By Rona Cohen
Last Friday, the Gulf of Maine became host to North America’s first grid-connected offshore wind turbine, as part of a performance test for an innovative floating technology that proponents hope will advance an industry that has struggled to gain a foothold in this country.
The prototype was designed by the University of Maine’s AEWC Advanced Structures and Composites Center, which for the last five years has led a public-private consortium dedicated to developing floating turbines designed to operate in the deep waters of the Gulf of Maine. The consortium aims to make offshore wind energy cost-competitive with conventional sources of electricity in less than ten years.
The consortium, known as DeepCWind, has received funding from the U.S. Department of Energy, the National Science Foundation, the State of Maine, and more than 30 industry partners. The project’s researchers and engineers at the University of Maine have worked closely with Statoil, which designed the world’s first floating turbine off Norway’s coast in 2009, adapted from technology used in deep-water oil and gas drilling.
Floating turbines are considered better suited than conventional ones for power generation in the Gulf of Maine, where the steadiest winds flow some 20 miles offshore in waters 60 to 90 meters deep — depths at which installation of conventional turbines is considered impractical. Proponents say that finding a cost-effective way to tap Maine’s abundant sea breezes could transform its economy, attracting more than $20 billion in private investment to the state and creating thousands of jobs. Maine residents typically send $5 billion a year out of state to pay for the fossil fuels that heat and power their homes and businesses. That amount is roughly 60 percent higher than the state’s annual budget.
While the U.S. lags far behind European countries in cultivating ocean-based wind, studies have documented the existence of powerful coastal air currents which, if harnessed, could produce enormous quantities of clean power for U.S. residents and industry.
The U.S. Energy Department has pegged the nation’s total offshore wind resource at 4,000 gigawatts (GW), roughly four times the current generating capacity of the entire electric grid. The Obama administration has set a goal of producing 54 GW of offshore wind power along the U.S. coastlines, the Gulf of Mexico and Great Lakes by 2030.
If the government’s ambitious vision is to be realized, a principal obstacle that must be surmounted is cost. The price tag of a typical ocean-based wind farm can easily top $1 billion. Capital costs are steep, and so is the cost of capital, due in part to the risk associated with building and maintaining massive turbines in uncertain ocean conditions.
These high costs are reflected in the power purchase agreements inked in recent years in conjunction with offshore wind projects in various stages of development in Massachusetts and Rhode Island. Prices contained in those agreements have ranged from 19 to 25 cents per kilowatt-hour (kWh), with annual price increases. Currently, electricity prices in New England average 14 cents per kWh, according to recent data from the U.S. Energy Information Administration.
Using turbines constructed with its floating technology and durable composite materials, the DeepCWind Consortium hopes to dramatically lower the cost of power derived from wind power at sea so that it can eventually compete with other forms of electricity without subsidies, says a press release from the University of Maine.
At a conference hosted by CSG/ERC in October 2011, Habib Dagher, a professor of civil and structural engineering at the University of Maine who directs the AEWC Advanced Structures and Composites Center, explained that the simplest design being experimented with is a spar buoy, which is basically a floating tube tethered to the sea floor. Installing it in the water involves a process that is akin to taking an empty water bottle and filling it halfway with sand, which causes it to stand up.
The unique floating design should enable developers to avoid the higher costs associated with installation of conventional turbines in European countries, where the standard practice is to use jack-up barges to install a turbine in the ocean floor – at a cost of $200,000 to $300,000 per day.
Through the experience gained from the current test turbine and a larger, 12 MW pilot project the University of Maine expects to deploy with industry partners in 2016, the consortium hopes to eventually reduce the cost of power from offshore wind in Maine to 10 cents per kWh by 2020.
The prototype turbine deployed last week is 65 feet high, produces 20 kilowatts of power and is one-eighth the size of a 6-megawatt turbine. The full-size turbine would stand nearly as tall as the Washington Monument, and each blade would be longer than the wingspan of a Boeing 747 airplane.
The turbines are composed of composite materials to avoid rusting, and were designed to be able to have a useful life of up to 100 years.
Under former Governor John Baldacci, Maine established a goal of deriving 500 MW of its electricity from turbines deployed offshore by 2020, and by 2030, deploying a series of floating wind farms capable of producing 5 GW – equivalent to the output of five nuclear power plants.
The turbines would be placed more than 20 miles offshore, where the curvature of the earth would prevent people from seeing them from land.
The technology that the University of Maine is developing is transferable to shallower water, and could potentially be deployed elsewhere on the East Coast, in the Great Lakes and on the West Coast, Dagher said during the 2011 conference.
If the Maine project proves successful, it could help propel dozens of projects in the Northeast and elsewhere, which have been proceeding slowly in recent years. Thirty-three offshore wind projects have been announced across the U.S., and of those, nine totaling 3,380 MW are considered to be in advanced stages of development, though none are yet under construction. All are aiming for completion by 2018. At least 13 states have formed panels or task forces to engage stakeholders to identify constraints and sites for offshore wind, says a recent report commissioned by the Energy Department.
The report, from Navigant Consulting, Inc., claims that an offshore wind industry could support up to 200,000 manufacturing, construction, operation and supply chain jobs across the country and drive over $70 billion in annual investments by 2030.
Globally, there are approximately 4 GW of offshore wind installed, the bulk of it in Northern Europe, which has been deriving power from ocean-based wind since 1999. The pace of development has been accelerating: there are forecasts that capacity there will quadruple to 16 GW by 2016. In recent years, the industry has gained a foothold in China, which currently has about 200 MW of offshore wind. China has also announced plans to dramatically increase installations, to 5 GW by 2015 and 30 GW by 2020, says the Navigant report.