The Port of Belfast is investing hundreds of millions of pounds as it seeks to position itself to take advantage of growing demand for offshore wind.
More than £300 million (€355m) is being spent over the next five years with almost a third of it used to develop a new deep-water berth that will it allow it to expand its renewables business.
The £90m being spent on the new quay is the biggest ever capital investment project undertaken by the port.
It hopes to have it finished by 2030.
Belfast is one of several harbours on the island of Ireland hoping to capitalise on anticipated demand for offshore wind.
Cork and Foynes are both advancing plans for facilities to capitalise on renewables.
The Irish Government is committed to producing at least 5GW of offshore wind by 2030 and to fast-track offshore wind development.
The Stormont Executive has a target of 1GW, as part of a wider UK target of 50GW.
Belfast Harbour said there are 30 proposed offshore wind farms within 200km of Belfast, many of them in the Irish Sea.
"Belfast Harbour's £90m investment in a new deep-water quay will support the deployment of the next generation of floating offshore wind farms and allow us to meet the growing needs of the offshore renewable energy developers," said chair of Belfast Harbour, Dr Theresa Donaldson.
"As part of an all-island single electricity market the investment stands to benefit everyone on the island."
Belfast port is also hoping its capital spend will attract further cruise ships.
The huge ships carrying several hundred thousand passengers every year have become an important part of the city's economy.
