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Wind Energy

Wed, 12/26/2007 - 2:19am — efadmin

"Wind power is both old and new. From the sailing ships of the ancient Greeks, to the grain mills of pre-industrial Holland, to the latest high-tech wind turbines rising over the Minnesota prairie, humans have used the power of the wind for millennia." During the late 1800s and early 1900s, American farmers harnessed the power of wind to pump water. "Small electric wind turbines were used in rural areas as far back as the 1920s, and prototypes of larger machines were built in the 1940s. When the New Deal brought grid-connected electricity to the countryside, however, windmills lost out."

Modern day interest in wind power resurfaced during the energy crisis of the 1970s, with commercial development beginning in earnest in California at the start of the 1980s. As fossil-fuel prices declined again in the mid-1980s, so did investments in wind power. Another boost in wind development occurred in the early 1990s. However, not until 1998 did the wind industry begin to experience continued growth in the United States, "thanks in large part to federal tax incentives, state-level renewable energy requirements and incentives, and – beginning in 2001 – rising fossil fuel prices."

"Wind is a clean, inexhaustible, indigenous energy resource that can generate enough electricity to power millions of homes and businesses. Wind energy is one of the fastest-growing forms of electricity generation in the world." "Global installations in 2005 reached more than 11,500 megawatts (MW) – a 40.5 percent increase in annual additions compared with 2004 – representing $14 billion in new investments."

"The United States can currently generate more than 10,000 megawatts (MW) of electricity from the wind, which is enough to power 2.5 million average American homes. Industry experts predict that, with proper development, wind energy could provide 20% of this nation's energy needs." "The U.S. wind energy industry is on track to add well over 3,000 megawatts (MW) to the nation’s power generating capacity in 2007, thereby topping last year’s record of 2,454 MW . . . . One megawatt of wind power produces enough electricity on average to serve 250 to 300 homes."

"Installed wind energy generating capacity now totals over 12,600 MW, and is expected to generate about 31 billion kWh of electricity in 2007. However, that is still less than 1% of U.S. electricity generation. By contrast, the total amount of electricity that could potentially be generated from wind in the United States has been estimated at 10,777 billion kWh annually – more than twice the electricity generated in the U.S. today." "Texas now has over 3,000 MW installed, strengthening its position as the state with the most wind power capacity. The ranking for the top five states remains Texas (3,352 MW), California (2,376 MW), Iowa (967 MW), Minnesota (897 MW), and Washington (818 MW)."

Wind power also creates economic development opportunities and jobs across the U.S., often in areas that have lost manufacturing jobs over the past years. "Manufacturing plants announced or opened this year [2007] include:

  • DMI: planning a tower production facility in Tulsa, Okla.;
  • Knight & Carver: opened a blade manufacturing facility in Howard, S.D;
  • LM Glasfiber: will open a blade manufacturing facility in Little Rock, Ark.;
  • PPG Industries: adapting a facility to produce high-tech fiberglass for blades near Shelby, N.C.;
  • Trinity Structural Towers: opening a facility in Clinton, Ill.;
  • Vestas: opening a wind turbine facility in Windsor, Colo."

"The wind resource – how fast it blows, how often, and when – plays a significant role in its power generation cost. The power output from a wind turbine rises as a cube of wind speed. In other words, if wind speed doubles, the power output increases eight times. Therefore, higher-speed winds are more easily and inexpensively captured."

"Wind speeds are divided into seven classes – with class one being the lowest, and class seven being the highest. A wind resource assessment evaluates the average wind speeds above a section of land . . . and assigns that area a wind class. Wind turbines operate over a limited range of wind speeds. If the wind is too slow, they won’t be able to turn, and if too fast, they shut down to avoid being damaged." "Wind speeds in class three (6.7 – 7.4 meters per second (m/s)) and above are typically needed to economically generate power. Ideally, a wind turbine should be matched to the speed and frequency of the resource to maximize power production."

Skeptics point to the variability of wind as a problem in integrating wind power into the electricity grid. However, recent studies demonstrate that this has not been a problem. "In a large utility system, the variations in power output from wind turbines are absorbed in the constant variation in electrical demand. The electric system is designed to handle unexpected swings in energy supply and demand, such as significant changes in consumer demand or even the failure of a large power plant or transmission line. . . . several recent U.S. based utility studies confirm that a significant amount of wind energy can be integrated into the electricity grid without large cost or reliability impacts."

Wind is an intermittent source of energy, because wind is not always blowing when the energy is needed. The variability of wind is known as the "capacity factor," "which is simply the amount of power a turbine actually produces over a period of time divided by the amount of power it could have produced if it had run at its full rated capacity over that time period." "A conventional utility power plant uses fuel, so it will normally run much of the time unless it is idled by equipment problems or for maintenance. A capacity factor of 40% to 80% is typical for conventional plants."

"A wind plant is 'fueled' by the wind, which blows steadily at times and not at all at other times. Although modern utility-scale wind turbines typically operate 65% to 90% of the time, they often run at less than full capacity. Therefore, a capacity factor of 25% to 40% is common, although they may achieve higher capacity factors during windy weeks or months." "It is important to note that while capacity factor is almost entirely a matter of reliability for a fueled power plant, it is not for a wind plant—for a wind plant, it is a matter of economical turbine design. With a very large rotor and a very small generator, a wind turbine would run at full capacity whenever the wind blew and would have a 60-80% capacity factor—but it would produce very little electricity. The most electricity per dollar of investment is gained by using a larger generator and accepting the fact that the capacity factor will be lower as a result. Wind turbines are fundamentally different from fueled power plants in this respect."

"Since the late 1990s, the DOE National Renewable Energy Laboratory (NREL) has been working with state governments to produce and validate high-resolution wind resource potential assessments on a state-by-state basis." Updated wind resource maps for Indiana released by NREL in January, 2006 reveal that Indiana has at least 40,000 MW of wind energy potential. This estimate is more than double the entire generation capacity of Indiana. The estimate of wind power potential in Indiana takes into account a number of factors. They include:

  • Wind class – the above estimate is based on summing up wind power potential for class 3, class 4 and class 5 winds;
  • Energy loss – the estimate assumes that 12% of the power generated is lost (due to down time, icing losses, transmission losses);
  • Tower height – 80 meters is the current industry norm. The estimate above is based on wind turbines at 70 meters;
  • Power potential per square kilometer – the study assumes that 5 MW of turbines are installed per square kilometer in areas determined to be windy. This is a standard assumption.
  • Land area – the study excludes environmentally sensitive land as well as developed land such as urban areas, airports, wetlands, etc. It also excludes high sloping areas and areas with small, isolated pockets of wind resources.

NREL’s updated wind resource maps dispel the long-held notion by many that Indiana lacks sufficient wind resources for electricity generation. This has helped to spur wind development in Indiana.

Construction began in late July, 2007 on the first commercial-scale wind farm in Indiana. Expected to be completed in May, 2008 (less than a year later), the Benton County Wind Farm’s 87 wind turbines will produce a total of 130 MW of power. A second wind farm under development is the Fowler Ridge Wind Farm, located in Benton and Tippecanoe Counties. It has recently been approved by the Indiana Utility Regulatory Commission, and the project is expected to be built, start to finish, in 2008 and to produce 200 MW or more of power. However, despite recent wind development initiatives, reflected in agreements by investor-owned utilities to purchase the power generated from these wind farms, wind development in Indiana is spotty, and will likely remain so unless Indiana joins twenty-one other states and the District of Columbia that have passed renewable electricity standards.

While the design varies from state to state, a renewable electricity standard (RES), sometimes referred to as a renewable portfolio standard (RPS), requires electric utilities to source a certain percentage of electricity from renewable resources. "Initially, state RPS policies were generally incorporated into much broader state electricity restructuring legislation. More recently, however, state RPS policies have been adopted through stand-alone legislation." "The RPS is sometimes viewed by policy-makers as a 'market-friendly' way of ensuring that a minimum amount of renewable energy development will be achieved, and is a widely used policy (relative to other renewable energy policy mechanisms) in part because an RPS does not typically require an explicit allocation of government funding."

"State renewable portfolio standards (RPS) have emerged as one of the most important policy drivers of renewable energy capacity expansion in the U.S. Collectively, these policies now apply to roughly 40% of U.S. electricity load, and may have substantial impacts on electricity markets, ratepayers, and local economies." "State-level renewable electricity standards . . . are also working as a primary driver of U.S. wind development. Nearly half of all wind power capacity built from 2001-2005 was attributable to state standards, according to the DOE’s Lawrence Berkeley National Laboratory." Cost has often been raised as a barrier to enactment of a state-level or federal RPS. However, numerous studies have shown that an RPS is generally expected to have minimal rate impacts.

A March, 2007 study of 28 distinct state or utility-level RPS cost impact analyses, conducted by the DOE’s Lawrence Berkeley National Laboratory, concludes: "Seventy percent of the state RPS cost studies in our sample project base-case retail electricity rate increases of no greater than one percent in the year that each modeled RPS policy reaches its peak percentage target." The report continues: "In six of those studies, electricity consumers are expected to experience cost savings as a result of the state RPS policies being modeled. On the other extreme, nine studies predict rate increases above 1%, and two of these studies predict rate increases of more than 5%. . . . the median bill impact across all of the studies in our sample is an increase of only $0.38 per month."

A November, 2006 study analyzed the rate impact of an Indiana RES, beginning with a 2% requirement in 2009 and rising to a 10% requirement in 2017 and following. "The study finds that the RES will have a cumulative impact of 2.00% in 2017 (i.e., rates would be 2% higher than they would be in the absence of an RES) . . . ."

Wind power is an environmentally friendly, renewable resource. While earlier experiments in wind development raised some concern over the noise produced by the rotor blades, aesthetic impacts, and that sometimes birds and bats have been killed by flying into the rotors, "[m]ost of these problems have been resolved or greatly reduced through technological development or by properly siting wind plants." "With increasingly competitive prices, growing environmental concerns, and the call to reduce dependence on foreign energy sources, a strong future for wind power seems certain. . . . As with any industry that experiences rapid growth, there will be occasional challenges along the way. . . . But new manufacturing facilities, careful siting and management practices, and increased public understanding of the significant and diverse benefits of wind energy will help overcome these obstacles."


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