Jens Peters

Life cycle assessment of sodium-ion batteries

Sodium-ion batteries are emerging as potential alternatives to lithium-ion batteries. This study presents a prospective life cycle assessment for the production of a sodium-ion battery with a layered transition metal oxide as a positive electrode material and hard carbon as a negative electrode material on the battery component level. The complete and transparent inventory data are disclosed, which can easily be used as a basis for future environmental assessments. Na-ion batteries are found to be promising under environmental aspects, showing, per kWh of storage capacity, environmental impacts at the lower end of the range published for current Li-ion batteries. Still significant improvement potential is given, especially by reducing the environmental impacts associated with the hard carbon production for the anode and by reducing the nickel content in the cathode active material. For the hard carbons, the use of organic waste can be considered to be promising in this regard. Nevertheless, when looking at the energy storage capacity over lifetime, achieving a high cycle life and good charge–discharge efficiency is fundamental. This represents the main challenge especially when competing with LFP–LTO type Li-Ion batteries, which already show extraordinarily long lifetimes.

Biomass Pyrolysis for Biochar or Energy Applications? A Life Cycle Assessment

The application of biochar as a soil amendment is a potential strategy for carbon sequestration. In this paper, a slow pyrolysis system for generating heat and biochar from lignocellulosic energy crops is simulated and its life-cycle performance compared with that of direct biomass combustion. The use of the char as biochar is also contrasted with alternative use options: cofiring in coal power plants, use as charcoal, and use as a fuel for heat generation. Additionally, the influence on the results of the long-term stability of the biochar in the soil, as well as of biochar effects on biomass yield, is evaluated. Negative greenhouse gas emissions are obtained for the biochar system, indicating a significant carbon abatement potential. However, this is achieved at the expense of lower energy efficiency and higher impacts in the other assessed categories when compared to direct biomass combustion. When comparing the different use options of the pyrolysis char, the most favorable result is obtained for char cofiring substituting fossil coal, even assuming high long-term stability of the char. Nevertheless, a high sensitivity to biomass yield increase is found for biochar systems. In this sense, biochar application to low-quality soils where high yield increases are expected would show a more favorable performance in terms of global warming.

Life cycle assessment of a Vanadium Redox Flow Battery

Batteries are one of the key technologies for flexible energy systems in the future. In particular, vanadium redox flow batteries (VRFB) are well suited to provide modular and scalable energy storage due to favorable characteristics such as long cycle life, easy scale-up, and good recyclability. However, there is a lack of detailed original studies on the potential environmental impacts of their production and operation. The present study fills this gap by providing a comprehensive life cycle assessment of a representative VRFB. Transparent and comprehensive inventory data are disclosed as a basis for further environmental studies. VRFBs are found to be promising regarding the assessed impact categories, especially at high energy-to-power (E/P) ratios. On the other hand, significant impacts are associated with the vanadium pentoxide production, which is why the origin and processing of the vanadium bearing ores are a key for further reducing the environmental impacts associated with the VRFB manufacturing. While the lower efficiency of the VRFB is a disadvantage in comparison to e.g. lithium-ion batteries (LIB), its recyclability is significantly higher. In this sense, the importance of taking a cradle-to-cradle life cycle perspective when comparing very different battery systems can be highlighted for further research on this topic.