A: The cost of solar farm battery storage can range from $200 to $500 per kilowatt-hour (kWh) of storage capacity or more, depending on factors like the type and size of the battery storage system, installation complexity, and any additional equipment required. . But what exactly drives the cost of these solutions? In 2022, a 2. 2 million (Source: Tonga Power Limited). "The right storage solution isn't just about upfront cost - it's about total lifecycle. . 4. 2 Limited technical expertise and skilled workforce in the solar energy sector in Tonga. 2 Percentage increase in the number of residential and commercial. . Tonga Power Limited is continuously expanding its Renewable Energy Portfolio, through the introduction of solar generation and most recently Tonga's first ever large scaled wind generation system in Niutoua. National Energy target by 2020, 50% of renewable energy (Solar and Wind) share on. . The majority of Tonga's electricity generators are supplied through imported fossil fuels leading to high and volatile energy prices and a negative impact on the environment.