What is an RPS?
An RPS is a Renewable Portfolio Standard. It is a state law that requires retailers of electricity to purchase a certain percentage of their power from renewable resources, including wind. The retailers, however, can purchase their renewable energy from whatever sources they wish, and this has the effect of encouraging the most cost effective renewable energy generation. RPS's have been successful at increasing the generation of power from renewable resources in certain US State, notably Texas.

How can the varying output of the wind be used for generating electricity?
Wind energy is an intermittent resource. When the wind blows between about 7 meters per second (16 miles per hour) and 27 meters per second (60 miles per hour), wind turbines can generate electricity. When the wind doesn't blow, or blows too hard, the turbines can't generate electricity. Unfortunately, the wind doesn't always blow when electricity is needed. Batteries can store only a modest amount of electricity to be used when the wind doesn't blow.

Power producers that are installing wind turbines understand and plan for the intermittent nature of wind energy. They also appreciate that wind turbines offer a number of benefits that conventional generation doesn't: shorter construction lead times, modularity (more turbines can always be added if loads grow), no fuel costs, no air emissions, and higher customer approval. If the wind resource is well matched to peak loads, wind energy can effectively contribute to system capacity. Winds are often higher in the afternoon, for example, when electricity usage is high.

If this technology is so great, why isn't it more popular?
Wind technology is, in fact, the fastest-growing generation source in the world. By the end of 2002, there was an estimated 31,000MWs of wind energy installed throughout the world. In the United States, growth is slow because power producers have delayed construction of all types of new generation until uncertainties about utility deregulation are resolved.

Despite the slowdown in new generation, the United States is experiencing the largest surge in utility-scale wind development since the 1980s. In the US, more than 11 billion kWh of electricity was generated last year, enough to supply 1.1 million homes. If that amount of electricity was generated by traditional fuels, that would emit 7.5 million tons of CO2. A forest of 4,000 square miles would be needed to absorb that amount of CO2.

How much of the time will wind turbines produce power?
Wind turbines produce power in wind speeds above about 13 km/hour. In most places where wind turbines are located, the wind would be above this speed 70-80% of the time. Production then increases until it hits a maximum power produced at 55 km/hour. Wind turbines will typically shut down at wind speeds above 90 km/hour for safety reasons. These numbers will vary depending on the model of turbine selected.

Are wind turbines harmful to wildlife?
Bird deaths are the most controversial biological issue related to wind turbines. The deaths of federally protected birds at the Altamont Pass wind farm site in California has raised concerns by fish and wildlife agencies and conservation groups. On the other hand, several large wind facilities have operated for years with only minor impacts on birds. Studies have shown that the average wind turbine kills 2 birds per year. This is less than the average car or house cat. In addition, wind turbines have no air or water emissions. So replacing other forms of generation with wind generation improves the environment, and therefore improves the survival rates of all species, compared to traditional sources of generation.

To prevent further bird deaths, both the wind industry and government agencies are sponsoring or conducting research into collisions, relevant bird behavior, and mitigation and avoidance measures at wind facilities. And project developers are conducting biological surveys to avoid choosing sites for new wind projects near major bird feeding, roosting, and resting areas, wetlands, rookeries, or low-level flight paths.

Although bird mortality is a serious concern for the wind industry, structures such as smokestacks and radio and television towers have been associated with far larger numbers of bird kills than have wind facilities. Other sources of bird mortality, such as highways and pollution, are responsible for a much higher proportion of total bird deaths.

I have heard that you can connect a small wind generator and run the meter backwards when you have surplus power.
Many US states have net metering laws, that require the utility to allow you to connect. On a windy day, when your power use is low, you can run your meter backwards. And on calm days, you purchase power from the utility as usual. You then pay only on your net power consumed.

Are wind turbines noisy?
Noise may be a concern to people living near wind projects. However, much of the turbine noise is masked by the sound of the wind itself, and the turbines only run when the wind blows. Noise from wind turbines has diminished as the technology has improved. Early model turbines are generally noisier than most new and larger models. As blades have become more efficient, more of the wind is converted into rotational torque and less into acoustic noise. Under most conditions, modern turbines are quiet.

Do wind turbines pose a safety hazard?
Unlike most other generation technologies, wind turbines do not use combustion to generate electricity and hence don't produce air emissions. The only potentially toxic or hazardous materials are relatively small amounts of lubricating oils and hydraulic and insulating fluids. Therefore, contamination of surface or ground water or soils is highly unlikely. The primary health and safety considerations are related to blade movement and the presence of industrial equipment in areas potentially accessible to the public. Depending upon their locations, wind facilities may represent an increased fire hazard. And like all electrical generating facilities, wind generators produce electric and magnetic fields.

Is wind power cost competitive?
A "Greenfield" fossil plant delivers power at around 5 cents (US), the same as a new large scale wind plant. The issue with wind is more its intermittency, than its cost.

Where are commercial wind turbines made?
The large scale commercial turbines are manufactured largely in Denmark and Germany. Spain, the US, Belgium, Netherlands and India also have domestic manufacturers.

How has the technology improved since wind turbines were first developed?
Turbines designs have improved since the 1980s, when a large number of turbines where put up in California. Many lessons were learned from the performance of these early designs. These improvements produced huge growth in the global construction of wind farms. As of August 2002, Europe had 20,447 MW of installed capacity.

Wind is an intermittent resource. What do you do when the wind isn't blowing?
Wind is designed to "compliment" power production from hydro and fossil plants. It is a perfect complement to hydro power as it allows the hydro producer to store water behind the dam when the wind is blowing: effectively “shifting” the need to use the water to a time when the wind isn’t blowing. It’s just like creating more rain. As an adjunct to fossil plans, wind provides low cost clean power allowing fossil generators to turn down or turn off their plants when the wind is blowing.

Are aesthetics a concern for wind farms?
Wind projects have different visual impacts than most other electric generation technologies, in part because wind projects usually are located in rural or even remote areas, often with few nearby homes and only occasional human visits and use. Aesthetics may be an issue, depending upon the value people place on the visual quality of the project setting and other considerations. Strategies to minimize visual effects involve the spacing, design, and uniformity of the turbines, markings or lighting, roads, and service buildings.

The FAQs listed above are used with permission courtesy of the Canadian Wind Energy Association (CANWEA) and the National Renewable Energy Laboratory (NREL) in the USA