FEATURE
9 October 2025
Lexi Richards: The young engineer helping to power New Zealand’s renewable future
Lexi Richards gets a thrill every time she’s driving along State Highway 5 just north of Taupō.
The landmark geothermal steam rising above the land pinpoints her place of work at Mercury’s Ngā Tamariki Geothermal Station.
“Even when I’m not driving to work and just passing by with friends and family in the car, it’s a cool landmark to point out and say, yeah, that’s the power station I’m helping to upgrade.”
Lexi has always been passionate about the environment and sustainability. She wanted to find a career path where she could combine those passions with her interest in engineering.
“The renewable energy sector looked to be an exciting option for me and the summer internships through Mercury provided a gateway for practical work experience.
“But engineering is just one option because there are a bunch of trades involved in the generation sector; it wouldn’t be difficult for anyone interested to find a role that fits.”
Lexi Richards is a graduate mechanical engineer working on the Ngā Tamariki Geothermal Power Station expansion near Taupō.
She liked the notion that the decisions she makes every day help to ensure the expansion project at Ngā Tamariki is a success, and in the long term, it will provide more affordable, renewable energy for the country.
“That’s what excites me about working for Mercury. I know that my contribution is helping to develop a renewable energy sector that has an important role to play in ensuring we have a secure energy supply.
The Ngā Tamariki expansion project involves adding a fifth generating unit to the geothermal power station. It will add another 46MW, boosting installed capacity to 132MW.
It will shift the average annual output of the station by 390GWh, to 1120GWh. The increase will be enough to power an extra 55,000 average homes.
In total, Ngā Tamariki will be able to supply enough renewable energy to power the equivalent of 158,000 homes when the expansion is completed.
The decisions Lexi makes every day ensure the expansion project remains on target.
Construction started in 2024 and first generation of the new unit is expected by the end of 2025. Full generation will be in early 2026.
Lexi began work as a graduate mechanical engineer on the expansion and in mid-2025 was appointed project engineer – mechanical.
Her role is to ensure the mechanical aspects of the project are completed correctly.
“That involves reviewing the technical engineering documents for the project.”
“If changes are needed, I can make decisions on how to develop solutions and present them to contractors and consultants for input.”
Lexi grew up in Christchurch, but Rotorua is her home now. She splits her time between working at Mercury’s Rotorua office and at Ngā Tamariki.
Many of the project team also live in Rotorua while others live in towns which neighbour the power station near Taupō or in South Waikato.
Lexi's role varies. It can involve conducting economical evaluations to managing upgrades of components as part of the plant expansion.
Everyone involved is committed to ensuring the project is a success, not just for Mercury, but for the country, the communities and customers that Ngā Tamariki will help keep powered.
“We have a mixture of people who have worked on the tools and others who have come from a university background, and we are all learning from each other to help make the project a success.
“It’s a chance to work with a variety of people to help improve my technical knowledge and project management skills.”
She said Ngā Tamariki is a “bustling environment” to work in during the expansion project.