Cape Sharp Tidal Inc. has unexpectedly announced plans to retrieve its OpenHydro test turbine from the turbulent waters of the Minas Passage, near Parrsboro.

The turbine was lowered into the sea nearly five months ago and the company says it has been producing electricity and is performing well.

However, Cape Sharp says it needs to make “minor repairs and upgrades” to the Turbine Control Centre (TCC) attached to the machine’s subsea base. The modifications will be made after the turbine arrives in Saint John, N.B. and the company says it will then be taken back to the Minas Passage for re-deployment.

In a statement released today, Cape Sharp adds that the earliest tidal window for raising the 16-metre, 1,000 tonne turbine will occur between April 15 and April 20.

Sarah Dawson, who speaks for Cape Sharp, says the same modifications will be made to the TCC on the second turbine that is still in Saint John awaiting deployment. She says the company is planning to deploy that second turbine sometime this year.

Buggy equipment

OpenHydro Turbine Control Centre

Cape Sharp describes the TCC, which is about the size of a school bus, as a component that transforms electricity produced by the generator into alternating current that is compatible with the Nova Scotia Power grid.

The TCC allows multiple turbines to transmit power from the sea to the grid using a single underwater cable. It also sends operational and environmental sensor data to shore through a subsea cable.

The company says it’s the first time this technology has been used anywhere in the world.

Meanwhile, in its first quarterly environmental report, Cape Sharp says another piece of equipment is not operating properly. Technicians have been unable to communicate with a video camera mounted on the front of the turbine.

And although other monitoring devices have been functioning, the report says retrieving the turbine will provide an opportunity to investigate problems with the camera, re-position sonar devices used to detect fish and marine mammals in the vicinity of the turbine and inspect other devices.

In 2009, the blades on a smaller, but similar OpenHydro turbine were smashed within 20 days of turbine deployment, but Dawson says that this time, the blades have not been damaged.

FORCE environmental report

The Fundy Ocean Research Centre for Energy (FORCE), which oversees the tidal test site, also released its quarterly environmental monitoring report today.

Highlights include:

• The turbine does not appear to have affected fish density, but more sampling is needed;
• A high frequency of harbour porpoise were detected at the site before turbine deployment, but at low rates (only seven minutes per day) and in few numbers. Analysis of data collected after turbine deployment is underway;
• Seabird monitoring included nine shore-based surveys in 2016, with two completed after the turbine was installed. Patrick Stewart, president of Envirosphere Consultants, notes: “Overall the number of birds observed at the site was lower than expected based on earlier baseline surveys, and reflects normal year-to-year patterns of bird abundance unrelated to activity at the FORCE site.”