• Media release
  • 23 Apr 2022
  • 2 min read

Underwater drone ensures safer hydro tunnel inspections

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  • Underwater drone ensures safer hydro tunnel inspections

The days of sending people deep underground to inspect hydro power station tunnels may soon be over as Genesis Energy tests new survey technology using a submersible drone.

Genesis has 70km of tunnels around its power stations at Tongariro, Waikaremoana and Tekapo – one measuring 19km, the longest hydro tunnel in the southern hemisphere. The tunnels need to be checked every 10 years for safety and performance. In the past this has involved draining the tunnels before driving a team through them to take photos in dim light, with complex communication systems to ensure the inspection teams were safe.

This was not only a safety risk, but also a struggle to ensure the tunnel interiors were accurately checked for damage and debris. It also took the local power station out of action for up to 13 days.

But in March a successful trial of a submersible drone was run in a 3km tunnel in Tongariro, connecting the undergound Rangipo Power Station to the Tongariro River. The 500kg machine attached to a tether travelled the length of the 4.5m-wide tunnel taking photos and 3D sonar recordings, mapping the tunnel’s interior and gathering detailed data. The tunnel did not require draining, the machine was remote-controlled from the surface, and the inspection was completed in less than a day.

Genesis’ Chief Operations Officer Rebecca Larking says the successful trial marked a significant step change in the safety of tunnel inspections.

“Ensuring the safety of our people and communities is paramount. This technology will ensure we can complete all our tunnel inspections to a high level of assurance, without creating safety risks associated with being in tunnels for our staff and contractors. The reduced inspection time also means our plants can resume generating electricity for New Zealanders sooner.”

Genesis will now work with the drone’s operator, Hibbard Inshore, to survey other hydro tunnels around its power schemes.

Media contact


Estelle Sarney


External Communications Manager



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