A proposed transmission backbone that would send offshore wind energy to major metropolitan areas from New Jersey to Virginia has received a boost with the addition of Elia, a Belgian-based transmission system operator.

Elia joins Google, Marubeni, Good Energies and Atlantic Grid Development in the project, which is expected to be as long as 350 miles and will cost an estimated $5.5 billion. The Atlantic Wind Connection project is the first high-voltage direct current offshore line to be developed in the U.S., and will enable an integration of up to 7 GW of offshore wind.

Off the coasts of New Jersey, Delaware, Maryland and Virginia, the backbone will have interconnections with the existing land-based transmission system, enabling the transmission of up to 2 GW between its onshore terminals and reinforcing the existing onshore grid in the Mid-Atlantic.

According to a press release posted on the Elia website, the company acquired from AGD a strategic 10 percent minority participation in the first segment and a 5 percent minority participation in the four other segments of the AWC project. The Elia Group is the fourth largest transmission system operator in Europe and operates the electricity transmission system in Belgium and the electricity transmission system in the northern and eastern part of Germany through its daughter company 50Hertz Transmission.