A Rhode Island project vying to beat out Cape Wind as the first offshore wind farm in the U.S. hit a major roadblock this week, a sign of the tough technical and economic issues developers face as they go farther offshore.
The state's Public Utilities Commission on Tuesday blocked a power purchase agreement to purchase electricity from an eight-turbine installation off the coast of Block Island. Regulators ruled that the proposed purchase price--24.4 cents per kilowatt-hour in 2013, which is almost double the retail rate in the state--was too high, a move which casts doubt on whether the project will move forward.
Cape Wind, meanwhile, on Wednesday announced plans to purchase 130 turbines from Siemens Energy. Developers of the controversial project are still negotiating a power purchase agreement with utility National Grid and are waiting a ruling on final federal approval from Interior Secretary Ken Salazar later this month.
Having seen the oppositionto Cape Wind, other wind developers are choosing to go farther offshore and into deeper waters, as they did in Rhode Island. That helps address complaints over the visual impact of wind mills, but it also adds to the technical complexity and cost of offshore wind, according to experts.
"The clear trend has been for projects proposed in federal waters (farther off shore). Part of that is due to wind resources and part of it is due to an effort to minimize opposition," said Matt Kaplan, an analyst at Emerging Energy Research. "The clear trend has been to minimize the visual impacts as much as possible."
The proposed location of Cape Wind--in the Nantucket Sound south of Cape Cod--was chosen as much for its wind resources as its waters depth. Building on a shallow shoal in the middle of the sound would allow construction crews to use monopile foundations, which work in depths of about 75 feet. This technology is used in hundreds of locations in eight European countries.
By contrast, the Rhode Island project, which had been pushed heavily by the state's governor, would have required a different type of foundation suitable for deeper waters. Wind developer Deepwater Wind in August last year installed a barge to test the ocean floor in advance of plans to install its jacket foundation, which can operate in 150 feet of water and doesn't require special vessels to transport components to offshore sites. … Read more