A Transmission Backbone Would Make Offshore Wind More Efficient

Governor Jack Markell has floated the idea of a transmission backbone to link offshore wind power projects along the east coast. As the News Journal reports, Professor Willett Kempton and his colleagues have published a paper in support of the idea.
The paper (available here) concludes that such a backbone would be a cost effective way to smooth out the expected fluctuations in wind power:

Is transmission an economically practical way to level wind? As an approximate cost comparison, a total of 2,500MW of offshore wind generation has been approved or requested by states from Delaware to Massachusetts (all those shown in Fig. 1, plus the 700MW New York request for proposals). Connecting them by a 3 gigawatt (GW) HVDC submarine cable would require 350 miles of cable. At early European offshore wind capital costs of $4,200/kW and submarine cable capital costs of $4,000,000/mile, the installed costs of planned offshore wind generation would be approximately $10.5 billion; the connecting transmission would add $1.4 billion. They are matched in capacity, each approximately 3 GW, yet the transmission adds less than 15% to the capital cost of generation. This is in line with the market cost of leveling wind via existing generation, currently estimated to add about 10% to the cost of energy (10% cost adder for wind penetrations up to 20%, then a higher percentage cost added at higher penetration of wind).

When Bluewater Wind was first given the go-ahead to build an offshore wind farm in Delaware, a natural gas backup facility was proposed to compensate for the fluctuations in output. Kempton and others argued that a backup plant might not be necessary. Now he has some analysis to back up his opinion.