t and determined that despite deep water close to shore creating headaches for placing turbines, offshore wind conceivably could meet up to 83 percent of the state's electricity demand.
Kempton says the reliability of the North America's coastal wind resource is a happy accident of geography. A similar exercise using data from Great Britain's coastal areas suggested considerably less promising results.
Researchers on the British study observed "large power swings in a 12-hour period" during the height of winter, when the region faces its highest demand for power. From that experience, lead researcher James Oswald of Coventry University suggested that "distributed generation would not help much" in the case of the British Isles, "since most of the region experienced the same wind conditions."
By contrast, according to Kempton, from the Bermuda High to the Nor'easter, "there is almost always a pressure gradient somewhere and cyclonic events move along the [Atlantic] coast. There are a few times of low power throughout, but they are not due to any one particular weather pattern."
An energy superhighway
Kempton calls his proposed cable interconnect the Atlantic Transmission Grid, although he imagines it as an "energy superhighway." It would shuttle power between wind farms spanning 1,500 miles (2,500 kilometers) of coastline, eventually sending that power to shore wherever it is needed.
"We have a uniform grid, in a sense, already. Everything in the Eastern Interconnection is all connected together. But this would make one line that would enable us to move a lot of power north and south."
Kempton estimates the transmission system would add less than 15 percent to the capital cost of offshore wind generation and says the figure is "in line with the market cost of leveling wind via existing generation."
There are also other start-up issues that will raise the price, including a provision in the federal Merchant Marine Act of 1920 that requires the ships used to build the offshore portions to be U.S.-built and U.S.-citizen owned, ruling out use of vessels and experienced crews from Europe.
Building the entire offshore wind generation and transmission system remains a significant undertaking, something the Stanford researchers also noted in the California study. "We haven't calculated the amount of steel that would be required," Kempton said, "but we have calculated in terms of production capability, and it's on the order of 10 or 15 full-size automobile production facilities."
That industrial capacity doesn't require an equivalent intellectual ramp-up, since the transmission technology is readily accessible. "There are undersea cables exactly like the one's we're describing that connect New Jersey to New York," Kempton said, in addition, "[t]here is a long run in Europe connecting Norway to Belgium" with a 580 km cable. "It's not that we're requiring some kind of new technology."
However, Kempton concedes an offshore interconnection would be costly and that "there is no agreed upon mechanism for the company that builds it to recover their costs."
An interstate offshore interconnect might prove a bit of a conceptual stretch for electric utilities and their regulators, who have been traditionally confined to arranging their affairs state by state. But Kempton believes existing power distribution by "independent system operators" that operate on a regional basis (take California's ISO, for example) could implement the "early phases of this without any new organizations or new structures." That, he believes, would achieve some of the desired "smoothing."
Even so, caveats remain.
"If you want to go the long distances that we show in our article, then you would need some authority that would have the ability to regulate and recover costs and determine who's got the right to use and how much they should charge." He has even proposed a name for this entity: the Atlantic Independent System Operator. "It's creating a whole new institution, although it would be similar to those that operate regional power distribution systems on land."
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