COMMERCIAL ENERGY SOLUTIONS

Peak Demand Shaving

Need far more power for a couple of hours a day than your grid connection can deliver? Instead of paying to upgrade the network, a battery quietly covers the spike — and solar makes it cheaper still. Here is exactly how the numbers work, using a real hospitality scenario.

The problem: a kitchen that outgrows its connection

A busy restaurant or pub has a 63 A three-phase supply, but its kitchen — ovens, fryers, cooktops, combi-steamers and dishwashers all running together — needs 400 A three-phase for about two hours over the lunch service, and again for dinner. The connection simply cannot deliver it. The traditional fix is to ask the network to upgrade the supply, which is slow and very expensive. Peak demand shaving solves it on your side of the meter.

Cooking loads are largely resistive, so kVA ≈ kW. The grid keeps supplying its 63 A; the battery only has to bridge the 233 kW gap on top.

The math — how much battery?

The battery covers the gap between what the grid delivers and what the kitchen needs, for the two cooking windows each day:

So the system needs to deliver roughly 233 kW of power and store ~930 kWh of usable energy per day. With our modular SafeBatt SolarStore cabinets and Victron power-conversion, that is engineered to the exact site — and real kitchens have load diversity (appliances cycle on their thermostats), so a proper Energy Usage Analysis usually lands the figure lower than the worst-case above.

With and without solar

Battery only. The battery still has to be refilled, and the only source is that same 63 A connection. At 43.6 kW it can push back about 872 kWh over the ~20 non-cooking hours — slightly less than the 933 kWh used. The connection ends up running flat-out almost around the clock just to recover, with no headroom, and every kilowatt-hour is bought from the grid.

Battery + solar. Add roughly 100 kW of rooftop solar (about 420 kWh/day in the Illawarra). The sun is highest right at lunch, so solar covers much of that service directly and recharges the battery through the day. Grid top-up falls to about 510 kWh/day — an average of ~26 kW (~37 A), leaving comfortable headroom on the 63 A service, and most of the energy is now free solar instead of bought power.

Cheaper than upgrading the network

Lifting a 63 A (44 kVA) connection to 400 A (277 kVA) is not a meter swap. The network typically needs new service mains, new metering and — almost always at this jump — an upgraded distribution transformer or a new padmount substation. That is a major capital project with a long lead time, and your demand charges step up permanently because they are billed on peak kVA.

Cost figures are indicative only and vary widely by site and network — confirm augmentation pricing with your DNSP and ask WISE Energy for a designed quote.

More than savings: reliability and energy security

• Keep trading through outages. The battery rides through grid interruptions, so the kitchen keeps cooking — no lost service, no spoiled stock.
• Protection from demand-charge and price shocks. Your measured peak stays low, and solar shields you from rising energy prices.
• Energy security. Less dependence on a constrained, ageing grid — valuable for coastal and regional venues where outages are more common.
• Power quality. The inverter system supports stable voltage during heavy kitchen switching.
• Future-proof. Add SolarStore cabinets as the venue grows, add EV charging, or expand solar — the platform scales.

Worked example for illustration using 400 V three-phase and worst-case continuous load. Actual system design depends on a site-specific load study, tariff and network conditions, and must be carried out by suitably licensed and accredited professionals. Figures are general information only, not financial advice.