G100 export limitation: installing a battery on a constrained grid connection

“Our grid connection is already constrained, so we probably can’t add a battery.” It is one of the most common things we hear, and it is usually the opposite of the truth. On a constrained connection, the battery is frequently the solution, not the casualty — and the tool that makes it work is a G100 limitation scheme.

The problem: a constrained connection

Many UK commercial sites are close to the limit of their agreed import capacity, especially in busy industrial corridors. When a business wants to add load — EV charging, a heat pump, more production — the DNO’s answer is often a network reinforcement with a six-figure cost and a wait of many months to over a year. That is enough to stop a lot of good projects.

What G100 does

G100 is an export (and import) limitation scheme. It continuously monitors the site’s power flow and automatically curtails the controllable assets — the battery, and sometimes chargers or generation — to keep the whole site within its agreed Maximum Import/Export Capacity. It reacts fast, typically within about fifteen seconds (with a defined maximum reaction time), so the site never breaches its agreed limit even as loads swing.

The practical effect is powerful: because the DNO can rely on the scheme to hold the site within capacity, you can install a battery — and frequently add new load behind it — without the reinforcement. The battery charges off-peak or from on-site solar, then discharges to buffer peaks, so the connection sees a smoothed load rather than the raw spikes.

Where it changes the answer

• EV charging hubs. Rapid and ultra-rapid chargers create severe demand spikes. A battery with G100 buffers those spikes so more chargers fit on the existing connection — often the cheapest way to electrify a depot or forecourt. See our EV-charging storage page.
• Adding production load. A manufacturer wanting more capacity can use a containerised battery with G100 to add load inside the existing agreement.
• Solar-plus-storage. A retrofit uses G100 export limitation to stay within agreed export capacity while lifting self-consumption.

What we actually do

G100 is not a box you buy; it is a scheme you engineer and prove. We design the limitation and its protection, agree the approach with your DNO before final design, and demonstrate the function at commissioning so both you and the DNO can see it holding the site within its limits. It is a core part of how we install on constrained networks across the UK.

If your connection is tight and you have been told a battery or new load is off the table, it may well not be. Send your half-hourly data and your connection details and we will tell you whether a G100 scheme opens it back up — and read our honest take on whether the whole thing is worth it.