11/21/2006 3:14:00 PM Wind farm near Grand Meadow capturing raw energy
A local agricultural combine and an imported Danish wind turbine, two very different types of technology, have a harmonious coexistence in southern Minnesota.
By Mary Whalen
Like the chorus of a ballet ensemble, massive wind turbines gracefully turn transforming raw kinetic energy to usable electric energy.
These turbines were manufactured in and shipped from Denmark. The impressive Siemens 2.3 MW wind turbines were brought across the Atlantic, traveling through the St. Lawrence Seaway to the Port of Duluth.
After arriving in Duluth's harbor, the various components were transported via semi truck (the special crane was imported to do the lifting on site, weighed around 500 metric ton and was hauled in 27 semi loads) to a location just south of Grand Meadow in Mower County. Besides the turbines themselves, the towers which were made in Fargo, N.D., and other special equipment were shipped in cargo containers and trucked to the site.
Many may wonder why Florida Power and Light Energy (FPLE) chose to invest in the Grand Meadow area. The answer is that FPLE bought this project from another company called Horizon, which had already completed most of the development work for a two-phase project.
For several years, Horizon had been working on the project development. They installed meteorological towers to study the wind resource in the area, found the transmission interconnect point, completed turbine layouts, and were well along in obtaining land leases for the turbine sites and roads as well as permits for construction.
FPLE did its own financial analysis of the data submitted by Horizon as part of the negotiations for sale and determined that the project was financially viable. Still readers may still find it odd that a company from Florida would invest in Minnesota's economy.
Understanding that FPL Group is a Florida corporation that has two main parts may help clarify this. Florida Power & Light is the regulated utility that serves approximately three-fourths of the state of Florida the same as various utilities in Minnesota. FPL Energy is an unregulated subsidiary that develops, builds, owns and operates independent power production projects that produce electricity for sale on open markets.
FPL Energy is a leader in developing projects that minimize environmental impacts and in renewable energy. It is the largest wind energy company in the United States and is constantly looking for areas where wind construction is economically viable.
This company had already invested in wind power in Minnesota through the purchase of the Lake Benton Project. The Wind Farm Project is located in Mower County along the central divide at 1,350 -1,420 feet above sea level. This area has few trees or other structures to inhibit the wind as it passes over the site. The combination of a good wind resource, a good transmission interconnect point, and a negotiated energy price is expected to provide returns to fit the company's economic objectives.
When asked, "How long did it take to decide on this location and what studies were done before making the final decision to come here?" Gary Bouska, FPL Energy project manager commented, "I believe Horizon had been working in this area about five years before we bought Phase One of the project. They worked with the interconnecting utility to do load and facility studies to make sure the transmission system could handle the additional generation load. They initiated environmental studies for threatened and endangered species, wetland impacts, cultural and archaeological issues and microwave interference. They initiated the site permit process with the Minnesota Public Utilities Commission."
Bouska continued, "We completed some of Horizon's permit efforts and studies. In addition, we completed the FAA licensing process and obtained various state and local permits for construction for wetlands, road entrances, construction of permanent met towers, and construction of the seven-mile transmission line."
The installed cost of wind generation is about $1.2 million to $1.5 million per megawatt. The projected day for all turbines to be operational was Nov. 10. The actual day the 43rd turbine became operational was Nov. 8.
The design of wind farms is pretty standard across the country. The turbine used on this project is the largest wind turbine currently being installed on land in the U. S. By using a larger turbine, fewer sites needed to be built, thereby minimizing the impact on the farms in the area.
The Siemens 2.3 MW Mark II is also designed for a medium intensity wind regime, which is the type in this area of Minnesota. This Siemens turbine has a hub height of 80 meters (approximately 262 feet) and a rotor with three 149 feet long blades attached to it making a diameter of 95 meters (approximately 305 feet). The rotor is attached to the nacelle, which houses the gearbox, generator, brake, cooling system and other electrical and mechanical systems. The rotor swept area is 6,800 meters (73.195 feet) squared.
Matt Trimm, Siemens site manager, explains that the Siemens 2.3 MW Mark II Wind Turbine is a three blade, upwind, active yaw, and active aerodynamic control regulated wind turbine with power/torque control capabilities. Trimm says, "The nacelle is aligned as the wind direction sensor communicates with the computer system so optimum power output is attained from all wind directions and speeds."
The energy produced at the site cannot be stored. Trimm explained that it enters as AC. Then it goes through a process which will convert the varying voltage and frequencies from the variable-speed generator to a DC voltage, and then using some form of power electronics to convert the DC voltage back to AC at a fixed frequency that matches the transmission grid frequency.
The site has 43, 2.3 megawatts turbines, giving the site a maximum output of 98.9 megawatts. The turbines do not produce at this level unless the wind speeds reach 13 meters per second (29 mph) or higher. The turbine output varies with the wind speed. The average wind speed expected for the site is slightly more than eight meters per second (18 mph). At that wind speed, the turbines should produce about 340 million kilowatt-hours of energy per year.
The electricity from this wind farm is interconnected to the 161 kV transmission system at the Adams, Minn., substation. The power is sold to Xcel Energy. They then decide if the energy may be used for their own retail customers or there is an option of selling it to other utilities or cooperatives. The power output of the wind farm could provide enough energy for 30,000 to 35,000 homes.
A major concern of any endeavor involving the vast number of companies and people working to construct and commission this wind farm is safety. "Safety is a value, which is different then being a priority," said Rod Courtney, Siemens safety supervisor.
With workers from the local area, from other states, and from Denmark, the chance of miscommunication allows more chances for mishaps. Courtney comments, "My goal is to help those working on this site to see the reason behind the regulations. I want to make the employees here want to be safe, because Siemens cares about them. Once safety measures become habitual, time is saved, tasks are completed more easily, and all of us can return home to our loved ones."
Once construction is completed, there should be an average of eight to 12 full-time employees operating and maintaining the site.
There are two types of maintenance that are routinely performed at a wind farm. The first is breakdown maintenance where some sort of electrical or mechanical fault will cause a turbine to stop. Maintenance personnel will investigate the cause of the shutdown and perform immediate repairs.
The second type of maintenance is scheduled preventative maintenance where certain features of the equipment are checked and maintained similar to having the oil changed in one's car every 3,000 miles. For the wind turbines, preventative maintenance is usually performed after a certain number of operating hours. The life expectancy of the generators is approximately 20 years.
In reference to any negative comments from people in the area, Bouska remarked, "We are not aware of any negative reactions from people in the area. Our state permit has a complaint procedure in it, and no complaints were filed against the project. During the construction, we worked very hard to keep landowners informed of our construction activities. Local tile repair crews worked alongside our excavation and trenching crews and performed over 800 drain tile repairs. Some of the landowners that lived in the work areas complained to us of dusty roads, and these were addressed immediately."
Bouska also commented, "Most reactions from landowners have been very positive in regard to cleanliness and lack of disruption during the project and our site restoration after construction. We worked very closely with Mower County and the local townships to perform gravel road repairs immediately during construction. Because the completion of the project is in the winter season, it was not prudent for us to perform other repairs to the paved and gravel roads impacted by our construction. We are currently making a payment of $420,000 to Mower County to do those repairs next year during the time of the year when the repairs will be more effective. We are performing similar long-term maintenance activities with the townships in the project area."
FPL Energy administrative coordinator Linda Bouska stated, "It's great to be part of an industry that is good for our environment and at the same time provides much needed energy to the consumers. It's been a pleasure being part of the construction team that built this wind farm. The folks we've met in Grand Meadow and Rochester have been extremely warm, friendly and everyone seems interested in the wind industry and receptive to our project."
On a more personal note, Linda Bouska reflected, "Being a native Floridian, I've loved living in a part of the country where there are 'seasons!' The summer was great (mid 80s!), the fall colors were exquisitely beautiful, and snow before Thanksgiving! Wow."
There are many Web sites where photographs of the process of manufacturing, shipping and producing energy by wind are available. But, better yet, take a drive into Mower County and stop to witness the powerful, clean, reusable energy wind turbines dancing into the sunset.
