--- title: "Grid-forming vs. grid-following inverters for BESS | Entogo" description: "Grid-following inverters follow an existing grid voltage, while grid-forming inverters set their own voltage and frequency so they can ride through weak…" url: https://entogo.ca/insights/grid-forming-vs-grid-following-inverters-battery-storage/ lang: en type: article image: https://entogo.ca/_astro/grid-forming-vs-grid-following-inverters-battery-storage.bidzTJDu.jpg datePublished: 2026-08-05 dateModified: 2026-08-05 site: https://entogo.ca/ llms: https://entogo.ca/llms.txt --- Home › Insights › Grid-forming vs. grid-following inverters for battery storage Energy Storage # Grid-forming vs. grid-following inverters for battery storage Entogo August 5, 2026 ![Commercial battery energy storage system connected to the grid through inverters](https://entogo.ca/_astro/grid-forming-vs-grid-following-inverters-battery-storage.bidzTJDu_Z16fCm6.webp) In short Grid-following inverters follow an existing grid voltage, while grid-forming inverters set their own voltage and frequency so they can ride through weak grids, island, and black-start. Here is how to tell which one a battery storage project needs and what to specify. ## Why does the inverter control mode matter for a battery storage project? For a century the grid’s voltage and frequency were “formed” by the spinning mass of synchronous generators. Their rotating inertia set a stable reference that every other device could follow. A battery has no spinning mass; it connects through a power-electronic **inverter**, and the way that inverter is controlled decides whether the battery merely follows the grid or helps hold it up. Two control philosophies dominate today’s equipment: **grid-following** and **grid-forming**. Choosing between them early shapes sizing, protection, interconnection studies, and cost, so it belongs in the specification rather than in a change order. ## How do grid-following and grid-forming inverters differ? ### Grid-following behaves like a current source A grid-following (GFL) inverter measures the grid’s existing voltage and frequency — usually with a **phase-locked loop** — and injects current in step with it. IEEE Spectrum describes these units as devices that “operate only if they can ‘see’ an existing voltage and frequency on the grid that they can synchronize to.” That makes them simple and efficient for pushing power in and out, but it also means they contribute no inertia and cannot run when the grid reference disappears. ### Grid-forming behaves like a voltage source A grid-forming (GFM) inverter creates its own internal voltage reference and holds it. A U.S. Department of Energy technical report puts it precisely: a grid-forming resource’s controls “maintain an internal voltage phasor that is constant or nearly constant in the sub-transient to transient time frame.” Because it sets the reference instead of chasing it, a grid-forming battery can ride through a weak grid, keep an island energized, and even **black-start** a network — roles historically filled only by synchronous machines. A battery suits this duty because it can source or sink real power on demand to back the voltage it is holding. ## Where does each control mode make sense? On a strong grid, where a large fault current is available and the interconnection is stiff, grid-following is often all a project needs. Behind-the-meter peak-shaving, energy arbitrage, and frequency response on a robust distribution feeder are well served by a conventional grid-following [battery energy storage system](https://entogo.ca/products/battery-energy-storage-system/). Grid-forming earns its added complexity where the grid is weak or absent: - **Islanding and resilience** — a facility that must keep running through an outage needs a source that can form voltage on its own, the core of any microgrid or [commercial and industrial storage](https://entogo.ca/solutions/commercial-industrial-storage/) project. - **Weak or high-renewable grids** — system strength is measured by the **short-circuit ratio**, and grid-following units can become unstable as that strength falls. IEEE Spectrum notes that beyond roughly “60 to 70 percent” instantaneous renewable penetration, grid-following inverters alone struggle to stay stable. - **Black start and remote sites** — off-grid and edge-of-grid installations, such as a [large-scale MW grid-connected and off-grid system](https://entogo.ca/products/large-scale-mw-grid-connected-off-grid-system/) or a [containerized battery energy storage system](https://entogo.ca/products/containerized-battery-energy-storage-system/), rely on forming their own reference. For projects that pair generation, storage, and load behind one connection, a [DC-coupled grid-forming hybrid system](https://entogo.ca/products/dc-coupled-grid-forming-hybrid-system/) keeps the forming intelligence on the DC bus, and the point of common coupling is managed through a [new-energy grid-connection cabinet](https://entogo.ca/products/new-energy-grid-connection-cabinet/). ## What should a buyer specify? Control mode is a system decision, not a checkbox, so tie it to the interconnection study and the governing standards: - **State the duty.** Say whether the system must island, black-start, or stabilize a weak grid, or whether it will always operate on a stiff grid. That single answer usually settles grid-forming versus grid-following. - **Cite the governing standards as context.** Distribution-connected storage is specified against **IEEE 1547-2018** and **UL 1741**; resources interconnecting to transmission are specified against **IEEE Std 2800-2022**, the first interconnection-and-interoperability standard for inverter-based resources on the bulk system. Grid-forming functions are addressed by the emerging **IEEE P2800.1** recommended practice. - **Size for fault and transient current.** A grid-forming inverter must supply current on demand to hold its voltage during faults, so its rating and the battery behind it are engineered differently from a grid-following unit of the same nameplate. - **Confirm ride-through and protection coordination.** Voltage and frequency ride-through settings, anti-islanding behavior, and how the inverter coordinates with upstream relaying all change with the control mode. ## Bringing it together Grid-following and grid-forming are not better or worse; they answer different questions. A strong-grid arbitrage project and an islanding microgrid need different inverters, and specifying the wrong one is expensive to unwind. Entogo builds battery storage and grid-connection equipment for both duties in its own factory — from utility-scale [renewable grid connection](https://entogo.ca/solutions/renewable-grid-connection/) to resilient sites served by [utilities](https://entogo.ca/solutions/utilities/) — designed and built to IEEE 1547, UL 1741, and IEEE 2800 as applicable; UL (cULus)/CSA certifiable on request. Matching control mode to the grid it will serve, backed by in-house engineering, keeps a project’s interconnection moving instead of waiting out the market’s long equipment queues. - Battery Energy Storage - Grid-Forming Inverters - Grid Interconnection - IEEE 2800 - Microgrids Glossary: [Grid-forming vs. grid-following inverter](https://entogo.ca/glossary/#grid-forming-vs-grid-following) [Battery energy storage system](https://entogo.ca/glossary/#bess) FAQ ## Common questions - **What is the difference between grid-forming and grid-following inverters?**: A grid-following inverter injects current in step with an existing grid voltage, while a grid-forming inverter creates its own voltage and frequency reference and can hold it when the grid is weak or absent. - **Do I need a grid-forming inverter for my battery storage project?**: You need grid-forming capability when the system must island, black-start, or stabilize a weak or high-renewable grid. For energy arbitrage on a strong grid, grid-following is usually enough. - **Can a grid-following battery system run during a power outage?**: No. A grid-following system shuts down when the grid voltage disappears because it has nothing to synchronize to. Islanding through an outage requires grid-forming control. - **What standards apply to grid-forming battery inverters in North America?**: Distribution-connected systems follow IEEE 1547-2018 and UL 1741, transmission-connected resources follow IEEE Std 2800-2022, and grid-forming functions are addressed by the emerging IEEE P2800.1 recommended practice. - **Does grid-forming cost more than grid-following?**: Grid-forming control changes how a system is sized because the inverter must supply fault and transient current on demand, so a storage project specified for grid-forming is engineered differently from a plain grid-following one. Keep reading ## Related insights [![Commercial battery energy storage system paired with rooftop solar at an industrial site](https://entogo.ca/_astro/lfp-vs-nmc-batteries-stationary-storage.D4PePhC4_Z1DbUzj.webp) Energy Storage ### LFP vs. NMC batteries for stationary storage: how to choose LFP and NMC are the two lithium-ion chemistries behind most stationary storage. LFP leads on cycle life, thermal stability and cost per kWh; NMC packs more energy into less space. Here is how to match chemistry to a project. View](https://entogo.ca/insights/lfp-vs-nmc-batteries-stationary-storage/)[![Commercial battery energy storage enclosures with rooftop solar showing thermal management for a BESS installation](https://entogo.ca/_astro/air-cooled-vs-liquid-cooled-battery-storage.CNRAR2SV_2b73rb.webp) Energy Storage ### Air-cooled vs. liquid-cooled battery storage: how to choose Battery cells age faster when they run hot, so a BESS cooling architecture largely decides its lifespan and footprint. Air cooling is simpler and cheaper; liquid cooling holds tighter temperatures for dense, high-throughput sites. Here is how to choose. View](https://entogo.ca/insights/air-cooled-vs-liquid-cooled-battery-storage/)[![Commercial and industrial rooftop solar with battery energy storage forming a microgrid](https://entogo.ca/_astro/when-does-a-commercial-microgrid-make-sense.B-97B3Ig_ZE6KsT.webp) Microgrids ### Do you need a microgrid? Islanding, resilience, and what to specify A microgrid lets a site keep critical loads running through an outage by islanding onto local storage and generation. It makes sense where outage cost is high or grid capacity is constrained, and it requires grid-forming inverters, a microgrid controller, and utility-approved protection. View](https://entogo.ca/insights/when-does-a-commercial-microgrid-make-sense/) Project inquiry ## Turn the brief into a specified system. 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