Megawatt-Scale Floating Solar Project For NZ

A PV project in New Zealand won’t just be the nation’s largest solar power installation, but also its first floating solar farm.

Utilities Watercare and Vector yesterday announced a megawatt-scale system to be constructed atop a wastewater treatment pond at Watercare’s Rosedale facility in Auckland’s North Shore.

“It’s the first time floating solar will be seen in New Zealand and the first megawatt-scale solar project to be confirmed,” said Vector Group CEO Simon Mackenzie.

The project is close to 2.5 times the capacity of New Zealand’s current largest solar array (410kW – Yealands Estate Winery).

The release notes more than 2,700 solar panels will be used for the project, which will be installed on 3,000 floating pontoons. To reach 1MW capacity, the panels will need to be around 370 watts each.

Australia’s biggest operational floating solar power installation as far as I’m aware is still a 99kW system in East Lismore, New South Wales. The largest in the world (operational) is a 40MW facility in Huainan, China.

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Correction: The largest operational floating solar farm is a 70MW facility in Anhui Province, China that was connected to the grid in March 2019.
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Aiming For Energy Self-Sufficiency At Rosedale

The project will go towards Watercare reaching goals of reducing energy use by 8GWh by 2022 and achieving energy self-sufficiency at its Mangere and Rosedale wastewater treatment plants by 2025.

“As a large user of energy, it’s important that we look at ways of reducing our environmental footprint and becoming more self-sufficient,” said Watercare chief executive Raveen Jaduram. “Innovative solutions like this on top of wastewater ponds are a smart way to reduce operational costs”.

According to this document, the utility’s water and wastewater treatment processes consumed 165 gigawatt-hours of electricity in 2016/17. 30% of its electricity was sourced from Watercare biogas (cogeneration) and hydro facilities, meaning approximately 115GWh was supplied from New Zealand’s national grid.

Watercare’s first solar installation went live earlier this year at its Pukekohe Wastewater Treatment Plant, which is a 122kW ground-mounted array consisting of 400 solar panels. The system will generate an estimated 170 megawatt-hours of energy per year, saving Watercare up to NZ $20,000 (AUD ~ $18.7k) annually.

Watercare is New Zealand’s largest water utility, supplying around 379 million litres of water to 1.79 million Aucklanders each day. Vector is the country’s largest distributor of electricity and gas.

Trivia: Renewables accounted for 80 per cent of electricity generation in New Zealand in Q1 this year. However,  PV is still very much a bit player in the country’s energy supply, providing less than 0.2% of total electricity generation in the country in 2017 according to Energy In New Zealand 18.