A commercial solar proposal can look complete while still leaving the central feasibility questions unanswered. Panel count, inverter capacity and a simple annual savings figure describe equipment. They do not establish how much generation the business can use, whether the site can connect the proposed system, or which certificate framework applies.
The first useful output is therefore not a product list. It is a bounded project brief that records the load, site, connection and commercial assumptions that control the design.
Start with interval demand
Annual electricity consumption is too blunt for system sizing. A business can consume substantial energy across a year while having little demand during the hours when solar generation is highest. Another can have a smaller annual total but a consistent daytime load that absorbs a larger share of generation on site.
The review should record at least:
- interval consumption across a representative operating period
- weekday, weekend and seasonal operating patterns
- demand peaks and the equipment that causes them
- planned electrification, production or tenancy changes
- tariff structure and demand charges
- periods when the site is closed
These inputs allow generation to be compared with load at the time it occurs. They also expose whether the proposal depends on export, future demand or a tariff assumption that has not been confirmed.
Establish the electrical and physical site
Available roof area is an opportunity, not a target. The practical scope also depends on roof condition, structural capacity, access, fire and maintenance clearances, switchboard condition, metering, phases, protection, cable routes and the point of connection.
The site record should identify which constraints are confirmed and which remain subject to engineering, structural, electrical or network review. A proposal that treats every unresolved item as an inclusion can give a false impression of certainty.
Identify the connection pathway early
Western Power states that a solar application meeting a narrow set of conditions, including inverter capacity of 5 kVA or less and standard supply, will in most cases avoid technical review. Systems outside those conditions require further checks and may require technical review.
Most commercial projects therefore need the connection pathway considered during feasibility, not after equipment has been selected. Export intent, inverter capacity, the existing supply arrangement and local network conditions can affect the information required and the outcome available.
The commercial connection pathway sets out the distinction between the current process and the reforms proposed by the WA Government in July 2026.
Keep certificate status separate from connection approval
At review on 14 August 2026, the Clean Energy Regulator's current eligibility guidance continued to define small-scale solar PV as no more than 100 kW, with annual output no more than 250 MWh. Systems above that boundary fall into the large-scale framework under current guidance.
The Commonwealth has announced an expansion of the Small-scale Renewable Energy Scheme to systems up to 1 MW from 1 October 2026, subject to regulations. That announcement is examined in Announced 1 MW Commercial Solar Rebate Cap. It should not be treated as an operative entitlement until the final instrument and regulator guidance establish the change.
Certificate eligibility does not grant network approval. Network approval does not establish certificate eligibility. Both need to be recorded independently.
Build an assumption register
A decision-ready feasibility record should state the basis of the commercial case rather than presenting one return figure. The assumptions commonly include:
- interval load and forecast changes
- expected generation and system losses
- self-consumption and export
- tariff and demand-charge treatment
- degradation, maintenance and equipment replacement
- curtailment or export limits
- certificate status and value
- financing terms and analysis period
Where a value is not confirmed, it should remain conditional. The purpose of feasibility is to make uncertainty visible early enough for the business to decide whether further design and connection work is justified.
The minimum decision record
Before a business accepts a system size, it should be able to see the load evidence, site constraints, connection pathway, certificate status and commercial assumptions in one record. The maintained commercial solar and network connection guide brings those checks together and links to the current primary references.
Primary references: Western Power, technical guidance for solar installers (opens in a new tab); Western Power, Basic Embedded Generator Connection Technical Requirements (opens in a new tab); Clean Energy Regulator, Renewable Energy Target eligibility (opens in a new tab); Clean Energy Regulator, defining small-scale and large-scale solar systems (opens in a new tab).
