Global energy demand is climbing rapidly due to population growth and continuing industrialization. Renewable energy is expected to provide a central solution to our need for a sustainable fuel. Many countries have announced plans in the use of clean energy. In 2020, renewable energy targets have been adopted in 169 countries at the national or provincial level and renewables had provided more than 26% of global electricity generation. However, major challenges presented by renewable energies, such as fluctuations in output, unavailability (e.g. sunlight in the night) and unpredictability (e.g. wind power), limit their implementation. As a solution to these problems, energy storage systems, acted as a buffer between power generation and grid, make a real difference in effective ways to improve power quality, stability and reliability of transmission and distribution system. For example, battery system (e.g. lithium battery, redox flow battery, or combination of these two) has the potential to provide many hours of high quality power from the kW- to MW- scale for grid services (e.g. load balancing and peak shaving). In a remote or weak grid area, utilisation of battery technology will allow users to store locally generated electricity and facilitate renewable energy deployment, and to use battery system as a stand-alone power system to replace diesel generators.