Large-Capacity Energy Storage Battery for Realizing a Decarbonized Society

In November 2021, the 26th UN Climate Change Conference (COP26) was held in Glasgow, UK. Previously, the 2015 Paris Agreement had aimed to hold the global average temperature increase to not more than 2°C above pre-industrial levels and introduced the ambitious goal of limiting warming to 1.5°C. COP26 was a continuation of efforts to limit the temperature rise, and the global climate target has been set even further from 2.0°C to 1.5°C. To achieve this target, a global agreement on “decarbonization” or net-zero greenhouse gas emissions by 2050 is necessary. Minimizing the use of fossil fuels is extremely effective for realizing a decarbonized society. To that end, it is essential to expand the use of renewable energy, such as solar and wind power.

However, there are some key issues. The power generation amount of renewable energy, which depends on natural phenomena, cannot be controlled in keeping with demand. Since the frequency fluctuates due to excess and shortage of generated power in a short period, stable power supply is difficult. Great expectations are placed on storage batteries, which can offset these disadvantages.

Sumitomo Electric began developing large-scale storage batteries about 40 years ago. The initial aim was to level the power load that fluctuates with time periods. As renewable energy has been increasingly introduced around the world, we have promoted the development of large-capacity redox flow storage batteries with the aim of ensuring grid stabilization. Hokkaido Electric Power Network, Inc. (HEPCO Network) started full-scale operation of a redox flow battery system in 2022. We have also conducted a large-scale demonstration project in California, USA, and made solid achievements. This issue reveals all the facts about redox flow storage batteries that support renewable energy.