Just a quick post today, it would be nice to pretend that I can contribute to this blog often and regularly but that's not always possible. Heard this neat story on Inside Science and so wanted to throw it up on the blog as it doesn't seem to have been very widely reported anywhere else.
Solar panels have, in theory at least, the potential to have a massive impact on our renewable energy consumption. While solar panel efficiencies have been climbing fairly steadily over the last few decades concerns have been raised regarding the toxic materials used in the manufacture of the solar cells. There are actually several areas in which the environmental impact of the life-cycle of solar panels may be less than ideal, as outlined here. However, the toxicity of some of the components (or materials used in the manufacture thereof..) seems to have been cause for widest concern, especially when it relates to the disposal of old solar panels.
There was good news on Wednesday for those of us who worry about such things when Jon Major of Liverpool University published a paper in Nature (link here, not sure about paywall access, etc). The paper claims that the toxic cadmium chloride used to 'activate' the solar cell (increasing the energy efficiency from less than 2% to more than 10%) can be simply and easily replaced with magnesium chloride, a compound typically used bath salts and in the manufacture of tofu.
Jon Major himself is quoted here as saying “The problem is cadmium telluride [sic]* itself is a highly toxic compound," Major said. "It’s been linked to genetic defect, and if it gets into the water supply, it can poison fish for generations.” The toxicology report for cadmium, which includes reports on cadmium chloride, makes for some fairly scary reading, detailing interstitial pneumonitis, diffuse alveolitis, fibrosis, increased lung weight, reduction in body weight, focal interstitial thickening, oedema, pulmonary haemorrhage and emphysema in rats exposed to cadmium chloride.
Not only is a reduction in the overall toxicity of the solar cell production process good news for the environment but, by using a naturally-occurring substance which will allow for a significant reduction in the costs of handling and disposal of materials, the overall cost of production will be brought down.
While there are still other environmental problems relating to the use of solar panels, including other toxic/hazardous materials, it is cheering to see that progress is being made. It is good to remember that many renewable energy sources are still in relatively early days as far as development is concerned. Ongoing research is constantly improving the methods and materials used in solar, wind and water power (not to mention fusion reactors).
A small aside I wanted to mention, having heard it reported recently (seems like a lot of my posts recently have been inspired by Radio 4, I'm clearly of a certain demographic these days!) is the rather strange legal situation home-owners might find themselves in in the UK. It is now fairly common for people to effectively lease their roof to a solar panel company in return for free electricity and installation of the solar panels, which remain the property of the company that market them. These sounds like a pretty good deal to begin with. However, there are rather harsh ramifications when it comes to re-mortgaging or selling the home, given that the solar panel company is now effectively a tenant on your roof! Certainly not a reason to not get some solar panels installed but good to be aware of.
*not sure if this is a typo/misquote or perhaps Jon Major simply mis-spoke, cadmium telluride is actually rather stable and not very soluble. Provided that it is disposed of correctly, it's pretty safe and, given the context I believe he meant cadmium chloride not telluride.
