Solar power production calculator in Australia
To use the solar power production calculator below, simply select your City and then enter the kW of panels in the second column.
e.g. if you have 3.3kW of panels on West and 3.3kW of panels on East, enter 3.3 against both W and E.
At the bottom of the table you can change the Export (FIT) price as well as the electricty price you pay.
The bill savings calculator below will automatically adjust itself based on what you enter.
The production results you will see are based on an unshaded 25 degree
tilted roof AFTER the first 12 months of operation,
thereby allowing for
the typical 2.5% Light Induced Degredation (LID) of 'P' type solar cells in their first year.
Select a City :
| Perth | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| kW of panels (e.g. 6.6) | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual | Avg. Per Day | % to N | |
Export Price:
Average export value of 4 cents based on:
85% of exports before 3pm at 3 cents:
15% after 3pm at 10 cents:
Import Price (inc GST):
Annual electricity bill savings
| Daytime power consumption | Savings Year 1 | Savings Per Bill |
|---|
'P' type solar cells typically degrade in output by 2.5% in the first year and then by 0.4 to 0.6% each year thereafter.
'N' type solar cells
typically degrade in output by 2% in the first year and then by 0.2 to 0.3% each year thereafter.
Time of day production
There's a bit of a solar myth that installing panels on a West facing roof will allow you to run your
air conditioning later in the day.
It's certainly true that a West facing roof will make more power than a North or East facing one after 4pm, but the difference isn't huge.
How the sun transits across the sky through the seasons and WHEN during the day solar power is made.
Most people know that the only two days of the year that the sun actually rises due East and sets due West are March 21st and September 21st, but it surprises a great many people how FAR South East the sun rises in Summer, and sets in the South West. In fact in January the sun is due West at about 3.30pm !!
You can also see that the arc is narrow, meaning the sun is more 'overhead' than the Winter picture shown underneath. It barely gets above Northbridge in the picture.
July image below. The Sun is rising in the East North East and setting West North West.
Notice how low in the sky the sun is with the top of the arc at Noon stretching up as far as Landsdale in the North in this picture.
Being so low in the sky greatly reduces solar production.
The tables below show WHEN the solar power is produced, every two hours, from dawn until dusk.
East facing roof
86% of the solar production is achieved, on average across the year by 2pm and over 97% by 4pm
Summer power production is quite evenly spread from dawn to 4pm
Winter power production is very concentrated to between 10am and 2pm
Dawn to 8am |
8am to 10am |
10am to Noon |
Noon to 2pm |
2pm to 4pm |
4pm to 6pm |
6pm to Sunset |
|
| Jan | 15% |
23% |
25% |
21% |
13% |
3% |
0% |
| Feb | 12% |
23% |
25% |
21% |
14% |
4% |
1% |
| Mar | 8% |
25% |
28% |
23% |
13% |
2% |
0% |
| Apr | 7% |
26% |
30% |
24% |
11% |
12% |
0% |
| May | 1% |
26% |
36% |
27% |
9% |
1% |
0% |
| Jun | 1% |
15% |
39% |
34% |
10% |
1% |
0% |
| Jul | 0% |
15% |
33% |
35% |
14% |
3% |
0% |
| Aug | 3% |
26% |
33% |
26% |
10% |
2% |
0% |
| Sep | 3% |
24% |
34% |
26% |
10% |
3% |
0% |
| Oct | 7% |
21% |
33% |
23% |
13% |
3% |
0% |
| Nov | 16% |
25% |
26% |
21% |
11% |
2% |
0% |
| Dec | 17% |
23% |
24% |
21% |
12% |
2% |
1% |
| Ave | 7.55% |
22.75% |
30.49% |
25.06% |
11.64% |
2.33% |
0.18% |
| Cum | 7.55% |
30.3% |
60.79% |
85.85% |
97.49% |
99.82% |
100% |
North facing roof
As with the East facing roof, North produces virtually no power after 6pm year round,
and virtually nothing
before
8am in Winter
Production is very evenly spread, year round, from 8am to 4pm
75% of daily power, on average, is produced before 2pm, and 95% before 4pm
Dawn to 8am |
8am to 10am |
10am to Noon |
Noon to 2pm |
2pm to 4pm |
4pm to 6pm |
6pm to Sunset |
|
| Jan | 5% |
18% |
24% |
24% |
20% |
9% |
1% |
| Feb | 4% |
17% |
23% |
24% |
22% |
9% |
1% |
| Mar | 3% |
17% |
25% |
27% |
20% |
8% |
0% |
| Apr | 3% |
17% |
26% |
27% |
21% |
6% |
0% |
| May | 1% |
15% |
29% |
30% |
22% |
3% |
0% |
| Jun | 0% |
15% |
30% |
31% |
21% |
4% |
0% |
| Jul | 0% |
14% |
30% |
31% |
22% |
3% |
0% |
| Aug | 1% |
17% |
30% |
31% |
18% |
3% |
0% |
| Sep | 3% |
18% |
28% |
28% |
16% |
6% |
0% |
| Oct | 6% |
20% |
28% |
27% |
17% |
2% |
0% |
| Nov | 7% |
21% |
27% |
26% |
16% |
2% |
0% |
| Dec | 7% |
19% |
24% |
24% |
19% |
7% |
0.% |
| Ave | 3.36% |
17.23% |
27.16% |
27.45% |
19.51% |
5.11% |
0.18% |
| Cum | 3.36% |
20.59% |
47.75% |
75.2% |
94.71% |
99.82% |
100% |
West facing roof
Worried about late afternoon shade from trees hitting your West roof after 6pm ?
Don't be...Only 0.45 % of your production happens after 6pm, whereas 2.88% HAPPENS BEFORE 8AM.
Over 40% of your average production happens before mid day and 90% by 4pm.
Dawn to 8am |
8am to 10am |
10am to Noon |
Noon to 2pm |
2pm to 4pm |
4pm to 6pm |
6pm to Sunset |
|
| Jan | 5% |
15% |
22% |
23% |
21% |
12% |
2% |
| Feb | 3% |
15% |
23% |
26% |
22% |
10% |
1% |
| Mar | 2% |
14% |
23% |
26% |
22% |
12% |
1% |
| Apr | 2% |
14% |
25% |
28% |
21% |
10% |
0% |
| May | 1% |
14% |
27% |
30% |
22% |
7% |
0% |
| Jun | 0% |
13% |
29% |
26% |
19% |
13% |
0% |
| Jul | 0% |
15% |
29% |
30% |
22% |
4% |
0% |
| Aug | 1% |
4% |
28% |
30% |
20% |
8% |
0% |
| Sep | 2% |
14% |
25% |
28% |
21% |
9% |
0% |
| Oct | 4% |
15% |
24% |
27% |
22% |
9% |
0% |
| Nov | 5% |
17% |
24% |
25% |
20% |
9% |
0% |
| Dec | 7% |
10% |
16% |
28% |
24% |
13% |
1% |
| Ave | 2.88% |
14.05% |
24.58% |
27.09% |
21.39% |
9.57% |
0.45% |
| Cum | 2.88% |
16.92% |
41.51% |
68.59% |
89.98% |
99.55% |
100% |