The 21-year-old Manapōuri Power Station mechanical fitter graduated with a New Zealand certificate in mechanical engineering (trade level 4) from Te Pūkenga Ara Institute of Canterbury this week.
She is now "living the dream" in her underground work place 230m below Lake Manapōuri, but admitted it has been a long and winding road to get to this point.
"All through school I worked hard," Miss Frewen said.
"I wasn’t a standout, but I kept at it and I never really had a celebration of my achievement - so graduation is huge for me.
"I’ve dedicated four years of my life to this."
Miss Frewen said she grew up in a workshop environment and was always tinkering with cars.
She took engineering at Twizel Area School and jumped into projects such as building a hovercraft and a jet boat.
After participating in the "Girls with Hi-Vis" introductory programme through Connexis Infrastructure Training, her eyes were opened to large-scale engineering.
She said the path to her dream job began with a Meridian Energy gateway programme at the Ohau chain of stations (on the upper Waitaki River) while still at school in Twizel.
One of the things she loved so much about the profession was being one of very few women in it, and she counted herself as "a bit of a ground-breaker underground".
"I’ve only encountered a couple of women contractors in my time so far, but I have noticed a lot more women in the electrical engineering field."
Working all day under fluorescent lights at Manapōuri, the work could be complex and physically demanding, but it ticked all of her boxes, she said.
"Working with cars is fiddly and difficult. The sheer size of what we deal with at the power station is so much easier.
"We don’t have tight awkward spaces, and the cranes and equipment we use can lift hundreds of tonnes. It’s so impressive.
"In short, I work underground all day on the mechanical components of the generating equipment for the Manapōuri hydro-electric station — everything from minor repairs to major overhauls.
"It’s honestly different every day."
