The Atlantic Wind Connection (AWC) project off the US east coast could be the first ever offshore Multi-Terminal HVDC (MTDC) network. When completed, AWC could transmit 6,000-7,000 MW of offshore wind power to shore, enough to supply more than 2 million US homes. According to plans all permits are expected to be in place by 2013, the first of five construction phases would be completed as early as 2016 and the complete network could be in place by 2021. There seems to be consensus that a MTDC network in Europe will not materialize before after 2020.
The AWC project will include the following facilities:
- Nine offshore and seven onshore nodes with voltage source converter (VSC) stations. Each offshore node is rated 500-1,000 MW.
- Two independent HVDC circuits totalling more than 1,200 km of circuit length, mostly located between 16 and 29 km offshore. Each circuit contains two power cables operated at 320 kV DC voltage, and a fibre optic communication cable. The transmission backbone is split in two to avoid faults in one circuit affecting the other.
AWC is a cheaper and more flexible Solution
The Brattle Group calculates the project cost to approximately $5 billion and says it would be far cheaper than connecting each wind farm to shore with independent cables. The flexibility in routing wind power to different market areas and relieving onshore transmission congestion are both strong arguments in favour of the project; A 2009 US DOE Congestion study deemed the Mid-Atlantic region a “Critical Congestion Area”.
Partly funded by Google
The project is led by independent transmission company Trans-Elect with Atlantic Grid Development as the project developer. Financial backing is provided by Google (37.5%), Good Energies (37.5%) and Marubeni Corporation (15%). The US Mid-Atlantic Bight holds potential for up to 60,000 MW of offshore wind power in relatively shallow waters, and the U.S. government this year announced four zones for offshore wind energy development in the area. The 450 MW NRG Bluewater Wind project off the coast of Delaware and scheduled for 2016 could be the first to connect to the AWC transmission backbone.