Integration of a new thermal energy storage in electrical grids: power supply and control options

Climate change problems cannot be addressed without a transformation of the energy production sector, since it is responsible for a significant share of total greenhouse gas emissions. For this reason, governments are promoting the use of Renewable Energy Sources (RES), especially wind and solar. In order to increase the penetration of RES, whose energy production cannot be controlled to follow the demand, more and more energy storage systems are needed, for ensuring adequacy and security to electrical power systems. This paper is focused on an innovative thermal energy storage technology based on fluidized solid particles, capable of receiving energy as electricity and storing it as heat for later use, e.g. produce steam for industrial applications. In such a system, electric energy is converted to heat by means of resistors, that can be supplied with AC and/or DC sources. In the paper, different use-case scenarios are presented, involving the grid and/or a photovoltaic plant as electric power sources. Then some possible configurations for power converters are described and compared, to find the most appropriate solution for each use-case scenario.