On the path to a low-carbon future, advancements in energy storage seem to be achieved on a nearly daily basis. However, for the use-case of sustainable transportation, only a handful of technologies can be considered, as these technologies must be reliable, economical, and suitable for transportation applications. This paper describes the characteristics and aging process of two well-established and commercially available technologies, namely Lithium-Ion batteries and supercaps, and one less known system, flywheel energy storage, in the context of public transit buses. Beyond the obvious use-case of onboard energy storage, stationary buffer storage inside the required fast-charging stations for the electric vehicles is also discussed. Calculations and considerations are based on actual zero-emission buses operating in Graz, Austria. The main influencing parameters and effects related to energy storage aging are analyzed in detail. Based on the discussed aging behavior, advantages, disadvantages, and a techno-economic analysis for both use-cases is presented. A final suitability assessment of each energy storage technology concludes the use-case analysis.

Accurate efficiency determination is very important in the field of electric drive research and development. Modern inverters generate pulse width modulated signals with short rise times and high frequencies. Thus, high-accuracy power measurements under nonsinusoidal conditions have to be performed. This requires high precision voltage and current probes, including frequency response flatness over a wide bandwidth and a high linearity up to a few hundred volts. This paper describes the development and characterization of a high-voltage differential probe, suitable for precise measurements in automotive electric drives. The main parts of the probe are two input voltage dividers with a further frequency compensation circuit and a difference amplifier. The complete circuit design and the compensation of parasitic effects are explained in detail. Final experiments show that the developed probe outperforms commercially available probes. The probe has a very flat frequency response up to 1 MHz, a bandwidth of 20 MHz, and a linearity better than 250 ppm up to the maximum differential input voltage of 1 kV.

In the field of solar power generation, concentrator systems, such as concentrator photovoltaics (CPV) or concentrated solar power (CSP), are subject of intensive research activity, due to high efficiencies in electrical power generation compared to conventional photovoltaics (PV) and low-cost energy storage on the thermal side. Even though the idea of combining the thermal and electrical part in one absorber is obvious, very few hybrid systems (i.e., concentrator photovoltaics-thermal systems (CPV-T)) are either described in literature or commercially available. This paper features the conversion of a commercial thermal parabolic trough collector to a CPV-T hybrid system using multi-junction PV cells. The design process is described in detail starting with the selection of suitable PV cells, elaborating optical and mechanical system requirements, heat sink design and final assembly. Feasibility is proven by practical tests involving maximum power point tracking as well as empirical determination of heat generation and measurement results are presented.

Data related to the performance of burst containments for high-speed rotating machines, such as flywheel energy storage systems (FESS), turbines or electric motors is scarce. However, development of optimized burst containment structures requires statistically significant data, which calls out for low-cost test methods as a strategic development tool. Consequently, a low-cost test rig (so called spin pit) for the investigation of burst containments was designed, with the goal to systematically investigate the performance of different containment structures and materials, in conjunction with the failure mechanisms of different rotors. The gathered data (e.g., burst speed, acceleration, temperature, ambient pressure, etc.) in combination with a post-mortem analysis was used to draw an energy balance and enabled the assessment of the effectiveness of various burst containments.