The 2:30pm to 8:30pm window is not arbitrary. It is the stretch of a hot NSW day when the grid is hardest to keep balanced, and the Peak Demand Reduction Scheme (PDRS) exists to pay for anything that takes load off it.
What the peak period is
Under the PDRS method rules, peak demand reduction is measured over the summer peak period, 1 November to 31 March, between 2:30pm and 8:30pm. A Peak Reduction Certificate (PRC) represents 0.1 kW of peak demand reduction capacity, averaged across that window. The more kilowatts a project can take off the network in those hours, the more PRCs it can create.
Why those hours
Three things collide in the late afternoon and early evening.
- Cooling load. Houses and offices have been heating up all day, and air conditioners work hardest from mid-afternoon.
- Household routines. People get home, cook, run appliances and turn on lights.
- Falling solar. Rooftop solar peaks around midday and fades from mid-afternoon, so the energy that carried the grid at noon is gone just as demand climbs.
That is why the grid operator sees its tightest margins here. Building generation and network capacity for a few hours a year is expensive, and shaving those hours is cheaper. The scheme turns that saving into a certificate market.
How batteries fit
A home or business battery that charges from midday solar and discharges during 2:30pm to 8:30pm does exactly what the scheme is designed to reward. Programs that connect a battery to a virtual power plant (VPP) go further, because the operator can dispatch many batteries together when the grid needs them. This is why the PDRS incentive for VPP connection sits alongside the federal battery STCs rather than replacing them. For the current state of the NSW battery pathways, read how the PDRS applies to batteries and the NSW VPP incentive.
What this means for installers
Method rules change, and the PDRS has had its activities suspended and restructured since 2025. Before you quote a customer on PRCs:
- Check the current PDRS method guide for the activity you are claiming.
- Confirm the peak-window assumptions in the guide, not an old training slide.
- Keep commissioning records that show the battery’s discharge capability.
What this means for you as a customer
If you are weighing a battery in NSW, the peak window explains why discharge timing matters. Setting your battery to hold charge for the evening, rather than draining it at 1pm, is what matches the scheme and usually your own tariff as well.
Where to go next
The wider picture of how ESCs and PRCs work is in our NSW ESCs and PDRS hub. If you are also claiming the federal discount, see battery STCs and the battery submission guide. Installers who want one desk for STCs, battery STCs and other certificates can read how it works.