You constantly hear discussion about the benefits of renewable energy, but what goes on behind the scenes, for example in manufacturing plants? If the manufacturing processes involved in making solar panels are not themselves particularly green, how does this affect the whole sector and what can be done to rectify it?
Manufacturing plants involved in making solar PV panels very often utilize a number of processes, materials and techniques that, in themselves, are not particularly green. For example, caustic chemicals such as sodium hydroxide and hydrofluoric acid are often used. The process uses large volumes of water for cooling, chemical processing and control of air pollution. However, the amount of water increases dramatically during installation, particularly for utility-scale projects where the panels need to be cleansed of all the dust generated by the project’s construction. Nevertheless, this is still far less water than that used by fossil fuel plants.
Electricity is another factor, which, depending on how it is generated, can involve the production of greenhouse gas emissions. More generally, there is also a great deal of manufacturing waste.
Some companies are attempting to clean up their act. According to the Solar Scorecard ranking system, created by the Silicon Valley Toxics Coalition (SVTC), Chinese manufacturer Trina Solar and California’s SunPower are top of the grade when it comes to making their manufacturing processes truly clean and green, closely followed by Yingli Green Energy and SolarWorld. However, the Solar Scorecard relies on self-reporting and according to SVTC it seems that there are fewer and fewer companies willing to disclose information on this subject.
The problem is that as the popularity of solar power grows, so there are more and more companies entering the market, and some of them are not as discerning about their environmental footprint as others. Unsurprisingly, they are usually the companies producing the cheapest panels. The situation is further complicated by the variety of different regulations and practices. So for example, according to a study by Northwestern University and Argonne National Laboratory, the carbon footprint of Chinese panels is less impressive than those from Europe, because China has fewer stringent environmental regulations in place. The country also has a great deal more coal plants, although the Chinese are working hard to close them down in favor of more renewable energy. Furthermore, protests are beginning to break out at Chinese PV plants. Jinko Solar is one company that has been affected by this recently, after its plant in Zhejiang was accused of dumping toxic waste into a river nearby. The Northwestern University study also found that when solar panels are manufactured in China and shipped to Europe, their carbon footprint is likely to be twice as high as those panels made and used in Europe.
In contrast, manufacturers in the US are governed by federal and state regulations covering disposal of toxic waste-water and other such activities while Europe recently passed legislation to reduce the disposal of electronic waste.
Recycling of old solar panels is particularly difficult, since there aren’t enough places where this can be carried out. At present, it isn’t economically viable to do so anyway since there aren’t (yet) enough old solar panels to recycle, the solar industry still being fairly new in comparison to conventional energy. Furthermore, solar panels use precious metals such as silver, tellurium and indium. Dustin Mulvaney, Assistant Professor of Environmental Studies at San José State University and a scientific adviser to Silicon Valley Toxics Coalition (SVTC), believes they could go to waste on account of the present lack of recycling facilities. “Companies that are reporting on a quarterly basis, surviving on razor-thin margins—they’re not thinking 20, 30 years down the road, where the scarcity issue might actually enter the conversation” he says.
The silicon used in solar panel manufacture is abundant, but it nevertheless needs a lot of energy to manufacture a silicon-based panel. Sometimes that energy is provided by coal plants, and that in turn affects the solar cell’s carbon footprint.
SVTC is working on the development of a sustainability standard for solar panels which could be based on the US Green Building Council Leadership in Energy and Environmental Design (LEED). Other organisations are also working on the issue. For example, First Solar has in place a set of sustainability metrics which includes recordable injury rate, energy and water use, waste generation and greenhouse gas emissions. The company has reduced the energy, water, waste and carbon intensity, since 2008, by improving module efficiency, manufacturing throughput and by changing to full-scale production. The company also operates a comprehensive module recycling operation to minimise the life cycle impact of its products.
In general it can be said that at present, the overall sustainability of a solar array really depends on where the panels are sourced. That’s pretty much the same with any product you buy. It’s also generally true that if you opt for cheaper, Chinese panels, rather than US or European-made products, with certain exceptions, the panels are going to be less sustainable.
I am an experienced freelance journalist with a wide and varied portfolio to my credit including web content, magazine articles, reporting, features, interviews, reviews and blogs. My special interests include environmental issues, particularly climate change, renewable energy, transport, green building and sustainable infrastructure. I have numerous secondary interests ranging from politics and current affairs to social justice, science, technology and innovation, historical topics and lifestyle subjects such as literature, psychology, contemporary spirituality and culture.