EnergyByte's June-26 & FY 25/26 generation review: BESS displace fossil fuel during crucial evening peak, renewables continue to outgrow BESS daytime charging load therefore soft daytime price persist. Solar and wind bundled prices fell 45% and 42% year-on-year.

Executive Summary

• FY25/26 in review: NEM-wide, wind (+18.6%), utility solar (+13.8%) and rooftop solar PV (+8.7%) all grew, while coal (–3.6%) and gas (–30.0%) eased back. BESS discharge and charging both roughly tripled, but off a small base.
• Renewables still comfortably outgrew batteries: at the NEM level, new renewable generation (+1,207 MW average) grew 935 MW more than BESS charging load (+272 MW) over FY25/26. Every region individually saw renewables growth exceed BESS charging growth on this rolling-annual view — the gap ranged from +28 MW in SA up to +452 MW in QLD.
• Storage isn't yet the daytime price fix: BESS charging growth remains well short of daytime renewable growth in most regions, so it is not absorbing enough of the midday surplus to lift shoulder prices on its own. Until demand-side growth — data centres, EVs, home batteries — catches up, as flagged in our Challenges facing renewables report, daytime prices will stay under pressure and those hoping for a solar/wind revenue recovery will have to wait longer.
• Gas was pushed hard out of the evening peak: NEM gas dispatch fell 79% in June-26 vs June-25 as BESS discharge more than doubled and took over the peaking role — consistent with the evening price collapse covered in our May-26 Generation Trends report.
• Solar and wind bundled prices kept falling: the NEM-average rolling-annual bundled price (spot GWA + LGC) fell to $37.71/MWh for solar (–45% year-on-year) and $63.04/MWh for wind (–42%) by June-26, as both the spot capture rate and the LGC price declined together.
• PPA buyers remain the exposed party: as the merchant/bundled price keeps falling faster than most legacy PPA strike prices, the gap that concerns off-takers — flagged in our Challenges facing renewables report — has widened further over the past month.

1.0  FY25/26 in Review

This section compares the average half-hourly generation profile for the 12 months to June 2026 against the 12 months to June 2025, across the NEM and by region. Average spot prices fell in every region over the same window — consistent with the detailed analysis in our companion June-26 Spot Market report, which this generation review is designed to sit alongside.

1.1  NEM-Wide Generation Profile

The shape of the NEM's day has shifted rather than transformed. Midday solar surplus is deeper and wider in FY 25/26 (renewable output peaks near 19,900 MW versus 17,800 MW the year before), and the batteries absorbing that surplus charge harder in the middle of the day and discharge more heavily into the evening ramp — but the batteries are still a modest layer sitting on top of a NEM that runs on wind, solar and coal for the bulk of its energy.

Coal fell 3.6% and gas fell 30.0% on a rolling annual average, while wind (+18.6%), utility solar (+13.8%) and rooftop solar PV (+8.7%) all grew. BESS discharge (+209%) and BESS charging (+188%) both roughly tripled, though from a small base of around 110–145 MW average to 340–420 MW average — material for the evening price signal, but still a fraction of the ~13,000 MW of average coal generation still running across the NEM.

Where the market share moved: three points in the day

Averages hide as much as they reveal, so it's worth looking at three specific points in the day rather than just the 12-month average. At the solar peak (12:30), combined utility and rooftop solar's share of total NEM supply rose from 51.2% to 53.5% — a real gain, but a modest one (+2.3 percentage points) given solar MW itself grew 10.6% at that instant, because wind and total supply were also higher. Coal's share fell a corresponding 2.8 points, from 33.5% to 30.7%.

At the evening peak (18:00), the story is a near one-for-one swap: gas's share fell 3.5 points (10.0% → 6.5%) while BESS discharge's share rose 3.2 points (1.7% → 4.9%) — almost exactly the size of gas's loss. Coal held broadly steady (55.1% → 54.2%) and wind added 2.4 points, so batteries are displacing gas specifically at the evening peak more than they are displacing coal.

Across the broader daytime shoulder (09:30–16:30 average), where NEM spot prices run softest, solar's combined share rose from 45.9% to 48.5% (+2.6 points) at coal's expense (37.1% → 34.1%, –3.0 points). BESS discharge's daytime share is still negligible (0.1% → 0.3%) — as expected, since this is when the fleet is charging, not discharging — which is exactly why the extra daytime solar and wind supply from Section 1.3 still has to clear the market rather than being absorbed by storage.

1.2  Regional Generation Mix

NSW

NSW's largest FY25/26 mover was BESS — discharge and charging both roughly quadrupled off a low base — while utility solar (+15.1%) and rooftop PV (+10.2%) delivered the biggest MW gains among renewables. Coal eased only 4.8%, still averaging 4,773 MW.

QLD

QLD remains the standout structural grower: wind averaged 699.8 MW, up 83.9% on the prior year, alongside double-digit growth in both utility solar and rooftop PV. Gas fell 32.1% and coal 3.6%, continuing the displacement trend documented in our May report.

VIC

VIC's wind fleet grew a further 13.5% and utility solar 22.2%, but rooftop PV grew only modestly (+4.6%). Coal was little changed (–2.1%), reflecting VIC coal continuing to run hard when interconnector economics support it.

SA

SA is the one region where utility solar went backwards on a rolling annual basis (–21.7%), consistent with the weaker 2025–26 irradiance and record curtailment covered in Section 3. Wind (+9.8%) and rooftop PV (+1.0%) still grew modestly, and gas fell 26.4% as the state's only synchronous fuel source was used less.

TAS

Tasmania has no coal, gas is now negligible (–65.9% to just 11.5 MW average), and hydro rose 16.1% — the direct result of Basslink's reduced transfer capability discussed in our Basslink Puzzle report, which forced TAS to replace mainland imports with domestic generation.

1.3  BESS Charging vs Renewable Growth

A natural question as the battery fleet scales up: is the NEM simply moving existing renewable output around the clock, or is BESS charging load now growing faster than the new wind, utility solar and rooftop solar PV being added? On a rolling 12-month view to June 2026, the answer is clearly no — in every region, net new renewable generation comfortably outgrew the new BESS charging load.

NEM-wide, renewable generation grew by 1,207 MW on average against 272 MW of extra BESS charging load — a gap of 935 MW of net new renewable supply that landed on the grid without any matching increase in battery demand to absorb it. QLD has the widest gap in absolute terms (+452 MW), followed by NSW (+239 MW) and VIC (+195 MW). SA's gap is narrowest among the mainland regions with BESS (+28 MW), a function of its solar decline discussed in Section 3. Tasmania has no BESS fleet at all, so the comparison does not apply there. The practical read: on a rolling-annual view, the battery fleet built over the past year is nowhere near large enough to soak up the extra daytime renewable output on its own. That extra supply still needs to clear the market, which is exactly why daytime (shoulder) prices remain under pressure. Absorbing it durably needs new demand — data centres, EVs, and home batteries charging from the grid — to grow into the gap, as discussed in our Challenges facing renewables report. Until that demand growth materialises at scale, storage is not offsetting the daytime renewable build-up, and those waiting on a daytime price recovery will be waiting a while longer.

Here is the insightful chart showing by Region and technology the half hour average generation profile for the last two financial years.

2.0  June 2026 in Review

The same comparison, narrowed to the single month of June, shows a more compressed and weather-exposed picture than the rolling annual view — as expected for the lowest-solar month of the year. Spot prices fell sharply in every region (see table below); the drivers are examined in full in our June-26 Spot Market report.

2.1  NEM-Wide Generation Profile

June is winter, so renewable output is dominated by wind rather than solar, and the midday BESS charging trough is shallower than the FY average — but it is still far deeper than a year ago: NEM BESS net position at 12:30 moved from –620 MW (net charging) in June-25 to –1,726 MW in June-26. The evening discharge peak more than doubled from 18:00's +1,175 MW to +2,489 MW, and gas dispatch at that same interval collapsed from roughly 3,300 MW to under 1,900 MW combined with coal easing back — the clearest single signature of BESS displacing thermal peaking plant this winter.

NEM-wide average generation by technology, June-25 vs June-26 (MW).

Where the market share moved: three points in the day

At the solar peak (12:00), combined utility and rooftop solar's share of total NEM supply rose from 41.4% to 43.5% (+2.1 points) — a smaller gain than the FY figure, as expected for the lowest-solar month of the year, but still a genuine share gain, mostly at gas's expense (2.7% → 0.9%, –1.8 points) and coal's (38.7% → 37.6%, –1.1 points).

NEM technology share of total supply at the solar peak (12:00), June-25 vs June-26.

At the evening peak (18:00), the shift is dramatic: gas's share collapsed from 16.2% to just 3.1% — a 13.1-point fall — while BESS discharge's share nearly tripled, from 3.9% to 9.6% (+5.7 points). Coal's share actually rose (55.0% → 60.2%), because total NEM supply at that half-hour was 14% lower this June than last; but of the generation still required, batteries and wind (11.8% → 16.1%) picked up almost all of the ground gas gave away, not coal.

NEM technology share of total supply at the evening peak (18:00), June-25 vs June-26.

Across the daytime shoulder (09:30–16:30 average), where prices are softest, solar's combined share edged up only 1.1 points (34.5% → 35.6%) — modest because June solar output is a fraction of the FY average — while gas's daytime share fell 2.8 points (4.0% → 1.2%) and coal held roughly flat (43.3% → 43.2%). BESS discharge's daytime share moved from 0.2% to 0.9%: still small, and still nowhere near large enough to be doing the work of firming daytime prices — that share is still charging load, not discharge, during these hours.

NEM technology share of total supply, daytime shoulder average (09:30–16:30), June-25 vs June-26.

2.2  Regional Generation Mix Executive Summary

• FY25/26 in review (rolling 12 months to June): NEM-wide, wind (+18.6%), utility solar (+13.8%) and rooftop solar PV (+8.7%) all grew, while coal (–3.6%) and gas (–30.0%) eased back. BESS discharge and charging both roughly tripled, but off a small base.
• Renewables still comfortably outgrew batteries: at the NEM level, new renewable generation (+1,207 MW average) grew 935 MW more than BESS charging load (+272 MW) over FY25/26. Every region individually saw renewables growth exceed BESS charging growth on this rolling-annual view — the gap ranged from +20 MW in TAS (no BESS) and +28 MW in SA up to +452 MW in QLD.
• June-26 tells a more mixed story: at the single-month level the NEM-wide gap narrows to just 384 MW, and NSW is a genuine exception — BESS charging growth (+116 MW) outpaced net new renewable generation (+17 MW) in June, a −99 MW gap, because NSW solar (both utility-scale and rooftop) was lower this June than last. VIC was close to break-even (+4 MW).
• Storage isn't yet the daytime price fix: BESS charging growth remains well short of daytime renewable growth in most regions, so it is not absorbing enough of the midday surplus to lift shoulder prices on its own. Until demand-side growth — data centres, EVs, home batteries — catches up, as flagged in our Challenges facing renewables report, daytime prices will stay under pressure and those hoping for a solar/wind revenue recovery will have to wait longer.
• Gas was pushed hard out of the evening peak: NEM gas dispatch fell 79% in June-26 vs June-25 as BESS discharge more than doubled and took over the peaking role — consistent with the evening price collapse covered in our May-26 Generation Trends report.
• Solar and wind bundled prices kept falling: the NEM-average rolling-annual bundled price (spot GWA + LGC) fell to $37.71/MWh for solar (–45% year-on-year) and $63.04/MWh for wind (–42%) by June-26, as both the spot capture rate and the LGC price declined together.
• PPA buyers remain the exposed party: as the merchant/bundled price keeps falling faster than most legacy PPA strike prices, the gap that concerns off-takers — flagged in our Challenges facing renewables report — has widened further over the past month.

Here is the insightful chart showing by Region and technology the half hour average generation profile for June year-on-year.

2.3  Does BESS Charging Exceed Renewable Growth

Repeating the same test for June-26 vs June-25 gives a more nuanced answer than the FY view. NEM-wide, renewables growth (+726 MW) still exceeded BESS charging growth (+342 MW), leaving a gap of 384 MW — clearly positive, but less than half the 935 MW gap seen on the rolling annual basis, because June is a low-solar month and the mainland BESS fleet has grown substantially in the meantime.

NSW is the one region where the answer flips: BESS charging growth (+116 MW) outpaced net new renewable generation (+17 MW), a −99 MW gap in June, because NSW solar output (both utility-scale and rooftop) was lower this June than last, leaving wind to do almost all of the renewable growth on its own. VIC was close to break-even (a +4 MW gap: 59 MW of renewables growth against 55 MW of BESS charging growth). QLD (+378 MW), SA (+97 MW) and TAS (+5 MW, no BESS) all still saw renewables growth outpace BESS charging. Even in the regions still running a positive gap, June confirms the same point made for the FY view: the battery fleet is still charging alongside the renewable build, not offsetting it. Daytime prices will keep waiting on genuine demand-side growth — not on storage — to firm them up, and that growth (data centres, EVs, home batteries) is still a multi-year story rather than a this-winter one.

Renewables growth vs BESS charging growth by region, June-26 vs June-25 (average MW).

3.0  Renewable Weighted Average Price Trends

This section tracks the rolling 12-month generator-weighted average (GWA) spot price and the rolling 12-month LGC weighted average (LGC) for solar and wind, by region, to June 2026. The bundled price (GWA + LGC) approximates the total merchant revenue per MWh a large-scale renewable generator earns before any PPA. It builds on our Challenges facing renewables report, which introduced these metrics as of May-26 — this section extends the series a further month and looks specifically at what the trend means for PPA buyers.

3.1  Solar

The NEM-average solar bundled price fell from $68.53/MWh a year ago to $37.71/MWh by June-26 — a 45% decline — and the fall is broad-based: every mainland region is down 35–49% year-on-year. The decline has two compounding causes. First, the spot GWA itself has fallen as the flat baseload benchmark (TWA) has softened and solar's own capture rate remains weak (see our May Challenges facing renewables analysis). Second, the LGC weighted average has fallen even faster in percentage terms — NSW's rolling LGC contribution alone dropped from around $17–19/MWh in May to the low single digits as older, higher-priced months roll out of the 12-month window. SA's curtailment has climbed further to 43.7%, the highest of any region and now materially propping up its bundled price by filtering out the worst-priced intervals — a mechanical effect, not a healthier revenue outcome, as our May report explained.

Solar rolling-annual GWA, LGC and bundled price by region, to June-26. Tasmania has no material utility-scale solar fleet.

3.2  Wind

Wind's NEM-average bundled price fell from $107.86/MWh to $63.04/MWh over the same 12 months (–42%), a similar magnitude of decline to solar despite wind's structurally higher spot capture rate. This confirms the point made in our Wind price-impact lessens report: wind is no longer being rescued from cannibalisation by scarcity pricing on low-wind days, because BESS has defused the evening price-spike risk that used to reward wind's absence. Wind curtailment remains low outside SA and VIC (2–4% in NSW, QLD and TAS vs 15–19% in SA and VIC), so the region-by-region bundled price differences mostly reflect the underlying baseload (TWA) each region is being measured against rather than curtailment.

Wind rolling-annual GWA, LGC and bundled price by region, to June-26.

3.3  Implications for PPA Buyers

The direction of travel matters more than any single month's reading. Both solar and wind bundled prices have now fallen for well over a year, and the LGC component — which used to cushion the decline in spot capture — is now falling in lock-step rather than offsetting it, since the CER-forecast LGC surplus persists through to the end of the scheme in 2030. For a PPA buyer who struck a contract when bundled prices were tracking materially higher, the gap between the contracted price and today's merchant reality keeps widening, reinforcing the “PPA regret” dynamic flagged in Challenges facing renewables. For PPA sellers, the contract continues to look like protection today, but the real test remains what happens at renewal, when the asset reverts to a merchant market where both the spot benchmark and the LGC price sit well below the levels many projects were financed on.

4.0  Related EnergyByte Coverage

This report builds directly on the following companion pieces:

• June-26 Spot Market — The demand-side companion to this report: FY25/26 and June-26 spot and gas price detail, including the late-June SA price event referenced throughout Sections 1–2.
• May-26 Generation Trends — The prior month's equivalent generation review, introducing the BESS evening-peak transformation and net renewable supply methodology used again here.
• Challenges facing renewables — Introduces the GWA / TWA / capture rate and LGC weighted average framework used in Section 3, and the PPA buyer/seller dynamic revisited here.
• Wind price-impact lessens — Shows how BESS has weakened the historical link between low wind output and extreme prices, the mechanism behind Section 3.2's wind capture findings.
• Basslink Puzzle — Background on the Basslink capacity reduction driving Tasmania's higher domestic hydro dispatch in both the FY and June comparisons in this report.

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