Watercare Services – Solar Feasibility and Implementation
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Watercare Services
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Pacific Energy
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Auckland, New Zealand
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Feasibility and business case development for PV deployment across 14 water and wastewater sites
Overview
Watercare Services is New Zealand’s largest water and wastewater utility, serving over 1.7 million Aucklanders with more than 400 million litres of water and treating over 409 million litres of wastewater every day. In alignment with its 2017 strategic goals for business excellence, cost efficiency, and environmental sustainability, Watercare sought to reduce its energy use and increase operational resilience.
Pacific Energy was engaged to help identify, evaluate, and prioritise renewable energy projects across 14 facilities — ultimately contributing to Watercare's transition toward energy neutrality and smarter infrastructure investment.
The Challenge
Watercare's strategic objectives included:
Reducing energy usage by 8 GWh by 2020
Achieving energy neutrality at key wastewater treatment plants
Improving resilience and operational efficiency
To support this, Watercare needed clear, data-driven evaluations of renewable energy opportunities — with a focus on financial performance, technical feasibility, and minimal operational disruption.
Pacific Energy’s Role
Pacific Energy led a structured and rigorous feasibility process, delivering:
Site Assessments: Conducted site visits to all 14 locations to identify viable areas for solar PV deployment and assess integration into each site’s existing electrical infrastructure.
Solar Resource Profiling: Compiled 10 years of hourly NIWA climate data from the nearest weather stations to build detailed solar generation profiles for each site.
Economic Optimisation Modelling: Developed a novel approach to determine optimal PV system size — using NPV as the primary optimisation criterion. The model considered the difference between offsetting on-site electricity costs versus exporting surplus power at lower buy-back rates.
Techno-Economic Analysis: Evaluated energy generation, capital costs, IRR, payback period, and carbon mitigation for each site.
Business Case Development: Developed detailed investment cases for three high-performing sites:
Two were selected based on superior economic return
One was selected on resilience criteria, incorporating a large battery energy storage system to enable nine months of energy self-sufficiency
Results and Impact
The three initial solar projects were approved by the Watercare board.
Their successful delivery gave Watercare confidence to proceed with the largest floating solar array in New Zealand (1MW), installed on the retired oxidation ponds at Rosedale.
Outcomes achieved:
170 MWh of clean energy generated annually
22 tonnes of CO₂ emissions avoided per year
Over $20,000 in annual energy cost savings
Simple payback of <10 years
These projects reinforced Watercare’s position as a forward-thinking utility, committed to financial responsibility, sustainability, and operational resilience.
About Watercare Services
Watercare is a council-controlled organisation serving Auckland with safe, sustainable water and wastewater services. With a strong focus on environmental performance, the organisation plays a critical role in shaping Auckland’s sustainable infrastructure future.
About Pacific Energy
Pacific Energy is a New Zealand-based engineering consultancy focused on renewable energy, embedded generation, and industrial energy optimisation. We provide full-lifecycle project support — from feasibility to delivery — helping both public and private sector clients navigate energy transitions with clarity, technical rigour, and independent advice.
