Cedar Creek wind turbines stand tall in the dryland farming region in northern Colorado.

In the rapidly expanding business of renewable energy, wind power stands tall as the fastest-growing sector. In 2007, more than 5,200 MW of wind power- generating capacity was installed in the U.S. For 2008, the total was about 7,500 MW, and wind now provides about 1.5 percent of total U.S. electricity generation. The U.S. Department of Energy (DOE) has defined a scenario in which 20 percent of U.S. energy can come from wind power by 2030 if the appropriate investments are made in technology and transmission infrastructure, and several states have enacted legislation establishing even more aggressive goals. The wind energy industry is responding to the demand, and new manufacturing capabilities are coming online in this nation and abroad. By 2020, it is estimated that the industry will be able to install 16,000 MW of new generating capacity each year.

The increasing demand for wind as an energy source is creating new opportunities for surveyors. Large-scale wind farms cover hundreds of acres of land (and, in some cases, water) and affect thousands more. The survey work needed for these installations is varied and challenging. Engineering surveys include aerial mapping, topographic information and route analyses. Extensive cadastral work is needed for property ownership, easements and rights-of-way. And construction surveys include roads, turbine locations and utility facilities.

A prime example of the new “Big Wind” industry is the Cedar Creek Wind Energy Project in northeastern Colorado. Located about 120 miles northeast of Denver, Cedar Creek is the biggest wind farm in Colorado and one of the largest in the country. It’s in an ideal location for wind power with strong, steady winds, ample open space and more than two million consumers nearby. The plant, which began operations in November 2007, produces 300 MW of electricity, which is enough to supply power to 90,000 homes. Westwood Professional Services, headquartered in Minneapolis, was selected to provide the surveying for the project.

Westwood’s Survey Crew Chief Jamie Meyer locates a corner at the Cedar Creek windfarm site using the Trimble R8 GPS receiver.

Organized for Productivity

Westwood first entered the energy sector in 1997 when the firm supplied an ALTA survey for a wind project near Lake Benton, Minn. As the industry began to grow, Westwood recognized the opportunity and set up a structure that enabled the company to focus on the energy sector. Today, Westwood’s energy division employs more than 60 people. The group provides specialized services including land acquisition, geographic information system (GIS) data, environmental background, cultural resource assessments, permitting and civil engineering. At the core of the new division, Westwood put into place the expertise needed to handle the large projects and the far-flung nature of the energy market. To manage the Cedar Creek work, Westwood assigned Rick Haglund, LS, as the project surveyor. Haglund is licensed in Colorado and was onsite to supervise the fieldwork there.

Planning on the Cedar Creek project was well under way when Westwood’s survey crews went to work in January 2006. The scale of the project was huge. Plans called for a wind farm of 274 wind turbines spread over 32,000 acres. Of the 274 turbines, 221 were 1,000-kW models manufactured by Mitsubishi Heavy Industries. They sit atop towers 226 feet high and have a rotor diameter of 202 feet. An additional 53 turbines were built by General Electric to produce 1,500 kW apiece with towers 262 feet high and rotors 253 feet in diameter. More than 15 miles of overhead collection lines were needed to gather electricity from the individual turbines. To connect Cedar Creek to the region’s electricity grid, a 230 kV transmission line was needed to carry the electricity 70 miles south to an existing switching station near Keenesburg. Before serious construction could begin, a mountain of survey work had to be completed.

In preparation for the work, Westwood was provided with constraint maps from project owners detailing the proposed location of the turbines, power-collection systems and transmission lines. The sites for the turbines were leased from numerous landowners, and a major part of Westwood’s work was to write the property descriptions for the leases. Strip surveys affecting more than 200 square miles were needed for the high-voltage transmission lines to Keenesburg. In addition to creating descriptions for easements and rights-of-way for the transmission lines, Westwood prepared documentation for the numerous access roads and collection lines. And financing requirements called for ALTA surveys on all of the properties that were occupied by the turbines and transmission towers.

A Westwood crew sets up a reference station for RTK. By midsummer, the frigid winter of Colorado’s plains would be replaced by temperatures above 100 F (38 C).

PLSS and Wide-Open Spaces

The project was a classic exercise in Public Land Survey System (PLSS) surveying. Most of the easements were aliquot descriptions and required complete section breakdowns to produce accurate information. Westwood started by identifying existing section corners and monumentation. The project team conducted extensive research on federal and county survey records and gathered input from local surveyors and landowners. The team needed to recover or restore many section corners that had not been visited since the original surveys. The wind farm alone occupied parts of 60 sections, and much of the terrain had not been surveyed since the original markers were set in the late 1800s. Many of the markers were stone monuments with no roads or fence lines to help crews find them. “It’s a fascinating feeling when you recover one of the old stones,” Haglund says. “You really become connected with the surveyors who were there more than a hundred years ago.”

During the course of the project, Westwood’s crews found and occupied more than 1,000 section and quarter corners. And they had to restore and set roughly 150 corners that they determined to have been lost or obliterated. Up to three two-person crews were on the job at one time. Throughout the survey, Westwood exercised strict field and office procedures for quality control. All of the monuments were measured multiple times using real-time kinematic (RTK) technology, and checks were made from multiple reference stations.

The Cedar Creek work combined long distances and wide-open skies with requirements for speed and high accuracy. It was an ideal environment for GNSS surveying, and Westwood’s survey crews relied exclusively on GNSS throughout the project. They used their existing Trimble R8 and Trimble 5700 GPS systems connected to Trimble TSC2 controllers running Trimble Survey Controller software. Westwood typically uses real-time kinematic networks (RTK networks, or RTN) on survey projects because Haglund likes the speed and convenience of working in a RTN and the fact that it gives his crews direct access to tight control. But no RTN exists in this part of Colorado, so the crews needed to establish their own reference stations.

Westwood tied the project to the Colorado state plane coordinate system using high accuracy reference network (HARN) or National Geodetic Survey (NGS) control stations in the area. Most of the control stations were 20 to 30 miles away. Westwood crews used static GPS to bring in control and establish locations for their own base stations. They used Trimble Geomatics Office software to process the GPS baselines and adjust their control network onto the state plane grid. The crews knew that they had a large area to cover, and they wanted to keep their control sufficiently dense to enable RTK. To meet both goals, they designed their control network to keep their RTK baselines shorter than six miles. As the project progressed, Westwood added new reference stations as needed making sure to maintain tight links to the surrounding geodetic control. Overall, approximately 40 control points were set using static GPS.

In addition to the Trimble GPS surveying equipment, Westwood’s crews carried laptop computers equipped with WiFi and phone cards. Cellular phones provided voice communications between crews and the main office. Crews in the field used both cell phones and UHF walkie-talkies. For mobility in the rugged terrain, the crews used four-wheel-drive vehicles and ATVs. Haglund noted that the remote site caused problems for communication. To get cellular signals, they often had to get to the top of a bluff.

Many of the recovered monuments were original stones set more than 100 years ago. There were few roads, fences or other physical clues to their locations.

Remote Project Management

The work to establish the new reference stations called on a variety of skills for project management and execution. Most of the data processing was done at Westwood’s office in Eden Prairie, Minn., where Westwood has a dedicated team for GPS processing and adjustments. Each day’s survey data were sent to Eden Prairie, where the information was logged in and checked by a crew coordinator who then passed it to the processing team. Using the Trimble software, the processing team produced the coordinates for the reference stations. The team was also responsible for checking and analyzing the results of each day’s RTK work. A project manager coordinated the computation work with the CAD technicians who produced maps and descriptions. The team in Minnesota prepared the data needed by the field crews searching for monuments and for the cadastral and construction stakeout. With overall responsibility for the surveying operation, Haglund divided his time between the Minnesota and Colorado locations.

Once the control was in place, the survey work turned to RTK. The size and schedule of the project provided abundant challenges. Before construction of the transmission line could start, Westwood needed to complete a strip survey 70 miles long during one of the harshest winters in the region’s history. “The snow, cold and wind combined to make things very difficult,” Haglund recalls. “We had to call in D8 bulldozers to clear snow to work on the surveys for the transmission line.” As the year moved into spring and summer, the physical challenges changed to include extreme heat and rattlesnakes.

The varying terrain of plains and bluffs made line-of-sight radio communications difficult. Even with the relatively short RTK baselines, it was common to use repeaters to ensure good data links between the reference stations and rovers. Westwood crews used their Trimble TRIMMARK 3 radios as base station transmitters as well as repeaters. The surveyors completed the ALTA work in five months, which met the project schedule. Construction of the wind farm began as planned in the summer of 2006, and work on building the transmission lines started that autumn.

In addition to carrying the heavy load of cadastral and construction work, the Westwood team was active in siting decisions for many of the wind turbines. While wind farms are designed with generally contiguous layouts, changes due to local conditions were common. For example, the Cedar Creek project is adjacent to the Pawnee National Grassland, an area known to be prime habitat for raptors. Sufficient spacing between the giant turbines is needed to ensure clean airflow, and the project designs called for the location of a number of turbines to take advantage of the bluffs. Accompanied by state biologists and wildlife experts, the project owners visited the proposed site of each turbine. Locations for many turbines were changed when the experts raised concerns that a turbine would adversely impact a nesting location or other sensitive site. In addition to concern for wildlife, the turbine locations also considered setbacks from existing farmhouses and facilities, pipelines and roadways.

Throughout the project, frequent and efficient communications played a key role. “We were in contact with the main office via cell phone and e-mail several times each day,” Haglund said. “Even in the remote locations, we found ways to stay in touch.” Westwood maintained efficient communications with the project owners and contractors, as well--in part by setting up a secure FTP site online for the project where the stakeholders could receive maps, legal descriptions and other survey information.

By the time the project was completed, Westwood had delivered nearly 100 sheets of detailed ALTA survey drawings in electronic and hard-copy formats.

No longer the tallest structure in sight, a rancher’s windmill is dwarfed by its new neighbor. Wind power has long been used in the region to pump water for livestock.

From Challenge to Opportunity

Less than 20 months after the first surveys, 280 MW of power began flowing from Cedar Creek. An additional 20 MW came online one month later. The entire project was completed on time and on budget.

It was no accident that Westwood played a key role in the success of Cedar Creek. The firm had already developed processes for working in large, remote sites and for rapidly surveying large areas. And by using dedicated experts in GNSS fieldwork, CAD and data processing, project teams were able to complete projects quickly and with high quality and consistency.

Westwood is also well positioned for future sucess. Knowing that the bulk of large wind- and solar-energy projects will be in the western U.S., the company has already put into place a team focused on PLSS work. Led by Certified Federal Surveyor Jay Wittstock, the group will handle the specialized research and computations needed to create and properly document the aliquot descriptions common to these projects.

Nearly 75,000 new wind turbines will be required to meet the DOE’s 2030 energy scenario. These new turbines will be supported by uncounted miles of transmission lines and access roads as well as new facilities for the manufacture and delivery of the oversized equipment. It all translates into an enormous amount of surveying. For companies with the right skills and capacity, taking advantage of the opportunity will be a breeze.