Generators are at their worst when they run lightly loaded for long hours. They burn fuel inefficiently, build up carbon (wet stacking) and need servicing more often. Adding a battery energy storage system (BESS) lets the battery carry the light loads, so the generator only runs when it’s really needed, and at a load where it’s efficient.

Three ways a battery helps

1. On sites that run generators every day. On off-grid farms, construction sites and remote plants, the battery carries the site overnight and at light load. The generator starts, charges the battery at an efficient load, then stops. Run hours can drop dramatically.

2. On standby sites. On a hospital, data centre or factory with standby sets, the battery can cover the 10 to 15 seconds a generator takes to start, with no break in supply. It can also do useful work the rest of the time, for example capping peak grid import.

3. Alongside solar. Without storage, solar on a generator site must be curtailed when it isn’t needed. With storage, it’s banked and used later, and generator run hours fall further.

What makes it work: the controls

The battery, its inverter (PCS), the generators and any solar all need to take orders from one controller. On PCAS systems that’s a ComAp InteliNeo, which manages:

• When the generators start and stop, based on battery charge and load
• How much the battery charges and discharges
• Solar curtailment, so PV never back-feeds the generators
• Regular full charges, to keep the battery charge reading accurate
• Import and export limits where the site is grid connected (G99)

Get the controls wrong and you get generators starting for no reason, batteries that never fully charge, and solar tripping offline. We’ve been called in to fix exactly that on more than one site.

Safety and insurance

Commercial BESS installations need proper fire detection and suppression, off-gas detection, and the right test certificates for your insurer, such as IEC 62619 and UL 9540A. Sort these out at the specification stage, not after delivery.

PCAS experience

PCAS has integrated battery storage on off-grid and hybrid farms in Shropshire, a BESS installation in Beverley, a BESS for a food manufacturer, and a utility head office BESS in Kenya, all on ComAp control.

Read about our commercial BESS services

PCAS provides 24/7 generator service agreements across Yorkshire, the North West and the UK. Call 0114 317 7939 or email support@pcasltd.com.

Have a question about this article? Email support@pcasltd.com or call 0114 317 7939.