Our team completed construction of an 82.8 kW solar carpark system, installation of 14 EV chargers and associated civil works at Parramatta Council’s Operations Centre. The project required careful planning and responsive design to manage complex ground conditions whilst being delivered in a live operational environment where minimising disruption to the carpark was critical.
Parramatta City Council wanted to convert their entire fleet of vehicles to EV’s, and needed to charge their fleet. Adding the 14 chargers would add significant load to their existing infrastructure, thus they also wanted solar. The roof was already full of Solar, so a solar car park was proposed to provide power to the EV chargers, and the rest of the site. The EV fleet and additional solar was also important for the council’s ESG objectives.
Geotechnical Challenges
The geotechnical investigation identified several critical issues:
- Deep uncontrolled fill across multiple boreholes, ranging from 3.3 to over 5 metres in depth.
- Lack of certification for fill compaction, posing a risk of uneven settlement if conventional shallow footings were used.
- Variable soil layers including sandy gravel fill, clay sand, and concrete obstructions, creating unpredictable drilling conditions.
- The site was an operational asphalt carpark, which had to be restored to a high standard following trenching and construction.
How We Addressed These Challenges
To ensure the solar structures, cable reticulation and associated infrastructure remain stable and reliable over their operational life:
- We designed and installed bored piers founded into verified, competent natural soils below the fill layer, eliminating the risk of settlement and damage to Council’s new assets.
- Pier depths were increased where required to ensure consistent end-bearing pressures, in line with structural and geotechnical advice.
- Open trenching was selected in place of underboring for electrical and civil works, giving our team full control over soil conditions and reducing the likelihood of a collapsed bore causing delays.
- Full reinstatement of the existing asphalt carpark was carried out to Council specifications, minimising long-term maintenance requirements and preserving the operational use of the site.
Significant Civil works
- Trenching works, pile installation, EV charger foundation concreting works, Inverter station and switchboard room construction
- Coordination between many contractors for civil, electrical works
- Coordination to keep the carpark as operational as possible
- Minimised impact to site operations
Noteworthy Engineering Feats
- Over 5.5 km worth of cable installed
- Bifacial modules used to maximise generation
- Performance has been guaranteed for this site
Annual Savings and CO2 Reductions
430 Tonnes of CO2 saved by transitioning to EV’s over it’s lifetime.
An additional 110 tonnes of CO2 saved each year from the Solar Carpark
Parramatta City Councils Fleet is now converted to EV’s supported by our infrastructure.
City of Parramatta: https://www.cityofparramatta.nsw.gov.au/council/latest-news/council-leads-way-with-new-solar-canopy-and-ev-chargers-for-fleet
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“These additional chargers and solar canopy will set us up for years to come and make our full transition to electric vehicles much easier,” Cr Zaiter said.
“This project reinforces Council’s commitment to sustainability and also showcases our approach to adding more electric vehicles to our fleet,” Cr Zaiter said.
“Council is prepared for a sustainable future, with eight-22 kilowatt and six-7 kilowatt charging ports for use by council vehicles, all powered by renewable energy generated from on-site solar panels.
“Moves like this will ensure we maintain our carbon neutral certification that has been in place since mid-2022.”
Cr Martin Zaiter
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City of Parramatta Lord Mayor
