Photovoltaic news and pv jobs

Producer responsibility is the key, consumer responsibility the catalyst!

07. September 2010 By:  Sasa Malek

So you have solar panels on your roof and are a firm believer that this makes you a sustainable person – contributing to the production of sustainable energy, plus it saves money, right? Well, it is not that simple – having solar panels also means having lots of hazardous waste in your “backyard” or – on your conscience.

Considering only the global warming potential (GWP), the production of one square meter of a solar panel produces from 20 to 25 grams of CO2 in Europe, while for the U.S.-based production, these figures double. Furthermore, CO2 comparisons do not make your head spin about all the heavy metals, hazardous chemicals, and dirty and expensive procedures used in the process of making of the “environmentally friendly” technology.

This year's EU PVSEC brings into the spotlight how simple changes in the production of the solar cells literally save millions if not (in some cases) billions of euros, besides preventing tons of hazardous waste and introducing producer's responsibility in a way that may potentially transform this industry in a profound way.

Considering only the toxic gases, so far the solar industry has been using damaging perfluorocarbons for the cleaning of the remaining silicon in the production process. In the process of cutting the silicon ingots, leftover silicon remains in the chamber and needs to be removed. Since silicon reacts well with fluorine, nitrogen triflouride (NF3) is used as a source for its removal. It is a toxic gas with a global warming potential (GWP) 17,200 times higher than CO2 and has an atmospheric life time of 740 years. And, funnily enough, it replaced sulfur fluoride, otherwise a non-toxic gas but with a much higher GWP (23,600), which was placed on the Kyoto-recognized greenhouse gases list.

An additional problem of the NF3 is that it also needs to be transported in high-pressured cylinders, causing attentional energy losses, air pollution and CO2 generation. This can now be avoided by an on-site fluorine generation, offered by the company Linde, which uses on site low-pressured fluorine generation.

The company provides the solar panel producers with low pressured F2 generated on site. This way they avoid several environmental impacts: they prevent transport, there is no need for high pressure storage, plus F2 is a non toxic compound that needs to dissociate (to F) only once, which means additional energy loss prevention.

Another problematical side of the ingot cutting is the usage of the highly abrasive silicon carbide slurry (mixed with chemicals). Huge amounts of slurry are used in the process, which leads to several thousand tons of liters of waste slurry in a months time. The slurry is reusable and many of recycling procedures involve again transportation to the reprocessing site as well as chemical procedures.

CRS Reprocessing Services provides another on-site solution for this problem, by installing reprocessing mechanical separation technology on site, which enables a 90 percent recovery rate of the slurry without the involvement of processes. A closed loop material flow in the solar industry is also part of the “solar sustainability path” the industry is into.

A new aspect of it may be the fact that some companies, like Atlumin, provide the solar panel industry with chemical compounds, but then remove them from the leftovers of the production processes and recycle them by selling them back on the market, or incorporating them into new materials for the same client. In such a way, the track of materials never gets lost and the producers responsibility over the impacts of its processes is fully executed. I believe that such closed-loop recycling-reuse producers responsibility should be the future of all processes around the world that include production or use or resources of any kind.

But it should also be supported with a responsibility from the consumers' side. Of course, it is impossible to expect from consumers of solar panels particularly to know all these dirty little details about the solar panels production. But it would, in my opinion, be very helpful if a common standard formula factor would be set up for all those industry sectors that claim to produce products for sustainable energy that would let consumers know how much of their activities is really sustainable.