Commercial Solar in Australia: Is It Worth It for Your Business?

While residential solar payback periods sit at 4–7 years, commercial solar frequently delivers paybacks of 3–5 years, with internal rates of return (IRR) of 20–40%. The difference comes down to one key factor: commercial electricity prices.

Why Commercial Solar Stacks Up Better Than Residential

• Higher electricity rates: Small-to-medium businesses in SA typically pay $0.35–$0.55/kWh, with demand charges on top. Every kWh generated by solar avoids this cost.
• Daytime load alignment: Most businesses operate Monday–Friday, 8 am–6 pm — exactly when solar generates. Self-consumption of 80–95% is achievable (vs 30–50% for residential).
• Tax incentives: Businesses can claim instant asset write-off on solar systems (subject to current ATO thresholds), significantly improving the after-tax return.
• Larger systems: Larger installations have lower cost per watt installed, improving economics further.

System Sizing for Commercial

Commercial systems are sized differently from residential:

• The goal is to maximise self-consumption, so the system should match your daytime load profile
• Network export limits may be more restrictive for commercial connections — particularly for embedded network sites
• Three-phase connections allow larger systems (100 kW+) without the export constraints of single-phase

Typical commercial system ranges:

• Small business (café, small office): 15–30 kW | Cost: $18,000–$35,000 | Payback: 3–5 years
• Medium business (factory, supermarket): 50–200 kW | Cost: $50,000–$180,000 | Payback: 3–5 years
• Large commercial/industrial: 200 kW–5 MW | Cost: $180,000–$3M+ | Payback: 4–7 years

Demand Charges — The Hidden Opportunity

Most commercial electricity tariffs include a demand charge — a fee based on your peak 15 or 30-minute demand interval in the billing period. A business that peaks at 50 kW for just 30 minutes on one day might pay demand charges based on that 50 kW for the entire month.

Solar can significantly reduce demand charges if peaks occur during solar generation hours. Battery storage can further clip peak demand, sometimes delivering savings of $500–$2,000+/month purely from demand charge reduction.

Financing Options

• Outright purchase: Best long-term return. Full tax benefits immediately. No ongoing payments.
• Business loan: Spreads cost over 3–7 years. Cash flow positive from day one if loan repayments are less than energy savings (common in good commercial sites).
• Solar as a Service / PPA (Power Purchase Agreement): Installer owns and maintains the system. You pay a per-kWh rate (usually 15–30% below grid rate) for the power generated. Zero upfront cost, but long-term returns are lower. Good for businesses unable to access capital or with uncertain tenure.
• Green lease / landlord-tenant arrangements: In some cases, a landlord installs solar and on-sells power to tenants under an embedded network arrangement.

Key Considerations Before Proceeding

• Roof condition and lease tenure: Solar is a 20–25 year investment. If your roof needs replacement in 5 years, or your lease expires in 3, the economics change significantly.
• Network connection capacity: Check whether your connection can accommodate additional generation. Your DNSP (distribution network service provider) may require a protection study for systems above 30 kW.
• STCs and LGCs: Systems under 100 kW receive STCs. Systems 100 kW+ are eligible for LGCs under the LRET. The STC/LGC value should be factored into your cost analysis.
• Structural assessment: Commercial roofs must be assessed for load-bearing capacity before installation. This is part of any reputable commercial solar proposal.