ESS will perform boulder clearance and pre-lay trenching before the cable is installed. Once ABB's cable is in place, ESS will bury it to protect the cable.
The Scotland-based company is expected to begin operations in December 2016. The 1.2GW Caithness-Moray cable is owned by utility SSE. It will carry renewable energy from the north to the south of the contract. Construction of a first substation near Caithness in northern Scotland began in January.
ESS completed boulder clearance at Dong Energy's 210MW Westermost Rough offshore project in January. The company said, depending on the final scope of the work, the £1.2 billion (€1.6 billion) contract would be the company's largest ever received.
In December, SSE awarded the £460 million (EUR 580 million) contract for the subsea cable system to ABB.
ABB will design, engineer and install the 160-kilometres of cabling between a substation in Keith, Moray and another converter at Spittal in Caithness. The link will travel under the Moray Firth.