Sub-system
A grid battery is containers of iron-phosphate cells, inverters, transformers and a control system, connected at transmission or distribution voltage. Most are built for around four hours of discharge, and the reason is economic rather than technical.
In one sentence
A utility-scale battery energy storage system stores electricity in lithium-ion cells and returns it to the grid through inverters, typically sized for two to four hours of discharge at rated power.
The chemistry choice is settled for now: iron-phosphate, because grid storage does not care about mass and cares a great deal about cycle life, safety and cost. Systems are built from standardised containerised blocks, which makes them fast to deploy compared with any other grid asset — commonly a year or two from decision to operation.
Revenue comes from several sources at once. Shifting energy from cheap hours to expensive ones. Being paid to stand ready to respond to frequency deviations. Being paid for capacity available at system peaks. And in some places, deferring a network upgrade that would otherwise be needed. Stacking these is what makes projects viable.
Adding duration adds cells linearly, but the extra hours earn progressively less: the price spread that pays for the first hour is far larger than the one available for the eighth. Capacity market rules that credit a four-hour system fully have reinforced the convention. The economics, not the technology, set the number.
Cells lose capacity with cycles and age, so a system contracted to deliver a given output must either start oversized or have cells added later. Augmentation — installing additional capacity partway through the contract — is standard practice, and it is why storage contracts specify guaranteed capacity over time rather than a single nameplate figure.
A large battery installation is designed around containing a cell failure: spacing between containers, deflagration venting, gas detection, and suppression. Standards and fire codes govern the layout, and site approval frequently depends on demonstrating that a failure in one unit does not propagate to its neighbours.
2 of these are marked as a chokepoint: a handful of qualified suppliers, a multi-year lead time, or a single geography.
The dominant chemistry for stationary storage, drawn from the same manufacturing base as vehicle cells.
LFP cathodesEvery system needs power conversion and a step-up transformer, both on extended lead times.
Power transformersLayout, spacing and venting are dictated by standards, and permitting depends on demonstrating containment.
What a battery can earn depends on how ancillary services and capacity are procured in that market.
Cells store direct current, and the inverter is what puts it on the network — increasingly while holding voltage and frequency rather than following them.
Grid-forming invertersA container holds thousands of cells that have to be monitored and balanced individually, and the same system is what detects the failure the safety design is built to contain.
Battery managementOther pages in this map that name Utility-scale batteries as something they cannot do without.
What each company supplies at this step, and — where a public figure exists — its share of this specific market — with what that share measures, the period it covers and who published it. Some rows also show the company’s own reported revenue for the segment covering this step, which is a different thing: it says how much this business matters to that company, not how much of the market it holds. Not a ranking and not a recommendation.
Manufactures and deploys containerised grid storage systems.
Energy Generation And Storage Segment segment — 13.5% of Tesla’s reported revenue ($12.8B)FY2025 · company filings · not a market share
Supplies grid-scale storage systems and control software.
Develops and operates large storage projects alongside renewable generation.
Supplies storage systems and the grid equipment they connect through.
Supplies the iron-phosphate cells most grid storage systems are built from.
Supplies the storage systems and the inverters inside them, the largest supplier outside Tesla.
Supplies containerised storage built on its own LFP cells.
Whether typical duration extends beyond four hours as penetration rises and spreads change.
Whether storage-specific cell supply becomes constrained by vehicle demand or remains ample.
Whether market rules evolve to pay for the grid services storage can actually provide.
Each page explains one technology in plain language, states what it depends on, and names companies by what they supply at that step. Company roles are described qualitatively and deliberately carry no market shares, revenue figures or rankings — those change faster than an explainer can, and a stale number is worse than none. Ticker links point at company pages on this site and are provided for reference only.
Nothing here is investment advice, a recommendation, or a forecast. A company named on a page about a technology is not thereby a good investment, and the chokepoints described are structural facts about supply chains rather than predictions about prices. Technology moves; where a page describes something as unresolved or in development, that was true when it was written.
Plutux is not an investment adviser. Market data and AI-generated analysis are for information and education only, not investment advice. Disclaimer