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Architects and Engineers Express Doubt About Bloomberg’s Windmill Proposal
Interviews with architects, engineers and energy experts on Wednesday suggest that Mayor Michael R. Bloomberg’s proposal to place wind turbines atop the city’s skyscrapers and bridges, as well as off the coastline of Queens and Brooklyn, would be complicated and expensive and barely begin to meet the growth in demand for electricity that is expected in the coming years.
“The smaller turbines that he’s talking about almost don’t pay in terms of kilowatts per hour produced,” said Daniel Karpen, a Long Island engineering consultant who has studied the feasibility of wind power. “He’s going to need money to build them, and then you end up with a tremendous amount of red tape. It’s a nightmare.”
The thought of making the most of a clean, bottomless resource like wind is certainly an attractive one. But the challenges of harvesting that resource in a densely populated city like New York are manifold, which is why several initiatives to experiment with wind in recent years have not taken flight.
Skyscrapers would have to be designed — or retrofitted at great cost — to accommodate the extra weight, vibration and swaying of the turbines. Insurers would have to be persuaded that turbines are worth the risk. And New York is not a particularly windy city, so a few buildings facing New York Harbor might be the only sites that make sense.
Even if Mr. Bloomberg could find investors willing to build turbines capable of generating 1,000 megawatts of electricity, experts said, operators of the city’s grid would be able to count on only 100 megawatts, or less than 1 percent of peak demand.
Solar panels, by contrast, can be put on an array of structures and are active on hot, sunny days when electricity use is high. (New York is windiest on winter nights, when demand is low).
“New York is really a solar city,” said Anthony Pereira, chief executive of altPower, a company that helps design, develop and install solar and wind power and is a member of the Alliance for Clean Energy New York, an industry group.
Mr. Pereira said that some solar panel installations could pay for themselves in four years, compared with as many as 25 years for small wind turbines.
Speaking on Wednesday in Washington Heights, the mayor said that his proposals for wind power were only the “very beginning” and that “if you don’t ask, you’re never going to find out” whether new ideas make economic sense.
“Windmills are no panacea for our problems, but they can help,” he said, a day after making his proposal in a speech at the National Clean Energy Summit in Las Vegas. “No one thing will fix the problems we have created over the years.”
The mayor said that he saw windmills off the shore of Blackpool, England, where they appeared as dots on the horizon. But the track record for such projects in New York is spotty.
Last year, the Long Island Power Authority’s proposal to build dozens of windmills off Jones Beach was shot down because the projected costs skyrocketed and the cost of electricity from the turbines would have been at least double that of power from traditional sources.
Wind turbines have been used at a handful of sites in New York City, including Battery Park City and 34th Street at the East River. They have been installed at the Brooklyn Navy Yard site and soon will be placed at a commercial building in the Melrose section of the Bronx.
A serious consideration of harvesting wind energy on New York’s skyscrapers and bridges, however, requires the abandonment of any fanciful idea about installing windmills on the Empire State Building or the towers of the Brooklyn Bridge.
First of all, it is unlikely that any existing structure would be able to withstand the extra swaying, twisting, vibrating and weight that turbines impose. So the tower’s structural framework would have to be retrofitted to handle the new loads, adding enormously to a project’s cost with relatively little yield.
Second, the familiar windmill or wind farm turbine has a horizontal rotor with radiating blades. These would pose a tremendous liability in the city, where a flying blade could do great damage. (Five people were killed in 1977 by a helicopter blade that snapped off atop what is now the MetLife Building on Park Avenue.)
There are vertical-axis wind turbines, some of which resemble giant food processor blades, that can collect wind from any direction and have been the choice of several architects who considered wind farms for the city.
Eight vertical wind turbines were integral to the original design of the new 1 World Trade Center, also known as Freedom Tower, by Skidmore, Owings & Merrill. They would have been situated within an open-air, cable-framed structure at the tower’s upper reaches, though they were never envisioned as a major power source.
“It would have been a small but identifiable portion of the building’s needs,” said Carl Galioto, a Skidmore partner. “We were hoping that, at peak capacity, it would have been enough to power the elevators. If it were able to do that, it would have been rather impressive.”
The turbines would also have served as a symbolic representation of perpetual renewal, certainly a meaningful theme at ground zero.
But Gov. George E. Pataki expressed concern about the danger the blades would pose to migrating birds, and others worried about them icing up. Before these issues could be resolved, the New York Police Department raised objections to the tower’s overall security provisions, compelling a redesign that abandoned the wind farm notion.
More than 30 vertical wind turbines, each about 50 feet tall and 12 feet in diameter, were included in the Kohn Pedersen Fox design of the stadium proposed for the New York Jets on the West Side.
“They were designed to capture the prevailing winds from the Hudson River,” said Trent J. Tesch, a senior associate principal at the firm. He added that their presence within the industrial-looking facade would have “expressed the frenetic energy of what was happening inside.”
In combination with photovoltaic cells, Mr. Tesch said, the plan called for the turbines to produce enough power to satisfy all the stadium’s needs when a game was being played and to generate energy for other users when the team was not playing. The stadium project was scuttled in 2005 when legislative leaders in Albany failed to support it.
Kohn Pedersen Fox is proposing an array of vertical turbines for an exhibition hall called the Ubiquitous Life Building in New Songdo City, South Korea. These would collect the wind that hits the building’s facade, forcing it to cross the rooftop. “They don’t necessarily have to be incredibly high up to be productive,” Mr. Tesch said.
Urban turbine farms might be productively situated at industrial sites around New York Harbor, where they could take advantage of low-rise surroundings and wind off the water, Mr. Galioto said. And there are other ways of collecting wind energy in large structures. Skidmore is working on the 71-story Pearl River Tower in Guangzhou, China, where the exterior walls of the mechanical-equipment floors are shaped into enormous scoops to direct the wind into turbines inside. These will generate energy for the heating, ventilating and air-conditioning, the firm said.
“There’s an example of building design,” Mr. Galioto said, “where wind power is integrated within the building and one doesn’t need all sorts of fanciful contraptions appended to the top.”
http://www.nytimes.com/2008/08/21/nyregion/21wind.html?ref=nyregion&pagewanted=print
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