Increased deployment of solar PV enables the transition to decarbonized
energy systems, capable of tempering the dire consequences of global
warming. Even though backsheets are very important regarding lifetime
energy yield of the PV module, the environmental impacts of their
production, use and end-of-life (EoL) processing are largely neglected.
As part of a recently finalized Dutch national project EXTENSIBLE
(Energy yield assessment of neXT gENeration and SustaInaBLE backsheets)
the environmental impacts for 7 different polymeric backsheets have been
evaluated via a life cycle assessment (LCA). The selected backsheets
include 3 traditional polyethylene terephthalate (PET) - based
backsheets with a fluorine containing outer layer (two white pigmented
and one fully transparent). The other 4 backsheets are novel
high-performance polyolefin (PO) -based backsheets, manufactured by
Endurans Solar ™, also including one transparent
version. From results of the LCA it is concluded that in comparison with
PET-based backsheets and fluoropolymer containing backsheets, PO-based
backsheets perform best in terms of energy yield, reliability and
environmental impacts. The production of fluoropolymer- and PET-based
backsheets cause substantial environmental impacts, especially regarding
climate change and ozone depletion. This conclusion is corroborated by
recent literature data. Regarding the EoL phase, it was shown from a
theoretical assessment that pyrolysis of the spent backsheets
potentially leads to much lower GWP when compared to incineration,
especially for the PO-based backsheets. Incineration of the shredded and
solid backsheet material causes direct emissions of CO 2
with a limited heat recovery potential only. Deploying pyrolysis for
spent PO-based backsheets significantly improves their life-time GWP per
kWh produced. Pyrolysis offers the possibility to recover a large part
of the polyolefin as an usable pyrolysis oil that might serve as
feedstock for chemicals or as transportable liquid fuel for the
generation of process heat in recovery boilers, thereby avoiding the use
of new fossil resources. EoL pyrolysis (or incineration) of
fluoropolymer-based backsheets is problematic due to the presence of
fluorinated hydrocarbons, leading to corrosive and/or toxic products.