In this article
A useful commercial solar proposal starts with your electricity use, not the size of your roof. For a Perth or Bunbury business, the question is how much solar you can use while it is being generated, what the site can support and how the whole project affects cash flow.
Start with your working day
Refrigeration, air conditioning, pumps and machinery can create a useful daytime load. Opening hours alone do not tell the whole story: weekend closures, seasonal production and equipment schedules all change how much solar your business can use.
Bring 12 months of electricity bills and interval consumption data, if available. Compare the proposed generation with that load profile, including quieter days. A business operating mainly after sunset needs a different assessment; adding a battery is a separate investment to model, not an automatic fix.
- Use on site: estimate the solar electricity that replaces purchases from your retailer.
- Export: confirm the permitted export capacity and the retailer’s actual payment terms. Do not value exported energy at your electricity purchase rate.
- Remaining bill: account for electricity still bought from the grid, fixed charges and any demand charges. Solar does not automatically remove them.
Check the site before committing
Roof condition, shading, structural suitability, switchboards and cable routes can affect the design and installed cost. For leased premises, resolve landlord consent, roof access, the remaining lease term and what happens to the system if you move.
Network approval is a separate step from finance approval. The applicable Western Power process depends on the proposed system and connection. Its commercial connection guidance includes feasibility assessment, technical studies and approval to operate. Confirm the application pathway, metering, export conditions and any engineering or network costs before treating the installation date or savings estimate as settled.
See Western Power’s commercial inverter connection process and our guide to commercial rooftop connection barriers in WA.
Compare the funding, not just the repayment
The routes below describe common arrangements, not a list of finance products currently offered by PSW. Availability, ownership and obligations must be confirmed in the actual contract. A low upfront payment does not establish the lowest total cost.
| Funding route | Payments and ownership | Before you sign |
|---|---|---|
| Cash purchase | You pay the agreed installed price and own the system, subject to the purchase contract. | Check payment milestones, inclusions, warranties and the working capital left for your business. |
| Business or equipment loan | You fund the purchase through a lender and repay principal, interest and any fees. Check the ownership and security terms. | Compare the cash price with the total amount repayable, including deposits, any final payment, security, guarantees and early payout costs. |
| Lease or rental | You pay to use the equipment over an agreed term. Ownership during and after the term depends on the agreement. | Check maintenance responsibilities, end-of-term purchase or return terms, and costs if the tenancy or agreement ends early. |
| On-site power purchase agreement (PPA) | A provider arranges the system and you pay an agreed rate for solar electricity. The contract sets ownership and maintenance responsibilities. | Check the rate and escalation, minimum purchases, who receives export credits, the term, buyout rights and what happens if you move. |
The Australian Government Solar Consumer Guide explains solar loans, leases and PPAs. business.gov.au’s business loan guide explains loan costs, security and application preparation.
Tax treatment needs its own check
Do not assume every repayment is fully deductible. Loan interest, asset depreciation, lease payments and GST need to be considered under the arrangement and your business circumstances. The ATO explains business interest expenses; ask your accountant to review the proposed contract and any applicable asset deduction rules before including a tax benefit in the business case.
Test the cash flow on the same basis
Ask for a comparison over the same period, using the same electricity prices and operating assumptions. Keep the upfront investment separate from the monthly operating result.
Ask what happens if daytime use falls, tariffs change, the system produces less than forecast or equipment needs replacing. Repayments can remain due even when generation or savings are lower. Any claim that the system pays for itself from day one needs to be demonstrated for your site, not assumed.
Plan the monitoring connection
Monitoring should let you check generation and, where the required metering is included, how much electricity the business uses, imports and exports. A generation-only portal does not provide the same picture as consumption monitoring.
Choose the connection for the actual inverter and monitoring equipment:
- Ethernet: confirm the device supports it, the cable route and your IT team’s network requirements.
- Wi-Fi: check compatible network settings and signal strength at the installed equipment, not just at the office desk.
- Cellular: where supported, confirm a compatible modem, local coverage, SIM or data plan, ongoing fees and responsibility for renewal.
Telstra has switched off its 3G network. An older 3G-only monitor needs an assessed replacement or a supported alternative connection; an active subscription cannot restore a retired network.
Solar Analytics describes different monitoring integrations and their requirements. Confirm the exact hardware, compatible service and consumption metering for your project. Do not assume the original article’s free hardware, two-site allowance or annual data price still applies.
Make the handover usable
Agree who owns the monitoring account, who receives alerts and who responds to them. Use individual authorised access where the platform supports it, complete the manufacturer’s account activation and change any initial password as instructed. Have the installer demonstrate fresh data and explain how to recover access or reconnect after a router change. Do not share your business Wi-Fi or portal password in an enquiry.
For owner-level connection help, use the Wi-Fi reconnect assistant. For an older monitor or an unclear fault, contact PSW Life Support with the equipment model and the last time data updated.
What your written quote should settle
- The design: panels, inverter capacity, expected generation, on-site use and export assumptions.
- The installed scope: structural work, switchboards, metering, connection applications, commissioning, exclusions and any incentive assumptions.
- The funding: provider, cash price, deposit, term, repayment schedule, all fees, security, final payments and exit conditions.
- The ongoing service: monitoring hardware, account access, subscriptions, data costs, warranties, maintenance and support responsibilities.
- The evidence: the bills and load data behind the forecast, landlord permissions where needed, and the approval steps still outstanding.
Bring your site address, recent bills, operating hours and ownership or lease details to discuss a commercial solar project with PSW. We can start with the site and electricity profile, then establish which design and current written terms are relevant.