The iwi decided to harness the nearby Pokaitu Stream behind the marae and divert the water flow through a culvert to three turbines and generate power.
There is capacity to install three more turbines to maximise generation up to 5kw/h - more than the marae presently needs, Eugene says.
Before the hydro was installed the marae was using around 18,000kw of power annually at around 22 cents a kilowatt, he says.
The three turbines can generate about 23,000 kw per year - slightly more than current power consumption for the marae and the associated farm trust, with the excess being sold into the grid.
The turbines are connected to the switchboard in the marae and an import-export meter installed to enable surplus power to be put into the main power grid.
Potaiku Stream, and other nearby waterways, have been historically, spiritually and culturally significant to the iwi for more than 100 years, Eugene says.
A waterwheel was installed on the stream for a flax mill, and the birds, eels and fish were used as food source.
Ngati Kearoa Ngati Tuara is one of three iwi involved in the Te Arawa River Iwi Trust assigned to help restore the Waikato River, he says.
The trust is involved in sustainable use of natural resources which fits well with the idea of installing a hydro power unit, Eugene says.
"It's not a complicated process to generate our own electricity and become independent of the national grid.
"We wanted to achieve sustainable energy generation with minimal environmental impact," he says.
Across the stream the iwi have fenced off riparian land and replanted 1000 native trees.
"If we want to be self-sustaining we have learnt you can't shake your finger at others unless you clean up your own backyard first."
For more info contact Eugene at nkntgm@xtra.co.nz.