New Zealand's largest solar array will be built on top of a sewage treatment pond on Auckland's North Shore.
Auckland's electricity and water utility companies - Vector and Watercare, respectively - said the panels will be installed on the Rosedale facility near the Northern Motorway.
Vector Group CEO Simon Mackenzie and Watercare Chief Executive Raveen Jaduram said the system could generate enough power over a year to run the equivalent of 200 average New Zealand homes for a year.
Mr Jaduram called it "is a fantastic example of how utilities can work together for the benefit of their communities".
The project is the first floating solar array confirmed for deployment in New Zealand, and the first megawatt-scale system as well.
It will involve about 3000 floating pontoons and more than 2700 solar panels.
The project is due to be installed by the first quarter of 2020.