B. Zimmermann

A comparative probabilistic economic analysis of selected stationary battery systems for grid applications

This Paper focuses on a comparative probabilistic economic comparison of sodium sulfur batteries (NaS), Lithium-Iron Phosphate batteries (LFP), Vanadium Redox Flow Batteries (VRB), Lead Acid batteries (PbA) and a Pumped Hydro Storage Plant (PHS). Two cases for a load leveling and peak shaving storage application were analyzed and compared. The comparison is based on a comprehensive literature review which showed remarkable deviations within most techno-economic values. This makes it difficult to assess the technologies by a deterministic approach. Therefore, a complementary probabilistic approach was developed in form of a Monte Carlo Simulation (MCS). The results show clearly that among batteries, PbA have the best cost performance followed by NaS and VRB. LFP has the highest costs within all scenarios. However, PHS is the most cost efficient technology for load leveling. In the case of peak shaving the battery costs decrease significantly due to lower initial investment costs.

Database development and evaluation for techno-economic assessments of electrochemical energy storage systems

A battery storage technology database was developed to assess the state of the art of different battery types by a literature and manufacturer data review. The database contains key techno-economic parameters to provide a solid basis for common assessment, modeling and comparison of battery storage technologies. A new approach is the comparison of literature data with manufacturer data to identify possible inconsistencies between different data sources.

Nanotoxicity and Life Cycle Assessment: First attempt towards the determination of characterization factors for carbon nanotubes

Carbon materials, whether at macro, micro or at nanoscale, play an important role in the battery industry, as they can be used as electrodes, electrode enhancers, bipolar separators, or current collectors. When conducting a Life Cycle Assessment (LCA) of novel batteries manufacturing processes, we also need to consider the fate of potentially emitted carbon based nanomaterials. However, the knowledge generated in the last decade regarding the behavior of such materials in the environment and its toxicological effects has yet to be included in the Life Cycle Impact Assessment (LCIA) methodologies. Conventional databases of chemical products (e.g. ECHA, ECOTOX) offer little information regarding engineered nanomaterials (ENM). It is thus necessary to go one step further and compile physicochemical and toxicological data directly from scientific literature. Such studies do not only differ in their results, but also in their methodologies, and several calls have been made towards a more consistent approach that would allow us model the fate of ENM in the environment as well as their potentially harmful effects. Trying to overcome these limitations we have developed a tool based on Microsoft Excel® combining several methods for the estimation of physicochemical properties of carbon nanotubes (CNT). The information generated with this tool is combined with degradation rates and toxicological data consistent with the methods followed by the USEtox methodology. Thus, it is possible to calculate the characterization factors of CNTs and integrate them as a first proxy in future LCA of products including these ENM.

Ecological assessment of nano-enabled supercapacitors for automotive applications

New materials on nano scale have the potential to overcome existing technical barriers and are one of the most promising key technologies to enable the decoupling of economic growth and resource consumption. Developing these innovative materials for industrial applications means facing a complex quality profile, which includes among others technical, economic, and ecological aspects. So far the two latter aspects are not sufficiently included in technology development, especially from a life cycle point of view. Supercapacitors are considered a promising option for electric energy storage in hybrid and full electric cars. In comparison with presently used lithium based electro chemical storage systems supercapacitors possess a high specific power, but a relatively low specific energy. Therefore, the goal of ongoing research is to develop a new generation of supercapacitors with high specific power and high specific energy. To reach this goal particularly nano materials are developed and tested on cell level. In the presented study the ecological implications (regarding known environmental effects) of carbon based nano materials are analysed using Life Cycle Assessment (LCA). Major attention is paid to efficiency gains of nano particle production due to scaling up of such processes from laboratory to industrial production scales. Furthermore, a developed approach will be displayed, how to assess the environmental impact of nano materials on an automotive system level over the whole life cycle.

Prospective time‐resolved LCA of fully electric supercap vehicles in Germany

UNLABELLEDnThe ongoing transition of the German electricity supply toward a higher share of renewable and sustainable energy sources, called Energiewende in German, has led to dynamic changes in the environmental impact of electricity over the last few years. Prominent scenario studies predict that comparable dynamics will continue in the coming decades, which will further improve the environmental performance of Germanys electricity supply. Life cycle assessment (LCA) is the methodology commonly used to evaluate environmental performance. Previous LCA studies on electric vehicles have shown that the electricity supply for the vehicles operation is responsible for the major part of their environmental impact. The core question of this study is how the prospective dynamic development of the German electricity mix will affect the impact of electric vehicles operated in Germany and how LCA can be adapted to analyze this impact in a more robust manner. The previously suggested approach of time-resolved LCA, which is located between static and dynamic LCA, is used in this study and compared with several static approaches. Furthermore, the uncertainty issue associated with scenario studies is addressed in general and in relation to time-resolved LCA. Two scenario studies relevant to policy making have been selected, but a moderate number of modifications have been necessary to adapt the data to the requirements of a life cycle inventory. A potential, fully electric vehicle powered by a supercapacitor energy storage system is used as a generic example. The results show that substantial improvements in the environmental repercussions of the electricity supply and, consequentially, of electric vehicles will be achieved between 2020 and 2031 on the basis of the energy mixes predicted in both studies. This study concludes that although scenarios might not be able to predict the future, they should nonetheless be used as data sources in prospective LCA studies, because in many cases historic data appears to be unsuitable for providing realistic information on the future. The time-resolved LCA approach improves the assessments robustness substantially, especially when nonlinear developments are foreseen in the future scenarios. This allows for a reduction of bias in LCA-based decision making. However, a deeper integration of time-resolved data in the life cycle inventory and the implementation of a more suitable software framework are desirable.nnnKEY POINTSnThe study describes how life cycle assessments (LCA) robustness can be improved by respecting prospective fluctuations, like the transition of the German electricity mix, in the modeling of the life cycle inventory. It presents a feasible and rather simple process to add time-resolved data to LCA. The study selects 2 different future scenarios from important German studies and processes their data systematically to make them compatible with the requirements of a life cycle inventory. The use of external scenarios as basis for future-oriented LCA is reflected critically. A case study on electric mobility is presented and used to compare historic, prospective static, and prospective time-resolved electricity mix modeling approaches. The case study emphasizes the benefits of time-resolved LCA in direct comparison with the currently used approaches.

A comparative analysis of the cumulative energy demand of stationary grid-integrated battery systems

Electro-chemical storage systems can be used in the electricity grid to store energy when demand is low and feed it back during demand peaks. The so-called load leveling might reduce the overall fossil fuel demand, but the production efforts for the batteries must be taken into account in a holistic approach. This study employs life cycle assessment with the cumulative energy demand impact assessment method. It is used as an indicator to evaluate if grid-integrated stationary battery systems in future load leveling applications create benefits which can offset the batteries production efforts. Lead acid, nickel metal-hydride and lithium iron-phosphate batteries are assessed. Only lithium iron-phosphate batteries with a long life-cycle can reduce the overall fossil cumulative energy demand. Battery efficiency and degradation were found to be significant parameters in this analysis.