood of a solar device?
Last but not least, if you can explain to me how Al Qaeda could build a dirty bomb with anything used in a solar device just let me know! You cannot put solar in balance with nuclear (which is the case in this text actually) without considering safety.
I like the fact that you are asking hard questions, but I think your skepticism about the longevity of PV modules is misplaced.
The basic technology used in most photovoltaic modules is not fundamentally different than what has been available for decades. You can find some longitudinal studies of module performance that show that degradation of electrical output is less than 1% per year. Most PV module manufacturers offer warranties of 20 years or more that include assurances of electrical output, so the manufacturers are backing up their claims with their own money.
It is valid to question the claims of PV manufacturers, but the questions you raise have been asked and answered.
Roald:
Can you tell me how long Cadmium remains toxic to human beings?
If you would like to find out about the state of the environment in Belarus or Ukraine, I highly recommend reading a carefully researched book titled Wormwood Forest, by Mary Mycio. You can find it via Amazon.com.
My initial nuclear education is not with the industry, but as an Engineer Officer in the nuclear navy. I completed the nuclear training pipeline, served as a division officer, attended graduate school, and served as the Engineer Officer of a 22-26 year old submarine for 40 months. In 1993, I left active duty and formed Adams Atomic Engines, Inc.
I totally agree, nothing but pure bad faith…
Especially when the whole world talks about this
http://www.ecogeek.org/content/view/1329/
I respect the author’s pro-nuclear, stance, which I share. I think that nuclear power is crucial.
However, his solar-skeptic stance is unfair, and it smacks of the fear-mongering used by anti-nuclear activists.
One can be pro/anti-nuclear only after working the numbers. How big is the waste problem? What are greenhouse gas emissions involved in mining? What is the energy amplification factor of mining Uranium and burning it?
One has to be be similarly rigorous when criticizing (or embracing) solar. This article doesn’t do that, and is essentially anti-solar fear-mongering.
I have wondered about this issue too, but the article does not get me much closer to the answer. The CdTe arrays the author mentions have awful downsides, including cost and environmental issues. That said, I don’t think anyone is seriously advocating CdTe arrays for general consumption. More likely silicon ribbon technology that is actually pretty clean to make.
Does anyone know the life cycle costs and impacts for a modern production photovoltaic? wind turbine? coal plant? nuclear plant?
Here is a study from the university of wisconsin that provides some numbers (and where they came from)
http://fti.neep.wisc.edu/presentations/sww_energy_ctr.pdf
Slide 8 is informative, in that it says wind gives back 23 times more energy than you put into it, fission 16 times, coal 11 times. Solar is not on the chart though..
“…no solar device will produce waste which will remain dangerous for centuries just as nuclear power does (and not only in power plants but also during extraction and enrichment).”
This material was not made dangerous from use in a nuclear power plant. It was dangerous from before we pulled it out of the ground. I never understood why we have such an issue either recycling nuclear waste back into fuel or putting that material back into the ground from which it came. There is a lot of uninformed and unwarranted fear causing inaction on this issue.
Further, the dangerous material from a nuclear plant is centralized at the nuclear plant. That makes the waste from a nuclear plant far easier to manage than waste from solar. Any dangerous material in a solar cell is going to be where the cells are located - namely, at your home or at the dump in 20 years.
That said, I wouldn’t paint all solar technologies with the same brush. Yes, some may be made of toxic materials, but various technologies are going into solar these days, not all of which are toxic. Namely, what kind of cells are Europe going to be making or buying in the future?
I am certainly of the opinion that we need both nuclear and solar. Few other technologies will be as cheap or effective for most places. Wind only really works in windy areas. Hydro is good, except people live everywhere now, making new dam construction difficult. Geothermal is good, but limited and with its own set of issues. Nuclear can provide the base load our civilization needs 24/7. Solar provides energy for daytime spikes, when people want to run heaters and air conditioners.
Peter:
The link that you provided is informative, but it does not really say that fission gives back 16 times the input energy/
What it says is that pressurized water reactors using 3% fuel enrichment provided by gas centrifuge enrichment plants that operate with a capacity factor of 75% for a total lifetime of 40 years will provide 16 times the energy input.
If the plant lasts 60 years, you can add 50% more to the return. If the average capacity factor is 80, 85, or 90% you can add some more back. If you shift from a once through then out fuel cycle, you can achieve a better return. If you shift technology to something like a high temperature gas reactor combined cycle, you can improve both fuel utilization and thermal efficiency.
In other words, the graph uses 1950s vintage nuclear fission technology.
When it comes to fusion’s placement on the graph, I have no idea what the source of the data could be since there has not yet been a fusion plant that provided a net power output for more than a few milliseconds.
Looking at the “Adams Atomic Engines” website, anyone can see you have a commercial activity based on nuclear engines, so how can you pretend having any dispassion in such a discussion?
Also, it’s easy to recommend a book about trees and bees around Chernobyl (trees grow fast when there’s nobody to pull them up). I would rather recommend one about people, people who are sick and die from the atomic contamination : “Le Crime de Tchernobyl : Le goulag nucléaire” (which means “Chernobyl’s crime : the nuclear gulag”) from Wladimir Tchertkoff. Unfortunately, it’s in French and it seems there is no translation to English (but you can buy it from Amazon.fr). It contains facts about many people living in contaminated land and their health condition is not very good.
Your question suggests that you want to raise the fact that cadmium cannot be degraded into something less toxic - cadmium is a chemical toxic - and this is true. Cadmium is an heavy metal and the human body has the property to accumulate heavy metals and this concentration can become dangerous. But interestingly, uranium, the most common fuel for atomic fission, is also an heavy metal. Therefore, its radiotoxicity left aside, it is also dangerous because of its chemical properties.
Two facts to show that its chemical properties makes uranium certainly more dangerous than cadmium :
- cadmium has no effect on health below 3 mg and its lethal dosis is between 350 and 500 mg;
- the lethal dosis for depleted uranium (which is not much radioactive) is 2 mg/Kg, which means something like 140 mg for a man.
And of course cadmium is not radioactive while the kind of uranium used in most power plants (PWR) is highly radioactive (and I do not even talk about the plutonium mixed with uranium in Mox) hence dangerous.