Caney River Wind Farm

Construction Phase

by

Terri R. Nicholson and Gayla R. Corley

Table of Contents
Introduction History
Construction Climate
Description of Study Site Geomorphology
Conclusions Gallery
References



Fig. 1 On location at Caney River Wind Project, Elk County, looking west to Elk River Wind Farm, Butler County, in the distance.


Introduction

The growth and development of green energy in Kansas has exploded in the last decade. In 2001 the Gray County Wind Farm was built with 112 turbines connected to the power grid. With the completion of the Caney River Wind Farm, the new total for the state will be 1028 turbines. Although other wind farms are planned throughout the state the Caney River Wind Farm is the last wind farm to be placed in the Flint Hills Physiographic Region.

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History

Kansas has an early history of using wind turbines to complete work for both communities and farms. Water is a key ingredient in the survivability of the homestead farms, and wind mills were often used to pump water to the surface. The first commercial working wind turbine was located on the west end of Warren Street in Lawrence, KS (Edson). A Dutch style mill which contained two pairs of grinding stones and provided energy to a neighboring wagon and plow shop. It seems Lawrence was ahead of its time, moving from the construction of the Dutch type mill, in 1863, to a turbine connected to the grid in 1976. Since this connection occurred Kansas has quickly become a leader in the production of green energy, Figure 2. Next year five new wind farms or expansion projects are proposed to start within the state. This will move the total number of working turbines to 2112.

Fig. 2 Completed wind turbines. Note the piles of soil and rocks from digging the pits for the concrete bases.

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Construction

The Caney River Wind Farm in Elk County is using the Vestas V-90 turbines in which each turbine will be producing 1.8 MW of energy. The V-90 model is 80 m (~262 feet) tall at the hub and has a blade length of 44 m (144 feet). The total height is 125 m (410 feet) with the blades extended to the full height and has a capacity factor of 31% (Trade Wind Energy). Model V-90 has a proven track record for long term productivity and durability, not only in the state, but also nationally. This Vestas model is so effective due to the area swept by the blades, which is 6,362 meters squared (Vestas). The turbines being constructed have an additional cooling system on top of the nacelles, Figure 3. These coolers were not added to the first phase of the Smoky Hills Wind Farm, and they have had over heating problems during the summer inside the nacelles. The addition of the "fin" on top has to be added during the manufacturing assembly, which makes retro-fitting the Smoky Hill turbines unavailable.

Fig. 3 Nacelle with large cooling fin on top. Note the liht and the wind speed controls for the blades on top the fin.

The field tour to the Caney River was made available by contacting Enel Green Energy Company and a representative conducted a tour of the site. The areas under physical construction were not available for the tour; however, the areas where the turbines were completed and waiting to be added to the grid could be visited. All of the foundation pads had been completed and back filled at one time before any turbines were constructed on the site, Figures 4 and 5. Bolts which hold the tower to the foundation were visible around the outside of the towers. These bolts were both numerous and large, about 4-5.5 cm (1.5-2 inches) in diameter, with another row of bolts located inside the tower, Figure 6.

Fig. 4 Tower foundation pad sit with rebar and bolts in place ready to finishs pouring cement. Photo courtesy of Enel on site. Fig. 5 Foundation pad poured and curing before being back filled with soil and rocks. Photo courtesy of Enel on site. Fig. 6 Base of tower with bolts in place. Photo by T.R. Nicholson.

Because this is an active construction site a visit to the areas where the towers were going up was not available. Building is going on twenty-four hours a day, seven days a week, and crews are present and assembleing towers. Using a Canon Power Shot S3 15 from the access road workers were captured working on top of the hub/nacelle, Figure 7.

Fig. 7 Men working on top of a tower.

From this same location the cranes, which are used to assemble the tower sections, were also visible, Figure 8. These large cranes could become a limiting factor on where the wind farms can be located. They are large and difficult to move from location to location (Gipe). Each area where the turbines are to be set requires a special road to support the mass and size of the cranes. Because of the difficulty of moving the cranes Enel uses two different sizes to assemble the towers. A smaller crane is used to assemble the first section of the tower on the foundation. They complete all of this part of the construction to all prepared footings. Using this technique enables them to move the smaller crane on to other jobs, such as unloading transport vehicles, and keeps the project moving forward.

Fig. 8 Large crane used in assembling towers, hubs, nacelles, and blades.

While on the tour transport support frames were located by towers completed ready to be sent back to the manufacturing company. These frames are used to stabilize the blades during either train or truck transport. To get a reference for the size of the frames our tour guide and a team member stood beside the blade support frame, Figure 9.

Fig. 9 Blade support frames shown with T.R. Nicholson and tour guide.

Just as the tour was ending information arrived of delivery of a tower by a transport crew to the construction site. The decision was made to wait at the top of the hill to observe the arrival as it passed the site entrance. Due to the mass and weight of several pieces they had to be assisted coming up the hill with a John Deere 9330, dualed four-wheel drive tractor, pulling the loaded trailer to the top of the hill, Figure 10. Enel uses thier own truck tractor to be pulled up the hill by the John Deere. This releases Enel's liability for damaging the transport company's truck with the tractor. Once at the top of the hill the transport company hooks their truck back to the trailers and hauls the turbine pieces to the individual building sites.

Fig. 10 John Deere 9330 pulling semi-trailer truck and tower section to tthe top of the hill.

Fig. 11 Transport company's truck delivering to building site after being pulled uphill by the tractor. Fig. 12 Hub being transported to top of the hill. Fig. 13 Nacelle being transported up to the top of the hill.

Elk River Wind Farm transmission lines are already in existence and will be used by the Caney River Wind Farm, Figure 14. After adding the additional energy from Caney River the transmission lines will be near maximum capacity. Any expansion of either of these farms will create a need for an increase in carrying capacity for the Elk River transmission lines.

Fig. 14 Elk River Wind Farm transmission lines that will carry Caney River Wind Farms production to customers.

The determination of where the wind farms will be located is the most fascinating and frustrating part of wind farm projects. Fascinating in how the locations are selected using the geomorphology of the land, putting out small towers with anemometers to detect wind movement and speed at the possible sites starts the project. Data are collected from those towers to prove which sites would give the best yield and be financially feasible. It is frustrating when dealing with all of the bureaucrcy of state, county, city, and local land owners to reach an agreement. Each of these groups are determined to get the best deal for themselves or are trying to stop the construction totally. The local land owners contacted around Caney River were in favor of the wind farms coming to the area. They did mention some of the neighbors were not as pleased with the wind farm and refused to allow the construction on their land. Whether the land owner is in favor or against the construction of the wind farm, it cannot be argued the companies building and assembling the towers put an effusion of money into a community both while they are constructing and after with the rent paid to the local land owners.

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Climate

The United States is divided into three ecosystem domains: 1) the dry domain, 2) the humid temperate domain, and 3) the humid tropical domain (Bailey, 1995). The Flint Hills are in the dry domain with characteristics including annual loss of water by evaporation exceeding the annual water gain from precipitation. Boundaries for domains cannot be set on a specific value of annual precipitation. Permanent streams do not originate in dry climate zones normally.

These domains are further divided into ecosystem divisions and provinces. The prairie division includes the Flint Hills and has a continental, mid-latitude climate (Bailey, 1995). Precipitation in Elk County averages 99 cm (39 inches) per year and falls in the range of 51-102 cm (20-40 inches) annually for prairie division lands. Evapotranspiration is more annually than the precipitation falling in this division. Trees do not have a long enough root system to reach deep water sources at higher elevations and the shallower soil is inadequate for tree growth. Summer time soil and air temperatures are quite high.

The Flint Hills weather is dry and the area receives less precipitation annually than it loses through evaporation per year. Below in Table 1 is an overview of the annual temperatures, humidity, precipitation and wind speed in Elk County (USA.com).

Table 1. Average Annual Elk County Weather
Wind SpeedPrecipitationSnowfall HumidityTemperature
AverageHighLowAverage AverageAverageAverage
29 km/h--18 mphJanuary 45 km/h--28 mph February 24 km/h--15 mph99 cm--39 in28 cm--11 in79%14 C--57 F

Caney River Wind Project, in western Elk County, is located in the eastern edge of the Flint Hills Physiographic Region of Kansas. This area supplies elevation and a decreased number of obstructions to the wind making it an ideal spot for location of a wind farm. Wind is a key component of a successful wind farm. The ideal wind speed for a turbine is a Force 4 on the Beaufort Scale, 5.5-7.9 m/s (18-26.9 feet/second) (Musgrove, 2010). This is a moderate breeze moving small branches on trees, blowing dust, and loose paper. According to the Nationalble Renewable Energy Laboratory(NREL) Kansas has the potential wind speed necessary for successful wind farms, Table 2.

Table 2. Wind Classification
ClassPotentialWind Speed 50 m (164 feet) Elevation
3Fair6.4-7.0 m/s--21-23 feet/second
4Good7.0-7.5 m/s--23-24.6 feet/second
5Excellent7.5-8.0 m/s--24.6-26.2 feet/second

The Caney Wind Farm Project was started in 2008 and Kansas Governor Sam Brownback declared a moratorium against wind farms in the Flint Hills in May, 2011, by executive order, expanding the previous protected area. This moratorium expansion in the Flint Hills has limited building to preserve the natural beauty of the area and tourism. The Caney Wind Farm Project was allowed to procedd with building since it had been started previous to the moratorium. Wind farms can no longer be built in the Flint Hills, but transmission power lines may be built across the area to carry electrical power to consumers.

The Flint Hills of eastern Kansas class of wind speeds according to NREL and published in their website are fair to excellent for the success of a wind farm. When the Caney River Wind Farm is completed in 2012 it will be the second wind farm using the wind potential of the Flint Hills. The Elk River Wind Farm is located to the northwest in southeastern Butler County and is visible from the Caney River Wind Project. A wind resource map for Kansas may be found at the NREL website, Figure 15. A color coded map showing more detail of wind classes may be found there also.

Fig. 15 Map of Kansas with the average annual wind power. Map courtesy of NREL.

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Description of Study Site

Elk County in eastern Kansas is located in three physiographic regions: through the center of the county the Osage Cuestas, the eastern side of the county the Chautauqua Hills, and on the western side the Flint Hills, Figure 16 (Kansas Geological Survey (KGS). The Flint Hills of eastern Kansas extend from southern Marshall County in the north to the Oklahoma state border to the south. This is an area of elevation of approximately 280 m (920 feet) in Wabaunsee County on the Kansas River to maximum elevation of 500 m (1640 feet) in Chase, Greenwood, and Butler Counties on the hill crests (Aber and Aber, 2009). The eastern margin of the hills is a sharp escarpment rising suddenly from the Osage Cuestas and the western margin has a gentle decline toward the Smoky Hills and the Arkansas River Lowlands.

Fig. 16 Physiographic Regions of Kansas with Elk County located, modified by G.R. Corley. Map courtesy of KGS.

Tall grasses and broad leaf forbs are dominate on the uplands and trees and woody shrubs grow on the lower hillsides and brushy draws. Grasses include big blue stem (Andropogon gerandii), little bluestem (Schizachyrium scoparium), switch grass (Panicum virgatum L.), and Indian grass (Sorghastrum nutans). Common forbs found in the Flint Hills are: Missouri golden rod (Solidago missouriensis), White prairie clover (Petalostemum multiflorum), stiff sunflower (Helianthus rigidus), snow on the mountain (Euphorbia marginata), blue sage (Salvia azurea), and purple coneflower (Echinacea purpurea).

Common wildlife of the area include white tailed deer (Odocoileus virinianus), black-tailed jack rabbits Lepus californicus), cottontail rabbits (Sylvilagus floridanus), raccons (Procyon lotor), and skunks (Mephitis mephitis). Non-poisonous snakes are found throughout Elk County include yellow-bellied racers (Coluber constrictor flaviventris), common garter snakes (Thamnophis sirtalis), bullsnakes (Pituophis catenifer), and black rat snakes (Elaphe obsoleta) to name a few. Timber rattlesnake (Crotalus horridus), Massasauga rattlesnake (Sistrurus catenatus) and the copperhead (Agkistrodon contortix) are the most common poisonous snakes found in Elk County.

Many different kinds of birds inhabit the Flint Hills. When building wind farms across the state efforts are made to avoid major migration routes of birds due to the danger of being killed by the wind mill blades. The Caney Wind Farm is not being built in major bird migration routes or areas occupied by the greater prairie chicken (Tympanuchus cupido).

Concern is being voiced for the safety and death rates of bats by wind turbines. This problem was not anticipated and has surfaced as a major problem among conservationist. Bats are major consumers of insect pests and are beneficial to farmers and ranchers (United States Geological Survey, USGS). Kansas has sixteen bat species and of those sixteen species only three species have a high risk of death from wind turbines (Aber, 2011). The bats with the highest risk of death are the silver-haired bat (Lasionycteris noctivagans), eastern red bat (Lasiurus borealis), and the hoary bat (Lasiurus cinereus) which belong to the bat family Vespertilionidae (tail not extended) bats.

Vesperilionidae are classed as "migratory tree bats" (USGS). These bats roost in trees the year around, migrating long distances in the spring and fall crossing international and intersate boundaries. The Flint Hills is a major migration route of the eastern red bat. Three fourths of the bats killed by wind turbines are these three species. Bat fatalities have been found at every wind farm across North America conducting bat surveys. Death is caused by collison with the blades or barotrauma (New Scientist Environment). Barotrauma is caused by the low pressure vortex created by the turbine blades. This low pressure causes the expansion of the bat's lungs and the blood vessels burst causing death by internal hemorrhage. An on going study is being conducted by the USGS on bat deaths and wind farms by the Fort Collins Science Center.


Geomorphology

The Caney River Wind Project is located in northwestern area of Elk County, 16 km (10 miles) west of Howard, the county seat, in the eastern edge of the Flint Hills. The wind turbines, transmission station, and local headquarters are located at an elevation of ~440 to 450 m (1440 to 1480 feet) above sea level. This high elevation provides the second key component of a wind farm, elevation on the highest terrain in an area.

The wind project is located on a dividing ridge between the Caney River and the Elk River trending from the southeast to the northwest. The escarpment of the ridge drops down into the Elk River valley to the east into the Osage Cuestas Physiographic Region of Pennsylvanian Age. To the west the uplands dips steeply into the Pennsylvanian Age Caney River Valley.

The Flint Hills are underlain by bedrock of lower Permian age, this time period lasted from about 286 to 245 million years ago, (KGS). Figure 17, is a map of the extent of Permian Age deposits in Kansas (Zeller, 1968). During the Permian Period Elk County was covered by a sea and the cyclothems, or repeated transgression and regression of the seas, laid down repeating layers of limestones and shales (Aber, 1991). Major cyclothems deposited thicker layers of shale and limestones, 15-30 m (50-100 feet), containing cherty limestone layers. Minor cyclothem units were not as thick, 8-12 m (25-40 feet) and the limestone layers were thinner. Probably the seas were shallow as the predominate color of the shales are green, maroon, and light to dark gray indicating deep water did not occur during the major transgressions. This was an indication of a more arid climate. Limestones and some shales are fossiliferous containing pelecypods, brachiopods, trilobites, and other invertebrate fossils.

Fig. 17 Permian Age deposit distribution of Kansas. Map from Zeller.

These lower Permian rock units of the Gearyan Stage contain three groups, the Admire, Council Grove, and the Chase (Zeller, 1968). A geological map locates the Flint Hills to the Western side of the county and illustrates each one of these groups presence in the area where the wind farm is being built, Figure 18, and the legend, Figure 19.

Fig. 18 Geological map of Elk County. Map from KGS.

Fig. 19 Legend for geological map Figure 18. Map from KGS.

The hilltops are covered with prairie grass and some scattered trees. Surface rocks are limestone and scattered gray cherts. The area of the wind farm toured is probably covered by the Council Grove Group of deposits. Where excavation occurred, to make the turbine bases, piles of soil are still present containing limestones and chert cobbles. The rock layers observed in an excavated ditch wall was thinly bedded limestone and chert cobbles. Farther to the west the map (Figure 18) indicates the Chase Group is located and drapes over the Council Grove Group. The limestones of this group contains large amounts of chert. On the downward slopes the map indicates the Admire Group which also contains lesser amounts of chert. Figure 20 is the stratigraphic columns of these three groups.
Fig. 20 Stratigraphic column of illustrating three groups found in Elk County. Stratigraphic column from Aber.

Soils of the area are mollisols. These soils have a mollic epipedon, dark colored, and are mineral soils (United States Department of Agriculture (USDA). Mollisols develop under grasses, do not have permafrost, but have enough moisture to grow perennial grasses. Most soils of Kansas are mollisols as noted in the map of soils of the United States, Figure 21.

Fig. 21 Mollisols of the United States. Map from USDA.

Three soil series compromise about 80 percent of the study area. They are Clime, Florence, and the Labette series. Characteristics of all the soil series are being well drained and slowly permeable on uplands. The Clime and Labette soil series are used mainly for native grasses, but may be farmed and the principal crops raised are winter wheat and grain sorghum. Range and hay land is the exclusive use for Florence soil series. A fourth soil series, Eram, is found on ridges and side slopes.

The Clime series are formed from the residuum from calcareous clayey shales. Slopes where these soils occur may grade from 1-60 percent. The Florence series are formed from the residuum of cherty limestones and have slope gradients ranging from 2-15 percent. The first soil horizon contains 15 percent chert fragments while the other soil horizons contain 80 percent chert fragments. Interbedded limestone and clayey shales are the residuum for the formation of the Labette soil series. Chert fragments range from 0 to 35 percent in these soils in all soil horizons and are up to 15 cm (6 inches) in diameter. Chert slopes from this series may be on gradients from 0 to 12 percent. Eram soil series were formed from interbedded shales and thin sandstone layers. Slopes where it is found grades from 1 to 20 percent and in the Flint Hills used for rangeland.

The Flint Hills were formed by water erosion during the Tertiary Period. The interior of the present North American continent was divided by the Western Interior Seaway. At the end of the Mesozoic Era rocks began to tilt and rapid erosion started (Williams and Lohman, 1949). During the Cenozoic Era the Rocky Mountain uplift occurred and waterways changed course and began to flow east and the interior sea began to drain. Cretaceous, Pennsylvanian, and Permian sediments toward the east were removed by active erosion. Erosion continued into the late Tertiary, Miocene, and Pliocene, removing soil and rocks.

Wind has had a part in the creation of the Flint Hills. During arid times when the grass cover was poor soil particles were blown by the wind. The soil would settle into the retreating seas and be deposited and in time would be added to the water deposited sediments to become shales. During the Pleistocene glaciers melted and large amounts of soil was left bare. This soil was picked up by the wind and blown, being deposited over much of Kansas and today known as loess. Loess may be seen in the Flint Hills today.

By the end of the Tertiary, 1.8 million years ago, the Flint Hills were shaped by the running water and the hard, cherty nodules resisting erosion. Chert is a microcrystalline or cryptocrystalline sedimentary rock composed of silicon dioxide (SiO2). It resists dissolving in water and therefore, protects the tops of the Flint Hills and erosion is slowed. This is why the Flint Hills uplands are present today.

The study site area of Elk County is rangeland, Figure 22 and 23. The soil types found here are slowly permeable and more water run off is present because of this slow permeability. Grazing cattle will not increase erosion greatly unless pastures are overgrazed and improperly managed. Soils have a delicate crust, called cryptogram, and the cattle trampling through the pastures breaks up the soil between vegetative crusts. This can increase water erosion. When the delicate crust is broken and becomes dust it is in danger of entrainment in the wind. The grazing alters the amount of grass cover and undesirable forbs will start growing. Grass holds soil better than the undersirable forbs and erosion will be worse.

Fig. 23 Wild horses owned by the Bureau of Land Management. Fig. 24 Cattle grazing in a pasture next to the wind turbines.

The Bush-Denton Oil Field is located in the same area as the wind farm, Figure 25. When oil field access roads are not used or properly maintained the grasslands may be damaged and grass destroyed by vehicles cutting ruts in off road areas creating areas for gully erosion to start. Poor practices of rangeland management and indifference to good practices by the oilfield industry will lead to unnecessary wind and water erosion in the Flint Hills.

Fig. 25 Bush-Denton oil tanks by access road with Elk River Wind Farm transmission lines in the background.

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Conclusions

The Flint Hills known today was created by water erosion following the uplift of the Rocky Mountains. As limestones weathered chert cobbles were left behind as they are very resistant to dissolving in water. These cherts now cap the Flint Hills continuing to resist the effects of water erosion and maintaining the high relief of the Flint Hills. Water erosion continues at a much slower rate today than during the early Cenozoic time. The high relief of the Flint Hills create ideal areas to build wind farms as it provides areas with less obstruction, good elevation, and ideal wind velocity for the operation of wind turbines.

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Gallery

Fig. 26 Fall colors and finished wind turbines. Fig. 27 Transformers at transfer station. Fig. 28 Wind farm's transfer station.

Fig. 29 Material from pit excavation, note limestone and cherts. Fig. 30 Ditch with thin bedded limestones exposed. Fig 31 Workers adding a wind turbine to the grid.

Fig. 32 Underground cable used to connect wind turbines to the grid.

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References

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All photographs are by Gayla R. Corley unless stated otherwise.

This webpage was created to meet the requirements of ES 546 Field Geomorphology at Emporia State University, Emporia, Kansas, and is the property of the authors. For more information contact the authors: Gayla R. Corley or Terri R. Nicholson

Created December 2011, for the Earth Science Department, Emporia State University: http://www.emporia.edu/earthsci/, at Emporia State University, Emporia, KS http://www.emporia.edu/