Commercial Solar Perth – Prices, Output and Payback Periods

Optus Stadium, Victoria Park Drive, Burswood WA, Australia

Solar power is an attractive investment option and great way to save money for businesses in Perth and across the rest of Western Australia. Solar Choice is not a solar installer and provides independent advise to businesses and organisations.

How much energy will Commercial Solar Panels in Perth produce?

As a rule of thumb, a solar PV system in Perth will generate roughly 5.3 kilowatt-hours (kWh) of energy per kilowatt of capacity per day on average throughout the year  based on 30 years of historical sunlight irradiance data from the Bureau of Meteorology.

This means that a 10kW solar system will generate about 53kWh of energy per day on average, while a 100kW solar system will generate about 530kWh per day (with more in the summer months and less in the winter). Actual energy yields will vary depending on location, orientation & tilt angle and components used. The below table outlines the expected out from some typical solar commercial solar system sizes.

Solar System SizeAverage Daily Generation (kWh)Annual Solar Generation (kWh)Assumed Rate Paid by BusinessAnnual Savings (assumes 70% self-consumption)
10kW5319,345$0.25 per kWh$3,385
39kW20775,445$0.20 per kWh$10,562
70kW371135,415$0.18 per kWh$17,062
100kW530193,450$0.15 per kWh$20,312
500kW2,650967,250$0.12 per kWh$81,249

Solar Choice’s engineers can review your energy bills and provide a detailed summary of the optimal system size, expected savings through the life of the project and a quote comparison from leading installers. Click the link below to get started.

Request a free solar business case and compare leading commercial installers

Connecting Commercial Solar Systems with Western Power

Solar Power Systems under 30kW

For small commercial systems that are less than 10kW per phase, there is a streamlined and no cost application process with Western Power. A Clean Energy Counil accredited installer can complete this process in around 10 minutes.

Based on Solar Choice’s experience allow 10 business days to receive invitation to connect

Solar Power Systems between 30kW and 150kW

The cost to install systems with an inverter capacity over 30kW in Perth significantly increases due to the mandatory connection requirements from Western Power. Western Power owns and operates the electrical network that covers Perth and surrounding areas. For systems between 30kW and 150kW there is a enquiry and application cost of $5,250 plus the costs of an engineering study and a requirement to install a Grid Protection Unit (GPU). In total this usually adds $12,000 to $18,000 to the cost of installing a Solar PV System. As a result, systems with a 39kW DC (solar panel rating) with a 30kVA inverter are very common to streamline the application process and avoid additional costs which don’t provide any benefits to the business.

Based on Solar Choice’s experience allow 4 to 8 weeks to receive invitation to connect

Solar Power Systems over 150kW

Solar Panel Systems over 150kW in inverter capacity are subject to the same requirements as systems between 30kW and 150kW, however have a slightly higher upfront application and enquiry cost of $8,500. Following a the engineering review by Western Power, larger systems are often subject to specific design requirement of export limitation or the requirement to install SCADA network protection which can affect the ROI of a project. It is important to deal with a qualified and established solar provider for these projects with experience navigating these requirements.

Based on Solar Choice’s experience allow 2 to 3 months to receive invitation to connect

Commercial solar system pricing in Perth and Western Australia

Solar Choice has pre-vetted a network of commercial solar installers across Australia over the last 12 years. As part of our service, we collect accurate price, product and warranty information from all of our network installers that can be shared with our commercial clients based on the size and complexity of their project. Solar Choice also publishes average commercial solar prices by city and system size – visit our Commercial Solar Price Index for a full summary.

As you can see in the below table the costs of systems over 30kW spike in Perth due to the Western Power costs that apply.

Adelaide, SA$9,750$30,480$53,420$75,750$93,580
Brisbane, QLD$10,180$28,330$47,580$68,410$87,390
Canberra, ACT$10,050$30,910$50,590$67,670$92,670
Hobart, TAS$12,540$27,490$47,100$65,330$78,100
Melbourne, VIC$9,890$25,870$47,150$62,620$84,100
Sydney, NSW$10,520$26,840$48,390$63,480$83,370
Perth, WA$11,920$30,790$59,130$72,630$96,010

* Note these figures include GST and the STC benefit available under the federal government rebate

Historically we have also observed ~40% decline in the cost of a fully installed commercial solar PV system in the last 5 years following significant improvements in Solar Panel efficiency and the increase scale of production.

Commerical Solar Prices

Figure 1 – Extract from Solar Choice Commercial Price Index

Financing for Commercial Solar Systems in WA

There are a number of different ways to finance a solar system in Australia which can provide a cash flow positive solution from day one with no upfront costs. The 3 most common options are detailed in the below table.

TypeDescriptionTypical Terms
Chattel Mortgage
  • Solar system becomes colateral for loan
  • Full ownership (and depreciation benefits) from day one
3% to 6%


2 to 10 years

Rent to Own (operating lease)
  • Solar system is ‘rented’ to business for certain term meaning repayments are deductible
  • Current tax rules deem that asset is on balance sheet
  • Business makes an offer to buy at end of term (usually 2 months of repayments) to acquire asset
3% to 6%


2 to 10 years

Power Purchase Agreement
  • Business pays only for the energy produced by solar at a lower rate than what they are paying their retailer
  • Responsibility to maintain the asset remains with ppa provider through term of agreement
  • Only financing method where asset is off balance sheet
  • Learn more about PPAs and see an example
8c per kWh to 15c per kWh


7 to 30 years

Read our balanced assessment of the pros and cons of each financing method and a detailed example.

3 things  to get right in a Commercial Solar Project

Commercial solar projects follow more rigorous procurement processes and it is important to ensure you have a robust approach that will lead to a great solar investment.

1. Independent financial model to confirm feasibility and ROI

While the environmental benefits of solar projects are clear, most commercial solar projects come down to an evaluation of the financial attractiveness of the project. The financial model for these projects should be developed by experienced photovoltaic engineers who are not trying to sell you a particular solution. Solar Choice offers a free service where any business can receive a customised Solar business case developed agnostically to products, brands and financing arrangements.

2. Get a range of quotes from qualified, reputable solar installers

The best way to ensure you getting a competitive and innovation solution for your project is to engage a number of high quality solar installers with relevant experience. We often hear about projects going wrong where installers are selected on the wrong criteria and insufficient due diligence has been completed on the winning contractor. Solar Choice has developed a pre-vetted network around Australia since 2008 including all major, reputable commercial installers – talk to us about running a tender for your project.

3. Understanding the federal rebates

Commercial solar prices are at all-time lows in Australia, partially due to the federal government solar subsidies available through Australia’s Renewable Energy Target (RET). For solar systems up to 100kW of Solar PV, the RET provides an up-front incentive in the form of Small-scale Technology Certificates (STCs). For systems larger than 100kW, the RET provides an ongoing incentive (until 2030) in the form of Large-scale Technology Certificates (LGCs).

Request a free solar business case and compare leading commercial installers

Jeff Sykes