Gaiergy Corp · Market Research

United States Flow Battery and Iron-Air Manufacturers

Company-by-company contact list, chemistry, product line, commercial status, and evidence. Covers pumped redox flow batteries plus the iron-air and other non-flow long-duration chemistries that compete for the same projects. Every entry is sourced at the point of use, and anything not confirmed against a primary source is labeled in place.

Version: v2 · Compiled: 30 July 2026 · Changes from v1: added iron-air and non-flow long-duration chemistries (Form Energy, Inlyte Energy), a location map, an architecture diagram, a duration comparison, and a counterparty capital chart · All web sources accessed: 30 July 2026 · Prepared by: Gaiergy Corp

The two families, side by side Logos drift and bounce off the walls. Hover one to hold it still.

Pumped redox flow14 manufacturers

TerraFlow Energyvanadium

ESS Techiron flow

Stryten Energyvanadium

Storion Energyelectrolyte

XL Batteriesorganic

Quino Energyorganic

Ashlawn Energyvanadium

StorEn Technologiesvanadium

Influit Energynanofluid

BEThe BESSt Companyzinc-polyiodide

Salgenxsaltwater

Lockheed Martincoordination

Invinityvanadium

CMBlu Energyorganic

Tanks, pumps, a stack. Energy and power scale separately. Every company in Section 4.1, plus Invinity and CMBlu from Section 4.4.

Iron-air and non-flow3 manufacturers

Form Energyiron-air

Inlyte Energyiron-sodium

Eos Energyaqueous zinc

Form Energy is the only true iron-air maker here. Inlyte (iron-sodium) and Eos (aqueous zinc) share the sealed, non-flow architecture, so they ride in this box rather than the flow box. All three are profiled in Section 4.2.

Company logos are the property of their respective owners and were fetched from each company's own website on 30 July 2026, reproduced here at favicon size purely to identify the company. The BESSt Company publishes no fetchable site icon, so it carries a plain monogram. Membership of each box follows the architecture classification evidenced in Section 4; nothing here is a ranking, and box position carries no meaning.

Goal of this document

Give a developer-owner a working call list of long-duration battery manufacturers that can supply, build, or partner in the United States, covering both pumped redox flow batteries and the non-flow chemistries (iron-air, iron-sodium, aqueous zinc) that bid for the same long-duration projects, with enough technical and financial context on each to decide who is worth a first conversation and who is not yet real. This is a sourcing and partnership screen, not an endorsement of any product, and it contains no pricing, because no verified vendor pricing was available from public sources at the time of writing.

01Takeaways

Read these six points and you have the market. Everything below is the evidence.

US-headquartered companies found

Fifteen companies headquartered in the United States are building long-duration batteries or their core components: eleven flow battery system builders (4.1), two non-flow long-duration builders (4.2), and two component suppliers (4.3). Five more in Section 4.4 manufacture outside the United States but have United States operations or announced United States factories.

Vanadium

Still the only volume-ready chemistry

Six of the thirteen United States companies sit in the vanadium redox flow battery (VRFB) chain: four system builders, plus an electrolyte joint venture (Storion Energy) and a vanadium chemicals supplier (U.S. Vanadium). Every organic and zinc entry here is at pilot stage or earlier, on the evidence in Section 4.

Companies with a real US factory under way

TerraFlow Energy (Bellville, Texas) and Storion Energy (Alpharetta, Georgia plus Wilmington, Massachusetts) are the two with domestic flow-battery manufacturing physically in motion. Everything else is a plan, a pilot line, or an import.

Form

Energy is the one at real scale

Form Energy's iron-air battery is not a flow battery, but it is the largest long-duration story in the country: a 550,000-plus square foot factory in Weirton, West Virginia already in commercial production, over 1.2 billion dollars raised, and a 300 MW / 30 GWh system with Xcel Energy for a Google data center in Pine Island, Minnesota. Nothing in the flow battery field is close to that scale.

Data
centers

are pulling the whole sector

TerraFlow, Storion, XL Batteries, and CMBlu Energy are all now positioning explicitly to artificial intelligence (AI) data center load. That is where the 2026 order flow and the capital are going, and it is the pitch that gets a meeting.

Watch

the word "flow"

Eos Energy Enterprises is widely described in trade press as a "zinc flow battery" maker. Eos's own product sheet describes an aqueous electrolyte held inside individual cells, which is not a pumped redox flow architecture. Figure 4 shows exactly what the difference is and why it changes the economics.

Credit

is the sector's binding constraint

ESS Tech reported total liquidity of 21.5 million dollars at 31 March 2026, falling to roughly 13.6 million dollars by 31 May 2026, while Eos Energy held 472.4 million dollars. Redflow was liquidated in December 2024. Figure 6 charts the gap. Balance sheet screening is not optional here.

02The landscape at a glance

First where they are, then where each one sits by chemistry family and by how far it has genuinely got toward commercial delivery.

1 ESS Tech, Wilsonville OR

2 Invinity, Vista CA

3 Inlyte Energy, San Francisco CA

4 Quino Energy, San Leandro CA (+ pilot line, Buffalo NY)

5 CMBlu US, Petaluma CA (+ planned plant, Phoenix AZ)

6 The BESSt Company, Tucson AZ

7 U.S. Vanadium, Hot Springs AR

8 TerraFlow Energy, Bellville TX

9 Salgenx, Madison WI

10 Influit Energy, Chicago IL

11 Stryten Energy, Alpharetta GA

12 Storion Energy, Alpharetta GA

13 Form Energy, Weirton WV

14 Eos Energy, Turtle Creek PA

15 Lockheed Martin Energy, Andover MA

16 XL Batteries, Marlborough MA

17 Largo Clean Energy, Wilmington MA

18 Ashlawn Energy, Webster NY

19 StorEn Technologies, New York NY

Figure 1. United States manufacturing and headquarters footprint. Marker positions are plotted from published city locations in each company's profile below, at city-level accuracy, on an Albers equal-area projection. Markers in the San Francisco Bay Area, greater Boston, and Alpharetta are nudged a few pixels apart so they can be read; treat their exact pixel position as indicative, not surveyed. State boundaries from the public PublicaMundi MappingAPI us-states.json dataset, accessed 30 July 2026. Alaska, Hawaii and Puerto Rico are omitted because no company in this list has a site there.

Figure 2. Chemistry family versus commercial stage. Chemistry family and company names are taken from the cited sources in each profile below. Horizontal placement (stage) is Gaiergy's own assessment based on the cited milestones in each profile (for example, an energized project versus an announced plan) and is not a vendor claim or a third-party rating. U.S. Vanadium is not plotted because it supplies vanadium chemicals rather than batteries or stacks. Largo Clean Energy is not shown separately because its vanadium redox flow battery (VRFB) division was contributed into the Storion Energy joint venture (source: Business Wire, "Stryten Energy and Largo Launch Long-Duration Energy Storage Company," 19 Dec 2024).

Figure 3. Chemistry mix of the United States field. Counts are derived by Gaiergy from the profiles in Section 4 of this document (one count per company, assigned to its primary chemistry), not taken from any published market study. Vanadium count comprises TerraFlow Energy, Stryten Energy, Ashlawn Energy, StorEn Technologies, Storion Energy (electrolyte and stacks) and U.S. Vanadium (vanadium chemicals). The two amber bars are Form Energy (iron-air) and Inlyte Energy (iron-sodium), which are not flow batteries and are counted separately for that reason. Largo Clean Energy is not counted here because its parent is Canadian and its vanadium flow division was contributed into Storion Energy.

03Quick reference: who to call

Compact contact table. Full evidence, product detail, and caveats for each company are in Section 4.

Company	Headquarters	Chemistry	Phone	Email	Website
TerraFlow Energy	Katy, TX (plant: Bellville, TX)	Vanadium	(281) 699-8916	info@terraflowenergy.com	terraflowenergy.com
Storion Energy	Alpharetta, GA	Vanadium electrolyte and stacks	Not published	storion.info@storion.com	storion.com
Stryten Energy	Alpharetta, GA	Vanadium	678.566.9000	stryten.info@stryten.com	stryten.com
ESS Tech, Inc.	Wilsonville, OR	All-iron	(855) 423-9920	Web form; recruiting@essinc.com	essinc.com
Form Energy	Weirton, WV	Iron-air (not flow)	Not published	info@formenergy.com	formenergy.com
Inlyte Energy	San Francisco, CA	Iron-sodium (not flow)	Not published	contact@inlyteenergy.com	inlyteenergy.com
Eos Energy	Pittsburgh, PA	Aqueous zinc (not flow)	(732) 225-8400	Web form	eose.com
XL Batteries	Marlborough, MA	Organic	Not published	Web form	xlbatteries.com
Quino Energy	San Leandro, CA	Organic (quinone)	Not published	Web form	quinoenergy.com
Ashlawn Energy	Webster, NY	Vanadium	(703) 461-3600	Not published	ashlawnenergyllc.com
StorEn Technologies	New York, NY	Vanadium	Not published	info@StorEn.tech	storen.tech
Influit Energy	Chicago, IL	Nanofluid suspension	Not published	info@influitenergy.com	influitenergy.com
The BESSt Company	Tucson, AZ	Zinc-polyiodide	Not published	Web form	thebesstcompany.com
Salgenx	Madison, WI	Saltwater / chlorine	608-238-6001	greg@infinityturbine.com	salgenx.com
Lockheed Martin Energy	Bethesda, MD (Andover, MA site)	Coordination chemistry	Not published for this unit	Not published for this unit	lockheedmartin.com
Largo Clean Energy	Wilmington, MA (parent: Toronto)	Vanadium	+1 416 861 9797	sales@largoinc.com	largoinc.com
Invinity Energy Systems	Vista, CA (UK parent)	Vanadium	+1 510 306 2638	connect@invinity.com	invinity.com/usa
CMBlu Energy, Inc.	Petaluma, CA (German parent)	Organic SolidFlow	Not published for US office	Not published	cmblu.com
U.S. Vanadium LLC	Hot Springs, AR	Electrolyte and vanadium chemicals	+1 (501) 262-1270	sales@usvanadium.com	usvanadium.com

Contact details in this table were read directly from each company's own website contact page on 30 July 2026. Per-company source links are given in Section 4. "Not published" means no phone or email was published on the company's public contact page as of that date, and it does not mean none exists.

04Company profiles

Grouped by role: flow battery system manufacturers headquartered in the United States, then the iron-air and other non-flow long-duration builders, then component and electrolyte suppliers, then companies that manufacture outside the United States but have United States operations or announced United States plants, and the caution cases throughout.

Figure 4. Flow versus non-flow architecture, and why a developer-owner should care. Left panel describes the pumped redox flow architecture common to every company in Section 4.1. Right panel describes the sealed architecture used by Form Energy, Inlyte Energy and Eos Energy, per each company's own published description cited in Section 4.2. The commercial consequence is the practical point: only the left-hand architecture lets you buy more hours by buying more liquid, and only the left-hand architecture supports the electrolyte leasing structure Storion Energy is marketing. This diagram is a general schematic drawn by Gaiergy to show the architectural distinction; it is not a representation of any specific vendor's product design.

Figure 5. Duration is the whole argument. Every figure plotted is the duration stated by the company or its cited project announcement in the corresponding profile in Section 4, not an independently measured result, and several are vendor claims flagged as such at the point of use. Omitted for lack of a published figure: Invinity, Quino Energy, XL Batteries, Salgenx, Influit Energy, Largo Clean Energy, Storion Energy and U.S. Vanadium. Colour follows Figure 3: teal for pumped redox flow, amber for non-flow long duration, light grey for foreign-parent suppliers. The practical read for a developer-owner: everything below about 8 hours is territory lithium iron phosphate already serves more cheaply and more efficiently, so the case for these technologies lives at the top of this chart, not the bottom.

4.1 Flow battery system manufacturers, United States headquartered

TerraFlow Energy Vanadium Plant under construction

Headquarters: 1040 Schlipf Rd., #248, Katy, TX 77493 (executive and engineering hub)
Manufacturing: 1321 Nelius Rd., Bellville, TX 77418 (system assembly and testing)
Phone: (281) 699-8916
Email: info@terraflowenergy.com (business development and technical) · media@terraflowenergy.com
Website: terraflowenergy.com
Technology: Vanadium redox flow battery (VRFB) in a skid-based architecture, marketed as LDUPS (long-duration uninterruptible power supply) aimed at artificial intelligence (AI) data centers, positioned as a buffer between volatile data center load and the grid.
Reference project: 9.6 megawatt (MW) / 48 megawatt-hour (MWh) five-hour system in Bellville, Texas, targeted for initial energization in the first quarter of 2027. A one-gigawatt (GW) storage commitment on an undisclosed Port of Victoria project has also been reported.
Supply chain: Strategic supply agreement with Storion Energy for vanadium electrolyte and manufacturing scale-up.
Founded: 2024. Reported plant capacity of approximately 300 MW per year near Houston.
Why it matters: Of every company in this list, TerraFlow has the clearest combination of a domestic factory, a named project with a date, and an electrolyte supply agreement. First call.

Sources: TerraFlow Energy contact page (addresses, phone, emails); Energy-Storage.News, "US flow battery players: TerraFlow plans 5-hour Texas project, ESS Inc.'s funding lifeline" (project size, date, Storion agreement); TerraFlow, "9.6 MW / 5-Hour Vanadium Flow Battery Project in Bellville, Texas"; Latitude Media, "Can flow batteries help fix data centers' power volatility issue?" (founding year, plant capacity, data center framing, Port of Victoria and additional pipeline). All accessed 30 July 2026. UNCONFIRMED: the exact groundbreaking month reported for the Houston-area plant ("May") is not stated with a year in the source read, so treat the construction start date as approximate until confirmed with the company.

ESS Tech, Inc. All-iron Liquidity risk

Headquarters: 26440 SW Parkway Ave., Bldg. 83, Wilsonville, OR 97070
Phone: (855) 423-9920 toll free, United States and Canada · +1-971-252-2207 international
Email: Sales inquiries via the website form. Published address on the page source: recruiting@essinc.com. Sales and accounts payable addresses are obfuscated by the site's email protection.
Website: essinc.com · New York Stock Exchange ticker GWH
Technology: All-iron flow battery using iron, salt, and water electrolyte. Products: Energy Warehouse, Energy Center, Energy Base. Marketed for 10 to 12 hour daily discharge, with the Energy Base line targeting 10 to 23 hour duration. Commercial, industrial, and utility scale only; the company states it has no residential offering.
Third-party validation: Burbank Water and Power operated an ESS system for a 21-month evaluation co-located with solar and reported to the American Public Power Association that the technology works as intended and has a use case in a utility storage strategy.
Financial status: Total liquidity of 21.5 million dollars at 31 March 2026 (15.5 million dollars unrestricted cash plus 6.0 million dollars short-term investments), reported as approximately 13.6 million dollars at 31 May 2026. Net cash used in operations was 13.5 million dollars in the first quarter of 2026. Adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) loss of 10.3 million dollars, a 31 percent year-over-year improvement. The company warned of a survival fight during an "operational reset" in 2025 and its chief executive resigned in February 2025.
Corporate development: Acquired the assets of VoltStorage GmbH (Germany), expanding its intellectual property base. Signed a letter of intent with Alsym Energy on next-generation, non-lithium battery solutions.

Flag before any procurement: ESS is the best-known United States flow battery brand and the technology has independent utility validation, but the balance sheet is thin. Any developer-owner engagement should assume supplier-credit risk and require warranty backstops, performance security, or escrowed spares. Do not model a 20-year warranty from this counterparty without security.

Sources: ESS contact page (address, phones, product names, no residential offering); Business Wire, "ESS Tech, Inc. Announces First Quarter 2026 Financial Results," 7 May 2026 (liquidity, cash use, EBITDA, VoltStorage, Alsym letter of intent); Energy-Storage.News, "Iron flow battery maker ESS Inc warns of survival battle through 'operational reset' period"; Business Wire, "ESS Highlights Third-Party Utility Validating Iron Flow Battery Technology," 6 May 2026 (Burbank Water and Power 21-month evaluation); Energy-Storage.News funding lifeline article (chief executive resignation, rescue financing). All accessed 30 July 2026. UNCONFIRMED: a StockTitan summary of an ESS Form 8-K is headlined as the company accelerating a "sodium-ion pivot amid cash strain and NYSE notice." The underlying filing was not read for this document, so treat any strategic shift away from iron flow as reported but unverified.

Stryten Energy, LLC Vanadium Large parent

Headquarters: Alpharetta, GA 30005
Phone: 678.566.9000
Email: stryten.info@stryten.com
Website: stryten.com
Technology: Vanadium redox flow battery systems alongside advanced lead and lithium products, intelligent chargers, and energy performance management software. VRFB targeted at data centers and microgrids needing 5 to 24-plus hours of resilience.
Scale: Founded 25 August 2020 as Stryten Energy, LLC. Company-reported employee band of 1,001 to 5,000. Sectors served include essential power, motive power, transportation, military, and government.
Recent activity: Unveiled its vanadium redox flow battery with joint venture Storion Energy at the Consumer Electronics Show in January 2026, aimed at data center load growth driven by artificial intelligence.
Why it matters: This is the one United States VRFB player with a large, diversified, established manufacturing parent behind it. Lowest counterparty risk in the vanadium group.

Sources: Stryten Energy contact page and embedded organization schema (address, phone, email, legal name, founding date, employee band, technology list); Business Wire, "Safe, Scalable Long-Duration Storage with Vanadium Redox Flow Technology to be Highlighted at CES," 5 Jan 2026. Accessed 30 July 2026.

XL Batteries Organic Pilot commissioned

Headquarters: 33 Locke Dr, Marlborough, MA 01752
Contact: Website contact form. No public phone or direct email published as of 30 July 2026.
Website: xlbatteries.com
Leadership: Tom Sisto, Chief Executive Officer
Technology: Organic flow battery combining conventional flow battery architecture with a patented organic chemistry. Company describes it as non-toxic, non-flammable, and non-corrosive. Founded 2019 by Columbia University scientists.
Reference project: First organic flow battery commissioned through a pilot with Stolthaven Terminals, announced 8 April 2025.
Recognition: Named a 2026 BloombergNEF (BNEF) Pioneer and "Most Inspiring Startup" at the Data Center World Innovation Challenge, announced 2 June 2026.

Sources: XL Batteries website (address, technology, chief executive); Business Wire, 8 Apr 2025 (pilot commissioning); Business Wire, 2 Jun 2026 (recognition, founding year and founders). Accessed 30 July 2026. Note: XL Batteries does not publish the specific organic chemistry used; do not assume a quinone system by analogy with Quino Energy.

Quino Energy Organic quinone Grant-funded demo

Headquarters: 2235 Polvorosa Ave, Suite 230, San Leandro, CA 94577
Contact: Website contact form. No public phone or direct email published as of 30 July 2026.
Website: quinoenergy.com
Leadership: Eugene Beh, Chief Executive Officer
Technology: Water-based flow battery storing energy in organic molecules called quinones, for commercial and grid applications.
Manufacturing: Pilot production line in Buffalo, New York, with a larger-scale production line in development. A 5 million dollar United States Department of Energy (DOE) grant supported the manufacturing process.
Reference project: 8 MWh flow battery at the High Desert Regional Health Center, Lancaster, California, backed by a 10 million dollar California Energy Commission (CEC) award. Permitting from the third quarter of 2025, groundbreaking expected fall 2026, system online early 2027. Described as the first United States commercial deployment of the technology.
Funding: Closed 10 million dollars in November 2025 to scale organic flow batteries.

Sources: Quino Energy contact page (address); Energy-Storage.News, CEC grant for 8 MWh demonstration; American Public Power Association, "Companies Awarded $10 Million in Funding for Calif. Organic Flow Battery System" (site, schedule); pv magazine USA, 10 Nov 2025 (funding); pv magazine USA, 10 May 2024 (Buffalo pilot line, DOE grant); Renewable Energy Magazine interview with chief executive Eugene Beh, 29 Sep 2025. Accessed 30 July 2026.

Ashlawn Energy, LLC Vanadium New York

Address: 710 Resende Rd, Bldg 199, Webster, NY 14580
Phone: (703) 461-3600
Email: Not published on the contact page as of 30 July 2026
Website: ashlawnenergyllc.com
Technology: VanCharg vanadium redox flow battery, a 32 kilowatt (kW) stationary system. Company states 4 to 14 hour duration, up to 30-year life, non-flammable and non-explosive water-based chemistry, and UL 9540A fire safety testing showing no flashpoint and no flame. Company launched 2008.
Recent activity: Leased a 10,000 square foot space on the Xerox Webster Campus, adding 20 jobs, reported 11 March 2026. The move follows a long-standing collaboration with the Rochester Institute of Technology (RIT) Center of Excellence in Advanced and Sustainable Manufacturing on design optimization and commercial scale-up. Earlier deployment history includes a DOE-reported project with the City of Painesville, Ohio.
Why it matters: The only vanadium flow manufacturer in this list physically located in New York State, which is directly relevant to a developer-owner's New York battery pipeline and to New York content or local-jobs arguments.

Sources: Ashlawn Energy contact page (address, phone); Spectrum Local News, 11 Mar 2026 (Webster lease, 20 jobs, RIT collaboration); NY-BEST member spotlight and CBS6 Albany (VanCharg rating, duration, life, UL 9540A); DOE Technology Performance Report, City of Painesville, Ohio, Feb 2015. Accessed 30 July 2026. Vendor claim: the 30-year life and 4 to 14 hour duration figures are Ashlawn's own statements as reported in local press, not independently verified.

StorEn Technologies, Inc. Vanadium Early stage

Headquarters: New York, New York (United States headquarters). Technical development team in Bologna, Italy.
Email: info@StorEn.tech
Website: storen.tech
Technology: Vanadium flow battery aimed at residential and industrial storage, with claimed improvements in stack electrical efficiency, electrolyte energy density, and module design. Company states 25-year life or more than 15,000 charge and discharge cycles without capacity decay, for durations in excess of 2 hours.
Background: Incubated at the Clean Energy Business Incubator Program (CEBIP) at Stony Brook University, New York. Has raised through Regulation A+ retail offerings and files Form 1-K annual reports with the Securities and Exchange Commission.

Flag: retail crowdfunding as a primary capital source, plus no announced utility-scale reference project found in this sweep, puts StorEn in the earliest tier. Useful as a technology conversation, not as a near-term supplier.

Sources: StorEn about page (email, incubation, technology framing, duration); New York State Pollution Prevention Institute case study; StorEn Technologies Form 1-K, fiscal year 2021, SEC EDGAR; StartEngine offering page. Accessed 30 July 2026. Vendor claim: the 25-year and 15,000-cycle figures are company statements, not independently verified.

Influit Energy, LLC Nanofluid suspension Defense-funded

Location: Chicago, Illinois (West Loop laboratory, reported at approximately 2,100 square feet)
Email: info@influitenergy.com
Website: influitenergy.com
Leadership: John Katsoudas, Chief Executive Officer (as quoted in Illinois Institute of Technology coverage)
Technology: Nano-Electro Fuel (NEF): a flow battery that suspends battery-active nanoparticles in a nanofluid rather than dissolving redox salts, giving higher energy density per unit volume than conventional flow chemistries. Company states non-flammable operation, a domestic supply chain, rapid fluid swapping, and an operating range of minus 30 to plus 80 degrees Celsius.
Markets: Electric vehicles, grid storage and stabilization, heavy industry and transportation, defense and aerospace.
Funding: Spun out of Illinois Institute of Technology. More than 10 million dollars in United States government contracts for prototype design and fabrication, with backing cited from the Defense Advanced Research Projects Agency (DARPA), the National Aeronautics and Space Administration (NASA), the National Science Foundation (NSF), and DOE.

Flag: Influit's core market is mobility and defense, not stationary grid storage. Relevant to a developer-owner only as a technology watch item unless a stationary product line is announced.

Sources: Influit Energy website (email, technology, markets, funder list); Illinois Institute of Technology news (spinout, laboratory, chief executive, government contracts); New Atlas, "Influit moves to commercialize its ultra-high density liquid batteries". Accessed 30 July 2026. Vendor claim: energy density, temperature range, and swap-time claims are company statements, not independently verified.

The BESSt Company Zinc-polyiodide Pre-commercial

Location: Tucson, Arizona
Contact: Website only. No phone or email published as of 30 July 2026.
Website: thebesstcompany.com
Leadership: Joley Michaelson, founder and Chief Executive Officer, previously at Tesla; also founder of The Sun Company (2018)
Technology: Zinc-polyiodide redox flow battery, with chemistry licensed from Battelle (the operator of Pacific Northwest National Laboratory). Patent-pending cell stack using domestically sourced earth-abundant alloy materials.
Stated product line: Residential 20 kW / 25 kWh (5 hours); commercial and industrial 40 kW / 100 kWh (6.5 hours); utility scale 200 kW to 2.4 MW with 400 to 1,600 kWh. Company-stated 320 watt-hours per liter energy density, up to 80 percent round-trip efficiency, 100 percent depth of discharge, 30-year warranty with electrolyte guaranteed 20 years.
Route to market: Commercial and industrial first, residential launch stated for early 2028. Manufacturing planned through United States contract manufacturing partners at multiple sites.

Flag: every performance number above is a company claim published at product launch in September 2025, with no third-party test data found in this sweep. The stated 320 watt-hours per liter would be a very large step beyond conventional vanadium systems. Treat as unverified until an independent test report or an energized reference project exists.

Sources: Energy Storage (ess-news.com), 29 Sep 2025 (specs, product lines, launch plan, chief executive quote); PR Newswire, "Tesla Alum Launches Lithium-Free Any-Duration Battery for Data Centers, Cold Storage and AI" (Tucson location, founder background, Battelle license). Accessed 30 July 2026.

Salgenx (a division of Infinity Turbine LLC) Saltwater / chlorine Unverified claims

Location: Madison, Wisconsin
Phone: 608-238-6001
Email: greg@infinityturbine.com
Website: salgenx.com
Technology: Membrane-free closed-loop chlorine flow battery using salt water (brine) as the primary electrolyte, which the company states also functions as a thermal battery. Company states roughly 25-year life, active material cost near 5 dollars per kWh, and total manufacturing system cost under 100 dollars per kWh, with on-site assembly using locally sourced containers.

Do not put these numbers in a model. The Salgenx cost and life figures come only from company-issued press releases distributed through wire services. No independent test data, no named reference installation, and no third-party validation were found in this sweep. Labeled UNCONFIRMED. If the cost claims were real they would be sector-changing, which is itself a reason for diligence before use.

Sources: Salgenx website (phone, email); Business Wire, 3 Dec 2024; Energy XPRT company listing (Madison, Wisconsin; division of Infinity Turbine LLC). Accessed 30 July 2026.

Lockheed Martin Energy (GridStar Flow) Coordination chemistry Army pilot

Corporate: Lockheed Martin Corporation, Bethesda, Maryland. Lockheed Martin Energy operates a facility in Andover, Massachusetts covering new product introduction, engineering, and manufacturing.
Contact: No dedicated phone or email is published for the energy storage unit. Route inquiries through Lockheed Martin corporate channels. UNCONFIRMED: a direct commercial contact route for GridStar Flow was not verifiable from public sources on 30 July 2026.
Website: lockheedmartin.com
Technology: Redox flow battery based on coordination chemistry, using engineered electrolytes made from earth-abundant redox-active metals and commodity chemical ligands. Designed for 8-plus hour large-capacity storage optimized for daily cycling, with duration scaled by adding electrolyte. Technology base originated with Lockheed Martin's 2014 acquisition of Sun Catalytix.
Reference project: 1 MW / 10 MWh system installed at Fort Carson, Colorado. The United States Army Engineer Research and Development Center has led technical evaluation and project management since 2022 and expects the system to serve the daily electricity needs of approximately 400 Fort Carson homes.

Sources: United States Army, "ERDC Celebrates Milestone with GridStar Flow Battery Installation at Fort Carson" (size, duration, evaluation role, homes served); Lockheed Martin GridStar Flow white paper for the American Council on Renewable Energy (ACORE) (coordination chemistry, electrolyte composition, 8-plus hour design, 20-year durability); Lockheed Martin, "Clean Energy Scientists Have a New Home" (Andover, Massachusetts facility); Renewable Energy World (Sun Catalytix acquisition). Accessed 30 July 2026.

4.2 Iron-air and other non-flow long-duration chemistries, United States headquartered

These are not flow batteries. They are here because they bid for the same 8-hour-plus projects, they are further along commercially than most of Section 4.1, and Form Energy in particular is the largest long-duration manufacturing story in the country. Each card states the architecture difference explicitly so nothing gets mislabeled downstream. See Figure 4.

Form Energy, Inc. Iron-air, not flow In commercial production Largest US LDES build

Headquarters and factory: 26 Iron Way, Weirton, WV 26062 (Form Factory 1)
Other offices: 30 Dane St., Somerville, MA 02143 · 793 Heinz Ave., Berkeley, CA 94710. International expansion includes Ireland.
Email: info@formenergy.com (general) · pr@formenergy.com (media). No phone published on the contact page as of 30 July 2026.
Website: formenergy.com
Leadership: Mateo Jaramillo, Chief Executive Officer · Ted Wiley, President and Chief Operating Officer · William Woodford, Chief Technology Officer · Yet-Ming Chiang, Chief Science Officer · Marco Ferrara, Chief Digital Officer
Technology: Iron-air battery selected as the company's first product at 100-hour duration, for multi-day grid storage. The company also offers Formware, software for utilities to model storage value. Founded 2017 with initial support from MIT's The Engine.
Architecture note: Not a flow battery. Iron-air stores energy by reversibly oxidizing and reducing solid iron with oxygen from ambient air. There are no external electrolyte tanks and no pumped liquid energy carrier, so energy and power do not scale independently the way they do in a redox flow battery. Do not apply electrolyte leasing or electrolyte-only duration extension to it.
Manufacturing: Form Factory 1 in Weirton, West Virginia: 550,000-plus square feet, construction completed 2024, commercial production started. Expansion to roughly 850,000 square feet, with the company targeting more than 750 employees at the site and at least 500 MW per year of production by 2028. Approximately 1,000 employees company-wide.
Flagship project: 300 MW / 30 GWh iron-air system in Pine Island, Minnesota under a Google and Xcel Energy agreement announced 24 February 2026, paired with 1.6 GW of new Xcel renewables (1.4 GW wind, 200 MW solar). Reported as the largest battery system by energy capacity announced globally.
Other projects: Binding agreement with Crusoe Energy Systems for systems delivering 12 GWh, with commercial production and initial shipments from Weirton on track to begin in early 2027. Earlier announced pipeline includes Great River Energy (1.5 MW / 150 MWh commercial pilot), Puget Sound Energy (10 MW / 1 GWh), Pacific Gas and Electric (5 MW / 500 MWh), New York (10 MW / 1 GWh), Maine (85 MW / 8.5 GWh) and Xcel Energy Minnesota (10 MW / 1 GWh).
Capital: More than 1.2 billion dollars raised across six financing rounds, investors including ArcelorMittal, Breakthrough Energy Ventures and T. Rowe Price. The 405 million dollar Series F closed October 2024 with GE Vernova, Breakthrough Energy Ventures and Energy Impact Partners, alongside a memorandum of understanding with GE Vernova covering manufacturing, supply chain, financing and sourcing.
Why it matters: On every measure that decides whether a supplier can actually deliver (factory built and producing, capital raised, order book, strategic partner), Form Energy is ahead of every flow battery company in this document. If the requirement is multi-day duration rather than flow architecture specifically, this is the first call.

What to probe in a first conversation: iron-air round-trip efficiency is materially lower than both lithium iron phosphate and vanadium flow, which is the accepted trade for 100-hour duration. Form Energy does not publish a round-trip efficiency figure on the pages read for this document, so ask for it directly, along with auxiliary load, footprint per MWh, and what a 100-hour product costs when the application only needs 8 to 12 hours. UNCONFIRMED: no verified pricing or round-trip efficiency figure was found in public sources.

Sources: Form Energy contact page (all three addresses, both emails); Form Energy about page (founding, leadership, 100-hour product, Formware, headcount, capital raised and investors, Form Factory 1 size); Form Factory 1 page; Renewable Energy World (expansion to 850,000 square feet, 750-plus employees, 500 MW per year by 2028); Utility Dive, "Iron-air battery developer Form Energy raises $405M, announces collaboration with GE Vernova" (Series F amount, date, investors, GE Vernova memorandum of understanding, earlier project pipeline); Utility Dive, "World's 'largest' grid battery part of Google-Xcel Energy agreement" and American Public Power Association (300 MW / 30 GWh, Pine Island Minnesota, 24 Feb 2026, paired renewables); Energy Storage, 25 Feb 2026; WTRF (Crusoe Energy Systems 12 GWh binding agreement, early 2027 shipments). All accessed 30 July 2026.

Inlyte Energy Iron-sodium, not flow US factory being sited

Headquarters: San Francisco Bay Area, California
Other site: Burton-on-Trent, United Kingdom (Beta Research Ltd), where the first full-scale system was built and tested
Email: contact@inlyteenergy.com. No phone published as of 30 July 2026.
Website: inlyteenergy.com
Leadership: Antonio Baclig, Chief Executive Officer · Ben Kaun, Chief Commercial Officer
Technology: Iron-sodium (sodium metal chloride family) battery, company-stated 4 to 48-plus hour duration, roughly 7,000 cycles or about 20 years, no thermal runaway risk, and dense configurations of up to 1 GWh per acre. Built on sodium metal chloride research spanning more than 40 years. Founded 2021.
Architecture note: Not a flow battery. This is a sealed high-temperature cell chemistry, not a pumped redox system with external tanks.
Milestones: Completed factory acceptance test of its first full-scale, field-ready system near Derby, United Kingdom in December 2025. First United States systems to be installed at Southern Company's Energy Storage Test Site in Wilsonville, Alabama in early 2026 for at least one year of evaluation. A 600 kWh (25 kW) pilot with NTS Colocation at a Tier IV facility in Bern, Switzerland is targeted by end of 2026, with potential expansion to 2 MW across NTS facilities by 2028.
United States manufacturing: Partnership with Horien Salt Battery Solutions to establish a first domestic plant targeting 2 GWh initial capacity, batteries stated at 70 percent domestic content, commercial shipments targeted 2027. Iron powder formulation work with Ervin Industries. The company planned to finalize a United States site during 2026.

Flag: Inlyte is roughly two years behind Form Energy commercially and its United States factory site was still being selected as of the sources read. Treat it as a technology watch item and a possible second source, not a near-term supplier. UNCONFIRMED: whether a United States site has now been finalized; no announcement was found on 30 July 2026.

Sources: Inlyte Energy website (locations, email, stated duration, life, applications); Energy Storage, 12 Dec 2025 and PR Newswire (factory acceptance test, Derby UK, US production plans); Energy Storage, 26 May 2026 (cycle life, 1 GWh per acre, NTS Colocation and Southern Company pilots, Horien partnership, 2 GWh plant, 70 percent domestic content, 2027 shipments, executives quoted); Energy-Storage.News. All accessed 30 July 2026. Vendor claim: duration, cycle life and density figures are company statements.

Eos Energy Enterprises, Inc. Aqueous zinc, not flow 4 GWh line target

Headquarters: Nova Tower 2, Two Allegheny Center, Pittsburgh, PA 15212
Research and development: Eos Ingenuity Lab, 3920 Park Avenue, Edison, NJ 08820
Manufacturing: 200 Braddock Ave, Turtle Creek, PA 15145 and 700 Braddock Ave, East Pittsburgh, PA 15112
Phone: (732) 225-8400 (sales)
Website: eose.com
Technology: Znyth zinc hybrid cathode, Z3 module. Eos's own product sheet describes an aqueous electrolyte held within individual cells providing dynamic separation of the electrodes, with energy stored through zinc deposition, for 3 to 12 hour applications. The electrolyte is described as a blend of water, halides, additives, and buffering agents.
Manufacturing scale: Commercial production began on a second battery line at the Thorn Hill facility in Marshall Township, Pennsylvania, with a target of 4 GWh annual capacity by the end of 2026.

Classification, verified rather than assumed: trade press (including pv magazine USA and Energy Storage in June 2026) describes the new Eos line as a "zinc flow battery." Eos's own Z3 product sheet describes electrolyte held inside individual cells, which is a static aqueous zinc architecture, not a pumped redox flow battery with external electrolyte tanks. Because architecture drives duration scaling economics, electrolyte replacement, and balance-of-plant, a developer-owner should classify Eos as an aqueous zinc battery and should not apply flow-battery assumptions (independent power and energy scaling, electrolyte leasing, electrolyte-only duration extension) to it. If duration-scaling economics matter to a specific deal, confirm the architecture directly with Eos engineering.

Sources: Eos contact page (all addresses and phone); Eos Z3 product sheet (cell-level aqueous electrolyte, zinc hybrid cathode, voltage range); Eos technology page; pv magazine USA, 17 Jun 2026 and Energy Storage, 16 Jun 2026 (second line, 4 GWh target, and the "zinc flow battery" wording this note corrects). Accessed 30 July 2026.

4.3 Component and electrolyte suppliers

Vanadium electrolyte is 40 to 70 percent of a VRFB system's cost, so these two are as commercially important as the system integrators.

Storion Energy, LLC Electrolyte and stacks Joint venture

Headquarters: 5790 Shiloh Road, Suite 300, Alpharetta, GA 30005
Second site: Product development facility in Wilmington, Massachusetts
Email: storion.info@storion.com
Website: storion.com
Ownership: Joint venture of a Stryten Energy affiliate (Stryten Critical E-Storage, LLC) and Largo Clean Energy Corp., a subsidiary of Largo Inc. Announced 19 December 2024, formed February 2025, built from the VRFB divisions of both parents.
Products: Domestically sourced, non-flammable vanadium electrolyte and high-performance stack power assemblies, sold to other flow battery manufacturers. Electrolyte is described as infinitely recyclable and represents 40 to 70 percent of VRFB system cost. Markets: grid storage, microgrids, data centers, and military.
Supply chain: Access to vanadium from what the parties describe as the only operating vanadium mine in the Western Hemisphere, combined with domestic electrolyte production, giving a vertically integrated chain. Storion has also been named safekeeper for held vanadium units and is positioning to lease electrolyte, which is a route to removing electrolyte capital cost from a project's balance sheet.
Customers: Strategic supply agreement with TerraFlow Energy. Presented at the International Flow Battery Forum in June 2026 on supporting artificial intelligence data centers.
Why it matters: If a developer-owner ever prices a domestic VRFB, this is where the electrolyte comes from, and the electrolyte leasing model is the single most interesting commercial structure in this whole list.

Sources: Storion Energy website and contact page (address, email, product, electrolyte cost share, markets); Business Wire, 19 Dec 2024 (joint venture structure, both sites); Stryten Energy, "Storion Energy Launched" (February 2025 formation, vertical integration); Business Wire, 16 Jun 2026; Barchart news item on safekeeper role and leased electrolyte demand. Accessed 30 July 2026.

U.S. Vanadium LLC Electrolyte and vanadium chemicals

Address: 4285 Malvern Road, Hot Springs, Arkansas 71901-8504
Main phone: +1 (501) 262-1270
Sales: sales@usvanadium.com · Corey McCollom, Director of Sales and Marketing, +1 (704) 242-4685, corey.mccollom@usvanadium.com
Operations: Christian James, General Manager, +1 (501) 547-2440, christian.james@usvanadium.com
Accounts payable: ap@usvanadium.com · +1 (501) 622-3026
Website: usvanadium.com
Products: Vanadium halide solutions, vanadium powders, and vanadium solutions, including material supporting vanadium flow battery technology.

Source: U.S. Vanadium contact page (all addresses, phones, emails, named contacts, product list). Accessed 30 July 2026. Named individuals and their direct lines are published by the company on its own public contact page.

4.4 Companies manufacturing outside the United States, with United States operations or announced United States plants

Five entries. Four have foreign parents (United Kingdom, Germany, Japan, Canada). The fifth, VRB Energy, has a United States listed parent, Ivanhoe Electric, but its manufacturing today sits in a China-based joint venture. Each either ships to, operates in, or has announced a factory in the United States, so all five belong on a domestic sourcing call list.

Invinity Energy Systems plc United Kingdom parent Vanadium

United States base: Vista, California, reported as its United States home base, with California manufacturing capacity expansion planned near term
Phone: +1 510 306 2638 (Americas and Asia Pacific sales) · +44 204 526 5789 (United Kingdom, Europe, Middle East and Africa)
Email: connect@invinity.com
Website: invinity.com/usa
Background: Formed by the merger of North America's Avalon Battery and the United Kingdom's redT energy. Operations in the United Kingdom, Canada, United States, Australia, India and China, with more than 65 MWh deployed across 70 sites in 14 countries.
United States projects: 32 MWh vanadium flow system for Pacific Steel Group's Mojave Micro Mill in Kern County, California, backed by the California Energy Commission, described as the largest vanadium flow battery system in North America. Invinity plans to manufacture in the United States with deliveries starting in early 2027, and engineering for local electrolyte production is expected to start in 2026.
Domestic content: Has been the subject of a Made in America waiver listing for federal financial assistance, which matters for any federally funded project.

Sources: Invinity contact page (phones, email); Invinity United States page; Energy-Storage.News, "Invinity hunts flow battery supply chain, manufacturing advantage" (Vista base, electrolyte engineering in 2026); Vanitec on the Pacific Steel Group 32 MWh project; Made in America waiver listing. Accessed 30 July 2026.

CMBlu Energy, Inc. German parent Organic SolidFlow

United States office: 621 2nd St., Suite A, Petaluma, CA 94952. No United States phone or email published on the contact page as of 30 July 2026.
Parent: CMBlu Energy AG, Industriestrasse 19, 63755 Alzenau, Germany, +49 6023 7062-0
Website: cmblu.com
Technology: Organic SolidFlow, combining solid-state and flow architecture: solid organic polymers as the storage medium with a liquid, organic, non-metal electrolyte, so energy capacity (kWh) and power (kW) scale independently. A described unit stores 200 kWh with 40 kW output. Marketed for 10-plus hour duration with no lithium, no cobalt, and no Foreign Entity of Concern (FEOC) exposure.
United States plans: Entered the United States market and has advanced United States manufacturing plans, with a potential site identified in Phoenix, Arizona in partnership with contract manufacturer Benchmark, targeted within roughly 12 months of July 2026 reporting. Full commercial production of the Organic SolidFlow system was planned to begin in 2026.
Company status: Crossed a 1 billion euro valuation on 30 April 2026, described as Germany's first non-lithium battery unicorn. Winner of The smarter E Award 2025 in the energy storage category.

Relevant to a developer-owner's tax-credit position: CMBlu's marketing explicitly claims no Foreign Entity of Concern exposure. Given that GFE's current storage pro formas exclude the investment tax credit because of Renon sourcing, a FEOC-clean supplier is worth understanding even if the technology is not yet proven at scale. Verify the FEOC claim against the actual bill of materials before relying on it.

Sources: CMBlu contact page (both offices); CMBlu, "German flow battery manufacturer CMBlu Energy enters the US market"; Energy-Storage.News on United States manufacturing plans (Phoenix site, Benchmark, 2026 production); Tech Times, 13 Jul 2026 (factory timing, FEOC framing); Energy Storage, 12 May 2025 (technology description, 200 kWh / 40 kW unit, award). Accessed 30 July 2026.

Sumitomo Electric Industries Japanese parent Vanadium

United States presence: Sells and supports vanadium redox flow batteries in the United States through Sumitomo Electric's United States organization. See global-sei.com/usa.
Website: sumitomoelectric.com/products/flow-batteries
United States track record: Launched a demonstration project with San Diego Gas and Electric (SDG&E) in California in 2015. First flow battery in the United States to receive UL 1973 certification for its cell stacks, in 2017, and the first flow battery to operate in California Independent System Operator (CAISO) markets, since 2018.
Current product: New VRFB unveiled at Energy Storage North America in San Diego, 25 to 27 February 2025, using long-life materials for a stated 30-year operational life, in three versions providing up to 10 hours of storage. Orders opened in 2025.
Why it matters: The longest United States operating record and the only flow battery in this list with documented CAISO market participation. That matters for any interconnection or market-qualification argument, even if the equipment is imported.

Sources: Sumitomo Electric SDG&E case study (2015 project, UL 1973 in 2017, CAISO since 2018); Sumitomo Electric press release, February 2025; pv magazine, 3 Mar 2025 (30-year life, three versions, up to 10 hours, orders from 2025). Accessed 30 July 2026.

VRB Energy (Ivanhoe Electric Inc.) United States listed parent Plan not confirmed

Structure: Ivanhoe Electric Inc. (United States listed) owns 90 percent of VRB Energy. VRB Energy is the minority partner in a 51 / 49 joint venture with a subsidiary of Shanxi Red Sun, which manufactures and sells vanadium redox flow batteries in Asian, African and Middle Eastern markets.
Announced United States plan: Ivanhoe Electric and VRB Energy stated they are establishing a separate United States vanadium redox battery business in Arizona, capable of producing 50 MW per year of VRB-ESS vanadium flow batteries, with 20 million dollars of transaction proceeds supporting it. Agreements signed 15 October 2024.
Websites: ivanhoeelectric.com · vrbenergy.com (the VRB Energy site did not respond to requests on 30 July 2026)

UNCONFIRMED: no evidence was found in this sweep that the Arizona facility has been sited, permitted, or built. The 50 MW per year figure is an announced plan from October 2024, not an operating capacity. Confirm status directly with Ivanhoe Electric investor relations before counting it as domestic supply.

Sources: Ivanhoe Electric news release on the Red Sun definitive agreements; Newsfile, "Ivanhoe Electric's VRB Energy Subsidiary Secures $55 Million Investment"; Energy-Storage.News, "VRB Energy plans flow battery factories in China, US". Accessed 30 July 2026.

Largo Clean Energy Corp. / Largo Inc. Canadian parent Vanadium

United States operation: Largo Clean Energy Corp., Wilmington, Massachusetts. Its VRFB division was contributed into the Storion Energy joint venture, and the Wilmington site is now described as Storion's product development facility.
Parent contact: Largo Inc., Toronto, Ontario. +1 416 861 9797 · info@largoinc.com · sales@largoinc.com
Website: largoinc.com (Toronto Stock Exchange and Nasdaq ticker LGO)
Product history: VCHARGE vanadium flow battery system using patented technology and proprietary vanadium electrolyte processing. Also signed an agreement with Ansaldo Green Tech for production and commercial distribution of flow batteries.

Read this before treating Largo Clean Energy as a standalone supplier: for United States VRFB hardware and electrolyte, the live counterparty is now Storion Energy, not Largo Clean Energy. Approach Largo for vanadium feedstock and corporate matters, and Storion for product.

Sources: Largo Inc. contact page (phone, emails); Business Wire, 19 Dec 2024 (VRFB divisions contributed, Wilmington and Alpharetta sites); Largo Inc. clean energy storage page; Ansaldo Green Tech press release. Accessed 30 July 2026.

05Not operating, or do not rely on

First, what the public balance sheets say about who can survive a build cycle. Then the names that appear in older market reports and vendor lists, which you should check before responding to any inbound approach or citing a market study.

Figure 6. Who can still be there in five years. Figures as reported by each company for the first quarter of 2026: Eos Energy 472.4 million dollars total cash including restricted cash at 31 March 2026 (Eos Q1 2026 results); Ivanhoe Electric 176.3 million dollars cash and short-term investments (Ivanhoe Electric Form 10-Q, Q1 2026); ESS Tech 21.5 million dollars total liquidity at 31 March 2026 falling to about 13.6 million by 31 May 2026 (ESS Q1 2026 results); Largo Inc. 11.2 million dollars cash against 108.4 million dollars of debt (Largo Form 6-K exhibit 99.1, Q1 2026, quoted directly: the company ended Q1 2026 with a cash balance of 11.2 million dollars and debt of 108.4 million dollars). Read these caveats: the Eos figure includes restricted cash and so overstates freely available liquidity; Largo's figure sits against current debt more than nine times its cash, and the forward-looking statements section of that same Largo release lists "the ability of the Company to continue as a going concern" among its forward-looking items. UNCONFIRMED: no auditor going-concern qualification was read for any company here; this chart is a screening prompt to read the filings, not a substitute for doing so. Form Energy, TerraFlow, Storion and the rest are private and file nothing comparable, so they cannot be charted: Form Energy's disclosed capital is more than 1.2 billion dollars raised across six rounds (see Section 4.2), which is not the same measure as cash on hand.

Redflow Limited Liquidated

Australian zinc-bromine flow battery maker with more than 250 installed sites in nine countries. Entered voluntary administration on 23 August 2024, ceased operations on 18 October 2024, and was liquidated in December 2024 after administrators could not find a buyer. Cited causes: difficulty raising capital, high component cost at low volume, and reliability issues driving warranty repair cost. Redflow still appears in market reports published before 2025.

Sources: Energy-Storage.News; Renewable Energy World. Accessed 30 July 2026.

Zinc8 Energy Solutions Project distressed

Zinc-air flow battery developer that announced a 68 million dollar first commercial manufacturing facility and American headquarters at iPark 87 (the former Tech City IBM Ulster campus) in Kingston, Ulster County, New York in January 2023, backed by 9 million dollars in New York State tax credits and a commitment of up to 500 jobs. By September 2023 the chief executive had resigned, employees had been laid off, and the share price had collapsed. UNCONFIRMED: no evidence of the facility operating was found in this sweep, and no post-2023 status update was located. Directly relevant to New York work because the incentive package and the site are New York State matters.

Sources: Energy-Storage.News; Office of the Governor of New York, 26 Jan 2023; Empire Center for Public Policy, "Another battery flop zaps NY taxpayers". Accessed 30 July 2026.

UniEnergy Technologies, Primus Power, Vionx Energy, EnerVault, ViZn Energy Status unverified

These five names still appear as active players in flow battery market reports, including a 2021 report projecting the market to 2026. UNCONFIRMED: no current operating evidence was found for any of them in this sweep, and no closure notice was verified either. Do not carry them into a shortlist without confirming they still exist. They are listed here only so that an inbound reference to them is recognized as stale.

Source of the stale listing: PR Newswire, "Global Flow Batteries Market Report 2021-2026," featuring these companies. Note that the same report lists Redflow, which was liquidated in December 2024. Accessed 30 July 2026.

06Timeline of the evidence

Every dated item below is drawn from a source cited in the profiles above. This is what "the flow battery market is moving" actually consists of.

October 2024

Form Energy closes a 405 million dollar Series F with GE Vernova, Breakthrough Energy Ventures and Energy Impact Partners, plus a GE Vernova memorandum of understanding.

Utility Dive

19 December 2024

Largo and Stryten announce the Storion Energy joint venture for domestic vanadium electrolyte and battery components.

Business Wire

February 2025

Storion Energy formally launched, built from the vanadium flow divisions of both parents.

Stryten Energy

February 2025

ESS Tech chief executive resigns.

Energy-Storage.News

8 April 2025

XL Batteries commissions its first organic flow battery in a pilot with Stolthaven Terminals.

Business Wire

May 2025

ESS Tech warns of a survival battle through an "operational reset" period.

Energy-Storage.News

29 September 2025

The BESSt Company unveils a zinc-polyiodide flow battery using chemistry licensed from Battelle.

Energy Storage (ess-news.com)

10 November 2025

Quino Energy closes 10 million dollars to scale organic flow batteries.

pv magazine USA

December 2025

Inlyte Energy completes the factory acceptance test of its first full-scale iron-sodium system near Derby, United Kingdom, ahead of United States systems going to Southern Company's test site in Wilsonville, Alabama in early 2026.

Energy Storage, PR Newswire

5 January 2026

Stryten and Storion show a vanadium redox flow battery at the Consumer Electronics Show, aimed at data center load.

Business Wire

24 February 2026

Google and Xcel Energy announce a 300 MW / 30 GWh Form Energy iron-air system at Pine Island, Minnesota, the largest battery by energy capacity announced globally, paired with 1.6 GW of new renewables.

Utility Dive, American Public Power Association

11 March 2026

Ashlawn Energy leases 10,000 square feet on the Xerox Webster Campus in New York, adding 20 jobs.

Spectrum Local News

30 April 2026

CMBlu Energy crosses a 1 billion euro valuation, described as Germany's first non-lithium battery unicorn.

Tech Times

6 May 2026

Burbank Water and Power's 21-month third-party evaluation validates ESS iron flow technology for the American Public Power Association.

Business Wire

7 May 2026

ESS Tech reports first quarter 2026 liquidity of 21.5 million dollars, falling to about 13.6 million dollars by 31 May 2026.

Business Wire, ESS Tech

16 June 2026

Eos begins commercial production on a second zinc battery line, targeting 4 GWh annual capacity by end of 2026. Storion presents at the International Flow Battery Forum.

Energy Storage, Business Wire

13 July 2026

CMBlu's United States factory plan for the Phoenix area is reported, targeted within roughly 12 months.

Tech Times

Early 2027 (target)

Form Energy targets commercial production and first shipments from Weirton under its 12 GWh binding agreement with Crusoe Energy Systems.

WTRF

Q1 2027 (target)

TerraFlow Energy targets initial energization of the 9.6 MW / 48 MWh Bellville, Texas system.

Energy-Storage.News

Early 2027 (target)

Invinity targets first deliveries of United States-manufactured vanadium flow batteries.

Energy-Storage.News

07How a developer-owner should use this list

Call first, in this order. The order reflects who can actually deliver, which is not the same as who has the most interesting chemistry.

Form Energy if the requirement is multi-day duration and the architecture does not have to be flow. It is the only company in this document with a factory in commercial production, a 300 MW / 30 GWh flagship project, and over a billion dollars of capital behind it. Ask for round-trip efficiency, auxiliary load, footprint per MWh, and what the 100-hour product costs when the need is 8 to 12 hours, because none of that is public.
Storion Energy for electrolyte supply and, more importantly, the electrolyte leasing structure. Electrolyte is 40 to 70 percent of VRFB system cost, so leasing it changes project capital structure more than any other single lever in this document.
TerraFlow Energy for a complete domestic vanadium system with a factory and a dated reference project.
Stryten Energy if counterparty strength matters more than novelty, because it is the only VRFB name here with a large diversified manufacturing parent.
Ashlawn Energy for anything in New York State where local manufacturing and jobs strengthen the case.
CMBlu Energy only if the Foreign Entity of Concern position is the deciding issue, and only after verifying that claim against the bill of materials.

What is missing from this document and why. No pricing appears anywhere above, because no verified vendor pricing for any of these products was available from public sources. Any dollar-per-kilowatt-hour figure for flow batteries should come from a written quotation, not from this list or from press coverage. Round-trip efficiency is also largely absent for the same reason: where a company publishes it, it is a vendor claim, and flow battery round-trip efficiency is materially lower than lithium iron phosphate, which changes revenue stacking assumptions.

The comparison that actually decides these deals. Flow batteries win on duration beyond roughly 6 to 8 hours, cycle life, and fire risk, and lose on round-trip efficiency, energy density, footprint, and supplier bankability. Given a developer-owner financing 2-hour and 4-hour systems, flow chemistry is not a like-for-like substitute for the existing offering. It is relevant to the 8-hour-plus product and to any data center customer that will pay for fire safety and load-buffering. That framing, not chemistry enthusiasm, should drive which of these companies gets a meeting.

Flow is not the only way to get duration, and it is not currently the most deliverable one. The honest conclusion from Figures 5 and 6 together is uncomfortable for the flow battery field: Form Energy offers longer duration (100 hours) than any flow product here, from a factory already in commercial production, backed by more capital than the rest of this list combined. If the requirement is "many hours of storage from a supplier that will still exist," iron-air currently answers it better than flow does. Flow keeps two advantages worth paying for: duration that can be extended after commissioning by adding electrolyte, and the electrolyte leasing structure that moves 40 to 70 percent of system cost off the project's capital stack. Decide which of those two things the deal actually needs before choosing the chemistry.

08Method, scope, and limitations

Method. Companies were identified through web searches on flow battery manufacturers, United States manufacturing announcements, and chemistry-specific searches (vanadium, iron flow, organic, zinc, saltwater, iron-air, iron-sodium), then each candidate was verified by reading the company's own website (contact page, technology page, or product sheet) plus at least one independent trade or financial source. All contact details in this document were read directly from the named company's own public website on 30 July 2026.

Scope. Included: companies that manufacture flow battery systems or their core components (electrolyte, stacks) for the United States market. Also included, and clearly marked, are foreign-parent companies with United States operations or announced United States factories, because they compete for the same domestic supply decisions. Also included, in Section 4.2, are the non-flow long-duration chemistries that compete directly for the same 8-hour-plus projects: iron-air (Form Energy), iron-sodium (Inlyte Energy) and aqueous zinc (Eos Energy). These are labeled as not-flow in their headings, in the figures, and in every count, so the distinction survives being copied into other documents. Excluded: pure research programs and national laboratories, project developers who do not manufacture, and lithium-ion.

Limitations, stated plainly. First, several companies publish no phone number or direct email, so the only route in is a web form; this is noted per company rather than guessed. Second, performance claims from early-stage companies (The BESSt Company, Salgenx, StorEn Technologies, Ashlawn Energy) are vendor statements without third-party test data and are labeled as such at the point of use. Third, one source (vrbenergy.com) did not respond on 30 July 2026, and one (ashlawnenergy.com over its alternate domain) returned a server error, so those entries rely on the accessible domain and on secondary sources. Fourth, this is a point-in-time snapshot of a sector with active financial distress; verify company status before any commitment. Fifth, no attempt was made to verify the existence of two companies ("Carbo Energy" and "GridFlow.tech") named in a third-party startup listing, because no primary source was found; they are therefore excluded rather than listed unverified.

Refresh cadence recommended. Quarterly, tied to public company earnings (ESS Tech, Eos Energy, Ivanhoe Electric, Largo Inc.), because the failure mode in this sector is financial rather than technical.

09Acronyms used in this document

ACORE American Council on Renewable Energy

AI Artificial Intelligence

BNEF BloombergNEF

CAISO California Independent System Operator

CEBIP Clean Energy Business Incubator Program

CEC California Energy Commission

DARPA Defense Advanced Research Projects Agency

DOE United States Department of Energy

EBITDA Earnings Before Interest, Taxes, Depreciation and Amortization

ERDC Engineer Research and Development Center (United States Army)

FEOC Foreign Entity of Concern

GW / GWh Gigawatt / Gigawatt-hour

ITC Investment Tax Credit

kW / kWh Kilowatt / Kilowatt-hour

LDES Long-Duration Energy Storage

LDUPS Long-Duration Uninterruptible Power Supply (TerraFlow product term)

MW / MWh Megawatt / Megawatt-hour

NASA National Aeronautics and Space Administration

NEF Nano-Electro Fuel (Influit product term)

NSF National Science Foundation

NY-BEST New York Battery and Energy Storage Technology Consortium

NYSE New York Stock Exchange

RIT Rochester Institute of Technology

SDG&E San Diego Gas and Electric

SEC United States Securities and Exchange Commission

UL Underwriters Laboratories (UL 1973, UL 9540A are safety standards)

VRFB Vanadium Redox Flow Battery