Massive wind turbines going up in Montezuma Hills
Credit: By Barry Eberling | Daily Republic | www.dailyrepublic.com 19 June 2012 ~~
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RIO VISTA – On the ground lay three blades that needed to be attached to a turbine tower hub some 250 feet above, with each blade as big as an airplane wing.
A red Manitowoc crane stood next to the white tower. It’s a monster of the heavy equipment world and it can give those blades a lift up to an altitude where the birds soar.
“This is one of the largest cranes in the world,” said Tim Callahan, a longtime Rio Vista resident who is the site manager for the Shiloh III project by the wind energy company called enXco.
It’s Tinker Toys for giants. Building turbines looks relatively simple in one sense – workers put up towers and then attach the gearbox and blades – but the parts are massive.
“The scale makes it very interesting,” Callahan said.
EnXco is building the Shiloh III project in the windswept Montezuma Hills to generate electricity. It will construct 50 turbines during the coming few months to join the some 800 turbines already existing in rural eastern Solano County between Rio Vista and Suisun City.
This is an assembly job, with all of the parts manufactured elsewhere and then spread out on the ground ready to go, just like pieces from a model kit. But a turbine is one huge model.
Simply getting the parts of a REpower turbine to the site is a big task. The towers are made in Fontana and in South Korea. The blades are made in Arkansas. The rectangular nacelles, which contain the generator, are from Germany.
The last leg of the journey involves shipping these parts by truck from Woodland and the Port of Sacramento to the Montezuma Hills. Enough parts to assemble a single turbine are shipped each night along Highway 113 in eight truckloads that must travel between 11 p.m. and 5:30 a.m. Three California Highway Patrol escorts go with each oversized truckload, Callahan said.
Wind turbine towers are 15 feet in diameter and even though new turbine models seem to get ever-taller, this diameter looks to remain a constant. The state’s freeway system ensures this.
“They have to make it under the overpasses,” Callahan said. “That’s the limiting factor.”
Even at 15 feet in diameter, the turbine tower pieces must be transported using Schnable trailers with a middle section that practically seems to touch the ground, providing that clearance room. The tower sections sit lower than the trailer wheels.
Step one of assembling a turbine is creating a massive foundation. Workers dig a hole 8 feet deep and 58 feet wide and pour in 338 cubic feet of cement, the amount contained in 41 cement trucks. Bolts extending 8 feet into the ground secure the turbine tower to the foundation.
Different size cranes assemble the towers. But the final steps of putting the 79-ton nacelle on the hub of the tower and attaching the blades require the biggest crane of all, the red Manitowoc.
Sometimes, the Manitowoc crane must move to different sites that cannot be reached by country roads. Nor can a crane this massive be driven down Highway 12. In such cases, workers must take the crane apart, truck it to a new site and then put it back together again.
Assembling the parts of a wind turbine takes about two days, Callahan said. But that’s only if the winds cooperate. A stiff, steady afternoon wind in the Montezuma Hills – a common occurrence – isn’t good weather for maneuvering turbine blades several hundred feet in the air.
The 50 turbines aren’t the only thing big about Shiloh III. There’s also the project price tag that enXco southwest region vice president Mark Tholke puts at $300 million. That includes everything from design to construction to permits.
About 125 people are putting together the turbines and this number could grow to 175, Callahan said. The crews are specialized – one crew puts in foundations, another puts up towers, another attaches the blades.
“It’s like a big train,” Callahan said. “It’s kind of like an assembly line.”
And that big, turbine-assembling train is moving fast through the Montezuma Hills.
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