Where does ESS Inc. (ESS Tech, Inc.) source the inputs in this product?

This map traces 40 inputs across 4 countries, including 10 mines and refiners. It is compiled from public sources and is not an audited bill of materials.

How much of the ESS Inc. (ESS Tech, Inc.) supply chain sits in a covered nation?

9 of 40 mapped inputs are sited in a covered nation (China, Russia, Iran or North Korea) or named on a federal restricted-party list. A further 12 carry elevated sourcing risk without either basis.

FEOC ComplianceProspector Labs

Back to supply chains

Where does ESS Inc. (ESS Tech, Inc.) source its components?

United States. Supply chain mapped to 40 inputs across 4 countries.

Federal screeningClean

No federal designation found. ESS Inc. is not named on any of the 3 federal restricted-party lists screened for this record (DOD Section 1260H, BIS Entity List, OFAC SDN List), and the United States is not a covered nation under the FEOC rules. Is ESS Inc. (ESS Tech, Inc.) a Foreign Entity of Concern?

Upstream sourcing exposure

Medium38% weighted

9 in covered nations - 12 elevated, of 40 nodes.

Where inputs are mined and refined. Not a FEOC determination for the company -- see the federal list screening above.

Refining chokepoint

3 of 4 processing/refining steps in covered nations

Where the exposure sits - by supply-chain tier

Producer1

Supplier2

Component10

Processing / Refining4

Raw Material17

Mine / Extraction6

designated covered nation elevated no known factor not assessed

Loading chain view...

Sourcing Concentration by Country

Covered NationAllied NationOther

Sourcing risk across the graph

Where each input is mined or refined. Not a FEOC determination for the company.

Designated (0%)

Covered nation (23%)

Elevated (30%)

No known factor (48%)

Legend

Node Types

Producer

Supplier

Component

Processing / Refining

Raw Material

Mine / Extraction

Logistics

Sourcing risk

Federally designated - named on a restricted-party list

Covered nation - sited in China, Russia, Iran or North Korea

Elevated - documented concentration risk, no federal listing

No known risk factor - not a compliance clearance

Not assessed - no sourcing judgement was made

Relationships

Transformation - manufactures / assembles

Refining - midstream processing (FEOC chokepoint)

Supply handoff - supplies / sources from

Arrows point in the direction material flows (input to product).

Every mapped input in the ESS Inc. (ESS Tech, Inc.) supply chain

40 nodes, grouped by supply-chain tier. Sourcing risk describes where an input is mined or refined; it is not a FEOC determination for ESS Inc. (ESS Tech, Inc.).

Producer (1)

Input	Origin	Sourcing risk	Basis
ESS Inc. (ESS Tech, Inc.)Wilsonville, Oregon (approx. 200,000 sq ft, ~1.05 GWh/yr automated + semi-automated lines)	United States	No known risk factor	Long-duration iron flow batteries (Energy Warehouse, Energy Center, Energy Base). Iron-salt-water chemistry sidesteps lithium/cobalt/nickel FEOC exposure; residual flags concentrate in China-refined carbon felt, fluoropolymer membrane and power electronics.

Supplier (2)

Input	Origin	Sourcing risk	Basis
Power Semiconductors (IGBT modules)IGBT die from JP/EU/US (Infineon, Mitsubishi, Fuji); packaging/assembly often in China	Japan	Elevated sourcing risk	DC->AC switching devices in the inverter. Front-end fabs allied, but back-end packaging concentrated in China -> review.
Circulation Pumps & Motors	United States	Elevated sourcing risk	Off-the-shelf polypropylene/immersion pumps and variable-speed motors. Motors may contain rare-earth magnets (China-refined) -> review.

Component (10)

Input	Origin	Sourcing risk	Basis
Iron Flow Cell StackAssembled in Wilsonville, OR on automated lines	United States	Elevated sourcing risk	Proprietary stack is ESS's core IP. Contains carbon felt electrodes, HDPE bipolar plate electrodes, ion-exchange membrane, flow frames and end blocks. Review: several sub-materials are China-refined.
Iron Chloride Electrolyte (anolyte/catholyte)	United States	No known risk factor	Food-grade iron, salt and water; same FeCl2 solution on both electrodes. Earth-abundant, domestically sourceable — ESS's key supply-chain advantage over Li-ion.
Electrolyte Storage Tanks	United States	No known risk factor	HDPE / polypropylene tanks store anolyte and catholyte separately; energy capacity scales with tank size.
Power Conversion System (Inverter / PCS)	United States	Elevated sourcing risk	DC/AC inverter, DC/DC converter and battery management controller. Relies on power semiconductors (IGBTs) with concentrated East-Asian/China packaging exposure.
Balance of Plant (pumps, motors, plumbing, controls)	United States	No known risk factor	Off-the-shelf variable-speed pumps and motors, filters, PVC/PP plumbing. ESS emphasizes standard, uncoated, widely available parts.
Steel Enclosure / Container	United States	No known risk factor	Containerized housing and structural steel for Energy Warehouse; standard fabricated carbon steel.
Carbon / Graphite Felt ElectrodePredominantly PAN-based felt from Chinese producers; SGL Carbon (DE/US) is the main non-China alternative	China	Covered nation	>90% of carbon fiber is PAN-based; graphitized battery felt supply chain is China-concentrated. Flagged: felt carbonization/graphitization midstream is dominated by China.
HDPE Bipolar Plate Electrode	United States	No known risk factor	Up to ~60 recyclable high-density polyethylene bipolar plastic electrodes per stack — an ESS design distinctive vs graphite bipolar plates. Made conductive with carbon black filler.
Ion-Exchange Membrane (PFSA)Chemours Nafion (PFSA/PTFE) is the dominant supplier; Chinese Dongyue and Fumatech are alternatives	United States	Elevated sourcing risk	Perfluorosulfonic-acid membrane separates anolyte/catholyte. Chemours (US) leads; Dongyue (China) is a growing low-cost source, creating dual-source review risk.
Copper Wiring / Busbars	United States	Elevated sourcing risk	Current-collection busbars and system wiring. Copper metal is fungible but ~50% of global smelting/refining is in China.

Processing and refining (4)

Input	Origin	Sourcing risk	Basis
Steel Mill / Pickling Line (iron refiner)US blast/electric-arc furnaces and steel pickling lines	United States	No known risk factor	Refines taconite pellets into steel; pickling generates the FeCl2 liquor stream. Domestic refining = clean.
Silicon Metal SmelterChinese silicon-metal smelting (with US/Norway/Brazil minority)	China	Covered nation	Carbothermic reduction of quartz to silicon metal — China holds the majority of global capacity. Flagged.
Copper Smelter / RefineryChina ~50% of world copper smelter/refinery capacity (Jiangxi Copper et al.)	China	Covered nation	Concentrate -> cathode refining chokepoint. China added ~97% of recent global refining capacity -> flagged.
Rare-Earth Separation / Magnet RefinerChinese REE separation and sintered-magnet plants	China	Covered nation	Nd/Pr oxide separation and magnet sintering overwhelmingly China-based, even for allied-mined ore. Chokepoint flag.

Raw material (17)

Input	Origin	Sourcing risk	Basis
PAN (Polyacrylonitrile) Precursor Fiber	China	Covered nation	Nonwoven PAN fiber is pre-oxidized, carbonized and graphitized into felt. PAN precursor and conversion capacity are China-heavy.
Acrylonitrile (ACN) Monomer	United States	Elevated sourcing risk	Petrochemical (propylene + ammonia) feedstock for PAN. US/Gulf Coast capacity exists but PAN polymerization for fiber-grade is largely offshore.
HDPE Resin	United States	No known risk factor	Polyethylene resin from US ethane-cracker petrochemicals; abundant domestic supply.
Conductive Carbon Black Filler	United States	Elevated sourcing risk	Furnace carbon black gives plastic electrodes conductivity. US production exists; conductive grades partly imported.
Fluoropolymer (PFSA/PTFE) Resin	United States	Elevated sourcing risk	PFSA ionomer + PTFE copolymer. Fluoropolymer capacity split US (Chemours) vs China (Dongyue); fluorspar feedstock is China-dominated.
Fluorspar (Acid-grade CaF2)	China	Covered nation	Feedstock for HF -> fluoropolymers. China is the dominant global producer/refiner of acid-grade fluorspar; US import-reliant.
Ferrous Chloride (FeCl2)	United States	No known risk factor	North American FeCl2 made from spent steel pickling liquor or scrap iron + HCl; ~96M kg/yr US output. Byproduct chemistry, domestically abundant.
Salt / Sodium Chloride (NaCl)	United States	No known risk factor	Mined rock salt / brine; widely produced domestically. Basis for electrolyte 'salt' and for chlor-alkali HCl.
Hydrochloric Acid (HCl)	United States	No known risk factor	~1.2B kg/yr US production; chlor-alkali byproduct from NaCl brine electrolysis. Used to convert iron/scrap to FeCl2.
Deionized Water	United States	No known risk factor	Electrolyte solvent; locally sourced and treated.
Iron Units (steel pickling liquor / scrap iron)	United States	No known risk factor	Iron source for FeCl2: spent steel pickle liquor and scrap iron — a recycled domestic stream traceable back to US iron ore.
Iron Ore (Taconite / Magnetite)Minnesota Mesabi Iron Range taconite pellets	United States	No known risk factor	Ultimate iron origin for domestic steel/scrap feeding the electrolyte.
Structural Carbon Steel	United States	No known risk factor	Fabricated steel for the container/enclosure; sourced from domestic mills (same Mesabi->EAF chain).
Silicon Wafer / Silicon Metal	China	Covered nation	Metallurgical-grade silicon feedstock for semiconductor/electronics; China dominates silicon-metal smelting midstream.
Copper Cathode	Chile	Elevated sourcing risk	Refined cathode extruded/drawn into busbar and wire stock. Allied-mined (Chile/US) but heavily China-refined globally.
NdFeB Permanent Magnets (in motors)	China	Covered nation	If pump/fan motors use permanent-magnet designs, NdFeB magnets are ~90% China-refined. Standard induction motors avoid this.
Plumbing & Frame Plastics (PVC/PP/PVDF)	United States	No known risk factor	Flow frames, gaskets and plumbing in PVC, polypropylene, PVDF. Domestic petrochemical supply; PVDF has some China exposure but volumes small.

Mine and extraction (6)

Input	Origin	Sourcing risk	Basis
Fluorspar MineChinese fluorspar mining districts (also Mexico, Mongolia, South Africa)	China	Covered nation	China mines the largest share of global fluorspar. US has near-zero domestic acid-grade production.
Rock Salt Mine / Brine FieldUS salt mines and brine wells (e.g. Gulf Coast, Great Lakes, NY)	United States	No known risk factor	Domestic salt extraction; no FEOC exposure.
Iron Ore Mine (Mesabi Range)Cleveland-Cliffs United Taconite (Eveleth) / Northshore (Babbitt-Silver Bay), Minnesota	United States	No known risk factor	Open-pit taconite; largest iron-ore pellet producer in North America. Fully domestic.
Quartz / Silica MineHigh-purity quartz deposits (e.g. Spruce Pine, NC) plus global sources	United States	Elevated sourcing risk	Silica ore for silicon metal. Some high-purity quartz is US-mined but downstream refining is China-heavy.
Copper MineChilean copper mines (also US: Arizona/Utah)	Chile	No known risk factor	Copper concentrate origin; allied/domestic mining is clean, refining is the flag point.
Rare-Earth Minee.g. Mountain Pass, CA (also Australia)	United States	Elevated sourcing risk	REE ore can be allied-mined (Mountain Pass) but is largely shipped to China for separation -> downstream flagged.

Material flow (44 relationships)

ESS Inc. (ESS Tech, Inc.) manufactures Iron Flow Cell Stack (Iron flow cell stack)
ESS Inc. (ESS Tech, Inc.) manufactures Iron Chloride Electrolyte (anolyte/catholyte) (Iron chloride electrolyte)
ESS Inc. (ESS Tech, Inc.) assembles Electrolyte Storage Tanks (Electrolyte storage tanks)
ESS Inc. (ESS Tech, Inc.) assembles Power Conversion System (Inverter / PCS) (Power conversion system)
ESS Inc. (ESS Tech, Inc.) assembles Balance of Plant (pumps, motors, plumbing, controls) (Balance of plant)
ESS Inc. (ESS Tech, Inc.) assembles Steel Enclosure / Container (Steel enclosure / container)
Iron Flow Cell Stack assembles Carbon / Graphite Felt Electrode (Carbon/graphite felt electrode)
Iron Flow Cell Stack assembles HDPE Bipolar Plate Electrode (HDPE bipolar plate electrode)
Iron Flow Cell Stack assembles Ion-Exchange Membrane (PFSA) (Ion-exchange membrane)
Iron Flow Cell Stack assembles Plumbing & Frame Plastics (PVC/PP/PVDF) (Flow frames / gaskets)
Iron Flow Cell Stack assembles Copper Wiring / Busbars (Current-collection copper busbars)
Carbon / Graphite Felt Electrode refines PAN (Polyacrylonitrile) Precursor Fiber (PAN felt carbonization/graphitization)
PAN (Polyacrylonitrile) Precursor Fiber supplies Acrylonitrile (ACN) Monomer (Acrylonitrile monomer -> PAN)
HDPE Bipolar Plate Electrode supplies HDPE Resin (HDPE resin)
HDPE Bipolar Plate Electrode supplies Conductive Carbon Black Filler (Conductive carbon black filler)
Ion-Exchange Membrane (PFSA) supplies Fluoropolymer (PFSA/PTFE) Resin (PFSA/PTFE fluoropolymer resin)
Fluoropolymer (PFSA/PTFE) Resin supplies Fluorspar (Acid-grade CaF2) (Fluorspar -> HF -> fluoropolymer)
Fluorspar (Acid-grade CaF2) sources from Fluorspar Mine (Acid-grade fluorspar ore)
Iron Chloride Electrolyte (anolyte/catholyte) supplies Ferrous Chloride (FeCl2) (Ferrous chloride (FeCl2))
Iron Chloride Electrolyte (anolyte/catholyte) supplies Salt / Sodium Chloride (NaCl) (Sodium chloride)
Iron Chloride Electrolyte (anolyte/catholyte) supplies Deionized Water (Deionized water)
Ferrous Chloride (FeCl2) supplies Iron Units (steel pickling liquor / scrap iron) (Iron units (pickle liquor / scrap))
Ferrous Chloride (FeCl2) supplies Hydrochloric Acid (HCl) (Hydrochloric acid)
Iron Units (steel pickling liquor / scrap iron) sources from Steel Mill / Pickling Line (iron refiner) (Steel pickling liquor stream)
Steel Mill / Pickling Line (iron refiner) refines Iron Ore (Taconite / Magnetite) (Taconite -> steel)
Iron Ore (Taconite / Magnetite) sources from Iron Ore Mine (Mesabi Range) (Iron ore (taconite/magnetite))
Salt / Sodium Chloride (NaCl) sources from Rock Salt Mine / Brine Field (Rock salt / brine)
Hydrochloric Acid (HCl) supplies Salt / Sodium Chloride (NaCl) (NaCl brine -> chlor-alkali HCl)
Electrolyte Storage Tanks supplies HDPE Resin (HDPE tank resin)
Power Conversion System (Inverter / PCS) sources from Power Semiconductors (IGBT modules) (IGBT power modules)
Power Conversion System (Inverter / PCS) assembles Copper Wiring / Busbars (Copper wiring/busbars)
Power Semiconductors (IGBT modules) supplies Silicon Wafer / Silicon Metal (Silicon wafer / metal)
Silicon Wafer / Silicon Metal refines Silicon Metal Smelter (Quartz -> silicon metal)
Silicon Metal Smelter sources from Quartz / Silica Mine (Silica / quartz ore)
Copper Wiring / Busbars supplies Copper Cathode (Copper cathode)
Copper Cathode refines Copper Smelter / Refinery (Concentrate -> cathode)
Copper Smelter / Refinery sources from Copper Mine (Copper concentrate)
Balance of Plant (pumps, motors, plumbing, controls) sources from Circulation Pumps & Motors (Pumps & motors)
Balance of Plant (pumps, motors, plumbing, controls) supplies Plumbing & Frame Plastics (PVC/PP/PVDF) (PVC/PP plumbing)
Circulation Pumps & Motors supplies NdFeB Permanent Magnets (in motors) (NdFeB motor magnets)
NdFeB Permanent Magnets (in motors) refines Rare-Earth Separation / Magnet Refiner (REE oxide separation / sintered magnet)
Rare-Earth Separation / Magnet Refiner sources from Rare-Earth Mine (Rare-earth ore)
Steel Enclosure / Container supplies Structural Carbon Steel (Structural carbon steel)
Structural Carbon Steel sources from Steel Mill / Pickling Line (iron refiner) (Fabricated steel from domestic mills)

Sources and methodology

Research-based supply-chain map compiled from public sources - not an audited bill of materials. Tiers reflect the standard industry structure for this product. Sourcing risk on a node describes where that input is typically mined or refined; it is not a FEOC determination for ESS Inc. (ESS Tech, Inc.), and it is not a screening result for the node itself unless a federal listing is cited against it. Verify against primary documentation before making a compliance determination.

Primary sources (5) - government, filings, standards bodies

Secondary sources (19) - trade press, analysts, reference works

Common questions

Where does ESS Inc. (ESS Tech, Inc.) source the inputs in this product?: This map traces 40 inputs across 4 countries, including 10 mines and refiners. It is compiled from public sources and is not an audited bill of materials.
How much of the ESS Inc. (ESS Tech, Inc.) supply chain sits in a covered nation?: 9 of 40 mapped inputs are sited in a covered nation (China, Russia, Iran or North Korea) or named on a federal restricted-party list. A further 12 carry elevated sourcing risk without either basis.
Is ESS Inc. (ESS Tech, Inc.) itself a Foreign Entity of Concern?: No federal designation found. ESS Inc. is not named on any of the 3 federal restricted-party lists screened for this record (DOD Section 1260H, BIS Entity List, OFAC SDN List), and the United States is not a covered nation under the FEOC rules. Sourcing risk in this map describes where inputs are mined and refined and is a separate question from the company's own federal screening.

Federal list screening for ESS Inc. (ESS Tech, Inc.)Open in workspace