Gunsynd Solar Farm

Introduction

Incon was engaged to provide structural engineering design and certification services for the Gunsynd Solar Farm project in Queensland. This large-scale renewable energy development involved the integration of solar generation infrastructure, substations, and associated civil works within a challenging rural site environment.

Project
description

The Gunsynd Solar Farm is a 111 MWdc / 94 MWac utility-scale solar facility, located approximately 14 km north of Goondiwindi, Queensland. The project included:

Solar PV array infrastructure and associated power conversion units (PCUs)
Substation and switching station interfacing with a 132kV transmission network
Structural and civil design for inverter stations, CCTV, fencing, and auxiliary systems
Earthworks, drainage, and site development across an approximately 200-hectare site

A key structural component involved the design and coordination of inverter skid foundations, supporting multi-inverter units and associated electrical equipment (as shown in the general arrangement and foundation layouts in the drawings).

Challenge

The project presented several technical and environmental challenges typical of large-scale solar farms:

Expansive and reactive soil conditions (Gilgai terrain) causing differential ground movement and potential impact on pile and foundation performance
Floodplain and alluvial soil profile, requiring careful consideration of settlement, drainage, and long-term stability
High equipment loads, including inverter skids (~23.6 tonnes total system weight) requiring robust and evenly distributed support systems
Strict operational requirements, including minimum access clearances (e.g., 1000 mm maintenance zones around inverter units)
Coordination with electrical and civil disciplines, ensuring compatibility between structural design, cable routing, and equipment interfaces

Solution

We delivered an efficient and coordinated structural solution through:

Design of reinforced concrete foundation systems and pile layouts tailored to support inverter skids and associated equipment, ensuring uniform load distribution
Integration of precise pile positioning and tolerances, with requirements for consistent pile head levels to maintain structural alignment (±5 mm tolerance)
Consideration of soil reactivity and ground movement, incorporating design strategies aligned with geotechnical recommendations for Gilgai conditions
Coordination with OEM requirements (Ingeteam systems), ensuring compliance with equipment geometry, load paths, and access constraints
Development of constructible foundation layouts, including allowances for cable entries, grounding systems, and maintenance access zones

Outcome

The project was successfully delivered with a robust, compliant, and constructible foundation design, enabling:

Safe support of critical solar farm infrastructure
Efficient construction across a large and geotechnically complex site
Long-term performance under variable environmental and soil conditions

Incon contributed to the delivery of a high-capacity renewable energy asset, supporting sustainable power generation in regional Queensland.

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