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Solar Panel Degradation Calculator (AU)

Estimate Australian solar panel output decay with first-year LID and annual degradation rates. Free CEC-aligned calculator for 25-year cumulative kWh.

Solar Panel Degradation Calculator

Output now
100%
8,456 kWh/yr
Output at year 25
86.9%
7,347 kWh/yr
25-year cumulative kWh
195,196 kWh
Lifetime kWh lost to decay
16,194 kWh
Revenue lost to decay
$5,506
Output by year
Year%kWh
198%8,286
596.1%8,122
1093.7%7,921
1591.4%7,725
2089.1%7,534
2586.9%7,347

How to use this calculator

Enter seven values and the calculator returns current output, output at year 25, 25-year cumulative kWh, and the lifetime kWh and revenue you’ll lose to natural decay:

  1. System size (kW) — total nameplate. The Australian residential median is 6.6 kW; the new-build standard is 10–13 kW with battery-ready inverter.
  2. Peak sun hours per day — Australian average 4.0 (Hobart) to 5.5 (Alice Springs). Clean Energy Council and BOM publish state-by-state values.
  3. System efficiency (%) — the derate factor. 78% is the AS/NZS 5033 default for grid-connected residential.
  4. Panel age today (years) — 0 for a new install; 6 for a 2020-era install.
  5. First-year LID drop (%) — 1.5–2.5% for standard p-type mono-PERC; 0.3–0.5% for n-type (SunPower Maxeon, LG NeON, REC Alpha).
  6. Annual degradation (%/yr) — Australia: 0.5–0.7% standard; 0.4% Tier-1 in mild climates; 0.7%+ for rooftop installs in tropical or coastal Queensland.
  7. Electricity rate (A$/kWh) — your current retail rate. Australian average late-2026 is around A$0.34/kWh peak.

How solar panel degradation works

Every solar panel loses output over time. The decay has three distinct phases:

Phase 1 — LID (light-induced degradation). In p-type crystalline silicon, the first 30–100 hours of sun exposure trigger boron-oxygen defects that drop output by 1–3%. The reaction completes within two weeks and never reverses. n-type silicon (SunPower Maxeon, LG NeON R) and gallium-doped p-type (modern Trina, LONGi, Jinko, Risen) are essentially LID-free.

Phase 2 — linear degradation, years 1–25. After LID stabilises, the panel decays at a steady 0.3–0.7% per year — and toward the upper end in Australia’s harsh climate. Causes include slow EVA yellowing, microcracks from thermal cycling, soldering fatigue, and PID (potential-induced degradation) where high-voltage stress drives sodium ions into the cell. The Australian Photovoltaic Institute (APVI) tracks 50,000+ rooftop systems via SunSpot — Australian medians sit at 0.55–0.65%/yr.

Phase 3 — accelerated failure, post-warranty. Beyond the 25-year warranty endpoint, failures accelerate: junction box delamination, glass fracture from thermal stress, backsheet cracking. Australian panels installed in 2010 under the original $7,000 federal solar rebate are now mostly past 15 years and still producing 88–92% of original output, depending on climate.

The degradation math

For year n of system life, output relative to STC nameplate is:

year_factor(n) = (1 - LID) × (1 - degradation_rate)^(n - 1)

For year 0 (before any sun exposure), the factor is 1.0. Year 1 the LID drop applies. From year 2 onward, the annual degradation compounds.

A worked example for a 6.6 kW Australian system, 2% LID, 0.6% annual degradation (reflecting Australian climate):

  • Year 1: 6.6 kW × (1 − 0.02) = 6.468 kW = 98.0% of STC
  • Year 5: 6.468 × (1 − 0.006)^4 = 6.314 kW = 95.7% of STC
  • Year 10: 6.468 × (1 − 0.006)^9 = 6.128 kW = 92.8% of STC
  • Year 15: 6.468 × (1 − 0.006)^14 = 5.948 kW = 90.1% of STC
  • Year 20: 6.468 × (1 − 0.006)^19 = 5.772 kW = 87.5% of STC
  • Year 25: 6.468 × (1 − 0.006)^24 = 5.602 kW = 84.9% of STC

That sits at the lower edge of what Tier-1 CEC-listed manufacturers guarantee. Use 0.4–0.5%/yr for cool installations (Melbourne, Tasmania, Adelaide); 0.6–0.7% for Brisbane, Darwin, and inland WA.

Degradation rates by panel type

NREL and APVI median rates by technology:

TechnologyFirst-year LIDAnnual rate AUYear-25 output
n-type mono (SunPower Maxeon, REC Alpha)0.3%0.30%/yr92.7%
Premium p-type mono (Q CELLS Q.PEAK, LONGi Hi-MO)1.0%0.40%/yr89.8%
Standard p-type mono-PERC (Jinko, Trina, Risen Tier-1)2.0%0.60%/yr84.9%
Polycrystalline silicon2.5%0.65%/yr83.7%
Tier-3 imports (not CEC-listed)3.0%1.00%/yr75.8%

The CEC approved-product list strongly weights customer outcomes toward the top three rows — Tier-3 panels can’t claim STCs and are rarely fitted by CEC-accredited installers.

What accelerates degradation in Australia

Temperature

Australia’s biggest degradation driver. Rooftop cells in Darwin, Cairns, Townsville, and inland WA routinely peak at 70–80°C in summer. Every 10°C above 25°C roughly halves the panel’s expected lifetime in Arrhenius models. Mounting solutions that maintain 60mm+ airflow gap, light-coloured roof colours, and choosing panels with low temperature coefficients (around −0.30%/°C versus the standard −0.36%) noticeably extend lifetime.

UV intensity

Australia receives the highest surface UV in the developed world. UV accelerates EVA polymer breakdown. CEC-listed panels are tested per IEC 61215, which includes UV preconditioning, but coastal sub-tropical installations show faster EVA yellowing in field studies.

Salt mist

Coastal Australia is severe. CEC requires IEC 61701 salt-mist certification for any panel installed within 500m of the coast. Without it, the panel warranty is typically void at coastal sites — verify before installation.

Bushfire smoke and ash deposition

The 2019–20 Black Summer caused 12–20% temporary production loss on east-coast systems for 4–8 weeks. Heavy ash on hot glass can etch the surface and cause permanent 1–3% loss. Annual cleaning is a worthwhile capex item in bushfire-prone zones.

PID (potential-induced degradation)

Australian residential transformerless inverters (Fronius, SolarEdge, Sungrow, GoodWe) can induce PID in non-resistant panels. Verify the datasheet lists IEC TS 62804-1 PID-free certification.

Reading your Australian warranty

Two warranties cover panel output:

  • Product warranty — 10–25 years, covers manufacturing defects. Australian Consumer Law (ACL) statutory consumer guarantees apply in parallel to any product warranty — useful if the manufacturer leaves the Australian market mid-warranty (a real risk; many brands have exited).
  • Performance warranty — 25–30 years, guarantees a minimum output curve. Linear curves are friendlier than stepped.

CEC-accredited installers must provide both warranties at handover. For STC claims through the Clean Energy Regulator, you’ll need the panel and inverter serial numbers, CEC accreditation paperwork, and installer signature.

Common mistakes

  • Buying non-CEC panels to save A$300–A$500. No STC discount, no insurance, faster degradation. The net cost is much higher.
  • Ignoring temperature coefficient. A panel with a −0.30%/°C temp coefficient produces noticeably more in summer than one at −0.40%/°C — and degrades slower.
  • Coastal installs without IEC 61701. Salt-mist failures void warranties and accelerate junction-box corrosion.
  • Forgetting bushfire smoke in production estimates. Models like NREL PVWatts don’t account for it; APVI’s SunSpot does for east-coast post-2019 data.

Sources

Frequently asked questions

What's the typical degradation rate for Australian solar panels?
0.5–0.7% per year is realistic for Australia. The harsh climate — UV intensity, summer rooftop temperatures of 70–80°C, and bushfire smoke deposition — pushes annual degradation toward the upper end of the global range. NREL's global median is 0.5%/yr, but Australian PV Institute field studies of 50,000+ rooftop systems put the Australian median closer to 0.6%/yr. Tier-1 panels approved by the Clean Energy Council degrade at 0.4–0.5%/yr; cheap unapproved imports degrade at 0.8–1.2%/yr.
Does Australia's climate accelerate panel degradation?
Yes, materially. Cell temperature drives EVA yellowing and microcrack propagation. Rooftop installations in northern Australia (Darwin, Cairns) routinely run cells at 70–80°C in summer — double the rate of yellowing versus 50°C European installations. UV intensity is also higher: Australia receives the highest surface UV in the developed world. Add bushfire smoke deposition (Black Summer 2019–20 caused 12–20% temporary output loss on east-coast systems) and salt mist on coastal installations, and Australian panels degrade noticeably faster than their European counterparts.
Does the Clean Energy Council require minimum degradation warranties?
The CEC approved-product list requires panels to carry a manufacturer performance warranty of at least 25 years with maximum 20% output loss at year 25 — equivalent to roughly 0.92%/yr linear degradation. In practice every Tier-1 panel on the CEC list does much better: 85–90% at year 25 (0.4–0.6%/yr). The CEC approval also requires IEC 61215, IEC 61730, salt-mist (IEC 61701 for coastal), and ammonia (IEC 62716 for farms). Non-CEC panels can't claim Small-scale Technology Certificates (STCs) under the SRES.
How does degradation affect my STC and feed-in tariff income?
STCs are calculated at installation based on system size and deeming period, then issued upfront — degradation has zero impact on STC value. Feed-in tariffs are different: state-mandated minimum FITs (currently 4.0c/kWh in Victoria) and retailer offers (8–12c/kWh through AGL, Origin, Energy Australia) apply to whatever you actually export. A 6.6 kW system losing 0.5%/yr would export roughly 12–15% less by year 25 — material but small versus the savings from self-consumption.
What about hail damage and bushfire smoke?
Hail: covered by household insurance, not panel warranty. The 2020 Canberra hailstorm wrote off thousands of residential systems. Most insurers now require IEC 61215 hail-resistance certification for the policy to apply. Bushfire smoke: deposition is mostly recoverable by rain or annual cleaning, but heavy ash on a hot panel can etch the glass and cause permanent 1–3% loss. Annual professional cleaning (use the [solar panel cleaning cost calculator](/calculators/solar-panel-cleaning-cost-calculator/)) is a worthwhile investment in bushfire-prone areas.

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