Supervise high-risk work.
Structured pre-start planning, validated work methods and visible supervision across civil, mechanical and electrical disciplines.
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Built at scale.
The scale is visible.
One connected
Complex conditions.
Variable ground.
High volume.
Distributed technology.
Quality, safety
The build finishes.
01 / MONITOR 02 / PREVENT 03 / RESTORE 04 / INSPECT 05 / PREPARE 06 / REPORT
From installed capacity
ACTUAL OUTPUT · OWNER-REPORTED>1,600 MWh ANNUAL GENERATION · OWNER FORECAST546 GWh
Plan the delivery.
WOLLAR SOLAR FARM · NEW SOUTH WALES
Built at scale.
Supported for the long run.
From complex ground conditions to grid integration. EPC delivery and ongoing operations & maintenance for a major Australian solar asset.
Explore the project storyMid-Western NSW / Owner: BJEI AustraliaProject delivery: Sunterra Energy Pty Ltd
346 MWdcInstalled solar capacity
280 MWacAC generation capacity
5,400Single-axis tracker systems
EPC + O&MDelivery through ongoing service
THE PROJECT IN A MINUTE
The scale is visible.
The coordination runs deeper.
Wollar turns sunlight into electricity for the NSW grid. Delivering it required engineering, construction and grid compliance to move together.
Located approximately 7 km south of Wollar, the project brings together thousands of trackers, a distributed inverter system and medium-voltage collection infrastructure. Sunterra’s role connects EPC delivery with ongoing operations and maintenance.
Follow the delivery journeyFROM ENGINEERING TO OPERATION
One connected
delivery journey.
Decisions made in design affect installation, commissioning and years of maintenance. Wollar required those interfaces to be managed across the project.
- 01
Engineering
Coordinate geotechnical, drainage and structural design with protection, grid modelling and plant controls.
- 02
Procurement
Identify long-lead equipment, verify factory readiness and sequence deliveries around installation needs.
- 03
Construction
Bring civil, piling, mechanical and electrical work fronts together under coordinated supervision and quality checks.
- 04
Commissioning
Validate controls and electrical performance through staged energisation, grid testing and handover.
- 05
O&M
Continue into O&M, with routine inspection, planned maintenance and site stewardship supporting ongoing operation.
Sunterra Energy Pty Ltd is the solar farm’s EPC and O&M contractor. The owner identifies TransGrid as managing substation construction; grid delivery involved multiple parties.
THE CHALLENGES BEHIND THE DELIVERY
Complex conditions.
Practical responses.
Three parts of the project show how engineering decisions, site execution and stakeholder coordination came together.
GROUND & CIVIL WORKSWork with the terrain.
Foundations, access and drainage planned together.
GPS piling
Drainage
Quality checks
01 / TURNING SITE CONDITIONS INTO A BUILDABLE PLAN
Variable ground.
Consistent installation.
THE CHALLENGE
Undulating terrain, drainage sensitivities and changing geotechnical conditions complicated foundations and site access.
OUR RESPONSE
Coordinate foundations with drainage and erosion controls. Use GPS-integrated piling systems to improve positioning, supported by engineering coordination and site quality checks.
DELIVERY OUTCOME
Sunterra’s project case study records piling productivity of approximately 400 piles per day, despite variable ground conditions.
COORDINATING THOUSANDS OF COMPONENTS
5,400tracker systems
3,600String inverters
58Medium-voltage stations
Factory verification↓Sequenced deliveries↓Pre-assembly & installation
02 / SYNCHRONISING SUPPLY WITH SITE READINESS
High volume.
Controlled work fronts.
THE CHALLENGE
Equipment manufacturing, logistics and parallel construction activities had to align across a large site, with peak mobilisation of approximately 400 personnel.
OUR RESPONSE
Identify long-lead items early, verify equipment at the factory and maintain material traceability. Sequence deliveries and use a central pre-assembly yard to support parallel mechanical and electrical installation.
DELIVERY APPROACH
Structured supervision and quality hold-points connected supply chain planning with installation readiness and consistent execution.
A STAGED PATH TO FULL OUTPUT
01Model & validatePlant controls · Protection · Grid performance
↓02Register & energiseCoordinate the regulatory and network interfaces
↓03Test at full capacityStage 3B milestone · 23 June 2025
03 / MAKING THE PLANT WORK WITH THE GRID
Distributed technology.
Coordinated validation.
THE CHALLENGE
The large string-inverter deployment introduced complex interfaces between plant controls, protection and grid performance modelling, including multiple R1 submission cycles.
OUR RESPONSE
Align technical validation and coordinate stakeholders through the R1/R2 modelling and testing program, progressing towards full-capacity generation through staged commissioning.
OWNER-REPORTED MILESTONE
Wollar reached 100% generation on 23 June 2025 after Stage 3B testing. Further Hold Point 3 testing followed as commissioning continued.
DELIVERY WITH ACCOUNTABILITY
Quality, safety
and site stewardship.
Large-scale delivery depends on daily controls as much as technical design.
Keep environmental controls in the program.
Integrate drainage protection, erosion controls, inspections and audit oversight into construction sequencing. Reinforce site controls and workforce training as issues are identified.
Plan for a connected asset.
Address access control, supply chain transparency and cyber security alongside plant delivery, with specialist support for security planning.
FROM HANDOVER TO ONGOING CARE
The build finishes.
The responsibility continues.
Sunterra’s ongoing O&M role extends the delivery relationship into the operating life of the solar farm.
LONG-TERM ASSET CARE
Equipment. Site conditions.
People who know the project.
Maintain the plant.
Look after the whole site.
The owner reports that locally employed staff have transitioned into on-site O&M. Its published operating activities cover both equipment condition and the environment around it.
Equipment inspection
Regular checks of solar panels and infrastructure to support safe, effective operation.
Ground cover & biodiversity
Vegetation and weed management aligned with the site’s Biodiversity Management Plan.
Local coordination
Pest management with neighbours and ongoing engagement with the Rural Fire Service on bushfire arrangements.
Site activities described in BJEI Australia’s 2025 Best Practice Charter report. These describe the owner’s operating program; individual service responsibilities follow the applicable contracts.
SUNTERRA’S O&M SERVICE PORTFOLIO
Capabilities that support an asset through its operating life. Services and response commitments are defined in each project’s O&M agreement.
Remote monitoring
Performance data, alarms and diagnostics help identify issues and inform maintenance priorities.
Planned maintenance
Scheduled inspections and servicing support equipment condition and availability.
Corrective maintenance
Fault investigation, response and rectification address equipment problems as they arise.
Thermal diagnostics
Drone thermal imaging supports panel-level fault detection and targeted investigation.
Inventory & spares
Critical component planning and stock management support maintenance readiness.
Performance reporting
Monthly and annual reports bring together generation, availability, maintenance records and trends.
HOW THE SERVICES CONNECT
Observe. Act. Review.
- MonitorReview data & alarms
- PlanPrioritise maintenance
- MaintainInspect, service & repair
- ReviewReport & inform the next cycle
An illustrative service workflow. Activities follow the asset’s maintenance plan.
PREPARING FOR THE OPERATING PHASE
The owner’s September 2025 update also reported construction of an on-site warehouse to hold spare parts for ongoing operations and maintenance.
THE VALUE AFTER ENERGISATION
From installed capacity
to useful energy.
Wollar’s value includes electricity generation, ongoing asset care and a lasting relationship with the local community.
In a single day.
By September 2025, the owner reported that the project’s highest daily generation had exceeded 1,600 MWh.
A reported daily high, not an average or a full-year result.
Expected each year.
Beijing Energy International’s September 2024 grid-connection announcement estimated annual clean electricity generation of 546 million kWh.
A forward-looking estimate, not verified annual production.
ASSET VALUE
Care beyond commissioning.
Ongoing inspection, maintenance and site management support the plant’s long-term operating needs.
COMMUNITY VALUE
A continuing local contribution.
The owner’s Community Fund offers up to A$100,000 annually, indexed to CPI, building on more than A$40,000 of construction-phase sponsorship.
KEY PROJECT MILESTONES
Progress, step by step.
Construction, first energisation and full-capacity testing are distinct stages in a utility-scale project.
Solar farm construction
Construction begins, following earlier access and preparatory works.
Initial energisation
The project connects to the grid, opening the next stage of commissioning.
Full-capacity generation
Stage 3B testing leads to the owner’s 100% generation milestone.
Preparing for handover
The owner reports final testing progress and spare-parts warehouse construction.
Dates follow the owner’s published project updates. The full-capacity milestone is separate from formal commercial operation and final completion.
Project information & sources
Engineering and construction descriptions draw on Sunterra’s Wollar project case study. Public owner updates provide the milestones and generation figures below.
- Wollar Solar Farm — project overview ↗
- Owner’s full-capacity generation milestone, June 2025 ↗
- Owner’s September 2025 community update ↗
- Beijing Energy International — grid-connection announcement, September 2024 ↗
- BJEI Australia — 2025 Best Practice Charter report ↗
- Owner’s Community Fund ↗
- Owner’s construction timeline and substation delivery context ↗
YOUR NEXT ENERGY PROJECT
Plan the delivery.
Think beyond handover.
Bring your site, grid requirements and operating priorities. Let’s discuss an energy project built around them.
