The southern Japanese island of Okinawa will host a 2MW storage battery and study into grid management, due to the local grid almost reaching the limit of capacity available for renewable energy projects.
According to Japan’s Ministry of Economy, Trade and Industry (METI), around 50MW has been connected on the island, leaving little spare capacity left for connecting new projects to the grid. Once 57MW of projects over 300kW in size of generation capacity have been reached, it is unlikely that more could be connected under current provisions.
The island lies a few hundred miles to the south of the main Japanese archipelago, and several utility-scale PV projects have been constructed or planned there since the introduction of the solar feed-in tariff in July 2012. The situation is thought to be similar to the one facing the northern island of Hokkaido, where due to the relatively high availability of land many utility-scale solar power plants were planned but only around a quarter have been successfully constructed and brought online, mainly due to grid connection issues.
METI announced the initiation of two possible solutions which are also likely to serve as demonstration projects. In the first, the regional utility Okinawa Electric Power, which is also responsible for the island’s grid, has introduced a 2MW lead-acid battery, which could increase available grid capacity by around 10%. The battery will initially be installed as a demonstration project for between one and two years.
The second, more general measure will see infrastructure investment combined with research into power and system management, including battery storage, overseen by METI. A budget request of around ¥44 billion (US$42.7 million) is expected to be made for next fiscal year for the latter measure.
The news follows a recent announcement that the Japanese regional grid system and electricity market will be reformed in the next few years to facilitate distributed energy. Currently 10 regional utilities are responsible for different sections of the grid and have a monopoly in each region for generation, transmission and distribution.