Polymer electrolyte membrane fuel cells (PEM FCs) are seen as a suitable technology supporting the transformation towards decarbonised societies. Decision makers face the problem that there is no sound basis of the environmental performance of cutting edge technology available. We developed a comprehensive product system for two types of high temperature (HT) PEM FCs and conducted a life cycle assessment. One system utilizes functionalized multiwalled carbon nanotubes (MWCNTs) as carbon support materials for platinum. The reference product applies carbon black. MWCNTs render possible platinum savings of 27% simultaneously retaining equal performance parameters as for the reference FC.The inventories include all components of a FC starting with the production of the carbon support material, the catalyst powder with platinum nanoparticles, a membrane, a gas diffusion layer, bipolar flow plates up to the FC stack and the FC unit including end of life treatment. Our analysis shows that platinum is the key material in HT PEM FCs and the benefits from platinum savings outweigh by far the impacts on the MWCNT production. The HT PEM FC was adjusted such that it typifies (1) a PEM FC for an electric vehicle (FCEV) allowing comparison with internal combustion engine vehicles (ICVs) and battery electric vehicles (BEVs) or (2) a PEM FC suitable for micro-combined heat and power (m-CHP) to be compared with a Stirling engine. We found an environmental advantage of a FCEV vis-à-vis the ICV, but only if hydrogen is produced with renewable electricity. We found similar environmental impacts for the FCEV and the BEV when both vehicles are propelled with renewable energy. Both m-CHP plants produce similar amounts of useful energy and have comparable environmental performance. Nonetheless, the PEM FC produces more electricity (less heat) than the Stirling engine. System expansion such that both systems deliver equal amounts of electricity and heat resulting in an advantage of nearly 20% for the PEM FC powered system. Thus, the PEM FC technology offers great potential to reduce a personal environmental (and carbon) footprint -a prerequisite on the way of a transformation to more sustainable societies. Broader contextThe prospect of changing electricity production from nuclear and fossil to predominantly renewable energy carriers as planned for example in Switzerland or Germany leads to new requirements of the electricity grid and a new electricity supply pattern. Renewable energy sources release energy congenitally intermittent over diurnal and annual cycles. The PEM FC technology can support the energy turnaround manifold. For individuals our results show that fuel cell electric vehicles provide an environmentally benign technology for individual mobility. PEM FCs in combined heat and power plants are efficient devices to convert a fuel into electricity and heat for housing applications. Both fields of application provide great potential to reduce the individual environmental footprint. Decision makers planning a nationwide strategy...

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Esta pesquisa teve como objetivo mapear e demonstrar a importância das áreas verdes em uma cidade de pequeno porte do centro-oeste paranaense. Utilizou-se imagens orbitais de altíssima resolução para mapear as áreas verdes dentro do perímetro urbano de Irati, Paraná, considerando as classes “áreas com cobertura arbórea” e “espaços verdes”. Foram registradas temperatura e umidade relativa em diferentes horários em 6 (seis) dias através de miniestações metereológicas instaladas em locais com situações distintas de ocorrência de áreas verdes. Resultados demonstraram sensível diferença na quantidade de áreas verdes de bairros centrais se comparados a outros mais periféricos. Foram verificadas correlações estatísticas entre temperatura e umidade relativa com os valores de superfície de área verificados num entorno de raio de proximidade fixa a partir de cada miniestação. Estes resultados podem alertar os gestores municipais quanto à importância das áreas verdes em todo o tecido urbano, mesmo em cidades de pequeno porte.