Renewable energy systems for generating electric power: A review

This paper reviews various schemes utilized for generating electric power from renewable energy resources, which are suitable for interconnecting with a power grid as well as for using as an isolated system. As all the renewable energy resources except geothermal energy, being climate dependent, the power generated from them is of varying magnitude-even sometimes no power is generated at all. The other drawbacks are the poor power quality and the high cost of generation, which are the big challenges for meeting the target of ever increasing demand of electric power by renewable energy systems in an efficient and effective way. The various schemes described in the literature for improving the power quality as well as the overall performance of the system by using developed technologies involving power electronics, are reviewed in the paper. In order to achieve the continuous power of constant magnitude up to the satisfactory level, the hybrid schemes using two or more renewable energy sources or any conventional system with some energy storage methods for backup are also discussed. Despite this technological development, still an urgent need to further investigate some other renewable energy source or scheme to provide continuous energy of constant magnitude at low cost is earnestly observed in the paper.