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Solar Feed-in Bill Savings Calculator (Australia)

Calculate your annual electricity bill savings under Australian solar feed-in tariffs. State-by-state FIT comparison, DMO retail rates, and battery economics for 2026.

Solar Feed-in Bill Savings Calculator

Bill without solar
$2,312
Bill with solar
$1,190
Annual savings
$1,122
Bill reduction
48.5%
How the math works
Annual production: 7,791 kWh
Annual imports: 4,463 kWh · Annual exports: 5,453 kWh
Bill without solar: $2,312 → Bill with solar: $1,190

How the calculator works

The Solar Feed-in Bill Savings Calculator estimates your total annual benefit from a domestic rooftop PV system under Australia’s gross-metering-plus-FIT model. It separates the two revenue streams:

  • Avoided imports — solar kWh consumed by your home directly, displacing imports at your retail rate (AER 2026 DMO average A$0.34/kWh).
  • Feed-in credit — solar kWh exported to the grid, paid at your retailer’s FIT rate (state-set minimum or higher market offer).

Plug in seven numbers and the calculator returns annual production, annual imports, annual exports, your gross annual bill before solar, your net bill after solar, dollar savings, and percentage bill reduction.

  1. System size (kW) — DC nameplate. CEC marketplace data shows the average Australian residential install in 2025 was 8.6 kW DC (up from 6.6 kW pre-2022).
  2. Peak sun hours/day — Bureau of Meteorology averages: Sydney 4.2, Melbourne 3.8, Brisbane 4.6, Perth 5.0, Adelaide 4.4, Darwin 5.7, Hobart 3.5, Canberra 4.5.
  3. Annual usage (kWh) — AEMC 2024 average: 6,800 kWh for a NEM household, 5,000 kWh in WA, 8,000 kWh in tropical QLD/NT.
  4. Retail rate ($/kWh) — AER 2026 DMO blended: NSW $0.34, VIC $0.27, SA $0.42, QLD $0.30. WA Synergy A1 standard $0.30. Use your actual bill rate if available.
  5. Feed-in credit ($/kWh) — typical market: 4–8c (NSW, QLD, SA), 3.3–6c (VIC after 1 July 2025 reset), 2.5c off-peak / 10c peak (WA DEBS). Origin Solar Boost up to 14c capped.
  6. Self-consumption (%) — 25–35% without battery, 70–85% with battery. Daytime-occupied households trend higher.
  7. Daily supply charge (annual) — typical $1.00–$1.30/day = $365–$475/year. Non-bypassable.

How the math works

annual_kWh_produced  = system_kW × peak_sun_hours × 365 × 0.77
self_consumed        = min(annual_use, annual_prod × self_pct/100)
imports_kWh          = max(0, annual_use - self_consumed)
exports_kWh          = max(0, annual_prod - self_consumed)
gross_bill           = annual_use × retail_rate + supply_charge
import_cost          = imports_kWh × retail_rate
fit_credit           = exports_kWh × fit_rate
net_bill             = max(supply_charge, import_cost - fit_credit + supply_charge)
annual_savings       = gross_bill - net_bill

The 0.77 performance ratio aligns with CEC Solar Accreditation guidelines for Australian conditions — covering inverter losses (3%), DC cable (1–2%), soiling (3–5%, higher in dust-prone WA/NT), thermal derating in 30°C+ ambient (8–12%), and module mismatch (1–2%). AS/NZS 4509 and CEC Design Guideline Section 4 use 0.75–0.80 in standard yield calculations.

Worked example: 6.6 kW in Sydney on AGL Solar Savers

  • System: 6.6 kW DC, 4.2 PSH (Sydney BOM), retail $0.32 (AGL Standing), FIT 6c
  • Annual production: 6.6 × 4.2 × 365 × 0.77 = 7,793 kWh/yr
  • Annual usage: 6,800 kWh, supply charge $1.10/day = $401.50
  • Self-consumption 30% no battery → 2,338 kWh × $0.32 = $748.16
  • Imports: 6,800 − 2,338 = 4,462 × $0.32 = $1,427.84
  • Exports: 7,793 − 2,338 = 5,455 × 6c = $327.30
  • Gross bill: 6,800 × $0.32 + $401.50 = $2,577.50
  • Net bill: max($401.50, $1,427.84 − $327.30 + $401.50) = $1,502.04
  • Annual savings: $1,075 — 42% bill reduction

Worked example: same system with 10 kWh battery

  • Self-consumption 80% → 5,440 kWh × $0.32 = $1,740.80 avoided
  • Imports: 6,800 − 5,440 = 1,360 × $0.32 = $435.20
  • Exports: 7,793 − 5,440 = 2,353 × 6c = $141.18
  • Net bill: max($401.50, $435.20 − $141.18 + $401.50) = $695.52
  • Annual savings: $1,882 — 73% bill reduction

Battery adds about $807/year, and with the Federal Cheaper Home Batteries Program rebate of ~$4,995 on a 13.5 kWh Powerwall, plus state add-ons (VIC Solar Homes interest-free loan, NSW Empowering Homes), battery payback in 2026 Australia is typically 5–8 years.

State-by-state FIT snapshot (Q1 2026)

StateMinimum FITTypical market FITNotes
Victoria3.3c (1 Jul 2025)3.3–6cESC review pushed minimum down from 4.9c
New South Wales4.9–8c (IPART benchmark)5–12cHigher market plans available (Origin Solar Boost)
Queensland~6c reference4–13.5cErgon regional often higher than south-east
South Australia4.3c4–14cAGL Solar Savings highest market plan
Western Australia2.5c off-peak / 10c peak DEBSSynergy/Horizon onlyTwo-rate TOU-based FIT
Tasmania8.94c8.94c+Aurora regulated FIT, no real market competition
ACT12c (legacy) / market only6–10c new connectionsLegacy 1:1 buyback closed
Northern Territory8.32c (Tier 1)Tier 1 onlyPower and Water regulated

Sources: ESC (VIC), IPART (NSW), QCA (QLD), ESCOSA (SA), Synergy/Horizon (WA), Aurora Energy (TAS), ICRC (ACT), Power and Water (NT). Verified Q1 2026.

STCs, Solar Battery Rebate, and the 2026 incentive stack

The Small-scale Renewable Energy Scheme (SRES) creates Small-scale Technology Certificates (STCs) at install time — currently 1 STC per MWh deemed generation, with deeming period reducing each year through SRES sunset on 31 December 2030. A 6.6 kW system in Zone 3 (most NSW/SA/VIC) creates ~75 STCs in 2026 at $400 spot = $30,000 — except the spot price has declined to ~$35/STC in 2025 due to oversupply, so the real STC value is around $2,625 on a 6.6 kW Sydney install. Use the solar panel tax credit calculator for current STC pricing.

The Federal Cheaper Home Batteries Program (launched 1 July 2025) adds an STC-style discount for batteries 5–50 kWh installed by CEC-accredited installers. First-year rate (2025–26) is approximately $370 per kWh useable, declining roughly 10% annually through 2030 sunset. A 13.5 kWh Tesla Powerwall qualifies for ~$4,995 in 2026.

State stack: VIC Solar Homes interest-free battery loan up to $8,800; NSW Empowering Homes loan; SA Home Battery Scheme grant (closed but private finance partners continue offering 0% loans). These do not affect the calculator output directly but shorten payback meaningfully.

DMO vs Market Offer — choosing your retail rate

The AER Default Market Offer (DMO) is the maximum a retailer can charge unless you’ve opted into a Market Offer plan. In NSW the 2026 DMO is roughly $0.34/kWh residential; in SA it’s $0.42; QLD $0.30. Market Offers are nearly always cheaper than DMO — Energy Made Easy (energymadeeasy.gov.au) ranks Market Offers by total annual cost net of FIT for your AEMO postcode. Picking a retailer 10% below DMO saves 5–8% on your post-solar net bill in most NEM regions.

VIC uses the Victorian Default Offer (VDO) instead, set by the Essential Services Commission; WA’s regulated market means Synergy A1 standard and Horizon are the only options (no shopping around).

Sources

  • Australian Energy Regulator, Default Market Offer 2026–27 Final Decision and Energy Made Easy plan database.
  • Clean Energy Council, 2024 Australian Solar Industry Report and Solar PV Design Guidelines.
  • Essential Services Commission Victoria, Minimum Feed-in Tariff Determination 1 July 2025–30 June 2026.
  • Australian Government, Cheaper Home Batteries Program guidelines (Department of Climate Change, Energy, the Environment and Water).
  • SunWiz, Australian PV Market 2025 Annual Report.
  • Bureau of Meteorology, Australian Solar Energy Map (NSRDB-equivalent).

Frequently asked questions

Does Australia have net metering?
Not in the strict one-to-one sense — Australia uses gross metering with a separate feed-in tariff (FIT). Your import meter records imports at your retail rate; your export meter records exports paid at the FIT rate. The economic effect is similar to a partial net-metering regime where the credit rate (FIT) is roughly 15–25% of the retail rate. State-set FIT minimums vary widely: Victoria mandated 3.3c/kWh from 1 July 2025, New South Wales IPART recommends 4.9–8c, Queensland uses ~6c reference, South Australia minimum 4.3c, Western Australia DEBS pays 2.5c off-peak and 10c peak (15:00–21:00). Retailers usually offer above the minimum to attract customers — Origin, AGL, and Red Energy often pay 6–12c depending on plan.
How much will solar save me on my electricity bill in 2026?
A typical 6.6 kW system in Sydney generates about 9,250 kWh/yr. With 30% self-consumption and the AER 2026 DMO at A$0.34/kWh, you save 2,775 kWh × $0.34 = $943 on imports, plus 6,475 kWh × $0.06 FIT = $389 in feed-in credit. Total annual benefit roughly $1,330. SunWiz and Solar Choice's 2025 market reports confirm $1,200–$1,500 annual savings is typical for a 6–7 kW system in NSW, VIC, and QLD on the default market offer. Pair with the 30% Federal STC rebate (worth ~$2,000–$3,000 on a 6.6 kW install) and Federal Solar Battery Rebate of ~$370/kWh useable through end of 2026, and payback periods are 4–7 years across most of Australia.
What is the difference between the FIT and the STC rebate?
The Small-scale Technology Certificate (STC) is an upfront subsidy applied at the time of install — typically $400–$500 per STC, with a 6.6 kW system in Sydney creating ~75 STCs ($30,000–$37,500 at $400 spot, multiplied by the SRES deeming period of 1 year remaining as of 2030 sunset). In 2026 it's about $2,000–$3,000 for a typical residential install. The FIT is the ongoing per-kWh export payment from your retailer. STCs are paid to your installer (passed through as a discount on the install price); FITs are paid as bill credits or quarterly cash by the retailer. Both exist together — they do not substitute for each other.
Should I take the highest FIT offer or the cheapest retail rate?
Cheapest retail rate, usually. The math: average self-consumption is 30%, so 70% of your generation exports. A 6.6 kW system in Sydney exporting 6,475 kWh × 2c higher FIT = $130/yr extra. Meanwhile imports of 4,600 kWh × 2c higher retail = $92/yr more on imports. The retail rate dominates if you import more than 30% of what you export. If you have a battery (self-consumption 75–85%) the FIT rate matters even less. Energy Made Easy (energymadeeasy.gov.au) is the AER's compare-the-deal site — it ranks plans by total annual cost net of FIT for your usage profile, which is the right metric.
Will the Federal Solar Battery Rebate help my payback maths?
Yes. The Federal Government Cheaper Home Batteries Program launched 1 July 2025 — eligible battery systems 5–50 kWh installed by CEC-approved installers receive a Small-scale Technology Certificate-style discount of about $370 per kWh useable as of the program's first year, declining annually through end of 2030. On a 13.5 kWh Tesla Powerwall, that's roughly $4,995 off. Combined with the existing STC rebate on PV and state-level rebates in VIC (Solar Homes battery loan) and NSW (Empowering Homes), battery payback in 2026 is 5–8 years across most of the National Electricity Market — down from 10–14 years in 2024. The calculator's self-consumption input captures the bill-side benefit of adding a battery.

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