Wind Power Handbook

By Timlynn Babitsky
We hear a great deal about wind farm development and even more about off-shore wind projects, but what’s being done on the urban wind scene? Are there wind projects afoot that will change the urban landscape?

Back in the 1970s a small Jacobs windcharger was installed on a tenement roof in Bronx, New York. The Bronx project succeeded. It proved that rooftop generated electricity could be fed back into a utility’s network without destroying the network, the building, or the city. And then the project was dismantled. What is the status of urban wind development today?

On the “can’t do it” side are wind experts like Paul Gipe. He has long claimed that rooftop mounting of wind turbines to capture urban wind is just not feasible for several very good reasons.

Turbines vibrate, and even strong commercial built-to-withstand-anything buildings will ‘feel’ those nasty ‘vibes’. If, like Jay Leno, we are mounting a turbine on a building that will only house our rare automobile collection, the vibrations are probably not a problem. But for homes, offices and other people-populated spaces, those building vibrations could jangle the nerves worse than a 4th cup of morning coffee. Has the vibration issue been resolved in today’s rooftop turbine designs?

Wind turbulence is another rooftop wind power problem. Ask any sailor about wind shadows and turbulence and they will tell you about the river of wind that flows unseen (but rarely unfelt) around and about every structure (natural or human-made) on the planet. Every building interferes with the natural flow of the wind, much like stones and rocks affect the flow of water in a stream. The building itself, the rooftop itself will affect the turbine’s operation by interfering with the natural flow of wind about the blades.

If a wind turbine is raised high above the roof line, the problem can be mitigated. But can the roof of the building and the building itself support the extra loads created by the wind turbine, the tower and the pull of the wind turbulence affecting both? Are tall turbines mounted on tall rooftops the only solution to rooftop turbine design?

Those are serious issues and unless today’s turbine designers have addressed these problems, the outlook for rooftop wind power projects looks rather bleak. Yet, several turbine manufacturers claim that they have at least part of the solution to the problem of capturing wind at the rooftop level without the past problems of vibration and noise. We’ll look into several of these in upcoming posts.

Is VAWT design an obvious answer? In several previous posts on my Wind Power Handbook blog site I take a look at small versus tall turbines and vertical axis wind turbines (VAWT) versus horizontal axis designs (HAWT). We’ll look into the current state of both in upcoming posts.

There are two bright beacons on the US urban wind energy horizon – converting urban brown fields into urban wind farms and New York City’s ambitious wind power agenda to populate the city’s rooftops, bridges, and skyscrapers with wind turbines to generate electricity.

“When it comes to producing clean power, we’re determined to make New York the No. 1 city in the nation,” claims Mayor Michael Bloomberg.

“If rooftop wind can make it anywhere, this is a great city,” claims New York City’s director of the Office of Long-Term Planning and Sustainability. “We have a lot of tall buildings.”

So is rooftop mounting of wind turbines feasible today or not? Has turbine design changed enough recently such that rooftop wind power is a real urban energy possibility today? What is the real viability of New York City’s urban rooftop wind agenda and the very interesting idea of converting urban brown fields into urban wind farms? Stay tuned as we do some deeper-digging homework and please do not hesitate to weigh in with a comment, a pointer to an interesting project or your general feedback on any of these issues.

With so much excellent wind power available in cities across the US,  can we really afford to drag our feet developing audacious means to tap and harness it?

As outspoken “green activist” Ted Turner said on Sunday’s Meet the Press interview, “…The days of fossil fuel are over.”