cadmium telluride (CdTe) and others. Cadmium telluride is a substance formed
from cadmium and tellurium and used as a solar cell material.
Cadmium telluride and copper indium diselenide (CIS) modules have a
small market share. They contain about 170g/kWp or 900mg/kg of cadmium.
However, CdTe modules are hazardous waste, and the industry has not come to
terms with it yet. This is because if these modules are improperly disposed of,
they can catch fire and produce poisonous gases. The PV industry has made
efforts to have all CdTe modules properly recycled, but compliance is not total.
Customers with this substance in their PV systems could still end up with a haz-
ardous waste issue.
CIS modules usually have thin layers of cadmium sulfide. The amount of the
cadmium in these modules is less than 1 percent of that in CdTe modules. Sele-
nium is another critical substance in CIS modules, but is used only in small
amounts. Generally, CIS modules are determined to be less hazardous than CdTe
Module Recycling Concepts
Factory recycling is another name for the reuse of discarded raw material from
manufacturing. Most manufacturers are using factory recycling because the
recovery of products is less expensive than buying new raw materials. Experts do
not anticipate that there will be significant amounts of waste until 2030. It will
probably be more cost effective to recycle than dispose of this waste.
There is no clear standard for recycling installed modules once they reach the
end of their useful lives.
It makes sense to recycle all substances in solar modules whenever possible.
PV commodity prices are going up. Recyclable parts include faulty solar modules
and systems that have already completed their service life. Additionally, silicon
cells, aluminum components, and glass can also be recycled. Recycling systems
and components saves up to 80 percent of manufacturing energy.
CHAPTER 9 The Business of Photovoltaics and Economics 177