Case Study: Excess Power
60kW DC Solar + 51.2kWh Battery Energy Storage System (BESS) Solution
Project Overview
Client: Excess Power
Project Size: 60kW DC Solar + 51.2kWh Battery Storage
Project Type: Commercial Solar & Battery System
Location: Western Australia
Installer: Westsun Energy
Westsun Energy was engaged to design and install a 60kW solar system paired with 51.2kWh Battery Energy Storage System (BESS) for Excess Power, a Western Australian commercial operation seeking to take control of its energy costs and reduce their dependence on the grid.
The objective was clear; reduce electricity costs, improve energy independence, and maximise the use of on-site solar generation through integrated battery storage – all without disrupting day-to-day operations.
As a WA-based commercial solar EPC and BESS provider, Westsun Energy delivered a tailored solution designed to support consistent daytime energy demand while ensuring reliable long-term performance.
The Problem
Before engaging Westsun Energy, Excess Power faced a challenge common to commercial operations across Western Australia: high grid electricity costs with limited ability to control or reduce them. Solar generation was being considered, but without a clear plan for how to store and use that energy effectively, the potential savings were at risk of being left on the table.
The key challenges included:
- Rising Energy Bills: High grid electricity costs during peak operational hours, with no mechanism to offset them through self-generated energy.
- No Integrated Energy Management: The site lacked the infrastructure to intelligently manage solar generation alongside battery storage, making it difficult to maximise self-consumption.
- Excess Solar Going to Waste: Solar energy generated during the day was being fed back to the grid at low feed-in tariff rates rather than being stored for use during the evening or low-generation periods.
- Complex System Integration: Designing a system that aligns with the site’s specific energy usage profile, roof orientation, and operational requirements — without disrupting business continuity.
Solution
Westsun Energy engineered and installed a high-performance solar and BESS solution featuring:
- 117 x 510W Canadian Solar Panels. High-efficiency modules selected to maximise energy production across the available rooftop.
- 1 x GoodWe Inverter. Delivering reliable power conversion, BESS management, and system performance.
- 2 x GoodWe 25.6kWh BESS Units (51.2kWh Total). A commercial-grade Battery Energy Storage System designed to capture excess solar generation and dispatch stored energy when and where it is needed most.
The BESS was configured to work in tandem with the solar array, with system design focused on:
- Maximising Energy Production. Generating strong daytime solar output to support operational demand.
- BESS Charge and Dispatch Optimisation. Programming the Battery Energy Storage System to charge from solar during peak generation hours and discharge during the evening or periods of high grid tariff.
- Reduced Grid Reliance. Supporting greater energy independence through the combined output of the solar array and BESS.
Results & Benefits
System Specifications
→ Solar System Size: 60kW DC
→ Battery Storage Capacity: 51.2kWh
→ Solar Panels Installed: 117 × 510W Canadian Solar modules
→ Inverter: 1 × GoodWe inverter
→ Battery System: 2 × GoodWe 25.6kWh battery units
Key Outcomes
→ Reduced Electricity Costs: Solar and battery integration helps offset grid usage.
→ Improved Energy Efficiency: Maximises use of generated solar energy.
→ Enhanced Energy Independence: Stored energy supports operations during non-sunny periods.
→ Sustainability Impact: Reduced carbon footprint through renewable energy integration.
Why Choose Westsun Energy
Westsun Energy is a Perth-based commercial solar EPC (Engineering, Procurement and Construction) contractor with extensive experience delivering solar and battery systems for commercial clients across Western Australia.
Experience. Westsun Energy has designed and installed commercial solar systems ranging from small business installations to large-scale commercial projects across WA.
Expertise. As a full EPC provider, Westsun Energy manages every stage of a project: system design, equipment procurement, installation, and commissioning. Clients deal with one team from start to finish.
Equipment. This project uses Canadian Solar panels and GoodWe inverter and battery technology. Both are commercially proven, widely deployed in Australia, and backed by strong manufacturer warranties and local support networks.
Local Knowledge. Operating in WA means Westsun Energy understands the local grid, tariff structures, and the performance conditions that make solar particularly effective in Perth and regional Western Australia.
Frequently Asked Questions
Is a 60kW solar system enough for a business?
Whether a 60kW solar system is sufficient depends on a business’s energy consumption profile, operating hours, and site characteristics. For many small-to-medium commercial operations in Western Australia, a 60kW system can offset a significant portion of daytime electricity usage — particularly for businesses that run Monday to Friday during daylight hours.
A 60kW DC solar system in Perth can generate approximately 240–270kWh per day on average, though actual output varies with roof orientation, shading, and seasonal conditions. When paired with battery storage — as in this project — the effective coverage extends beyond daylight hours, allowing stored energy to meet demand during the evening and early morning.
The key is matching system size to load profile. Westsun Energy conducts a detailed energy assessment before every commercial installation to ensure the system is appropriately sized for the site’s actual consumption — not just a round number. In some cases, a 60kW system will be the right fit; in others, a larger or smaller system may deliver better return on investment.
How much power does a 60kW solar system generate in Perth?
Perth is one of the sunniest capital cities in the world, making it an exceptional location for solar generation. A well-installed 60kW solar system in Perth typically generates between 240kWh and 270kWh per day, or approximately 87,000–98,000kWh per year, based on Perth’s average of around 4.5–5 peak sun hours per day.
In practical terms, this translates to offsetting a substantial portion of a commercial property’s electricity bill — particularly for businesses with high daytime energy usage such as manufacturing, cold storage, hospitality, or retail.
Actual generation will vary depending on panel orientation and tilt angle, system shading, inverter efficiency, and seasonal variation (Perth summers produce significantly more solar energy than winters). A system like this one — featuring 117 × 510W Canadian Solar panels and a GoodWe inverter — is engineered to perform reliably across all seasons, maximising annual energy yield and return on investment.
What is a BESS and how does it work with commercial solar?
A BESS, or Battery Energy Storage System, stores solar energy generated during the day for use in the evening or during peak tariff periods. Rather than exporting excess solar to the grid at low feed-in tariff rates, the BESS captures that energy and makes it available to the business first.
Conclusion
The Excess Power project demonstrates how integrating solar generation with battery storage can significantly improve energy efficiency and reduce reliance on grid electricity.
By installing a 60kW solar system with 51.2kWh of battery storage, Westsun Energy delivered a solution that supports long-term cost savings, energy independence, and operational reliability.
This project highlights Westsun Energy’s capability in delivering integrated solar and battery systems across Western Australia, engineered for performance, reliability, and long-term value.
For more information on how Westsun Energy, Perth’s best commercial solar installer, can assist with commercial solar solutions, contact us today.
