Construction of Østerbø hydropower plant - planning and executing with ROVs

Wednesday, March 4, 2020 / Nykjevatnet, Bjordal, Norway

Sogn og Fjordane Energi Produksjon AS (SFE) is progressing with Østerbø power plant construction in Sognefjorden, Norway. The Blueye Pioneer underwater drone is surveying geology and monitoring probe drilling and planning blasts in the reservoirs. The use of brand new technology in conjunction with 3D modeling of geology has produced outstanding results for the project.

From Pilot to Professional Client

Blueye met SFE for the first time in early 2018 during a demonstration of the Blueye Pioneer prototype here in Trondheim. SFE quickly envisioned the different applications with the underwater drone and joined a pilot program before the Blueye Pioneer officially launching to the market. SFE has used the underwater drone in the construction of Østerbø powerplant after the pilot program. During the project, they've learned how valuable photogrammetry from an underwater video is.

SFE and their Blueye Pioneer underwater drone
SFE and their Blueye Pioneer Photo: Sogn og Fjordane Energi

SFE has mainly used underwater drones to survey geology and results from probe drilling and reservoir blasts at 75 meters depth at Nykjevatnet in Sogn og Fjordane. The planned completion of a fully operational hydropower plant is by the summer of 2020.

SFE in their boat at Nykjevatnet
SFE in their boat at Nykjevatnet Photo: Sogn og Fjordane Energi

To watch the actual explosion from 700 kg dynamite to create the opening between the mountain and the water, SFE used the Blueye Pioneer. Even though the tunnel pressure got too excessive and pulled it into the tunnel (see video), they managed to capture footage of great value for future projects. We also learned that the underwater drone handles a blast that forceful - pretty impressive!

Blueye Pioneer in the water at Nykjevatnet
SFE equipped the Blueye Pioneer with extra 10 000 lm lights Photo: Sogn og Fjordane Energi
Probe drilling at Nykjevatnet
Probe drilling at 77 m Photo: Sogn og Fjordane Energi

3D Photogrammetry from underwater video

Utilizing photogrammetry software to create 3D models from an underwater video has been carried out by SFE themself without special training.

This enables knowledge acquisition relatively cheap and easily accessible. Surveying using underwater drones and 3D modeling is groundbreaking and has not been used in this type of work, as far as I know. - Øystein Kristiansen, Analyst, SFE

3D photogrammetry of probe drilling
3D model of probe drilling holes By: Sogn og Fjordane Energi

The significant advantage for SFE by creating 3D photogrammetry was to get an overview of the volume and distances by using the drill holes as reference points. The recorded sound (from GoPro mounted on the drone) also enabled SFE to disseminate information about air pockets in the mountain - which had to be filled before the explosion.

Watch our video tutorial on how to create 3D photogrammetry models from underwater video.

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