Wind Turbine Troubles By Dr. Jimmy Tragle, Part I

Part I

Increasing concern about the environment has been emerging over the last few years and attempts to decrease green house gas emission are being put forth. The installation of large industrial wind plants has been occurring at an increasing rate over the last few years as one attempt to bring one cleaner source of electricity to meet growing demand. This push for placing large numbers of wind turbines in various locations has been met with resistance and support and the disagreement between both factions is growing stronger. This is becoming a relevant issue for Delaware as there is talk of placing an offshore facility in the waters off the Delaware coast. Several topics will need to be considered in order to form an informed opinion.

Both sides have been busy compiling a list of myths they claim the other side has put forth to support its position.

Before going on I must confess that at one time I thought wind energy was a good idea. After extensive reading on the subject I am no longer of that mind. I make no apologies for this as I am certain my bias will show through most if not all of the time.

First a little about the wind turbines themselves. The current trend is to build taller wind turbines. Modern turbines use a pole type tower, usually three blades, and a generator situated atop the tower that the turbines are attached to. The generator is housed in a structure known as a nacelle. The generator contains several hundred gallons of oil for lubrication and cooling. Blades on the some of the newer ones are about 135 feet in length and the hub height for the nacelle is in the neighborhood of 265 feet above the ground. The blades on such a turbine will sweep an area from 130 feet above the ground to 400 feet above the ground (or ocean surface for offshore turbines). That translates to each turbine covering an area a bit greater than one acre in the blade swept area. The blades tend to turn relatively slow, around 15 to 20 revolutions per minute (RPM) at optimum speed. For perspective this will give a blade tip speed somewhere around 180 MPH. Nacelle and blade assemblies usually weigh in excess of 90 tons.

Modern turbines have a nameplate capacity of around 1.5 to 2.0 MegaWatts (MW). For Comparison there is a nuclear fired plant in California that generates 555 MW.

Nameplate rating refers to what the generator would produce if the wind were blowing at optimum speed all the time. Turbine proponents claim about a 30% factor on this issue and experience in other countries with larger numbers of them has been limited to about 15 to 16%. Depending upon which figures used a 1.5 MW turbine will produce either about 0.5 MW or 0..24 MW on average. The reasons for this reduction are that below optimum wind speed production falls off and above optimum wind speeds turbines must be locked down to prevent damage.

For an installation to be worthwhile on a commercial basis there must be several turbines situated on it. I believe a minimum of 20 or so, and developers tend to prefer 40 or more.An attempt is made to site turbines in areas where winds blow often enough to validate siting. This may include vast open stretches or ridgelines extending above other topography, and of course coastal waters. Each of these locations will have peculiarities specific to layout patterns, but there is a minimum distance between them in terms of placing them on a site. Turbines cannot be placed close together as the efficiency will be lost if they are too close together. I believe turbulence off the blades is a big factor. As an example I know of a siting proposal on a ridge in West Va that amounts to 44 1.5MW turbines covering a 6.4 mile stretch of ridge line. One must realize that additional acreage is demanded for transmission lines to get the power to a substation (17 miles for this project) and access roadways.

Battles rage over many issues and with Joe's grace along with any evidence of interest I'll bring those forward bit by bit over the next few days or weeks. Those issues include:

I. Impacts on wildlife, livestock, and humans. These can further be divided into construction phase issues as well as operational phase issues.

A. Construction issues:

1. Damage to cave ecosystems.
2. Damage to spring water sources.
3. Forest habitat destruction and fragmentation.
4. Water runoff due to forest clearing.
5. Carbon emissions due to manufacture, transportation, and construction of turbines and their components.

B. Operational events include:

1. Blade strikes to birds and bats.
2. Blade throw and other accidents.
3. Noise pollution - various sounds emitted from a variety of sources.
4. Strobe effect - light reflection off blades when the sun is near the horizon.
5. Shadow flicker - shadows from blades when the sun is near the horizon.
6. Stray voltage - issues primarily for livestock in situations where metal objects like gates and fences may cause electrocutions when animals contact them.

II. Property Values

A. Altered viewsheds.
B. Health effects.

III. Whether or not the turbines can actually contribute to the production of electricity on an appreciable level. Electrical grid complexity and wind intermittence are key concepts.

IV. Economical Controversy surrounding the development of industrial wind facilities.
A. Availability of temporary jobs to local workers.
B. Availability of permanent jobs to local workers.
C. Financial advantages for local municipalities and county governments.
D. Tax incentives for developers.