The facts about wind turbines 

We read with interest Billy Weitzenfeld’s essay regarding wind farm development in Floyd County (“First, gather facts on wind farms,” Feb. 26). We agree with the need for an informed citizenry wherever wind farms are proposed but particularly in our mountainous areas. Wind energy can and does displace fossil fuel energy, and has value. The intermittent nature of wind energy, however, restricts the ability of the wind turbines to fully meet customer needs for reliable service.

Ridge-top installations required to gain exposure to higher wind speeds also result in major environmental impacts. Any proposed projects should be carefully examined to determine if the value of the energy produced justifies the environmental impacts that will occur.

Energy value: It is important to understand that electricity is produced essentially as it is used. For that reason there must be a continuous balance between production and usage for the electrical system to remain reliable. This requires that all generators supplying power to the network must be capable of instantaneously changing the amount of generation to match changing customer loads and providing spinning reserve sufficient to make up for unexpected outages.

Since wind turbines have little, if any, ability to vary output to match load variations or provide for spinning reserve, they must contract with an owner of a fossil fuel unit to provide these services. The average capability of a wind turbine over a year is generally 30 percent or less of its potential maximum capacity while capability during the peak load periods in the summer averages 13 percent and at times is zero during the peak periods.

Environmental impacts: Wind farms create major environmental impacts, including bird kills, impact on property values and noise levels.

Although less frequently discussed, the access roads required impose the greatest impact, in our opinion. A typical wind turbine with a capacity of 2 to 2.5 megawatts will use blades of approximately 165 feet in length. To prevent the trailer hauling these blades from hanging up on the road surface, the longitudinal slope must be held relatively constant with no significant bumps. A road 36 feet wide in straight sections (16 feet of the 36 feet to be graveled) would be typical. Interstate traffic lanes are 12 feet wide, so we are talking about the equivalent impact of clearing and grading more than one side of an interstate highway to each of the wind turbine locations.

In addition to the transport of the structures, blades, turbines and cranes, numerous trips by concrete trucks, drilling rigs and foundation material haulers will be required. The typical structure to support the turbine is more than 250 feet in height with foundations 15 feet in diameter and 20 feet in depth.

The visual impact of ridge top installations is of great concern. Considering the wind turbines will reach heights of approximately 400 feet, or three times as high as the typical 765-kilovolt tower, be spaced at intervals of approximately 700 feet and utilize tubular steel poles with diameters of 13 feet or more, there is no question that there will be an extremely adverse impact to the entire view shed.

Tradeoffs: Comparing the energy contribution to the environmental impact, let’s assume a wind farm capable of producing 1 percent of the energy consumed by Appalachian Power customers in 2010. Using the most favorable sized wind turbine (2.5 MW) and the 30 percent capacity factor, the wind farm would require 59 turbines to be installed. At a 700-foot spacing interval, nearly 8 miles of ridge line would be impacted.

Is 1 percent of Appalachian’s power supply worth 8 miles of severely impacted mountains?

We believe that the better locations for wind turbines would be flat lands or similar locations where the impacts are minimal.

An even better answer would be to locate the wind farms offshore off the East Coast. Offshore installations not only can provide energy with minimum impact but also reduce the need for additional transmission lines. The offshore technology exists and is being used in Europe.

Simmons is a consultant and retired Appalachian vice president. Tanger is chairman of Friends of the Rivers of Virginia. He lives in Hollins.