Global Energy Storage Deployment Surges, Outpacing Government Targets; Japan Has Not Set Any

With the COP31 (the 31st Conference of the Parties to the United Nations Framework Convention on Climate Change) approaching in November, the world’s energy storage systems are expanding significantly, driven primarily by battery storage. However, they are projected to fall short of the target set at COP29, which calls for a sixfold increase compared to 2022 levels.

China and Europe are the main drivers of battery storage deployment, while Japan is lagging behind, even in setting deployment targets. This article summarizes the current status and challenges of battery storage, a key element in achieving decarbonization, alongside the expansion of renewable energy sources such as solar power.

New installations in 2025 hit a record high

The graph below, produced by the UK-based think tank Ember, illustrates the evolution of global energy storage system deployment over time. The dark blue section at the bottom of the bar charts represents pumped-storage hydroelectricity, while the blue section above it represents battery storage. The left chart shows annual additions, and the right chart displays the cumulative total installed capacity.

Annual new additions have recently shown a stark contrast: pumped storage hydropower has fallen below 10 GW, while battery storage capacity has surged at an astonishing pace. In 2025, installations reached an all-time high of 108 GW, representing a 17-fold increase over the past five years. It took only four years to scale from 10 GW to 100 GW—a tenfold expansion. Compared with other technologies, this rate of deployment far outpaces solar photovoltaics, which required nine years to reach a similar scale, and wind power, which took 15 years.

As shown in the graph on the right, battery storage surpassed pumped storage in total installed capacity in 2024, rapidly emerging as the dominant component of the energy storage system.

The 2030 target of 1,500 GW is difficult to achieve

However, according to Ember’s assessment, even with such momentum, the 2030 global energy storage target of 1,500 gigawatts—six times the 2022 level—set out at COP29 in 2024 will not be met.

The topmost dark blue dotted line in the graph above represents the 1,500 GW commitment for global energy storage. The dark green dotted line two positions below it indicates the 822 GW aggregate of new targets set by national governments since COP29. In terms of actual market trends, BloombergNEF forecasts 1,200 GW (the second light gray dotted line from the top), but this falls short of the 1,500 GW target.

While the figures discussed thus far have been global, China and the EU are currently driving the actual expansion. Their targets stand at 460 GW for China and 200 GW for the EU, accounting for over 80% of the total.

Coordination with solar power generation is critical

Having reviewed the targets and achievements in battery storage deployment, there is no debate that the ultimate goal is to expand renewable energy for climate change mitigation, particularly by improving the utilization efficiency of solar power.

A report by Ember released in August graphically illustrates the actual share of global electricity demand met by solar power in the first half of 2026, as shown above. During daytime peak hours, solar power supplies approximately one-quarter of global electricity demand, while generation drops to nearly zero at night when there is no sunlight. This is because the deployment of battery storage has not yet progressed sufficiently. If this situation can be reversed through the expansion of battery storage, the utilization of solar power will be significantly enhanced, ushering in the "era of anytime solar" referenced in the title of Ember’s report.

Japan, Which Has No Targets for Battery Storage Deployment

Japan is currently experiencing an unprecedented boom in battery storage. The number of applications for grid-connected battery storage has surged, accumulating to 191 GW by the end of March this year. However, only 0.84 GW has been connected to the grid, meaning the pipeline of applications is more than 200 times larger than the installed capacity (according to data from the Agency for Natural Resources and Energy, August 6). On the other hand, a commissioned study by the Ministry of Economy, Trade and Industry (March 2026) projects that the maximum deployment capacity for grid-connected battery storage by 2040 will be just 9.6 GW, which is remarkably low. A significant gap is evident between the enthusiasm of those seeking to deploy battery storage and the government’s policy measures.

Here, let us examine another chart by Ember. It ranks the top 20 countries by installed solar power capacity as of 2025. China leads by a wide margin with over 1,200 GW. Japan, with just under 100 GW, has been overtaken by India and Germany over the past two years, dropping from third to fifth place.

The key issue is whether countries have set targets for battery storage deployment. Of the top 20 countries in solar power installation, 12 have established such targets. The remaining 8 countries, including the United States, Germany, and Japan, have not quantified their goals. Japan already exhibits a pronounced over-reliance on solar power generation, to the point where output control measures are now significantly impacting power generation operations.

In other words, we have reached a stage where policy support for battery storage deployment, including grid reinforcement, is essential for the efficient utilization of solar power. While technological development, including cost reduction, is certainly important, it is also imperative to set government targets to enhance investor predictability.

After working as a reporter for a commercial television network and producing environmental programs, the author studied in Germany in 1998. Upon returning to Japan, they became involved in biomass-related venture businesses. In 2011, they founded the Japan Renewable Energy Comprehensive Research Institute, and in 2013, they established Japan Renewable Energy Link. In 2019, they assumed the role of Representative Director of the Regional Activation Energy Link Council. As an energy journalist, they conduct lectures, write articles, and serve as a producer and scriptwriter for energy-related television programs, focusing on gathering and disseminating information to promote the adoption of renewable energy. Additionally, they provide consulting services to private companies on renewable energy and decarbonization, serve as an advisor to local governments, and support regional revitalization by assisting in the establishment and operational support of regional and municipal new power companies.