Back in September we ran a story about a wind turbine blade that fell off its own transporter in an S-curve in the Black Forest, and an Enercon rep standing next to the wreck told reporters he’d never seen a failure like it in his career. I read that one as a freak event. Well, it’s been about seven weeks.<\/p>\n
Shortly after midnight on October 16, a self-propelled blade transporter grinding up a gravel forest track toward the Hohe Molmert wind farm, on a ridge above the town of Plettenberg in Germany’s Sauerland hills, went over in a bend. The blade it was carrying landed on the forest floor. Two workers, Italians aged 38 and 56, went to the hospital with minor injuries, and the first damage estimate from the transport company is a seven-figure number in euros.<\/p>\n
So it’s a different forest and a different company, with more or less the same picture at the end of it. Is something going on with German blade transports?<\/p>\n
Frankly, two crashes in seven weeks isn’t a trend, and as we found out last time, nobody in Germany keeps a national statistic on blade transport accidents, so I can’t tell you whether this is a bad year or a normal one. What I can tell you is what went over, how they got it back on its wheels, and what it’s doing to a wind farm that was supposed to be sending power by now.<\/p>\n
The vehicle in question isn’t a regular truck and trailer. It’s what the industry calls a self-propelled unit: a powered, multi-axle platform that grips the blade by its root and tilts it up toward the sky, so the tip swings over the treetops instead of through them. The whole point of carrying a blade that way is that you don’t have to cut down trees or widen the track to get a 272-foot blade up a mountain, which is more or less how Joel Otte, who ran the recovery for Dietrich Trucks, the firm hired to pull the wreck out, explained it to WDR<\/a>, the regional public broadcaster.<\/p>\n According to police in the M\u00e4rkischer Kreis, the blade and the unit under it weighed roughly 149 tons together. The blade is the lighter part by a wide margin: each one headed for Hohe Molmert is 272 feet long, weighs about 26 tons and is molded from fiberglass-reinforced plastic, according to Lokaldirekt<\/a>, the local news site that has been following the transports since the first one in mid-September. Which means the thing lying on its side in the woods was mostly transporter, with a very long and fairly fragile piece of fiberglass attached to it.<\/p>\n Police got the call at around 12:30 a.m. The fire department mopped up the fuel and fluids that leaked out, and the state workplace safety office was notified, per Lokaldirekt’s report<\/a> on the morning of the crash. The cause? Police say it’s unclear, and I haven’t seen anything more definitive since. In the Black Forest it was a hydraulic failure. Here, the police still haven’t given one.<\/p>\n If you’ve never seen one of these convoys, the pace is kind of absurd. The blades for four of the five turbines, 12 in all, are staged at a yard in L\u00fcdenscheid, the next town over. The transports are only allowed at night, they move at roughly 3 mph, and the first one took just shy of six hours. P-Wind, the local company building the farm, said after that first run that it expected the trips to get a little shorter and wanted to bring up one blade a day.<\/p>\n The route runs out of L\u00fcdenscheid on a federal road, then two smaller roads down to the village of Selscheid, and from there up a farm track to the ridge. That last stretch is the one with the gravel and the bends.<\/p>\n It’s also the stretch where the blade is standing nearly on end. If you’re wondering what that looks like, picture an airliner wing tilted up behind a tractor, crawling through the dark with a crew in reflective vests walking alongside. It looks completely wrong the first time you see it, and it’s exactly the trick that gets a blade this long through a forest without a chainsaw. We’ve seen the same math play out with 292-foot blades in the Australian desert<\/a>, and this week with a 213-foot blade that can’t make a roundabout<\/a> outside a McDonald’s.<\/p>\n Righting it took most of a long weekend. By Sunday, three of the vehicle’s four units were back on their wheels, with 30 specialists on site, some of them brought in from Denmark, England and the Netherlands to work alongside the local crew, plus a mobile crane and an excavator. Dietrich Trucks finished the job on Monday. “The challenge is the space we have to work in,” Otte told WDR, which is a pretty understated way of describing a 149-ton vehicle lying across a wooded bend with a 272-foot blade next to it. He also said it took a lot of equipment and a lot of deliberate, slow decisions to avoid wrecking anything else, hurting anyone or making the spill worse.<\/p>\n About that spill. Diesel and oil leaked from the powered unit, though Otte said the amounts were small. An excavator is scraping off the contaminated soil and fresh dirt goes in after it, a job WDR said would take several hours.<\/p>\n Then there’s the blade. Marco Wirtz, also of Dietrich Trucks, told WDR that lifting it out of the woods in one piece would be tough because of its length, so the likely outcome is that crews cut it up where it lies and lift the sections out with the crane. Whether it’s worth repairing at all is the turbine manufacturer’s call, and as far as I can tell nobody has announced one. A blade that has been dropped off a tipping transporter onto a forest floor doesn’t strike me as a strong candidate for a second life, but I’m not the one holding the warranty paperwork.<\/p>\n P-Wind Plettenberg, a local outfit whose two managing directors say they live in the area and will be looking at these turbines themselves, is putting five of them on the Hohe Molmert ridge. Four have a hub 538 feet up and a tip height of 820 feet; the fifth is shorter, 390 feet to the hub and 656 feet overall. All five are rated at 7.2 megawatts, 36 megawatts in total, and the company expects around 80 million kilowatt-hours a year out of them, enough for about 20,000 households. The whole project runs about 50 million euros.<\/p>\n The towers were already up when the blade transports started in September. When the company first walked local politicians through the plan, the grid connection was penciled in for September or October. In September, with the first blade on the ridge, the managing director’s line was that the plan was still to have the turbines running before the end of the year. That was five weeks before one of the blades ended up on the ground.<\/p>\n So does a dropped blade push the switch-on into next year?<\/p>\n I don’t know, and I can’t find anything P-Wind has said publicly since the crash. It’d be a little surprising if it didn’t. Each turbine needs its full set of three, a replacement blade has to be built or pulled from stock and driven up the same track at 3 mph, and that track just had a 149-ton vehicle lying across it from Friday to Monday. The one thing working in the farm’s favor is that 12 blades were scheduled for four turbines, and I don’t know how many had already made it up before the crash, so parts of the site may be further along than this one bend suggests.<\/p>\n Two dates are solid, though. In the Black Forest, the blade transports restarted on September 28, a month after that crash. At Hohe Molmert, Dietrich Trucks finished pulling the vehicle out of the woods on October 19, and when WDR filed its report that day, the blade was still lying in the forest.<\/p>\nThree miles an hour, at night, uphill<\/h2>\n
Thirty people and a crane to put it back on its wheels<\/h2>\n
The farm was supposed to be making power by now<\/h2>\n