STC value by zone and system size.
Certificates = kW × zone rating × deeming years, rounded down. 2026 installs get 5 years, 2027 installs get 4. Valued at $37 a certificate, a few dollars under the 2026 spot price to allow for trader fees. Zone 3 (rating 1.382): Bendigo, Ballarat, Shepparton, Mildura, plus parts of Melbourne's north and west such as Craigieburn, Epping, Melton and Sunbury. Zone 4 (rating 1.185): most of Melbourne, Geelong, Gippsland and Warrnambool. Zones from the Clean Energy Regulator's postcode table, checked 23 September 2026.
| System size | Zone 3 certificates | Zone 3 value | Zone 4 certificates | Zone 4 value |
|---|---|---|---|---|
| 5 kW | 34 | $1,250 | 29 | $1,050 |
| 6.6 kW | 45 | $1,650 | 39 | $1,450 |
| 8 kW | 55 | $2,050 | 47 | $1,750 |
| 10 kW | 69 | $2,550 | 59 | $2,200 |
| 13.2 kW | 91 | $3,350 | 78 | $2,900 |
| System size | Zone 3 certificates | Zone 3 value | Zone 4 certificates | Zone 4 value |
|---|---|---|---|---|
| 5 kW | 27 | $1,000 | 23 | $850 |
| 6.6 kW | 36 | $1,350 | 31 | $1,150 |
| 8 kW | 44 | $1,650 | 37 | $1,350 |
| 10 kW | 55 | $2,050 | 47 | $1,750 |
| 13.2 kW | 72 | $2,650 | 62 | $2,300 |
| Postcodes | Zone | Rating |
|---|---|---|
| 3000 to 3035 | Zone 4 | 1.185 |
| 3036 to 3038 | Zone 3 | 1.382 |
| 3039 to 3044 | Zone 4 | 1.185 |
| 3045 | Zone 3 | 1.382 |
| 3046 | Zone 4 | 1.185 |
| 3047 to 3049 | Zone 3 | 1.382 |
| 3050 to 3058 | Zone 4 | 1.185 |
| 3059 | Zone 3 | 1.382 |
| 3060 | Zone 4 | 1.185 |
| 3061 to 3064 | Zone 3 | 1.382 |
| 3065 to 3074 | Zone 4 | 1.185 |
| 3075 to 3076 | Zone 3 | 1.382 |
| 3077 to 3098 | Zone 4 | 1.185 |
| 3099 | Zone 3 | 1.382 |
| 3100 to 3292 | Zone 4 | 1.185 |
| 3293 to 3302 | Zone 3 | 1.382 |
| 3303 to 3308 | Zone 4 | 1.185 |
| 3309 to 3319 | Zone 3 | 1.382 |
| 3320 to 3333 | Zone 4 | 1.185 |
| 3334 to 3337 | Zone 3 | 1.382 |
| 3338 to 3339 | Zone 4 | 1.185 |
| 3340 to 3758 | Zone 3 | 1.382 |
| 3759 to 3760 | Zone 4 | 1.185 |
| 3761 to 3764 | Zone 3 | 1.382 |
| 3765 to 3999 | Zone 4 | 1.185 |
Source: Clean Energy Regulator postcode zone ratings. Victorian postcodes are mapped today; Zones 1 and 2 and the other states follow as each range is checked. How many systems each postcode already has is on solar installs by postcode.