The two battery storage facilities installed in Tonga are complementary: the aim of the first 5 MWh / 10 MW battery is to improve the electricity grid's stability (regulating the voltage and frequency), while the second 23 MWh / 7 MW battery is designed to transfer the. . The two battery storage facilities installed in Tonga are complementary: the aim of the first 5 MWh / 10 MW battery is to improve the electricity grid's stability (regulating the voltage and frequency), while the second 23 MWh / 7 MW battery is designed to transfer the. . The two battery storage facilities installed in Tonga are complementary: the aim of the first 5 MWh / 10 MW battery is to improve the electricity grid's stability (regulating the voltage and frequency), while the second 23 MWh / 7 MW battery is designed to transfer the electrical load in order to. . Tonga Power Limited is currently undertaking renewable energy projects, network upgrade projects aswell as Battery Energy Storage projects which all contribute to ensuring Tonga Power provides power that is sustainable, reliable and safe for the people of Tonga. Learn more about our projects plans. . The Government of Tonga has formulated targets to transform its energy sector by achieving a 50 percent share of renewables in the country's energy generation mix by 2020 and 70 percent by 2030. However, achieving these targets require catalytic investments to transform the country's energy. . Under the background of power system energy transformation, energy storage as a high-quality frequency modulation resource plays an important role in the new power system [1,2,3,4,5] the electricity market, the charging and discharging plan of energy storage will change the market clearing results. . Let's explore how this initiative works, why it's a model for others, and what lessons it offers for global renewable energy storage solutions. Traditional diesel-powered grids struggle with three critical issues that the Tonga Integrated Energy Storage Power Station addresses: 1.