Atlantis has redeployed two Andritz Hydro Hammerfest turbines at its 6MW MeyGen Phase 1A tidal array in Scotland’s Pentland Firth.

The Edinburgh developer said two of the three Andritz turbines had been successfully reconnected and have recommenced power generation to the grid following.

The third Andritz turbine will be reinstalled during the next workable neap tide in August.

The turbines were removed in the spring to "implement system enhancements derived from the lessons learned during installation and subsea commissioning," said Atlantis.

A fourth turbine – an Atlantis AR1500 unit – retrieved in the spring will be redeployed with the third Andritz turbine next month.

Atlantis said the device was removed to assess the effects of a prolonged grid connection outage, which was caused by damage to part of the onshore power distribution network near the MeyGen site. 

The cable damage has since been repaired and the site's grid export capacity has been restored.

After assessment of the turbine it was decided that one of the components of the turbine's pitching system should be replaced and upgraded as a result of the exposure to "an unexpectedly long idle cycle". 

Following redeployment, the turbines will enter into their final contractual performance and autonomous reliability tests after which they will be signed off for commencement of long term operations.  

It is expected that MeyGen Phase 1A will be operating autonomously at full 6MW capacity by the end of September.

Atlantis chief executive Tim Cornelius said: “We expect this to put the project on track to achieve capacity factors significantly in excess of 40%.

"We expect to be generating at full output from the end of Q3 and for the suppliers to fully hand over the turbines to the project operating team shortly thereafter."

Image: AR1500 at MeyGen 1A (Atlantis)