A cranberry bog in early November, flooded shallow and red, with the vines under the water.<\/p>\n
Lying across it is something long and white that does not belong in a field.<\/p>\n
It is the better part of a hundred feet, split open at one end, mud pushed up along one side.<\/p>\n
A few hundred feet away a tower stands with two blades on it instead of three.<\/p>\n
Nobody saw it come down<\/strong>.<\/p>\n Several people heard it<\/strong>.<\/p>\n A turbine blade is not bolted to a hub at its edges. It is anchored through a ring of studs set into the thick root end, which is the only place the composite is strong enough to take that load.<\/p>\n That ring bolts into a pitch bearing, a large slewing ring that lets the blade rotate about its own axis to catch more or less wind.<\/p>\n Everything the blade does passes through that one circle of steel. Weight, thrust, bending, and the twisting load of pitching in gusts.<\/p>\n It is also the most heavily instrumented joint on the machine, because the control system must know the pitch angle of each blade at all times.<\/p>\n So when a blade leaves, the imbalance is immediate and enormous, and the controller senses it within a fraction of a rotation.<\/p>\n The machine stopping itself is the design working<\/strong>, not a lucky outcome<\/strong>.<\/p>\n The site sits on Head of the Bay Road in south Plymouth, near the Bourne town line, and it carries four turbines rather than a single one.<\/p>\n The machines are about 300 feet tall, rated at 2 megawatts each, and they came online roughly a decade ago.<\/p>\n The blade that came off belongs to one of them. The other three were stopped as a precaution and the whole project was taken out of service.<\/p>\n That decision is worth pausing on, because nothing was known to be wrong with the other three.<\/p>\n Machines installed together tend to share a build date, a component batch and a service history, so an unexplained failure in one is a question about all of them.<\/p>\n Shutting a whole site is cheap caution<\/strong> until a cause exists<\/strong>.<\/p>\n The call came in at about 1:52 in the afternoon on a Friday, from a neighbor who looked up and counted two blades where there had always been three.<\/p>\n Firefighters found the blade several hundred feet from the base of the tower, out in open bog, and reported no injuries and no fire on the ground.<\/p>\n Two residents described the sound rather than the sight. One heard a boom like an explosion, another felt a rumble inside the house and compared it to a small earthquake.<\/p>\n Those are useful and they are not measurements.<\/p>\n The operator said it had shut the project down and begun a root cause analysis with the company that built the machines.<\/p>\n State environmental regulators are monitoring the removal<\/strong> rather than investigating the failure<\/strong>.<\/p>\n One detail from the scene has carried most of the speculation since, and it deserves handling carefully.<\/p>\n A television crew reported that the nacelle at the top of the tower appeared charred. That is the housing behind the rotor, not the hub the blades bolt into.<\/p>\n Other outlets covering the same scene the same day reported no fire, no scorching and no burn marks, and the fire department account mentions none.<\/p>\n So what exists is one visual impression of one component, from the ground, at distance, on a gray afternoon.<\/p>\n Even taken at face value it settles nothing about sequence. Heat at the top of a tower can follow a violent mechanical separation as easily as it can precede one.<\/p>\n Blades also come off for reasons with no heat in them at all, as a parked machine off Yorkshire showed when it lost 351 feet<\/a> of blade in a storm.<\/p>\n The charred appearance was reported by a Boston station<\/a> and has not been confirmed as a finding.<\/p>\n A scorch seen from a road is an observation<\/strong> and not a cause<\/strong>.<\/p>\n The wreck is now an environmental job before it is an engineering one, because the ground it is lying in is a working agricultural wetland.<\/p>\n A licensed site professional is drawing up a removal plan, and the bog surface will not carry ordinary heavy equipment.<\/p>\n Then comes the part with no good answer. Blade shells of this generation are glass fiber in cured thermoset resin, which does not melt back down and resists conventional recycling.<\/p>\n Cutting and burying has been the default, and the alternatives are only now reaching real volume, including an Iowa plant that shreds blades<\/a> without heat or solvents.<\/p>\n The site details, the ownership and the removal process are set out by the local paper<\/a>.<\/p>\n The machine behaved correctly on the way down, and the question left standing is why the blade<\/strong> did what it did<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" A cranberry bog in early November, flooded shallow and red, with the vines under the water. Lying across it is something long and white that does not belong in a field. It is the better part of a hundred feet, split open at one end, mud pushed up along one side. A few hundred feet … Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":36866,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"4 turbine site","rank_math_title":"At a 4 turbine site beside a Massachusetts cranberry bog, a blade between 75 and 100 feet long tore free and landed several hundred feet away, and the hub left behind appeared charred","rank_math_description":"A blade detached from one of 4 wind turbines near Plymouth, Massachusetts, landing in a cranberry bog hundreds of feet away. The charred hub at the top re","footnotes":""},"categories":[8],"tags":[],"class_list":["post-36860","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-energy"],"_links":{"self":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/36860","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/users\/28"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/comments?post=36860"}],"version-history":[{"count":3,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/36860\/revisions"}],"predecessor-version":[{"id":36869,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/36860\/revisions\/36869"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/36866"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=36860"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=36860"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=36860"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}What holds a blade on and what lets go<\/h2>\n
Four machines, one of them now short<\/h2>\n
The afternoon, and who reported what<\/h2>\n
The mark on the tower and what it is worth<\/h2>\n
Getting it out of the bog<\/h2>\n