Two of the issues that come up frequently when discussing wind energy options are the noise and the actual output of the turbine.
The noise issue is more of a problem for big turbines. They may look majestic from far away, but when you live nearby they can make a bit of noise. People have also complained about health problems as a result of the turbines, but there are conflicting opinions in the medical field as to the real effect of the turbines on health. Interestingly, research has shown that the noise only bothers certain people in certain locations. For example, a quiet island might have more complaints than a busy suburb. Urban wind turbines are in a unique situation because they are smaller units that exist in a louder environment, but are also much closer to other residents.
As for the actual output of the turbines, it depends on who you talk to.
One tech firm, The Archimedes, has designed an urban solution to the problem with wind turbine noise, based on the real (Ancient Greek Mathmetician) Archimedes’ screw pump design. It looks a little wonky, but the 165 pound, 5-foot turbine is designed to eliminate blade noise—it lacks the traditional blades—while putting out an impressive energy yield. By impressive, I mean that this seems too good to be true. The company says its Liam F1 Urban Wind Turbine has an energy yield that is “80 percent of the maximum that’s possible.” According to gizmag.com, most conventional turbines produce between 25 to 50 percent, so take the promise with a grain of salt.
The circular design means the turbine is able to swing to whichever way the wind is blowing, and that it produces much less noise than traditional blades. The company says the turbine is capable of producing an average of 1,500 kilo-watt hours of energy per year at a wind-speed of 5 m/s. The company asserts that equals about half of the power consumption of a common household. That being said, the U.S. Energy Information Administrationputs the average U.S. household consumption at 10, 837 kWh/year. Louisiana has the highest at 15,046 kWh and Maine had the lowest at 6,367 kWh. However, the global average is around 3,500 kWh, so that might be the number they’re using or the number might be based on a typical Dutch home in the Netherlands, where the company is based.
So to answer the question: This might shave off a chunk of your bill, but it’s not going to be half of it (unless you up and move). There are definite benefits to a roof turbine, but the numbers are a little off for the average U.S. household. The Liam F1 will hit the American market on July 1st with a price tag of just over $5,400.
It's important to note that the urban wind turbine isn't hugely popular in most of the United States with typically larger homes and high energy usuage. However, for an apartment in an urban setting it might actually eliminate quite a portion of the electric bill, given that the bill itself will be smaller than in a traditional house. The usage number broken down by dwelling-type don't exist--please send them along if you find any--so it will be interesting to see if this is a viable option for people living in cities.