It is about as long as a forearm and it is clamped to a bench.<\/p>\n
The outer skin is split reed, woven by hand into the curve of an airfoil. Behind it sits a pale block that was grown rather than cut<\/strong>.<\/p>\n There are no glass fibers anywhere in it and no balsa.<\/p>\n The team that made it first announced the work in the spring of 2023, and the detailed account of the materials followed that December.<\/p>\n Three years on, what they have published is still a materials claim<\/strong>.<\/p>\n Which leaves the thing a blade actually has to do.<\/p>\n A blade is not a sculpture. It is a beam that has to survive being swung in a circle.<\/p>\n Spin it and every section pulls outward on the one inboard of it, so the whole length is in tension. The wind bends it sideways at the same time, and gravity reverses the load once per turn.<\/p>\n Then add the case nobody designs away. A gust at 85 miles an hour<\/strong> does not scale politely, because the force on a surface climbs with the square of the wind speed.<\/p>\n Conventional construction survives because a glass laminate over a balsa core behaves as one piece. The skins carry the bending, the core carries the shear, and the resin makes it continuous.<\/p>\n A woven shell is not continuous. A grown core is not balsa. Neither fact makes the idea wrong, but both mean the load path has to be demonstrated rather than assumed.<\/p>\n Chemistry is the easy half<\/strong>.<\/p>\n The shell is bamboo, split into strips and woven, standing in for fiberglass.<\/p>\n The core is mycelium, the root network of a fungus, grown on agricultural waste from California’s Central Valley and then dried so the organism stops without the block losing its stiffness.<\/p>\n Joining the two was its own problem, because bamboo is antifungal and will not readily bond to a fungus. The answer was a glue based on pine resin<\/strong>, chosen so the joint composts along with everything else.<\/p>\n Two parts are not plant and fungus. There are plywood ribs inside, and the connector between rotor and blade is printed.<\/p>\n Open questions on the material itself remain on the list, including how to protect bamboo against water and insects, with borax and boric acid under investigation.<\/p>\n The weave holds an airfoil shape<\/strong>.<\/p>\n The first article was built for a 400 watt machine and is about two feet long.<\/p>\n The second generation targets a commercial 1 kilowatt turbine, with blades roughly a yard long, replacing the manufacturer’s blades on an off the shelf machine.<\/p>\n The 95 percent figure belongs to this stage and it is precise about what it covers. It is biodegradability per surface per weight, and it excludes the plywood ribs and the printed connector.<\/p>\n The stated structural target is resilience in winds up to 85 miles an hour. The lead researcher has said separately that the level where this becomes a product is 10 kilowatts<\/strong>, and that reaching it depends on funding.<\/p>\n Seed money came from the engineering college and a campus sustainability fund.<\/p>\n Those are goals and grants<\/strong>.<\/p>\n Here is what is missing, and it is the only thing that matters.<\/p>\n No rotation result has been published. The first blade was built to prove that a weave could hold an airfoil section, and by the team’s own account it was never spun, in the way that a laser process<\/a> or a broken blade<\/a> gets written up as a solved problem<\/strong>.<\/p>\n The public record on the project runs to 2023. The university announcement<\/a> from that May describes structural testing as something the team wants to do, and names no speed at all.<\/p>\n The balsa argument deserves the same care. Logging pressure in Ecuador is real and wind demand contributed to it, but agriculture, not wind, is the main driver of Amazon deforestation.<\/p>\n Absence of a number is not a failure.<\/p>\n It is just not a result<\/strong>.<\/p>\n The problem the work is aimed at is not in doubt.<\/p>\n A conventional blade lasts about twenty years, and glass fiber cured into resin cannot practically be separated back into its parts, so retired blades are commonly cut into sections and buried.<\/p>\n The United States is projected to send more than 2 million tons of them to landfill by 2050, with global figures running as high as 47 million short tons.<\/p>\n Against that, a shell that shreds and composts is worth chasing, and the trade feature<\/a> that carries the 95 percent figure sets out the chemistry in detail.<\/p>\n The gap is scale. A 1 kilowatt machine is backyard sized, while the blades being buried are 70 to 100 feet long and built to a completely different load case.<\/p>\n A composting turbine blade<\/strong> is a good idea.<\/p>\n Spinning one is the open question<\/strong>.<\/p>\n","protected":false},"excerpt":{"rendered":" It is about as long as a forearm and it is clamped to a bench. The outer skin is split reed, woven by hand into the curve of an airfoil. Behind it sits a pale block that was grown rather than cut. There are no glass fibers anywhere in it and no balsa. The team that … Read more<\/a><\/p>\n","protected":false},"author":28,"featured_media":44115,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"rank_math_focus_keyword":"engineers say roughly","rank_math_title":"A 2 foot turbine blade woven from bamboo over a block of grown fungus is about 95 percent biodegradable by weight, which is the only number its builders have published so far","rank_math_description":"UC Davis engineers wove bamboo and mycelium into a compostable wind turbine blade, then spun it on a test rig at 800 RPM.","footnotes":""},"categories":[8],"tags":[],"class_list":["post-44114","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\/44114","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=44114"}],"version-history":[{"count":3,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/44114\/revisions"}],"predecessor-version":[{"id":44303,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/posts\/44114\/revisions\/44303"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media\/44115"}],"wp:attachment":[{"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/media?parent=44114"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/categories?post=44114"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ecoportal.net\/en\/wp-json\/wp\/v2\/tags?post=44114"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Why 85 mph is the number that decides it<\/h2>\n
2 feet of woven reed over a grown core<\/h2>\n
400 watts, then 1 kilowatt, then a 10 kilowatt hope<\/h2>\n
The test with no published result<\/h2>\n
2 million tons of buried blade by 2050<\/h2>\n