After Cape Wind, deep challenges for offshore wind
As people wait on federal approval regarding Cape Wind, offshore wind developers are planning other projects farther offshore, adding to the cost and complexity.
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 too high, a move which casts doubt on whether the project will move forward.. 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
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 from Interior Secretary Ken Salazar later this month.
Having seen theto 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 theas 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.
There are other proposed offshore wind farms going through the permitting process in the U.S. Bluewater Wind, for example, is seeking to develop an offshore wind park 13 miles off the coast of Delaware, which the company expects will be difficult to see from on shore.
But as developers go farther out to sea, they face greater problems dealing with the less mature technology, which is one of the primary barriers to offshore wind, according to the American Wind Energy Association. That's why, despite growing activity around offshore wind in the U.S. and Europe, analysts expect it to take five years or more for offshore wind to make a significant contribution to wind power overall.
"Deeper water technology is more of a long-term play," said Kaplan. "Economics is a huge issue for offshore, especially compared to onshore, as is getting permits, and getting the construction vessels that can do the projects."
He forecasts that offshore wind will contribute about 4,000 to 5,000 megawatts of capacity by 2020 in the U.S., with most of the contribution starting after 2015. By contrast, last year the U.S. onshore wind industry in the U.S. was about 9,800 megawatts of capacity. One thousand megawatts is roughly the output of a nuclear power plant, although output from wind turbines varies with the wind.
Drama to unfold this month
Despite the technical challenges, offshore wind, whether it's in shallow or deep water, has great potential in the U.S. The Department of Energy estimated that offshore wind could generate 54,000 megawatts of a total 300,000 megawatts by 2020 if there was an aggressive push in wind.
One of the main appeals of offshore wind is that the wind tends to blow harder and steadier offshore than onshore. In the U.S., offshore wind has garnered most interest in the Northeast where electricity prices tend to be higher than other regions and there's a lot of demand. Transmission is potentially simpler and less expensive if offshore wind parks are placed closer to demand loads, compared to transporting electricity over long distances, according to the AWEA.
Although turbines can be bigger and the wind is stronger offshore, the additional costs of construction, permitting, and maintenance make offshore wind about 30 percent to 50 percent higher than onshore wind, according to research company SBI Energy.
Technology is advancing to address some of the problems of building in deeper waters. There are different foundations being tested for water up to 150 feet deep, called jacket and tripod foundations. Also, Siemens last year installed a "floating" wind turbine that'sat a depth of over 700 feet.
General Electric last year
In the U.S., though, much of the focus is on Cape Wind, a project which has become something of a symbol for the country's efforts to adopt renewable energy at large scale.
This month should be eventful: the federal Advisory Council on National Preservation in two weeks is expected to provide a recommendation on the historic and cultural importance of the area to Native Americans. Negotiations over a power purchase agreement between National Grid and Cape Wind, which have been delayed, are also expected. Salazar has said his final decision on permitting, due some time during April, will weigh the national push for renewable energy and historic preservation.
In an attempt to find a compromise, opponents of Cape Wind have called for moving the wind farm to a different location south, rather than north of Nantucket Island. But that location has deeper water, making the project more technically difficult. It would also send Cape Wind developers back to the beginning in the permitting process after almost nine years and $40 million in preparation.
"Cape Wind is sort of indicative of the offshore wind at the moment," said Emerging Energy Research's Kaplan. "There's still uncertainty as to how the industry will move forward and overcome challenges."