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Abstract-The utilization of wind and sun as renewable sources causes uncontrollable fluctuations in power generation. Furthermore, the ratio between peak power and average power is high for systems with a limited number of households. In small autonomous renewable energy systems (ARES), energy storage is needed; however, the use of Lead-acid batteries as energy buffers is problematic, since it is not possible to cover fast power fluctuations without dramatically reducing the batteries' lifetime. In this paper Super Capacitors are applied to relieve fast changes in the battery storage system. Batteries are used to meet the energy requirements and Super Capacitors are used to meet the instantaneous power demand. At the end of this paper, a sizing method is proposed for the Super Capacitor system.

Nowadays, power utilities are adopting Asset Management as their framework in order to cope with the challenges introduced by the privatization and market competition in this sector. Stedin, a Dutch Distribution System Operator recognized the vital role that an Asset Management system has for its organization. Therefore, Stedin, has adopted the publicly available specification, BSI:PAS55, as a standard to perform the Asset Management responsibilities and tasks of their electricity and gas networks. Equipment life cycle and technical performance activities form an integral part of the implementation of an Asset Management system. In this context, Stedin felt the strong need to have access to systematic techniques and guidelines on how to deal with information of equipment lifetimes. In this paper a systematic method, based on Statistical Life Data Analysis, which deals with limited or incomplete life time data of large populations of assets with the aim of obtaining an indicator of the future failure expectancy is discussed. The methods and analytical tools developed in this contribution share a basic framework for decision-making and specify the evolution of the failures of asset population over time.

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