An interesting, if somewhat belated post on urban wind power:
You don’t usually think of cities as prime sites for wind turbines, but Eastern Wind Power (EWP), a manufacturer of vertical-axis wind turbines (VAWT), is evaluating installations on 10 Boston high-rises.
Chicago, justifiably, has earned the moniker, “The Windy City,” but Boston is even windier, EWP notes. The company has installed Onset Computer Corp. weather stations atop two buildings, according to a June 14 press release, including 60 State St. and the Massachusetts Eye and Ear Infirmary. Connected to the Web, the weather stations will provide EWP the data it needs to assess the potential for its VAWTs to cost-effectively produce clean, renewable electrical power for on-site use. Assessments for the remaining eight high-rises are expected by 2013.
Getting a Handle on Wind Speeds at Elevation in Boston
Wind energy’s power potential is proportional to the cube of its speed. As such, obtaining accurate, comprehensive readings on wind speed over time are critical to evaluating possible sites, EWP explains. The Department of Energy estimates that an average wind speed of 5.6 meters/second, about 12.6 mph — which is about the average in Boston — has almost twice the energy available as a site with a 10 mph average.
At the utility scale, wind turbines keep getting bigger, with the latest models slated for use in offshore wind farms capable of generating as much as 6 MW of electrical power. In contrast, vertical-axis and small-wind turbines are “Lilliputian” in scale, Eastern points out. The vertical-axis design and much smaller footprint of EWP’s 50-kW VAWT makes installing them in densely built-up urban areas feasible, however.
Another important aspect of EWP’s plan to install its VAWTs on Boston high-rises is that wind speeds increase substantially with elevation. At 509-feet, the 60 State St. building isn’t Boston’s tallest, but EWP expects encouraging data from the weather station it has installed there.
Based on a site study conducted atop MIT’s Green Building in Cambridge, EWP estimates that a Sky Farm array made up of 10 of its 5-kW VAWTs erected atop a 500,000-square-foot high-rise could cut purchased grid power by 10%. A single Sky Farm installation would generate around 45,000 kWh of clean, renewable electricity per year, sufficient to power six to eight homes, EWP says.
“One turbine can power a building’s electrical emergency/backup, eliminating the need for a diesel generator,” commented EWP president Jonathan Haar. “It can also produce more usable energy than a 10,000-square-foot solar photovoltaic array.”
EWP has been working with Siemens to improve its generator and inverter. A working prototype was installed at Martha’s Vineyard Airport in 2010 and is now grid-connected and generating electricity.