Grid tied Roof top solar: Problems, learnings and solutions

The depletion of fossil-fuel resources on a worldwide basis has necessitated an urgent search for substitute energy sources to meet up the present day demand. Solar energy is clean, inexhaustible and environment-friendly resource among all renewable energy options. But neither a standalone solar photovoltaic (PV) system nor a wind energy system can provide a continuous supply of energy due to seasonal and periodic weather variations. Therefore, in order to satisfy the load demand, grid connected energy systems are now being implemented, that combines solar and utility grid, where the grid acts as an infinite like energy storage. In this paper a 10kWp grid tied roof solar system is implemented with a rechargeable energy storage system (RESS) in a home to overcome the frequent shut downs of the utility grid. In a country like India, the utility grid is shut down for few hours during the day time when the power from the solar is at maximum rate. During this shut down period, the energy from the solar system is stored in RESS apart from the loads connected in the home. The stored energy can be utilized during the night without taking much power from the utility grid. The power consumption from the utility grid can be nullified with the proposed system and in addition to this the excess stored power from the solar system is used for reducing usage of other energy purchases such as cooking gas and supplied back to the grid which is beneficial to the user. The proposed system is experimentally tested and the results are presented.