PROJECT OF THE MONTH
Wind power used to be the domain of energy corporations and off-the-grid conspiracy theorists, but recent product innovations are bringing it from its rural origins to the urban landscape. Size, noise and cost have come down dramatically in the last ten years, making owning a wind turbine possible for concerned citizens.
A wind turbine is a fan blade connected to a generator, turning the kinetic energy of wind into electricity. There are hundreds of different designs, but two main types: the horizontal axis turbine (think desk fan) and vertical axis turbine (think ceiling fan). The Joe-consumer designs come in all different scales—from a three-foot diameter fan mounted to a building to a 12-foot diameter fan atop a pole towering 35-70 feet off the ground.
People are seeking out wind power for a number of reasons: a drive for self-reliance, reduced energy costs, a smaller carbon-footprint or escape from the guilt of oil-based energy. A 15 kWh turbine supplied with 12mph+ average winds can reduce a household's energy needs by half and keep 1.2 tons of airborne pollutants and 200 tons of greenhouse gases out of the air over its lifetime.
After years of incubating in the labs of universities across the world, companies have spawned and products are just now being released to meet the emerging demand for wind power. The products have become smaller, more efficient, quieter and easy to install, but there is one achievement that trumps them all—"net metering." It's the ability for the wind turbine to connect with your household (or commercial) power meter. In times of no wind, power will draw entirely from the utility grid, but as the wind blows, the power consumption will slow or reverse, letting the household sell its energy back to the grid. Selling back to the grid provides a much faster payback on investment (approximately 5-20 years).
It's not all warm summer breezes for wind-driven power. Applications for wind power have to be seriously considered before installation, or turbines will become expensive lawn ornaments. First, the wind "resource" has to be calculated. Does the land/building see enough wind to justify a wind turbine? Average winds generally need to be above 12mph to begin to see significant power generation. If wind exists, then where should the turbine be placed? Turbulence from buildings and trees reduces power generation. Systems like the Skystream 3.7 are placed on posts and recommend installation 20 feet above the tallest object with a 250-foot clearance radius (). That's not going to happen in many Seattle neighborhoods, for instance. Noise has been greatly reduced through better propeller design, but during operation expect to hear at least +5db above ambient noise. Zoning, permitting and utility agreements will take time and work, but web resources exist to help with the process (www.awea.org/smallwind/toolbox2 and www.awea.org/smallwind/Washington.html). Interference with birds and bats is also a concern, and while studies are sparse, it is agreed by the manufacturers that collisions occur.
While wind power has traditionally shied away from commercial buildings, new innovative designs are embracing them. For those new to aerodynamics, a box isn't a wind-friendly form. Its edges and planes create turbulence, making it difficult to draw sustained winds through turbines. But this challenge hasn't deterred companies like Aerotecture and Aerovironment from developing systems that are intended for commercial buildings in urban environments. These companies employ multiple turbine units that run along the roof edges of the building to capture the deflected wind energy.
There are other big dreams shedding the constraints of past designs, such as the Magenn Air Rotors (www.magenn.com). Their design comprises a helium-filled balloon with finned rotors that spin on an axis tethered via wire to the ground. It's a stunning solution that Magenn hopes to ship by 2010.
Another non-traditional concept was inspired by the Tacoma Narrows Bridge collapse. Shawn Frayne has developed Windbelt generator technology, which works like a blade of grass fluttering in the wind. It uses an oscillating movement to create energy without a turbine. Its simple, compact form makes it a prime candidate for urban energy generation. Honolulu-based Humdinger Energy is still developing Windbelt technology and likely licensing the technology to companies in the years to come (www.humdingerwind.com/#/windbelts_worldwide/).
Wind energy in the urban environment is under intense development. There is a new urgency created by the political instability and environmental consequences of oil or coal-based energy. While progress is being made, given the dense spacing of urban homes, the ideal product for many consumers is still in the clouds.
This article originally appeared in the Spring 2009 issue of ARCADE.
Illustration by Kristin Will.
© Copyright 2009, AROUNDTHEHOUSE
