Sumitomo Electric said in a press release that with this project and further sales expansion of redox flow batteries, the company will “contribute to the introduction of renewable energy and the reduction of greenhouse gases”. While the majority of recent global grid-scale energy storage systems use lithium-ion batteries, the electrolytes in flow batteries do not degrade over long periods of charging and discharging and can withstand many more cycles.
This means that in theory, they may be more suitable for long-duration, bulk storage of energy than lithium batteries, which are generally more suited to high power, fast-response applications that balance the grid. Sumitomo also pointed out that its flow batteries can be operated at room temperature and do not run the risk of thermal runaway, which can cause fires or the release of dangerous gases, as lithium batteries have done in some extreme cases.
The northern Japanese island of Hokkaido is populated by more than five million people but has limited interconnection with the rest of the country. Japan’s electricity network is split into 10 separate regions and Hokkaido Electric Power is the main power utility for the island.
Hokkaido’s T&D operator, Hokkaido Electric Power Network Co is currently investigating how to enable the grid integration of larger shares of renewable energy and is working on a joint program with the national New Energy and Industrial Technology Development Organization NEDO, as well as with another regional utility, TEPCO.
The network company has already determined that new wind and solar plants must be equipped with equipment to control their grid output, with a recently completed solar farm in the region among the first in Japan to be combined with large-scale battery storage. Hokkaido Electric Power Network targeted deploying around 600MW of wind farms between 2017 and 2022, to be combined with about 90MW of four-hour duration battery storage in the first phase of a push for greater wind capacity and then a second phase of about 400MW of wind power and 60MW of four-hour duration battery storage is expected to begin, with timescale and other considerations to be decided on dependent on what the company – and region – learn in the first phase.