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Book Reviews

April 15, 2010
Paul Gipe

Urban Wind Energy--A Review

Urban Wind Energy by Sinisa Stankovic, Neil Campbell and Alan Harries is a slick book, in the positive sense, with a colorful, modern layout and lots of illustrations. Earthscan didn't skimp on production quality and send the book off to China like so many others--they actually printed it in Great Britain.

I feared the worst when I saw the title. As an outspoken critic of so-called "Urban" wind and especially the British variety, I thought the book would be destined for the dust bin after the first page. But I was wrong--and not the first time. The adage should be not to judge a book by its title. In this case there was enough in the book about what I call real urban wind to keep me reading.

Nevertheless, one of disturbing themes of the book is integrating renewable energy technologies into buildings, in this case, wind turbines. Solar yes, wind no.

The authors are all principles in BDSP Partnership, a consulting company specializing in building services and energy efficiency. Through their firm they have been the principle academic and engineering proponents of "urban" wind energy through a grant from the European Union to study "Wind Energy in the Built Environment".

Fortunately, they at least included some working examples of real urban wind that makes sense like the turbines in Hull, Massachusetts, or the famous WindShare turbine in downtown Toronto.

There also are ever useful sidebars on estimating the energy in the wind and what a "typical" wind turbine will generate at an average annual wind speed of 5.5 m/s. However, their assumption that typical modern turbines operate with a coefficient of performance of 30% is optimistic at best and grossly overestimates what small wind turbines will actually deliver. It's as though they've been so busy promoting urban wind that they haven't bothered to measure those urban wind turbines that have been installed.

There are three categories of integrating wind into urban environments, say the authors: small wind, large-scale stand-alone turbines, and building-integrated turbines. Where I differ with the authors is in the first and last categories. Large-scale wind turbines in urban environments can make sense. However, "building integrated wind turbines" is simply an architect's wet dream and the examples given are sufficient proof that this is a dead-end strategy except as way to earn architectural commissions. Small turbines in urban environments--often placed on rooftops--are another example of a how hard it is to kill a bad idea.

To the authors' credit they acknowledge the problems with rooftop small wind. For example, "standard walls and chimneys are not built to withstand the types of prolonged stresses originating from a turbine mast. . . they could pose a real safety threat . . ." No kidding.

And they go on to warn that the "misuse of 'small wind'" can cause unnecessary damage to not only the movement for urban wind but to wind energy in general.

Yet the authors' tie themselves in knots trying to justify their support for rooftop wind when they say "Despite the lack of widespread applicability, there is still some potential for home-mounted wind turbines and the subject is still worthy of discussion." Is it? Or is the subject simply worthy of more consulting fees to write reports on why the last batch of rooftop wind did so poorly, but the next batch will be better?

For example, on page 37 where this passage occurs, the authors argue that a 2 meter diameter wind turbine at a 5.5 m/s site "can generate about 40%" of the demand from a typical three-bedroom British home. First, no 2-meter turbine has done that yet. Second, there's no evidence that any rooftop turbine has ever seen 5.5 m/s average wind speed. Thus, the conclusion is extremely unlikely.

On the same page in Figure 2.3 the authors show a Proven 6 kW on a short tower among trees! Urban wind my eye. That's just greenwashing.

On the preceding page, a Windsave is shown below the roofline on a home in Scotland. The photo is by Stewart Russell who uses the picture to illustrate the folly of "building-mounted" wind turbines on his personal web site. Not the kind of photo you want to use to show urban wind in the best light.

And the examples of "urban wind" in the book just get worse. On page 40, Figure 2.4 there's another Proven on a short tower at a BP station backed by a multi-story hotel-greenwashing by a company that's a master at it.

On page 43, Figure 2.7, there is Skystream in San Francisco that rises to just above the rooftops. The authors report that at this "windy location it is reported to produce around 600 kWh per month." In the writing business that's about as non-factual as you can get. It's akin to reporting rumors or hearsay. For perspective that's 7,200 kWh per year. Southwest Windpower "reports" that the Skystream will produce 7,200 kWh per year at an average wind speed of 7.5 m/s or nearly 17 mph! That's one hell-of-a-rip-snorting site for San Francisco. The authors, in their zeal to find something good to say about rooftop wind, have been snookered by either Southwest Windpower's well-connected PR firm, or fellow architects.

Under the category of large wind, the authors need to get up to speed by spending more time on the continent. They note, "Long-term experience in large-scale turbines in urban areas is still currently lacking . . ." This is simply not true. There are reams of data on "urban" wind turbines in Denmark and Germany and now in Canada and the US.

To their credit, the authors do come to their senses eventually. "From the number of successful installations of large-scale wind turbine seen in urban areas over recent years it is becoming increasingly clear that the potential for significant wind energy generation on our doorstep (where the energy is required and consumed) could be high." Indeed, this is the only application of "urban wind" that makes sense and there is sufficient promise in it to justify all the architects and "urban wind" fans to start doing something productive that could provide real benefits.

But these early chapters are just the warm-up for the architectural wonders-or nightmares--of the future under the rubric of "building-integrated wind turbines". Let's just say, several of these wonders were designed by the authors' very own BDSP. The drawings and visualizations are stunning even if laughable from a practical perspective.

One concept, the three turbines inside the World Trade Center in Bahrain, was actually put in place in 2008. The question now, and it should be the question asked anytime such proposals are splashed across glossy architectural magazines is, How much have they generated? And a series of related but probably more telling questions are, Are they still there? Have they been removed? Are they still operating? The answers to those questions will say more about "building-integrated" wind than all the books and architectural studies ever will.


Part I: Wind Energy in Context

Part II: Urban Wind Energy Potential

Part III: Urban Wind Energy Feasibility Study

Part IV: Turbine Technology

Part V: Building Integrated Wind Turbines

Urban Wind Energy by Sinisa Stankovic, Neil Campbell and Alan Harries, Earthscan, 2009, 234 x 156mm, 200 pages, $97.50, cloth, ISBN 9781844072828.

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