Completion date, other facts about Blue Sky Green Field 

As of Monday morning, 74 of the 88 wind turbines in the Blue Sky Green Field wind farm in the Johnsburg/Mount Calvary/Marytown area had been commissioned, according to We Energies officials.

Andy Hesselbach, project manager of Blue Sky Green Field, and Richard O’Conor, project engineer, said they are still expecting completion of the project by the end of this month or possibly even a few days earlier.

The remaining 14 turbines yet to be commissioned are erected but final wiring and testing is in the process of being completed.

Of the 74 turbines which have been commissioned, 51 have been turned over to We Energies by RMT Wind Connect, the general contractor on the project. The V82, 1.65-megawatt turbines were purchased from Vestas Wind Systems.

Here are some other odds and ends about Blue Sky Green Field shared by Hesselbach and O’Conor on Monday:

– The center of each hub stands 262 feet from the ground. When a blade is at its highest point, it is 397 feet above the ground. There are larger turbines on the market and most manufacturers use a little larger blade, but about 90 percent of turbines in use have a similar hub height to the ones in the Holyland area.

– As was previously reported in the Tri-County News, rechecking and retensioning of bolts on the turbines did take place and is a common practice. When workers found that about 2 percent of the bolts on two turbines had less tension than they expected, they took workers out of the turbines for about two weeks until all the bolts could be checked and retensioned. Hesselbach said there are about 11,000 bolts used throughout the wind farm.

– Not all the turbines are spinning at this time because, again, they are not all completed. Even when they are, Hesselbach said it would be uncommon that all 88 would spin at the same time as routine maintenance will be a constant at the wind farm. Each turbine is also equipped with a sensitive vibration monitor which, if tripped, will shut down a turbine.

– The wind farm will employ a service crew of about a dozen people plus one or two managers. Workers generally will be on site six days per week.

– All the turbines are monitored at three places-the permanent building on the north side of Johnsburg; by We Energies in Milwaukee; and by Vestas in Portland, Ore. as part of a service agreement.

– The entire farm is expected to produce 145 megawatts of electricity or enough to power about 36,000 homes. The electricity it generates, however, goes into “the grid” so the wind farm is not necessarily powering homes, farms and businesses in the area.

– The hub on top of a turbine turns based on wind direction and the pitch of the blades also change based on the wind.

– A breeze of 7 mph is needed for the turbines to spin and produce electricity. The average wind speed in the area is 14 mph. The turbines are designed to shut down if winds reach 53 mph.

– A ladder is located inside each turbine. Platforms are located at several levels inside the turbine. Hoists are available inside and outside the turbine for workers to haul up oil, tools or parts to maintain the units.

– The turbines are designed for a 20-year life expectancy, but the We Energies officials said they are planning for 30 years with good maintenance.

– At one time about 300 people were working on the project.

– Each turbine required nine large truck deliveries.

By Mark Sherry
TC News editor

Tri-County News

15 May 2008