2020-09-16, Schmidt, Felix, Lenz, Markus, Schaeffer, Andreas, Zimmermann, Yannick, Alves dos Reis Benatto, Gisele, Kolvenbach, Boris, Krebs, Frederik

The low environmental impact of electricity generation using solar cells crucially depends on high energy-conversion efficiencies, long lifetimes and a minimal energy and material demand during production. Emerging thin-film photovoltaics such as perovskites on plastic substrates could hold promise to fulfil all these requirements. Under real-world operating conditions photovoltaic operation is challenged by biological stressors, which have not been incorporated for evaluation in any test. Such stressors cause biodeterioration, which impairs diverse, apparently inert materials such as rock, glass and steel and therefore could significantly affect the function and stability of plastic-based solar cells. Given that different photovoltaic technologies commonly use similar materials, the biodeterioration mechanisms reviewed here may possibly affect the efficiency and lifetimes of several technologies, if they occur sufficiently fast (during the expected lifetime of photovoltaics). Once the physical integrity of uppermost module layers is challenged by biofilm growth microbially mediated dissolution and precipitation reactions of photovoltaic functional materials are very likely to occur. The biodeterioration of substrates and seals also represents emission points for the release of potentially harmful photovoltaic constituents to the environment

2020, Schmidt, Felix, Schaeffer, Andreas, Lenz, Markus

Renewable energies, such as sunlight, wind and geothermal heat, are resources that are replaced rapidly by natural processes. However, wind, hydro and solar installations strictly require raw materials that are, in fact, not renewable. Many raw materials are already facing a supply shortage which cannot be easily overcome. This work reviews the problem of critical raw material (CRM) use in photovoltaics (PV) as an example and explains why supply cannot be easily increased to meet demand. We discuss whether there is indeed a 'struggle for elements' in a Darwinian sense, which ultimately leads to a 'survival of the fittest' race in renewable energy technology. In the case of PV, the perception of the definition of 'fittest' needs to change from that considering energy conversion efficiency alone to that which holistically considers net energy produced per emission under the premise that sufficient environmentally and socially acceptable raw material supply exists for renewable energies and all other sectors.