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Solar Carport Design for Maximum Energy Output – Optimising a Multi-Tenant Site (Part 4)
Standard solar carport structures cover the parking bays and leave the central driveway open, sacrificing a significant portion of the available rooftop area. At this Charlestown facility, NGG designed a two-column structure that spans the entire rooftop car park, including the driveway, balancing the full structural load across just two columns on either side. The result was an increase in energy generation capacity by approximately 63% on the same footprint. This video walks through the structural engineering decisions behind that outcome and the construction approach that allowed the installation to be completed in two weeks with minimal disruption to the car park during construction.
Key Insights
A two-column spanning design increases solar carport energy output significantly.
By extending the carport structure across the full rooftop including the driveway and balancing the load across two perimeter columns, this design increased generation capacity from approximately 270kW to 440kW on the same site footprint.
Solar carport structures on split-level car parks can maintain a uniform slope across both levels.
Despite a two-metre level change between sections of this car park, the structure was designed with a continuous slope from end to end, integrating cleanly with the facility’s existing architecture rather than stepping to match the levels below.
Built-in construction tolerances allow the solar carport structure to be completed in two weeks.
Horizontal beams with adjustable bolt-and-nut connections eliminate the need to drill each connection point individually, enabling fast, precise assembly on site with minimal disruption to car park operations.
Solar Carport Design for Maximum Energy Output
Most commercial solar carport structures are designed around the parking bays. The canopy covers the spaces on either side of the driveway, with the central lane left open. It’s a simpler structural solution, but it leaves a significant portion of the available roof area unproductive.
At this Charlestown site, NGG and our install partner engineered the structure to span the entire rooftop car park, covering both the parking bays and the central driveway with a single continuous canopy. The structural load is balanced across two columns on either side, with no intermediate supports breaking up the usable space below. The generation capacity of 440kW on this footprint compares to approximately 270kW under a standard carport approach. That 63% increase comes from the same site and the same available area. The difference is in how the structure was engineered.
Adapting the Structure to Site Conditions
This car park has two split levels separated by approximately two metres. A stepped structure that follows those levels would have been the path of least resistance, but it would have created a broken roofline that read as an afterthought rather than a deliberate design element.
The carport structure was instead designed with a uniform slope from one end to the other, absorbing the level change gradually across the full length of the canopy. The result is a clean, continuous roofline that integrates with the facility’s existing architecture. It’s the kind of outcome that matters to the building’s owner and landlord, not just the energy performance.
The carport columns are aligned with the building’s structural columns below, ensuring the load path is correct and the rooftop slab carries only the loads it was designed for. Getting this right requires the carport design to be reviewed and approved by a structural engineer before installation begins.
Solar Carport Construction on an Operational Site
Installing a 440kW solar carport structure on an operating commercial facility requires a construction sequence that minimises disruption to the people using it. Closing the car park for the duration of the build wasn’t an option.
The structural system has adjustable connection points built into the horizontal beams. Each connection can be positioned and tightened to the correct torque without drilling individual fixing points, which accelerates assembly and reduces the precision required during column installation. This tolerance in the system is what allowed the full structure to be erected in two weeks.
Once the structural frame was complete, the car park was returned to operation. A staging area was allocated for the electrical installation crew, who then installed the 440kW of panels with the facility operating around them. Any closures required during the build were kept brief and limited in scope.
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Watch Next
Watch the other parts in this series to follow the full Charlestown project from embedded network setup through to BESS integration and the revenue loop.
Optimising a Multi-tenant Site with Solar & Battery (Part 1)
Optimising a Multi-tenant Site (Part 2): Spatial Engineering & VPP Readiness
Optimising a Multi-Tenant Site (Part 3): Switchboard Conversion & Future-Proofing
Optimising a Multi-tenant Site (Part 5): BESS Integration and the Revenue Loop
What is the 30in30 initiative?
This video is part of Next Green Group’s 30in30 initiative. We’ve committed to deploying 30 Megawatt-hours of behind-the-meter commercial & industrial (C&I) battery storage across Australia over the next 30 months. We’re opening our internal playbooks to show C&I leaders the engineering and financial reality, empowering them to navigate the energy transition confidently.
Next Green Group is a vertically integrated energy solutions provider delivering complete asset lifecycle management. With 14 years of industry experience and more than 15,000 energy projects delivered, we bridge the gap between behind-the-meter energy infrastructure and front-of-meter wholesale market dynamics through our retail energy arm, Next Business Energy. We engineer, construct, and provide ongoing operations and maintenance for commercial energy assets to strict ISO & Australian standards. Backed by global powerhouse Sojitz Corporation, we combine this technical execution expertise with structured financing solutions to remove capital barriers and ensure long-term commercial performance.