Question 1

What size battery storage does a commercial site need?

Accepted Answer

Usually two to four hours of discharge at the site’s peak import, which on a distribution-connected industrial site commonly means a few hundred kilowatts and a megawatt hour or so of capacity. Sizing comes from the half-hourly export and import record, not from a rule of thumb, because the shape of the peak matters more than its size.

Question 2

Is battery storage worth it without solar PV?

Accepted Answer

Yes, on the right tariff. Arbitrage between cheap overnight or midday imports and dear evening imports, plus demand-charge reduction, can carry the case on their own. Solar improves it, because self-generated power stored and used later avoids more of the bill than grid power moved in time, but a site with a sharp evening peak and no usable roof can still justify cabinets.

Question 3

How long do commercial batteries last?

Accepted Answer

Lithium iron phosphate cabinets are warranteed against capacity retention rather than to a fixed life, commonly around 70 per cent of original capacity at ten years with cycle limits alongside. Degradation is a function of depth of discharge, temperature and cycles per day, which is why the dispatch strategy is part of the commercial case. Saber operates the asset and carries the replacement risk inside the contract.

Question 4

Does battery storage give a site backup power?

Accepted Answer

Some, and it should not be sold as more than that. A grid-tied system normally sheds and restarts rather than islanding, and the hours of backup are the hours of stored energy divided by whatever the site is drawing. Where a site needs genuine resilience, that is a different design with an explicit islanding specification, and it is cheaper to say so at the start than to discover it during a loss of supply.

Question 5

Do we need a new grid connection for battery storage?

Accepted Answer

Often not. A BESS that charges within the site’s existing capacity and discharges into the same load usually needs a cutout or fuse change and a G98 or G99 notification, not a new connection agreement. Where the plan is to trade with the grid as well as serve the site, the capacity question becomes a DNO conversation, which is exactly the queue a Bridge to Grid arrangement is built to avoid.

Battery storage (BESS)

What does on-site battery storage actually earn?

One technology is rarely the answer on its own.

What buyers ask about BESS.

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