Commercial Battery Storage Installation, Engineered and Commissioned

Physical installation is typically 1-6 weeks on site for a behind-the-meter system. The overall programme, however, is set by the DNO: a G99 study and connection can run 3-18 months depending on network capacity in your area. We submit the G99 application alongside the survey so the clock starts immediately, and use a G100 limitation scheme where it lets the project proceed sooner. Grid-scale standalone projects run 18 months to several years including planning.

G99 is the Energy Networks Association connection agreement required for storage above 16 A per phase, which covers almost every commercial system. The DNO reviews the connection, may require a network study, and sets the protection and metering requirements. Because network capacity is limited in many areas, the study and connection offer are usually the longest item on the programme. We prepare the application, single-line diagrams, and protection proposals, liaise with the DNO, and, where the network is constrained, engineer a G100 export/import limitation scheme so the site can connect within its existing agreed capacity.

It comes down to space, capacity, and fire strategy. A containerised outdoor system is usually the fastest route to multi-MWh capacity and keeps the fire and space constraints outside the building, but it needs prepared hardstanding, separation distances, and firefighting access. An indoor cabinet suits smaller systems (roughly 60-500 kWh) at sites with a suitable plant room or switchroom, but the room must be compartmented, ventilated, and fire-detected. We assess both against your available space, target capacity, and insurer requirements at the survey.

We design to PAS 63100:2024 principles for installation and fire protection, BS EN 62619 for cell safety, and BS EN/IEC 62933 for system safety, with NFCC guidance for larger and grid-scale sites. We specify lithium-iron-phosphate (LFP) cells for their thermal stability, and engineer separation distances, detection, thermal monitoring, and appropriate compartmentation or bunding. A fire risk assessment is produced and the insurer, and where necessary the fire authority, engaged before installation.

We handle it as part of our scope: the G99 application, single-line diagrams, protection settings, half-hourly metering arrangement, DNO liaison, and witness-test coordination, plus the G100 limitation design where the network is constrained. You get one accountable contractor across survey, design, connection, install, and commissioning rather than having to coordinate a battery supplier, an electrician, and the DNO yourself.

In most cases yes. The tie-in to your existing switchgear is planned around your operations using temporary supplies, out-of-hours working, or a short pre-agreed outage only where unavoidable. We establish your supply arrangement, available fault level, and switchroom access at survey so the connection method is designed, method-statemented, and risk-assessed before we mobilise. Minimising disruption is a design-stage decision, not an on-the-day improvisation.