Award-Winning Innovation in Renewable Energy Pool Heating: Second-Generation Geothermal Design at City of Joondalup Craigie Leisure Centre

Early adopters of renewable energy geothermal pool heating, Western Australian local government aquatic centres had begun to experience challenges with reduced heating capacity and increasing costs.

Craigie Leisure Centre, one of Western Australia’s largest public aquatic facilities, was no exception, with reliance on electric backup heating undermining the original sustainability objectives of the system.

Through innovative second-generation geothermal heating design, Oceanis transformed the declining 20-year-old geothermal pool heating system into a high-performance renewable asset, sextupling thermal output while avoiding bore replacement and its associated embodied carbon.

Facility Overview

The project involved redesigning heat exchangers and hydraulic configurations, implementing cascading geothermal water use to extract additional energy, upgrading filtration systems to manage fouling, and optimising thermal storage and control strategies. Delivered within a live public facility and without additional bore drilling, the rehabilitated system now produces up to 1,600 kW of thermal energy, compared to approximately 250 kW prior to remediation.

Geothermal heating systems provide environmentally sustainable solutions well-suited to the high, continuous heating demands of aquatic centres. As these systems age, declining performance is commonly interpreted as geothermal resource failure, leading to recommendations for bore replacement. The Craigie project challenged this assumption.

An investigation undertaken by Oceanis identified that the geothermal system’s poor performance was driven not by depletion of the geothermal resource, but by low-temperature geothermal water combined with frequent bore clogging arising from early construction and surface infrastructure design limitations. Redesign of the surface infrastructure of a low-temperature geothermal bore presented Oceanis with significant technical challenges.

Innovation in Design

Rather than pursuing bore replacement, Oceanis applied second-generation geothermal engineering principles to unlock substantially greater thermal value from the existing well. The innovation was not a single component upgrade, but a holistic re-engineering of the surface infrastructure and control strategy to maximise usable energy from constrained geothermal conditions.

Key innovations included:

• Cascading geothermal water use, enabling multiple stages of heat extraction from the same groundwater volume before discharge, maximising thermal yield without increasing abstraction.
• New heat exchanger design, optimised for low-temperature geothermal water to improve temperature differentials and overall heat transfer efficiency.
• Complete hydraulic reconfiguration, improving extraction rates from the existing bore while minimising system pressure drop and pumping energy.
• Targeted filtration upgrades, addressing bore clogging and improving long-term operational reliability without increasing energy demand.
• Optimised thermal storage and control strategies, prioritising geothermal energy availability and significantly reducing reliance on electrical backup heating.

Supporting these measures, an optimally sized geothermal pump was selected to match the revised system hydraulics and operating conditions.

These innovations resulted in greatly improved energy efficiency, enabling the facility to heat pools during winter with near-zero reliance on backup electric heating — all without additional drilling or expanded groundwater abstraction.

The project represents a shift from replacement-led sustainability to optimisation-led sustainability, establishing a transferable framework for extending the life and performance of renewable infrastructure in energy-intensive public facilities. The methodology developed at Craigie now informs similar geothermal projects across Oceanis’ portfolio, demonstrating replicability beyond a single site.

Sustainability Integration Throughout the Project Lifecycle

Sustainability principles were intentionally integrated throughout the Craigie Leisure Centre project lifecycle, from early investigation and planning through to design and delivery, up until the ongoing optimisation. Rather than treating sustainability as a design overlay, the project embedded environmental, economic, and operational considerations into each decision-making stage.

Investigation and Planning

Upon commencement of Oceanis’ investigation, lifecycle thinking was applied to assess alternatives to bore replacement for the underperforming geothermal system. Comparative analysis evaluated environmental impact, capital cost, operational risk, and long-term performance outcomes.

Bore replacement, which is often considered the default response to geothermal degradation, would have required new drilling, significant embodied carbon, geological risk, and major disruption to a live public facility. In contrast, surface infrastructure optimisation offered a lower-impact pathway capable of restoring and exceeding original system performance. This approach directly aligned with the City of Joondalup’s Sustainability Policy commitment to financially, socially, and environmentally responsible decision-making and to ensuring intergenerational equity in public asset management.

Design Integration

Design development translated sustainability principles into targeted engineering interventions. Oceanis designed new heat exchange systems to maximise thermal extraction from low-temperature geothermal water and reconfigured all hydraulics to improve extraction rates from the existing bore while minimising system pressure drop and pumping energy.

Optimised thermal storage and surcharge control strategies were introduced to prioritise geothermal energy availability and reduce reliance on electrical backup heating. Most critically, Oceanis developed cascading geothermal water use, enabling multiple stages of heat extraction from the same groundwater volume before discharge, maximising usable energy without increasing abstraction.

Supporting measures included the selection of an optimally sized geothermal pump and installation of new geothermal fluid filtration to mitigate bore clogging and improve long-term reliability. Each design decision prioritised extending the life of existing infrastructure while reducing operational energy demand and maintenance burden.

Delivery and Commissioning

Works were delivered within the constraints of a live public facility, with staging strategies implemented to maintain uninterrupted operation. Commissioning focused on validating thermal performance, optimising control strategies, and ensuring operators were equipped to manage the system efficiently.

Successful commissioning resulted in a step-change in energy efficiency, enabling the facility to heat pools during winter with almost zero reliance on backup electric heating, which had been required to operate for the last 18 years, and extend geothermal heating to additional building areas — enabling the city to save hundreds of thousands of dollars per year.

Ongoing Optimisation

Post-commissioning performance monitoring validates system outcomes and supports continuous improvement. This ongoing feedback loop ensures sustainability benefits are sustained in operation rather than limited to design intent, embedding long-term efficiency into day-to-day facility management.

Outcomes & Impact

The Craigie Leisure Centre geothermal rehabilitation has delivered measurable environmental, economic, and social benefits by enhancing the performance of existing renewable infrastructure.

Environmental

The project achieved a six-and-a-half-fold increase in usable geothermal thermal output, from approximately 250 kW to up to 1,600 kW, using the same bore and groundwater resource. This performance improvement has dramatically and measurably reduced reliance on electric backup heating, which had operated continuously for more than 18 years prior to remediation.

Over one year, the geothermal system achieved an estimated reduction of approximately 349.2 tonnes of CO₂ emissions relative to a conventional air-to-water heat pump system, which the facility previously operated.

These outcomes were achieved entirely without increasing groundwater abstraction, drilling new bores, or expanding plant footprint, preserving the geothermal resource while maximising its utilisation.

By avoiding bore replacement, the project also eliminated the embodied carbon associated with drilling operations, materials manufacture, and construction activities typically required for new geothermal infrastructure.

Economic

The facility now delivers annual operating cost savings of over $100,000 per annum based on typical local government electricity tariffs, driven by reduced electricity consumption and lower peak demand. External consultant assessments of the geothermal system place annual savings between $200,000 and $300,000 per annum. Over the projected 20+ year operating life of the rehabilitated system, cumulative savings are expected to significantly exceed the retrofit investment.

In addition, the project avoided the substantial capital expenditure, risk, and operational disruption associated with bore replacement, while reducing long-term maintenance requirements linked to historic clogging issues. These outcomes improve whole-of-life asset value for the facility owner.

Social

Craigie Leisure Centre serves thousands of community users each week. Improved thermal reliability enhances patron comfort, supports consistent programme delivery, ensures continuity of aquatic services during peak winter periods, and reduces operational risk for a major public asset.

Together, these outcomes demonstrate that extending the life of renewable infrastructure can deliver superior sustainability benefits across environmental, economic, and social dimensions.

Completed in August 2024, verified performance monitoring confirms material and sustained reductions in energy use, operating costs, and associated carbon emissions. The project, awarded the LIWA Aquatics 2024 Sustainability Award, demonstrates a strong endorsement of CLC’s commitment to reducing carbon emissions and Oceanis’ expertise in energy-efficient aquatic centre design.

Lasting Positive Effects Beyond the Project

The Craigie Leisure Centre geothermal remediation delivers lasting positive effects across environmental, economic, community, and industry dimensions.

Environmentally, the rehabilitated system is expected to operate for more than 20 years, delivering cumulative carbon emissions reductions far exceeding initial annual savings. By avoiding bore replacement, the project demonstrates a lower-carbon pathway for managing ageing renewable infrastructure and reduces long-term pressure on the electricity grid.

Economically, sustained operating cost reductions and avoided capital expenditure improve long-term asset value for the City of Joondalup while supporting delivery of its Environment Strategy 2024–2034 objectives.

For the community, improved thermal reliability ensures continuity of essential aquatic services, enhances user comfort, and strengthens resilience during peak winter demand periods.

At an industry level, the project establishes a proven, replicable model for rehabilitating underperforming geothermal systems. The methodology now informs Oceanis’ work at Scarborough Beach Pool, Perth High Performance Centre, Armadale Aquatic Centre, the Regina Indoor Aquatic Centre in Canada, amongst others, demonstrating transferability across jurisdictions and project types.

The project challenges the assumption that superior sustainability outcomes require new construction, demonstrating that existing infrastructure, when approached with innovative engineering, can deliver exceptional long-term performance.

In recognition of these outcomes, the Craigie Leisure Centre geothermal rehabilitation has been selected as a finalist in the Superior Sustainability category of the 2025–26 Consult Australia Awards for Excellence.