WALNUT, Iowa (AP)—At a western Iowa wind farm, a demolition crew saws through red slashes marked on 120-foot turbine blades, cutting them into thirds before stuffing the thinnest piece inside the base's hollow cavity, making more room on a flatbed trailer.

The work is part of MidAmerican Energy's efforts to "repower" almost 110 turbines, updating towers with longer blades, new hubs and refurbished generators. When the work is done, the wind farm will generate almost 20% more energy, Des Moines-based MidAmerican says.

But the upgrades for Iowa's growing wind industry, which is already among the nation's largest, are creating some unexpected challenges.

MidAmerican's retired blades, destined for the Butler County Landfill near David City, Nebraska, about 130 miles away, are among hundreds that will land in dumps across Iowa and the nation. Critics say the blades' march to a landfill weakens the claim that wind is an environmentally friendly energy source.

"This clean, green energy is not so clean and not so green," said Julie Kuntz, who opposes a wind project in Worth County in north-central Iowa. "It's just more waste going in our landfills."

Daniel Laird of the U.S. Department of Energy told the Des Moines Register that most of a turbine can be recycled, including "a lot of metal — steel and copper."

But he acknowledged that disposing of the blades is a challenge. Wind energy generation, now topping 100 gigawatts nationally, will create 1 million tons of composite waste, said Laird, director of the National Wind Technology Center at the National Renewable Energy Laboratory in Colorado.

"The scale of the issue is quite large," said Laird, whose group is working to develop new blade materials that will allow them to be reused. "It's quite a bit of material. And it's a larger sustainability issue. We would like everything that's manufactured to be reusable or recyclable."

Disposing of turbine blades is an issue that will likely linger for years in Iowa. Large, investor-owned Iowa utilities are investing heavily in new wind projects as well as replacing blades to extend the life of older turbines.

MidAmerican will have spent $11.6 billion on wind energy from 2004 through this year, and Alliant Energy is spending $2.4 billion to build wind farms in Iowa. Iowa had 5,073 turbines last year, seven times more than in 2004, data from the U.S. Energy Information Administration show.

Kerri Johannsen, the Iowa Environmental Council's energy program director, said more recycling solutions are needed. But, she added, it's not a reason to "turn away from wind energy — a solution that can help mitigate the most dangerous threats from climate change."

As older wind farms receive face-lifts, so far, only one facility in northern Iowa is taking old blades.

Landfill operators thought that the composite blades, cut in sections of 40 feet or longer, could be readily crushed and compacted. "But blades are so strong — because they need to be strong to do their job— they just don't break," said Amie Davidson, a solid waste supervisor in the Iowa Department of Natural Resources.

"Sometimes, pieces fly off and damage equipment" in the compacting process, she said. "Landfills are really struggling to manage them, and they just decide they can't accept them."

Bill Rowland, president of the Iowa Society of Solid Waste Operations, said he's not sure that "we as a society" considered what would happen to the blades as older turbines are refurbished.

"There wasn't a plan in place to say, 'How are we going to recycle these?' 'How are we going to reduce the impact on landfills?' " said Rowland, director of the Landfill of North Iowa near Clear Lake.

"One way or another, we have to deal with it as a state," he said. "They've been promoted. They've been built. In our opinion, there needs to be a way to handle the waste that's derived from them."

The difficulty in reusing blades adds to the complaints of wind energy opponents. Some who live near the turbines complain that low-frequency noise and flickering light from the blades make them ill. And the spinning blades can kill migrating birds and bats.

Blade disposal is "just one of many factors we're concerned about," said Kuntz, theWorth County wind farm opponent.

MidAmerican, which began building its own wind farm in 2004, said it relies on turbine manufacturers —who then hire contractors — to decide how best to dispose of old blades, hubs and electronics.

When it started investing in wind, the utility believed that a blade recycling option would emerge. "Thus far, it hasn't," spokesman Geoff Greenwood said.

In South Dakota, Donny Kuper, superintendent of the Sioux Falls Sanitary Landfill, said the landfill imposed new requirements on turbine blades after studying how much space 100 blades from an Iowa wind farm took up.

Concerned that accommodating the massive pieces will shorten the life of the landfill, Kuper said, the operation will require the blades to be cut up in smaller pieces so they can be compacted like other waste.

That should make it easier and safer for Kuper's crew to manage the blades, one of which got caught in a 120,000-pound compactor wheel. It flew up and broke the machine's windshield, idling the $900,000 piece of equipment for a week.

"There's definitely risk involved," Kuper said. "The blades themselves are pretty slick, so compactors can get on top of a blade and slip off. It's not happened to us, but I've heard it happened in other landfills, where a compactor has tipped over."

The Waste Management facility near Lake Mills in northern Iowa is accepting the blades, but its workers are "shearing" them — or cutting them into smaller pieces, said Julie Ketchum, a Waste Management spokeswoman.

The facility takes in about six blades a day, or the equivalent of two wind turbines, she said.

Davidson, of the Department of Natural Resources, said other landfills are discussing whether to accept the blades. One of the issues that has emerged is who should be responsible for cutting them into smaller pieces, she said.

Davidson said she's not sure whether many recycling options are available. Laird, of the DOE, said most options involve cutting up the material and using the pieces in other products. But it's unclear whether that's financially viable over the long term.

The problem with recycling blades, Laird said, is that there is no easy way to separate the materials.

Using food analogies, he said some materials in the blades are like a fried egg. Once they're cooked, they can't be changed. If those materials were more like chocolate, they could be melted, reformed and used to make something else.

His team is working to see if blades can be made differently, maintaining their toughness while allowing for reuse when they've done their job.

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