APB 350 Autonomous PowerBuoy, New Jersey









New Jersey




Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player



OPT's first Mark 3 PowerBuoy® was successfully deployed at sea in April 2011 by a team including Scotland-based Global Maritime Scotland Ltd, Port Services (Invergordon) Ltd, and OPT, with the support of the Cromarty Firth Port Authority. The Mark 3 is the largest and most powerful wave power device designed by OPT to date and has concluded its ocean trials.

PowerBuoy tow out

The ocean trials were conducted at a site approximately 33 nautical miles from Invergordon, off Scotland's North East coast, and lasted six months – three months more than planned.

  Deployed PB150B1


A broad range of operations and functional tests was performed, examining the response of the PowerBuoy’s structure and mooring system to the waves and the power produced by the onboard generator. An on-board system simulated grid-connection conditions. A wave data buoy located near the site provided detailed information regarding incoming waves. Data collected during the trials were transmitted from the PowerBuoy in realtime for analysis by OPT’s engineers in both the UK and the US.

Wave conditions encountered during the ocean trials included storm waves, and electrical power generated by the Mark 3 has included peaks of over 400 kilowatts. Average electrical power of 45 kilowatts was generated at wave heights as low as 2 meters. These levels of power exceeded OPT’s expectations of performance for this first Mark 3 deployment, and verify that the system could produce significant energy in higher wave conditions.

The power take-off system’s performance also exceeded expectations with respect to its energy conversion efficiency in the irregular ocean wave conditions encountered. Using information received during the trials, OPT’s engineers calculated the power levels that should have been achieved by the Mark 3 and analyzed these against actual power generation. The result of this process confirmed the Company’s ability to predict accurately the PowerBuoy’s performance in varying wave conditions.

Mark 3 Float Assembly

Mark 3 Bridge Assembly

Spar transport from Nigg to Invergordon

Mark 3 just prior to deployment in Scotland





Off Invergordon, Scotland


Environmental consents obtained
Ocean trials concluded

Total Generating Capacity:

Peak generator capacity of 866 kilowatts




Buoy Specification:

Mark 3


Ocean trials, including grid-connection simulation

Major Components:

One Mark 3 PowerBuoy with mooring system and onboard grid simulator





Ocean Power Technologies

Development Partner:

Scottish Government


Mark 3 PowerBuoy on quay at Cromarty Firth