The contract requires A2SEA to install 49 MHI Vestas wind turbines, each producing 8.3MW of electricity.
The company will carry out the work using its Sea Installer installation vessel, which has been purpose-built for such engineering projects.
A2Sea CEO Jens Frederik Hansen said: "As pioneers of offshore wind installation and with Denmark as pioneer country, we are proud to be chosen to install Horns Rev 3.
"We look forward to working with Vattenfall on this project, and I am confident that our team of experienced employees both onshore and offshore will deliver on time, on budget and most importantly in a safe manner."
Horns Rev 3 is an extension of Horns Rev 1 and 2 wind farms, which are owned by Vattenfall and built by A2Sea in 2002 and 2009 respectively.
It is the latest extension to the wind project located 20km off the shore of Esbjerg in Denmark. The location for the project was identified in 2011 and Danish government approved the project in 2012.
Tender notices were given in October 2013 and Vattenfall won the bid for construction in 2014.
The monopile structures will go at least 10 to 20m below the seabed and the diameter of the rotors will be about 146m. The wind farm will be spread across in an area of 144km2.
The offshore wind farm will be connected with 3 onshore cables with an average length of 45km. It is expected to reduce more than 570,000 tonnes of CO2 and 13,000 tonnes of SO2 of emissions every year.
The project owner, Vattenfall is confident that when the construction of Horns Rev 3 is complete and its starts its operations, the average cost of power production would come down to as much as €0.1031 per kWh.
Image: A2Sea wins contract from Vattenfall to assemble wind turbines at Horns Rev 3 offshore wind farm. Photo: Courtesy of A2SEA A/S.
