December 16, 2025: Long duration energy storage systems are moving rapidly toward bankability, with clearer pathways for investment than ever before, according to a new report.
The LDES council report Accelerating LDES bankability, published on December 9, followed two workshops with investors and technology providers this year — one in London and the other in New York City.
The council, launched in 2021 by energy firms and developers such as Ambri, Highview Power, ESS and CellCube, held the workshops in collaboration with global CEO advisory group Teneo.
Several recent major financial raises supporting LDES technology are highlighted in the report, including that of Form Energy, a developer of iron-air battery tech up to 100 hours duration, which raised around $1.4 billion in its latest round in 2024.
Gravity-based LDES and BESS tech developer, Energy Vault, had raised a total of almost $800 million as of this year, according to the report.
Key findings arising from the workshops include a need for long-term procurement or market mechanisms with guaranteed revenues to de-risk investment.
Combining sovereign guarantees with multilateral finance and local co-investment to partially support LDES projects, particularly in emerging markets, can also reduce political and credit risk while enabling rapid development.
Meanwhile, the report urged policymakers to introduce public funding programmes that can play catalytic roles, by reducing risks and the levels of finance needed by investors.
Investors should consider becoming part of consortia, the report said, noting that while co-investment can complicate projects and relations among businesses involved, LDES technologies often provide opportunities for a variety of strategic players that seek exposure to different types of risk.
Anna Siefken, lead on the report and North America policy and markets lead at the LDES council, said: “Long duration energy storage is advancing rapidly toward bankability, with clearer pathways for investment than ever before.
“The sector now has a defined roadmap, supported by detailed analysis of the remaining barriers spanning technology performance, revenue certainty, and risk allocation. Each part of the ecosystem has a specific role to play in unlocking LDES at scale, and we hope this paper helps instil the confidence and clarity needed to make a fully bankable LDES market a reality.”
Batteries International reported in August that Google had made an undisclosed investment in Italian energy tech firm Energy Dome and had signed a commercial arrangement to use the technology to help power its operations.
Energy Dome claims its CO2 Battery is capable of continuously dispatching energy for periods of eight to 24 hours to meet both the baseload and flexibility requirements of large energy users.
