Which startups have raised the most funding in the LDES market?

Last updated: 13 March 2026

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market research pitch 2026 statistics LDES market

In our LDES market deck, you will find everything you need to understand the market

The LDES market (long-duration energy storage) is attracting billions of dollars from venture capitalists, strategic investors, and public markets.

We built this ranking to track every LDES startup we could find, sorted by total equity raised, and we update it every month with the latest funding data.

Below you will find our latest dataset with 65 companies, funding details, key investors, and a confidence score for each entry.

And if you want to better understand this new industry, you can download our pitch covering the LDES market.

A quick summary table

Metric Value
Most funded LDES startup Form Energy ($1.2B)
Second most funded LDES startup Energy Vault ($745M)
Largest single LDES funding round $405M (Form Energy, Series F)
Median LDES startup funding $23M
Share of funding captured by the top 10 ~72%
Median time since last round ~21 months
LDES startups that raised funding in the last 12 months 21 out of 65
Total LDES startup equity tracked ~$6.4B across 65 companies
Most active LDES venture investor Breakthrough Energy Ventures (7+ portfolio companies)
Active private LDES startups in the dataset 53 out of 65 (82%)
chart VC fundraising startup years LDES market

In our LDES market deck, we show you long-term trends so you can make better decisions

Top startups in the LDES market ranked by total funding raised

Here is an updated table that ranks the top startups in the LDES market based on the total amount of funding they have raised to date.

The table also includes the total number of funding rounds, the date and size of the latest round, the financing type (e.g. Series A, equity financing), key investors, the startup's current status (active, IPO, acquired, or shut down), and a confidence score based on the data collected (we excluded startups with very low data confidence, to make sure everything is reliable).

If you're interested in knowing how much these startups are worth, you can check our list of the top startups in the LDES market ranked by valuation.

# Startup What They Do Total Raised ($) Total Rounds Last Round Date Last Round Amount ($) Last Round Type Key Investors Current Stage Confidence
1 Form Energy Iron-air multi-day grid batteries $1.2B 7 October 2024 $405M Series F T. Rowe Price, GE Vernova, Capricorn Active Strong
2 Energy Vault Gravity and hybrid grid storage $745M 4 October 2025 $300M Preferred Equity Orion Infrastructure Capital IPO Strong
3 Highview Power Liquid-air long-duration storage $663M 4 November 2025 $166M Growth Equity Scottish National Investment Bank, Centrica, Goldman Sachs Active Strong
4 Hydrostor Compressed-air long-duration storage $485M 4 February 2025 $200M Growth Equity Canada Growth Fund, Goldman Sachs Alternatives, CPP Investments Active Partial
5 EnerVenue Metal-hydrogen grid batteries $445M 3 October 2023 $308M Series B Aramco Ventures, IDG Capital, SLB Active Full
6 ESS Tech Iron flow long-duration batteries $323M 2 January 2026 $15M Registered Direct Offering Undisclosed institutional investors IPO Partial
7 Eos Energy Enterprises Zinc-based long-duration batteries $220M 3 June 2024 $75M Preferred Equity / Strategic Investment Cerberus IPO Partial
8 Antora Energy Thermal batteries for industry $200M 3 February 2024 $150M Series B Decarbonization Partners, Temasek, BlackRock Active Partial
9 Ambri Liquid-metal grid batteries $194M 3 August 2021 $144M Late-stage private round Reliance New Energy Solar, Paulson & Co., Bill Gates Acquired Partial
10 Azelio Thermal storage with Stirling engine $180M 5 October 2022 $27M Rights Issue Existing shareholders Shutdown Low
11 Sage Geosystems Geothermal power and storage $154M 3 January 2026 $97M Series B Ormat Technologies, Carbon Direct Capital, SiteGround Capital Active Strong
12 Rongke Power Vanadium flow batteries $145M 1 April 2023 $145M Series B Junlian/Legend Capital, Dalian Jintou, Rongtuo Capital Active Strong
13 Invinity Energy Systems Vanadium flow battery systems $132M 3 September 2025 $33M Subscription Atri Energy Transition, Next Gen Mobility IPO Strong
14 VRB Energy Vanadium flow batteries $131M 5 September 2024 $55M Strategic equity / JV Red Sun, Ivanhoe Electric Active Partial
15 Malta Thermal long-duration energy storage $108M 3 December 2023 $22M Series C Preferred Siemens Energy Ventures, Alfa Laval, Breakthrough Energy Ventures Active Strong
16 CMBlu Energy Organic flow battery storage $107M 1 October 2023 $107M Strategic equity / Series D STRABAG Active Partial
17 Brenmiller Energy Thermal energy storage systems $104M 7 September 2025 $4M Preferred Equity Closing Alpha Capital Anstalt IPO Partial
18 Primus Power Zinc-bromide flow batteries $92M 5 March 2017 $32M Undisclosed Success Dragon, Matador Capital, Anglo American Platinum Active Strong
19 Energy Dome CO2-based long-duration storage $71M 3 July 2023 $16M Series B extension Barclays, Novum Capital Partners, Elemental Excelerator Active Strong
20 H2, Inc. Vanadium flow battery systems $67M 4 January 2025 $16M Bridge STIC Investments, KRUN Ventures, Lighthouse Combined Investment Active Strong
21 e-Zinc Zinc-air long-duration batteries $58M 3 June 2024 $31M Series A2 Evok Innovations, Mitsubishi Heavy Industries, Export Development Canada Active Strong
22 RedoxBlox Thermochemical storage for heat/power $41M 3 October 2024 $30M Series A extension Prelude Ventures, Imperative Ventures, New System Ventures Active Strong
23 ESI Asia Pacific Iron flow battery deployment $40M 1 September 2024 $40M Strategic investment Queensland Government Active Partial
24 Fourth Power Thermal battery energy storage $39M 2 September 2025 $20M Series A Plus Munich Re Ventures, DCVC, Breakthrough Energy Ventures Active Full
25 Corre Energy Compressed-air long-duration storage $35M 3 February 2023 $9M Placing / Subscription Institutional investors Active Full
26 VFlowTech Vanadium flow battery systems $34M 4 May 2025 $21M Series A2 Granite Asia, EDBI, MOL PLUS Active Strong
27 Redflow Zinc-bromine flow batteries $34M 3 September 2023 $8M Post-IPO Existing shareholders Shutdown Partial
28 Noon Energy Carbon-oxygen ultra-long storage $31M 2 January 2023 $28M Series A Clean Energy Ventures, Aramco Ventures, Emerson Collective Active Full
29 VoltStorage Iron-salt long-duration flow batteries $31M 2 July 2022 $24M Series C Cummins, Korys, EIT InnoEnergy Acquired Partial
30 Elestor Hydrogen-bromine flow batteries $30M 2 August 2022 $30M Series A Equinor Ventures, Invest-NL, Royal Vopak Active Partial
31 Redox One Iron-chromium flow batteries $30M 2 February 2024 $20M Series A Tharisa Active Strong
32 Quidnet Energy Geomechanical underground energy storage $29M 4 May 2024 $10M Series C Hunt Energy Network Active Partial
33 Photoncycle Seasonal hydrogen home energy storage $23M 2 March 2026 $17M Series A NordicNinja, Voima Ventures, Lifeline Ventures Active Full
34 XL Batteries Organic flow batteries for grid $18M 2 September 2025 $8M Seed Merrin Investors Active Partial
35 Quino Energy Organic aqueous flow batteries $16M 3 November 2025 $10M Series A Atri Energy Transition Active Full
36 Offgrid Energy Labs Zinc-bromine stationary battery systems $15M 2 September 2025 $15M Series A Archean Chemicals Industries, Ankur Capital Active Partial
37 1414 Degrees Thermal storage for industrial heat $15M 5 October 2025 $1M Placement Existing shareholders IPO Strong
38 Time Energy Storage Aqueous organic flow batteries $15M 1 October 2023 $15M Series A GL Ventures, Bondshine Capital, Su Venture Capital Active Strong
39 Allegro Energy Water-based flow batteries $12M 2 September 2024 $12M Series A The Grantham Foundation, Lightbank, Origin Energy Active Partial
40 Ore Energy Iron-air multi-day battery storage $11M 1 May 2024 $11M Seed Positron Ventures, SPRIND Active Full
41 Sinergy Flow Sulfur-based long-duration flow batteries $10M 2 March 2026 $8M Late Seed CDP Venture Capital, 360 Capital, Exergon Active Full
42 MGA Thermal Thermal blocks for heat storage $10M 4 December 2024 Undisclosed Pre-Series B Electrifi Ventures, Climate Salad Active Strong
43 Sizable Energy Offshore pumped-hydro ocean storage $8M 2 October 2025 $8M Seed Playground Global, Exa Ventures, Verve Ventures Active Partial
44 Green Gravity Mine-shaft gravity energy storage $7M 2 October 2024 $6M Series A HMC Capital, BlueScopeX, Pacific Channel Active Strong
45 Qnetic Long-duration flywheel energy storage $7M 2 March 2026 $5M Private round SOSV, Kingscrowd Capital, D3VC Active Strong
46 Cheesecake Energy Thermal plus compressed-air storage $6M 3 August 2022 $4M Pre-Series A BGF, Perivoli Innovations, Sir John Egan Active Strong
47 KEMIWATT Organic flow batteries $5M 2 October 2025 $5M Capital increase Stolt Ventures, Impact Océan Capital, GO Capital Active Partial
48 StorEn Technologies Residential vanadium flow batteries $5M 6 June 2024 $600K Crowdfunding Crowd investors, StartEngine, ANYSeed Active Partial
49 CellCube Vanadium flow battery systems $5M 3 August 2019 $225K Undisclosed Invinity Active Low
50 Flux XII Aqueous flow battery materials $4M 1 November 2025 $4M Seed The Grantham Foundation, WARF, gener8tor Active Full
51 STOLECT Carnot battery electricity storage $4M 1 May 2022 $4M Venture round Undisclosed Active Full
52 Jolt Energy Storage Technologies Organic flow battery materials $4M 2 December 2024 $4M Series A Undisclosed Active Strong
53 Gravitricity Shaft-based gravity energy storage $4M 3 June 2024 $1M Seed / Crowdcube Crowdcube investors Shutdown Partial
54 HalioGEN Power Membraneless redox flow batteries $3M 1 January 2024 $3M Seed SPRIND, University of Manchester Active Strong
55 Build to Zero Industrial thermal storage $3M 1 September 2023 $3M Seed Axon Partners Group, Digital Five Investment Active Strong
56 Bryte Batteries Nordic vanadium flow batteries $2M 2 June 2023 $1M Seed extension Kjeldsberg, Bjørn Simonsen, MP Pensjon Active Partial
57 Gravity Power Deep-shaft pumped hydro storage $2M 1 January 2009 $2M Series A 21 Ventures, Quercus Trust Active Partial
58 VisBlue Residential-commercial flow batteries $2M 3 December 2017 Undisclosed Seed / follow-on SOKI Holding, Borean Innovation Active Partial
59 Volterion Flow-battery stacks $1M 3 October 2017 Undisclosed Seed HTGF, Fraunhofer Venture, EIT InnoEnergy Acquired Partial
60 Zhonghe Energy Storage Flow battery materials and systems $1M 2 August 2024 Undisclosed Angel Hidden Hill Capital, CMB International, Sequoia China Active Partial
61 TerraStor Advanced compressed-air grid storage $1M 1 December 2023 $1M Seed Plug and Play Tech Center Active Low
62 Rivus Batteries Organic electrolytes for flow batteries $609K 1 December 2023 $609K Seed xista science ventures, NAVCAP, EIT InnoEnergy Active Strong
63 ARKLE Energy Solutions Vanadium flow battery systems $460K 1 March 2025 $460K Seed pi Ventures, IPTIF Active Strong
64 Tharam-Thiran Green Energy Flow Sulfur-iron flow batteries $61K 1 June 2023 $61K Seed Social Alpha, IIITDM Kancheepuram Active Strong
65 Carbo Energy Waste-based long-duration flow batteries $20K 1 March 2024 $20K Seed Techstars Active Partial
market map chart top companies startups LDES market

In our LDES market deck, we will give you useful market maps and grids

Key funding trends in the LDES market

Insights

  • Form Energy alone accounts for roughly 25% of all identified equity funding across the 65 LDES startups tracked, which signals extreme capital concentration at the very top of the long-duration energy storage market.
  • Breakthrough Energy Ventures appears as an investor in at least seven LDES companies (including Form Energy, Malta, Fourth Power, and RedoxBlox), making Breakthrough Energy Ventures the single most active venture fund in long-duration energy storage.
  • The top five funded LDES startups collectively raised approximately $3.5B, while the bottom 30 combined raised under $150M, a steep power-law distribution that mirrors how capital flows in deep-tech energy sectors.
  • Iron-air battery technology (led by Form Energy and Ore Energy) has attracted over $1.2B in combined LDES funding, more than any other single storage chemistry, reflecting strong investor conviction in iron-air cost trajectories.
  • Sage Geosystems raised $97M in a single Series B in January 2026, the largest identified early-stage LDES round outside of Form Energy, signaling growing investor appetite for geothermal-based energy storage solutions.
  • EnerVenue raised $308M in a single Series B round, the largest identified single venture round in the entire LDES dataset, driven by outsized conviction from Aramco Ventures and SLB in metal-hydrogen battery chemistry.
  • Energy Dome, Sinergy Flow, and Quino Energy are all based in or connected to Southern European ecosystems, collectively raising over $97M and suggesting Italy is emerging as a notable LDES innovation cluster.
  • Goldman Sachs entities appear across both Hydrostor and Highview Power, collectively backing over $1.1B in combined equity, which positions Goldman Sachs as the most capital-deployed traditional financial institution in the LDES market.
ldes trend chart

In our LDES market deck, we have collected signals proving this market is hot right now

A few word about our methodology

As you can see, we built a database that ranks LDES startups based on their total cumulative fundraising. To create this ranking, we reviewed many sources and cross-checked information across multiple places.

Whenever possible, we prioritized official company communications, since they are the most reliable source for funding amounts. When those were not available, we relied on reputable industry sources such as TechCrunch, Crunchbase, Financial Times or Forbes (to name a few).

We excluded random blogs, unverified websites, and any sources that could not be validated.

When funding rounds were announced in other currencies such as euros, Swiss francs, Singapore dollars, Australian dollars, or rupees, we converted them into approximate USD equivalents for consistency.

Sometimes different sources report slightly different numbers, or the exact round size is not fully disclosed. In those cases, we flag the uncertainty and assign a confidence label to each LDES startup, visible in the last column.

Here is what they mean.

Full confidence: The LDES company's equity fundraising history can be reconstructed completely from public sources. The rounds, dates, amounts, and key investors are clearly identified, with no meaningful gaps.

Strong confidence: The fundraising history is largely complete and reliable. There may be a small missing detail, such as incomplete investor information or a minor round with limited data, but the overall record is clear.

Partial confidence: The main fundraising rounds can be identified, but the record is incomplete or somewhat mixed. Some rounds may be missing or certain funding events may be difficult to separate clearly.

Low confidence: Public information is too limited, inconsistent, or ambiguous to reliably reconstruct the LDES company's equity fundraising history.

When the confidence level is too low, we take a conservative approach and exclude the company from the ranking. We don't want to include data that cannot be reliably verified.

This reflects how we conduct all our research, including the work behind our report covering the LDES market.

In a world where LLMs hallucinate and unreliable information is everywhere, our goal is simple: provide data you can trust.

If you want the full detail on a specific calculation, feel free to contact us and we will gladly explain.

Finally, know that we update the dataset once per month, so come back here if you need fresh information.

chart form energy long duration energy storage market

In our LDES market deck, we identify repeatable patterns you can use if you’re building in this market

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