Solar PV and battery storage technologies are known to provide savings to customers in the form of reduced electricity charges. Currently, these savings are only determined for the volume component (kWh) and not the demand component (kW or kVA). As interest grows in commercial solar PV and battery storage installations, the need to predict demand charge reductions is great. The aim of this research is to determine, with accuracy and reliability, the ability of solar PV and battery storage technologies in reducing demand charges. Results have shown that when simulated against a commercial-scale electricity consumption profile solar PV was able to reduce the maximum demand across five electricity networks in Australia by 0.05–1.51%. When coupled with a 12 kWh battery storage an additional 1.31–2.02% reduction was experienced. Battery utilisation strategy was shown to be critical in yielding greater demand reduction from the battery storage. Notably, it was shown that in the Ergon Energy electricity network, battery storage was able to supply demand at 34% lower cost ($/kW) than the network was able to. The results detail the first instance of demand reduction evaluation of solar PV coupled with battery storage, focusing on physical and financial outcomes in an Australian context.