Start with your network operator
Before installing or materially changing commercial generation or battery storage, establish the applicable process with your distribution network operator and a competent installer. The arrangement matters: existing solar, aggregate generation, inverter type testing, intended import/export and operating modes all affect the application. This guide concerns Great Britain; Northern Ireland has different connection arrangements.
What G99 addresses
G99 sets requirements for generation equipment connected in parallel with public distribution networks. Battery storage can operate as generation when discharging, so its connection arrangements need appropriate assessment. Your installer should determine the correct route from the complete installation rather than assuming a battery qualifies for a simplified process because it has an export cap. Use current DNO guidance: the March 2026 ENA guide includes updated storage requirements.
What G100 addresses
G100 concerns customer export and import limitation schemes. A limitation scheme monitors flow at the connection point and controls generation or demand to remain within an agreed limit. It is more than a software target: equipment behaviour, fail-safe operation, commissioning and the accepted site arrangement matter. G100 is not a replacement for G99, and setting zero export is not itself permission to connect.
Why a cap does not settle every constraint
An agreed import or export limit can address some operational constraints. It does not automatically resolve fault level, voltage, power quality, protection or every thermal constraint. A DNO may still require network works. Likewise, a battery that covers a modelled peak may be unavailable, at low state of charge or power-limited at the time it is needed. Design and operational controls must account for those conditions.
What to ask your installer
Ask which connection route applies, what limits will be requested, what happens when control or communications fail, and which tests and documents are required. Confirm the limits in the connection agreement and who may change settings. Material changes to operating mode or capacity can require a connection-agreement modification. Our headroom tool is an illustration of power and energy; it cannot provide approval or certify a compliant design.
Sources & further reading
Use current documents and confirm the requirements with your own network operator.
Created by Arcgrid. Educational information for commercial sites in Great Britain, not an engineering design or a guarantee of savings. Scenarios are illustrative. Northern Ireland has different connection arrangements.
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