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Commercial Solar System Sizes
Understand common kW system sizes and find the right fit for your business. From 20kW entry-level systems for small offices to 1MW+ industrial installations.
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What size commercial solar system does my business need?
Most businesses don't need the biggest system possible, they need the right system size designed around when and how they use electricity.
If your monthly power bill is $800–$1,500, you need a 20kW system. If it's $1,500–$3,000, you need a 30kW system. If it's $7,000–$15,000, you need a 100kW system.
The goal of commercial solar sizing is to maximise onsite solar consumption, reduce reliance on grid power, and improve ROI over time.
Commercial solar system size is based on:
- Your last 12 months of electricity bills
- Operating hours and daytime load profile
- Available roof or site space and shading
- Export limits and grid connection requirements
- Switchboard capacity and compliance needs
- Future plans (EV charging, expansion, electrification)
Solar System Sizes
#Find the Right Commercial Solar System Size
Below is a simple guide to common commercial solar system size ranges. Your best fit depends on your roof space, operating hours and how much of the solar power your business can use onsite.
20kW – 30kW Commercial Solar Systems
Small Offices & Entry-Level Commercial
20kW solar systems are the perfect entry point for small commercial operations. Ideal for solo practitioners, small retail shops, and offices with modest daytime energy usage.
- Power bill offset: 30-50% for small operations
- Roof space: Only 80-100m² required
- Best for: Professional services, cafes, boutique retail
- Payback: 3-4 years with ~$8,000-$12,000 STC rebate
If you're paying $800-$1,500 monthly, a 20kW system is likely your sweet spot.
30kW – 75kW Commercial Solar Systems
Small to Medium Businesses
30kW–75kW systems suit offices, retail, clinics, and hospitality venues with steady daytime energy use. These fall under the STC scheme and benefit from an upfront rebate.
- Power bill offset: 40-60% for small-to-medium operations
- Roof space: 120-300m² required depending on size
- Best for: Medical clinics, restaurants, warehouses
- Payback: 2-4 years with ~$11,200/year savings (50kW)
A 50kW system suits businesses paying $3,000-$7,000 monthly in electricity.
100kW - 250kW Commercial Solar Systems
Growing Businesses & Manufacturing
100kW systems suit growing businesses with higher energy demand and steady baseload. This is the largest size eligible for upfront STC rebates before moving to LGCs.
- Power bill offset: 50-70% for growing operations
- Roof space: 400-700m² required for optimal installation
- Best for: Manufacturing, food production, logistics, clubs
- Payback: 2.5-3.5 years with ~$40,000-$45,000 rebate
A 100kW system generates ~140,000kWh annually, saving $22,400 per year.
250kW – 500kW Commercial Solar Systems
High-Load Commercial & Industrial
250kW–500kW systems suit high-load facilities with significant energy demand. These are designed for warehouses, cold storage, and larger manufacturing operations.
- Power bill offset: 60-80% for industrial operations
- Roof space: 1,000-2,000m² or ground-mounted options
- Best for: Cold storage, warehouses, processing facilities
- Payback: 3-5 years with ongoing LGC credits (100kW+)
Systems at this scale require detailed engineering and network approval.
500kW – 1MW Commercial Solar Systems
Industrial-Scale & Enterprise Projects
500kW–1MW systems suit industrial-scale operations across distribution centres and large manufacturing. These are custom engineered for enterprise sites with significant demand.
- Power bill offset: 70-90% for large-scale operations
- Roof space: 2,000m²+ rooftop or ground-mounted arrays
- Best for: Distribution centres, agribusiness, infrastructure
- Payback: 4-6 years with long-term cost certainty and LGCs
Projects require staging plans and careful electrical infrastructure integration.
1MW+ Commercial Solar Solutions
Engineered for Enterprise & Infrastructure Projects
1MW+ systems are custom engineered for enterprise sites with significant energy demand. These include large industrial facilities, agribusiness, and multi-site operations.
- Power bill offset: 80-95% for enterprise-scale operations
- Roof space: 4,000m²+ or ground-mounted solar farm arrays
- Best for: Large manufacturing, water treatment, multi-site
- Payback: 5-7 years with LGCs and long-term energy certainty
Projects require feasibility studies and network grid connection agreements.
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#Commercial Solar Rebates & Incentives for Businesses
Taking advantage of commercial solar incentives can reduce your upfront investment by 30-50%. Depending on your system size and business location, you may qualify for:
Small-Scale Technology Certificates (STCs): Available for commercial solar systems under 100kW. STCs provide an upfront discount based on expected generation. Typical rebate: $400-$600 per kW installed. A 20kW system typically receives approximately $8,000-$12,000 in STC rebates upfront. A 30kW system receives approximately $12,000-$18,000. A 100kW system receives approximately $40,000-$45,000.
Large-Scale Generation Certificates (LGCs): For 100kW solar systems and larger, LGCs provide ongoing annual credits based on actual energy generation rather than upfront discounts.
Instant Asset Write-Off: Australian businesses can immediately deduct the full cost of commercial solar installations up to $150,000. This applies to 20kW, 30kW, 100kW, and larger systems. We handle all incentive applications and paperwork as part of your installation.
#Need Help Choosing a Solar System Size?
Get expert advice on selecting the right commercial solar system for your energy usage, business type, and infrastructure — from 20kW systems to multi-megawatt installations.
#FAQs About Commercial Solar System Sizes
The right size depends on how much electricity you use and when you use it. Small offices often need 20kW, retail typically needs 30kW-50kW, medium operations need 100kW, and large facilities need 250kW+. A commercial solar system is usually sized to maximise daytime self-consumption and avoid over-exporting, which can reduce returns.
Yes. A 20kW commercial solar system generates approximately 28,000 kWh annually, enough to power most small offices, cafes, or retail shops with 1-5 staff. If your power bill is $800-$1,500 per month, 20kW is likely ideal.
It comes down to your daytime baseload, operating hours, roof space, and tariff. 20kW systems suit small operations with limited roof space, while 30kW systems suit standard small businesses. 100kW+ is for growing businesses with higher energy demand.
A 20kW solar system can generate around 28,000kWh per year, a 30kW system around 42,000kWh, while a 100kW system can produce about 140,000kWh annually.
Typically, a 20kW commercial solar system costs $15,000-$25,000 after STC rebates, while a 30kW system costs $25,000-$35,000. The per-watt cost usually decreases as system size increases.
Not always. If your system is too large for your onsite usage, you may export more solar to the grid, which can lower the overall value depending on feed-in rates, tariffs and network rules.
Your load profile, demand peaks, energy tariffs, switchboard capacity, shading, roof structure, export limits, and network approvals can all influence the best commercial solar system size.
Yes. Many businesses stage a commercial solar installation to align with budgets, growth plans, site works or approval requirements. Staging can also help confirm performance before expanding capacity.
Often, yes. Depending on size and location, commercial systems may require network approval, export limits confirmation, metering changes and engineering checks, particularly on larger installations.
Not necessarily, but battery storage can help if your business uses more power after hours, exports a lot of solar, or wants added resilience. In some cases, batteries improve self-consumption and strengthen the business case.