Here is an excellent article by Brian Braginton-Smith.  I take issue however with his opinion of Building Integrated Wind Turbines which can be quiet with no vibration and very aesthetic.   A web link is provided for all to review the new field of SOLARTECTURE    RZ.

Distributed Architectural Renewable Energy Generation

Brian Braginton-Smith Executive Director Sustainable Resources Group

In today's energy marketplace professionals and planners are lamenting the looming potential of wholesale energy supply shortages. Issues concerning the growing energy supply demands include every sector from the long term availability of non-renewable fossil fuel resources to issues relating to transmission and distribution constraints and limitations. In many areas of the world it is not the availability of generation but the availability of transmission capacity to wheel the power around from where it is generated to where it is needed that is the issue.

The potential costs associated with increasing the efficiency of and expanding the capacity of transmission and distribution infrastructure, are staggering and difficult to get financed. Another potential facet of the energy supply scenario is the concept of distributed generation, on the village or consumer level. A facet of this venue has become known as architectural or building integrated energy, this article will discuss renewable energy specifically.

The Return of Distributed Generation

This distributed generation model existed prior to the establishment of the national electrical grid network, before power companies and transmission and distribution were initiated in the early 20th Century by federal programs such as the Rural Electrification Administration and regional entities like the Tennessee Valley Authority. Distributed generation as a resource lost the debate, as fossil fuel costs were low and the promise of nuclear generation with rates too low to meter, were promised.

Distributed generation has long been the domain of the solar industry where small scale solar thermal arrays and photovoltaics (commonly known as PV) are installed at consumer locations where direct retail offset of the retail energy supply is accomplished. This distributed generation provides a venue for the mitigation of centralized plant supply shortages and transmission and distribution infrastructure constraints. The world of consumer based supply technology has been quietly evolving as centralized plant facilities and technologies have taken center stage.

Today, with the demand for electricity growing and aging and insufficient transmission and distribution infrastructure becoming a serious concern for everything from the basic availability of power to the reliability of the centralized grid, distributed generation as an alternative resource in its own right has become a topic of interest, discussion and debate. It is also a topic for discussion as we contemplate the potential for renewable energy supply for the urban environment or for areas where demographic density limits the availability of open space and inversely impacts the cost of land. Unlike rural environments where large tracts of relatively inexpensive open land are available for the installation of large scale wind energy, or centralized power facilities a shortage of available vacant land renders the utility scale model difficult and costly. Hence, the potential importance of distributed structure mounted generation, as an alternative resource.

According to recent publications by the British Wind Energy Association, distributed renewable energy generation in small scale solar and wind energy resources represent a significant potential electrical supply opportunity for the built environment. In the urban environment the potential to incorporate renewable energy into building architecture represents a vast untapped marketplace.

An Urban Resource?

Building integrated solar co-generation systems such as the Dawn Solar building integrated products, present a substantial opportunity for enhanced efficiency while also reducing the amount of energy required to be supplied by the grid. These technologies are also important components in achieving key green building criteria. As solar technologies have evolved they have gone from crude boxes attached to the roof to nearly invisible substrate components which turn the roof into the solar collector.

This “architectural” approach of blending the resource into the building structure has a number of advantages including reduced wear on the technology and improved aesthetics and roof systems integrity. Cost is the only serious disadvantage of the distributed consumer based capacity. Where the commercial or utility cost of a kWh of power is around 6 or 7 cents, the kWh of small scale installations can be closer to 18 to 25 cents. However, the overall efficiency of point of use generation provides obvious benefits in the elimination of T&D costs and losses. Government incentive programs can also have a dramatic impact representing drastic reductions in the overall final installed costs which can bring the real cost of energy to within the range of present retail electrical rates providing a reasonable return on investment while increasing our renewable energy supply.

Building integrated micro-scale wind energy generation or architectural wind energy technology has been a much different scenario. Where solar panels are relatively passive in their performance while converting the radiant and light energy to alternative energy, wind energy is a mechanical process with the collateral impacts of the mechanical process of turning the wind into energy such as noise, vibration and ultimately conversion efficiency. Unlike sunlight, wind energy depends upon a variable resource which is much more complex. Wind variability includes the turbulence of the air impacted by terrain and structures including the structure to which it might be mounted. Due to these issues, the discussion regarding architectural wind energy has also been a very short debate. However, as the wind industry has grown, technical innovation and mechanical efficiency have improved dramatically in all aspects of the field including small wind turbine design.

Ed. Note.   Building integrated energy systems will require substantially different wind turbines than what the author is suggesting.   For a review of some of this SOLARTECTURE please visit:  http://www.synergyii.com/synergyca/GLOBAL%20POWER%20SOLUTIONS%20from%20Reinholdi.pdf

One innovative design which has emerged as a leader in this new field of architectural wind energy is the Swift turbine developed by Renewable Devices of Scotland. The Swift turbine utilizes a patented blade design which incorporates a five bladed configuration within an aerodynamic ring diffuser. The ring diffuser has a dramatic impact on a number of key areas which had been concerns for the growth of structure mounted wind in the past including vibration and noise. In fact the impacts of the elimination of the noise issue, have just begun to settle in, in the planning debate regarding building mounted or architectural wind technology. According to a U.K. study the Swift turbine design which boasts an acoustical footprint of 35db throughout the wind spectrum makes the Swift turbine quieter than the background noise of a typical urban environment. The ring diffuser also has a quieting effect on the vibration, due to the blades being connected at their root and tip to a common structure. The ring also eliminated the wing tip vortice a key ingredient in noise, vibration and turbine efficiency.

Ed. Note.  What is needed is a machine that does not have to track the wind.   This type of machine is a vertical axis rotor which can also be mounted horizontally.

Renewable Devices, has recently completed negotiation with Cascade Engineering of Grand Rapids, Michigan to manufacture the blade assemblies for Swift turbines worldwide. Cascade is also the North American distribution company for the Swift structure mounted technology. The first US voltage Swift turbine was installed in September, 2007 at the Cascade manufacturing facility in Grand Rapids, Mich., and a national technology validation is presently underway with installations planned for a number of locations to validate the production and performance of the technology. Through technology breakthroughs such as these, distributed building integrated renewable energy could become an important part of the growing renewable energy market while also helping to improve the scenario confronting energy industry planners as we come to grips with our aging infrastructure issues and how to effectively wean ourselves from our dependence upon conventional imported energy supplies.