Principal
investigators: Erik Alsema, Evert Nieuwlaar
Keywords: life-cycle assessment, solar cells, environmental impacts
Funding: Novem (Netherlands Agency for Energy and the Environment, 1991-2002).
The use of solar cell modules normally does not produce waste products that have any impact on the environment. However, the production of the cells does require energy and materials and may emit pollutants. Also the management of the waste at the module's end of life may have impacts on the environment.
The question adressed in this research project is: "To what extent may the production, use and end-of-life decomissioning of solar cell modules contribute risks to health, safety and the environment". For this purpose the environmental impact, safety and raw material exhaustion aspects of four types of solar cell modules have been studied by means of a life-cycle assessment (LCA).
The investigated module technologies are based on the following materials:
* multi crystalline silicon (also called poly- or semi crystalline silicon) (report nr. 95057)
* amorphous silicon (report nr. 93008)
* cadmium telluride (report nr. 91059)
* copper indium selenide (report nr. 91059)
In 1996 a summary report (report nr. 96074) was published which gives an overview and update of the main results of the total project.
The final conclusion of this research project was that - at least for the immediate future - there are no major bottlenecks from environmental point of view for the considered solar cell technologies. However, during module production substances are used which may be harmful for workers, the public or the environment. Therefore manufacturers should take proper measures to avoid harmful exposures or emissions. Also for some module types the waste management needs due attention.
Points which deserve further attention both from manufacturers and researchers are: the energy requirements of modules (and module frames and supports), the use of heavy metals, gas safety issues and module recycling possibilities.
The above research project was started in 1991 and ended
in 1996. It was commissioned by the Novem.
The research is part of the PhD work of Erik Alsema.
Within an European project on the large-scale
manufacturing of photovoltaic modules, named MUSIC-FM, Erik Alsema coordinated
a study task on the health, safety and environmental aspects of thin film
modules, based on CdTe, CuInSe2 and a-Si solar cells. In this study potential
bottlenecks were reviewed, waste management strategies were evaluated and
module recycling options were investigated. Although no major bottlenecks
were identified for the short term, it was concluded that in the longer term
module recycling will become necessary to avoid problems with module waste
disposal and resource availability. This project was funded by the European
Commission and ended in 1996. The results were reported in a paper at the 14th European
PV Solar Energy Conference in Barcelona.
In June 1997 an international expert workshop on "Environmental Aspects of Photovoltaic Power Systems" was organized by Utrecht University, under the auspices of the International Energy Agency and Novem. A report on this workshop, including all papers, was published in december 1997. A selection of the papers presented at workshop were published in a special issue of the journal Progress in Photovoltaics (March-April 1998, Vol 6, number 2).
Environmental
Life Cycle Assessment studies
For two types of photovoltaic systems an full environmental life cycle assessment study was made. In 2000 a report on Solar Home Systems (=PV system with battery) was published which showed that the (lead-acid) battery is primarily responsible for the environmental impacts of Solar Home Systems. Therefore battery recycling schemes are of great importance in Solar Home System deployment programmes. Nonetheless Solar Home Systems can significantly reduce greenhouse gas emissions of rural households in developing countries if the systems replace kerosene lights.
In 2002 an assessment was made of a number of roof-top PV installations, with special focus on the Balance-of-System components (i.e. array support, cabling, inverter). Although the contribution of BOS components to the overall environmental impact of the roof-top systems was found to be relatively small in present systems, this contribution will probably increase as module technology improves. Points of attention were identiefied with regard to the inverters, impacts of copper usage (cables) and the module frames. Both these studies were funded by Novem.
In cooperation with ECN Solar Energy the
environmental aspects of advanced production technologies for silicon solar
cells are investigated by means of a Life Cycle Assessment. The study covers
new technologies for production of “solar-grade” silicon feedstock, new methods
for producing thin silicon “sheets” and novel cell processing techniques. Also the aspects of building integration
are considered. The results of this study will be published in 2003.