2012-03-01 / News

Putting a turbine together is no small job

BY HARLEY LEE


Eighth-grader Rachel Warner of Stephanie Pamula’s Lawn Avenue School art class had this creative interpretation of two turbines on the island’s landscape. Eighth-grader Rachel Warner of Stephanie Pamula’s Lawn Avenue School art class had this creative interpretation of two turbines on the island’s landscape. Recently we’ve been working on a potential layout for the Jamestown wind turbine. In addition to all the usual issues this involves like avoiding wetlands, minimizing shadow flicker, minimizing clearing and connecting to the grid, one of the key issues is where to put the crane.

Installing a wind turbine in Jamestown will require a big crane. The crane has to not only lift three tower sections but then has to lift the nacelle – the box that holds the generator – up 220 feet to the top of the tower. The nacelle weighs 160,000 pounds – as much as 32 SUVs.

This requires a big crane. The type of crane used for wind turbines is so big that it has to be brought in on 30 tractor-trailers. It can take a week just to assemble it. The boom on the crane is upwards of 300 feet long. It will take a couple days to install the turbine and then the crane will be disassembled and trucked off to its next wind project.

For planning purposes, we’ll need a level firm crane pad right next to the foundation and also next to the access road. This allows a truck to deliver the first tower section and the crane to pick it up and gently place it on the foundation. The bolts sticking up out of the concrete will hopefully align perfectly with the bolt-holes in the tower. Then the second section is lifted while technicians wait at the top of the first section with their wrenches. (Fingers stay inside the tower.)

The third section is lifted next, and then the nacelle. Once the nacelle is bolted on, the rotor is lifted. Sometimes the three blades are connected to the hub and lifted as one assembly and other times the hub is installed and the blades are lifted one at a time. It’s generally easier to assemble the rotor on the ground but it takes up a lot of space.

Once all the major components are in place, technicians hook up all the wires and other components and then begin the commissioning process. (The construction on the electrical interconnect can begin well before the turbine is installed so that it’s ready once the wind turbine is installed.)

Two weeks ago Town Councilor Bill Murphy and Planning Commission Vice Chairman Duncan Pendlebury joined me for a trip to the construction site in Providence. Gilbane building company is installing three similar sized wind turbines at the sewage treatment plant for the Narragansett Bay Commission. Although Jamestown’s sewage treatment plant has some space limitations, this site was more crowed. It was interesting to see how the crane contractor had laid out its equipment. To put a rotor together, it had one blade hanging over a parking lot and another over a sewage treatment tank. When we made our visit, two turbines were already up and the crew was preparing to lift the third one. That allowed us to see both installed turbines as well as components on the ground.

You can see these turbines as you drive into Providence on Interstate 95. They are straight ahead just as you enter a sharp left turn. Drive carefully.

When the state Department of Environmental Management installed a wind turbine at Fishermen’s Memorial State Park last October, the parking lot filled up with spectators. It even included a crane enthusiast who was delighted to talk shop with the crane operator.

There is a video from the National Renewable Energy Lab showing a turbine installation at YouTube.com/watch?v=eY9EmLV8pnE.

The author is president of Endless Energy Corporation, a consultant chosen by the Town Council in December to conduct studies necessary to determine the costs and potential profitability of a Jamestown wind turbine.

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