One offshore substation platform with two 230 kV power lines is appropriate to transmit to shore every 500 MW to 700 MW of wind power capacity constructed off the coast of Virginia, according to a new report conducted by ABB Power Systems Consulting at Dominion Virginia's request.
The study evaluated the offshore transmission options to support future projects and built its recommendations on a 2010 study that looked at potential onshore interconnection options and upgrades needed to support offshore wind generation projects. According to Dominion, the studies complement each other, as transmission lines from the four recommended offshore service platforms would likely be routed to two separate onshore interconnection points.
The report acknowledges the potential cost savings that may be achieved through construction of offshore transmission infrastructure completed in stages with a potential for standardization. The approach also limits the potential for stranded transmission investment as offshore wind farms are constructed, according to Dominion and ABB.
The report estimated that the cost for each offshore service platform, its equipment and submarine transmission cables would be approximately $652 million.
Dominion is planning to respond to the U.S. Bureau of Ocean Energy Management's call for information for wind generation in about 113,000 acres of leasing areas approximately 24 miles off the Virginia coast.
The company has a $500,000 grant from the U.S. Department of Energy to work with partners and find ways to reduce the costs of offshore wind generation.