Engineering giant ABB has won an order worth $800 million (£496m) for a subsea power line to connect the grids on either side of the Moray Firth in Scotland.

The Switzerland-based firm will design, engineer, supply and commission the Caithness-Moray transmission link, which is scheduled to come into operation in 2018.

The subsea cable will be capable of carrying up to 1,200MW of electricity – equivalent to the power needs of around two million homes – between Caithness and Moray.

The deal with SSE’s network arm Scottish Hydro Electric Transmission comes after energy regulator Ofgem ruled there was a need for the power link.

Claudio Facchin, Head of ABB’s Power Systems division said: “We are pleased to support this major transmission project that will enable integration of a significant amount of renewable energy into the grid and supply clean, emission-free electricity to millions of people.”

It is said to be the largest investment in north Scotland’s electricity network since the hydro development era of the 1950s.