Solar vs storage: two competing forces

Since 2023, registered battery power has grown faster than PV capacity, from a much smaller base. Distributed PV has also continued to grow. The Australian Government's Cheaper Home Batteries Program began in July 2025, around the time home battery registrations accelerated. The policy likely helped, but these snapshots cannot measure its share of the increase. They use different utility and distributed power bases; a September 2025 change to the DER data also limits year-on-year comparisons.

The capture ratio rose from 38% to 55% for January to 29 September, even though the absolute capture price for that whole period was slightly lower: $37.5/MWh in 2026 versus $38.6/MWh in 2025. Flat prices fell faster. In Q3 alone, the absolute solar capture price rose from $26.5/MWh to $34.1/MWh. Across Q1–Q3, the 2026 points sit above a simple line fitted only to 2023–25 capture observations.

In Q2, prices at or below zero during solar hours fell from 22.9% to 18.7% of intervals year on year. Among strictly negative intervals, the mean price moved from −$22.8/MWh to −$7.1/MWh. We cannot say from these prices alone how much of the change came from battery charging. Q4 has historically brought more surplus solar and weaker daytime prices; Q4 2026 was still unobserved at this data cut-off.

Using five-minute AEMO dispatch records, the share of available mainland utility solar not dispatched fell from 18.8% in Q3 2025 to 12.4% in Q3 2026. Q1 and Q2 did not show the same year-on-year decline. Q4 was the high point in each of 2023, 2024 and 2025.

This measure is availability minus the dispatch target, divided by availability. It includes economic offloading, network constraints and differences between forecasts and dispatch targets. It is broader than AEMO's network-only curtailment measure and is not a metered estimate of lost generation.

In AEMO's Step Change pathway, average daily solar output remains roughly twice the fleet's theoretical six-hour charging limit from 2030. The ratio falls from 2.7 times in 2026–27 to 1.8 times in 2029–30, then sits near 2.2 times later in the pathway.

The charge limit is the lesser of each storage type's energy depth and its power multiplied by six hours, summed across types. Pumped hydro illustrates why nameplate energy alone can mislead: Snowy 2.0 has substantial storage depth, but its 2.2 GW charging power limits what it could absorb in six solar hours. Actual charging will also depend on where storage is built, its state of charge, dispatch and competing demand.