Offshore wind builders are encountering an sudden problem on the East Coast seafloor: a crushable, inexperienced mineral known as glauconite, typically exactly the place they plan to put in wind generators. The mineral – which dates again to the age of the dinosaurs – is weaker and fewer predictable than sand, scientists say, presenting a brand new engineering puzzle for researchers and wind builders to resolve.
Glauconite’s habits poses a “important threat” to offshore wind growth, mentioned a paper revealed this 12 months by the U.S. Bureau of Ocean Vitality Administration, the lead regulator of offshore wind. It mentioned glauconite formations are “plentiful” alongside the continental shelf, and that wind builders will “inevitably” encounter the fabric throughout development.
Not less than two builders have run into the mineral in a complete of three offshore wind initiatives – two south of Massachusetts and one south of Lengthy Island, New York. In a doc revealed final month, BOEM wrote that the geotechnical properties of the mineral make it an “extraordinarily troublesome materials to construct upon,” particularly for fixed-bottom wind generators.
Glauconite’s presence has already triggered BOEM to reject proposed wind turbine layouts which may have minimized a challenge’s potential results on marine life and the fishing {industry}.
Offshore wind generators will attain greater than 500 toes above the ocean’s floor. They’re normally constructed on foundations pushed greater than 60 toes into the seafloor, however glauconite’s resistance to pile driving – which could result in “pile refusal” – may make reaching goal depths a bit more durable.
Glauconite may elevate the development prices of offshore wind initiatives and decelerate challenge progress for an {industry} that’s already dealing with headwinds from inflation and provide chain points.
“Untimely driving refusal can lead to added prices that are orders of magnitude larger than these for onshore initiatives, and is a foremost threat consider offshore developments,” mentioned an industry-funded examine, revealed final month.
To deal with the problem, 5 builders with initiatives deliberate alongside the East Coast are funding a yearslong {industry} challenge with a Norwegian agency to review glauconite’s habits, develop scientific fashions, and devise strategies to reduce uncertainty and threat.
The habits of glauconite
Layers of glauconite stretch from Massachusetts to the Carolinas and may be discovered on land and underwater. A educated eye can spot glauconite embedded in Homosexual Head cliffs on Martha’s Winery or dug up at a fossil website in New Jersey.
Samples of the millions-years-old mineral sit in a repository at Rutgers College, in tubes, glass bottles, and cores. The cores, which seize millennia in mere meters, boast gradations of inexperienced, clumpy sediment: glauconite. There within the repository, marine geologist Kenneth Miller poured some from a small container onto a lab bench.
“That’s a sand; you’ll be able to see the grains,” he mentioned.
Then, with the butt of a glass container, he hammered the glauconite, pulverizing it with out a lot effort right into a powder, like silt or clay. He took a pinch of it and rubbed it between his fingers, now subtly coated in a inexperienced hue: “There’s no grains.”
Geologists and engineers describe glauconite as crushable, as Miller demonstrated. Rubbed between one’s fingers, it looks like sand – a more durable sediment that’s higher understood and sometimes constructed on. However when uncovered to strain and friction, glauconite transforms.
“You begin with sand, however your strategy of making an attempt to get by means of it, whether or not by hammering or drilling, makes mud, and meaning you get caught,” mentioned Miller.
Caught isn’t a very good factor, significantly when wind builders are hammering multi-million-dollar turbine foundations into the ocean ground with specialised vessels that may price a whole bunch of 1000’s of {dollars} a day to function.
Throughout offshore set up, the primary turbine items to go in are the foundations. A standard sort is a metal monopile – a hole cylinder that may exceed 30 toes in diameter.
In a course of known as “pile driving,” a vessel geared up with a big “hammer” smashes the pile to its goal depth by means of vibration or hydraulics. As a result of the piles will bear the burden of skyscraper-tall towers and 600-ton mills – and since they have to stand up to 30 years of waves and storms – engineers decide the depths they have to attain within the seafloor to stay safe.
Earlier than any of that development takes place, although, builders conduct geotechnical surveys and acquire soil samples. That’s when glauconite has been turning up.
When glauconite is manipulated – in offshore wind development, that might occur throughout basis set up – it begins to crush, altering from sand-like to clay-like.
“From a geotechnical perspective, that’s like night time and day,” mentioned Zachary Westgate, affiliate professor of civil engineering at UMass Amherst and a researcher on the industry-funded glauconite challenge. Getting the monopiles into the seabed is essential to putting in wind generators with fastened foundations, so if pile refusal happens, it may current an added problem.
He framed it as a difficulty from a “pile drivability” perspective. After set up, glauconite’s habits may find yourself being benign: “The {industry} has to form of handle this and scale back the uncertainty about putting in their foundations.”
Offshore wind developer Equinor has discovered glauconite at its two wind challenge areas, off Massachusetts and New York, respectively.
At Equinor’s Empire Wind challenge, deliberate for the New York coast 15 miles south of Lengthy Island, 22 of 71 deliberate turbine positions pose a excessive threat of pile refusal resulting from glauconite, based on the challenge’s ultimate environmental assessment, launched by BOEM final month. Which means there’s a threat the developer couldn’t set up foundations to needed depths in these areas.
Equinor has additionally discovered glauconite at its different lease, Beacon Wind, which sits south of Martha’s Winery, based on an organization spokesperson. Equinor’s geological surveys and knowledge evaluations for Beacon Wind are ongoing, however the firm stays dedicated to its challenge timelines with New York and BOEM, the spokesperson mentioned.
Already, glauconite has scuttled a few of Equinor’s efforts at working with the fishing {industry} over potential turbine layouts for its Empire Wind challenge.
Equinor had mentioned attainable turbine positions with the Accountable Offshore Growth Alliance, a coalition of fishermen and fishing firms. The discussions knowledgeable a proposed different for the Empire Wind challenge that might have eradicated seven generators to permit extra space for fishing vessels to cross by means of.
The Massachusetts Workplace of Coastal Zone Administration supported that different, along with one other, in hopes of accelerating entry for fishermen, together with New Bedford scallopers.
A special different, really helpful by NOAA Fisheries’ Larger Atlantic workplace, would have eliminated as much as six deliberate generators close to Cholera Financial institution, in an effort to reduce potential impacts to an essential fish habitat.
However BOEM concluded this September that the alternate options supported by RODA and NOAA Fisheries, respectively, had been not viable as a result of presence of glauconite. Due to the chance of pile refusal, BOEM concluded, glauconite lowered the variety of “appropriate positions” for generators inside a part of the Empire Wind lease space to 49. Adopting the alternate options, the company discovered, would preclude the developer from assembly vitality contracts with the state of New York.
Ørsted, a developer that has a number of wind initiatives deliberate alongside the East Coast, discovered “varied ranges” of glauconite at its Dawn Wind lease space, which is south of New Bedford and east of Lengthy Island, based on a spokesperson. In a February 2023 letter to BOEM, Ørsted wrote that it anticipates pile refusal might happen throughout basis set up at “a number of” of its 102 proposed turbine areas as a result of presence of glauconite. The corporate mentioned in its letter that it plans to suggest an alternate format of turbine areas.
An Ørsted spokesperson advised The Mild that glauconite isn’t anticipated to have an effect on the challenge timeline or its skill to satisfy agreements to ship energy to the states. Ørsted didn’t reply to questions of whether or not it has discovered glauconite at its different lease websites, and what number of turbine positions may be impacted at its Dawn Wind lease.
Glauconite present in MA, NY initiatives
Glauconite can kind over tens of 1000’s of years. The older it’s, the darker it’s – nearly black; youthful glauconite ranges in hues from a light-weight jade inexperienced to greenish beige. It’s fashioned partially from fecal pellets and tiny marine organisms, however “it’s not all poop,” mentioned Miller.
Glauconite may be round 70 million years previous (or youthful), but researchers are discovering a few of it in seafloor strata which can be lower than 2.5 million years previous. Miller says it may have been transported by water from glauconite beds on land.
How a lot glauconite is current at future wind farm websites off the East Coast isn’t but clear. Some initiatives won’t run into it in any respect – or may discover it in skinny sufficient layers that it gained’t trigger points throughout basis set up.
Builders are nonetheless conducting surveys and geotechnical evaluation, and so they deal with the data they’ve gathered as proprietary. Public knowledge that does exist on glauconite’s presence in america is many years previous and solely a restricted sampling of the expansive continental shelf.
“It might look straightforward, however the secure transportation of those parts miles over the open water isn’t any small feat. Whereas we’ve had many firsts, as soon as this turbine is put in, it is going to stand as a proud image of [America’s] vitality transition.” – Winery Wind CEO Moeller
Off Massachusetts, Beacon Wind and Dawn Wind have confirmed the presence of glauconite. A spokesperson for SouthCoast Wind mentioned geotechnical surveys have been accomplished of its lease space, however the evaluation has not.
Avangrid, co-developer of the Winery Wind farm now underneath development, didn’t reply the query of whether or not it has discovered glauconite at any of its East Coast lease websites.
An Avangrid spokesperson mentioned the corporate is contemplating completely different basis varieties and set up strategies to “account for several types of seafloor situations in our lease areas.” The spokesperson mentioned the corporate is collaborating with {industry} companions to “advance the collective understanding of glauconite and its potential affect on offshore development.”
A spokesperson for Attentive Vitality, which holds an offshore wind lease off the New Jersey coast, acknowledged that glauconite is of “regional concern” alongside the New Jersey and New York coasts – likening it to concern over boulders in New England. The spokesperson asserted that the presence of any glauconite gained’t have an effect on the challenge’s skill to satisfy its power-generating capability.
Attentive Vitality may flip to a number of mitigation measures if glauconite is found, the spokesperson mentioned, together with different turbine foundations (as an alternative of a monopile) or set up strategies.
Authorities seeks higher grasp on glauconite
The federal authorities, which leases components of the seafloor to wind builders, can also be making an attempt to get a greater grasp on glauconite. A 2017 BOEM report recognized the Atlantic Outer Continental Shelf as a “frontier.” There, “little data exists in regards to the geologic situations and the way these situations might influence growth of offshore wind farms,” the report learn.
“There are not any specialists on the subject,” a BOEM official wrote in an early 2023 e-mail about an upcoming glauconite assembly to the company’s renewable vitality chief, Karen Baker.
Glauconite is presenting obvious difficulties for NOAA Fisheries – a federal company that works with BOEM to assessment offshore wind initiatives.
In a letter this 12 months to BOEM, NOAA Fisheries mentioned data on glauconite was a lacking piece within the company’s skill to completely consider potential environmental impacts of the SouthCoast Wind challenge.
“We perceive that the presence of glauconite is creating development feasibility points for some initiatives,” wrote Mike Pentony, a regional administrator for NOAA Fisheries’ Larger Atlantic workplace, “and the gathering of geotechnical cores essential to establish these constraints is going on late within the course of.”
Cores and different geological knowledge are collected by the developer by means of surveys. If the surveys are usually not carried out previous to the company’s environmental evaluation, “we take into account that to be ‘late within the course of,’’’ mentioned a NOAA Fisheries spokesperson in an announcement to The Mild. “Adjustments to the proposed motion at that time within the environmental assessment might trigger delays.”
BOEM, by means of a spokesperson, didn’t reply to a collection of questions on glauconite – together with the place it’s discovered on the outer continental shelf and what number of offshore wind initiatives have encountered it.
The spokesperson mentioned by e-mail that the wind {industry} is learning measures to mitigate pile refusal in glauconite, and that BOEM will consider proposed mitigation measures because the company’s challenge opinions proceed.
In 2021, the Norwegian Geotechnical Institute (NGI) began learning glauconite with wind builders. As of 2023, Ørsted, Equinor, RWE, Attentive Vitality and Avangrid are contributors of this joint {industry} challenge, known as “Piling in Glauconitic Sands.” The 5 builders have no less than a dozen initiatives mixed slated for development alongside the East Coast.
Collectively, the builders have invested about $4 million in fieldwork, onshore pile driving checks, and laboratory checks to grasp how glauconite will behave throughout turbine set up and long run, based on researchers working with NGI.
“Glauconite is unquestionably one thing that we have to higher perceive, in order that we’ve extra alternate options, in order that we don’t remove turbine positions which may be truly installable in spite of everything,” mentioned George Hagerman, offshore wind techno-economic lead on the Nationwide Renewable Vitality Laboratory. “The extra turbine positions which can be geotechnically viable, the higher, as a result of it offers everybody extra flexibility.”
Hagerman, who’s reviewing knowledge on glauconite for BOEM, mentioned it’s in all people’s curiosity to get a greater deal with on the fabric: “When you’ve signed a lease, you’ll be able to’t go exterior that lease, and so that you need to have the ability to use as many turbine positions in that lease as attainable, or no less than have them accessible for tradeoffs.
“It’s a win-win for the atmosphere, a win for the builders, a win for all of the stakeholders if we are able to discover methods to make use of turbine positions which have glauconite,” he mentioned, “both by discovering an alternate basis or basis set up technique, something that might permit us to need to not write off these positions.”
Researching towards an answer
Engineers have encountered different difficult supplies on the ocean ground earlier than, like carbonate soils off the Australian coast (which triggered the other situation – piles would fall into the collapsing sediment). They’ve discovered methods to assemble on these sediments.
Glauconite just isn’t a completely novel materials for engineers, who’ve constructed on it in England and Belgium. “Glauconite sands have been efficiently monopiled in Europe, however the focus in European areas offshore just isn’t as nice because the glauconite focus at U.S. websites,” mentioned Hagerman.
Reporting on pile set up in Belgium the place glauconite was current, researchers with Ørsted wrote in a current convention paper that whereas the piles had been put in to their goal depths, “set up was time consuming, and a excessive variety of blows was required.”
Proserpine Peralta, a geotechnical engineering supervisor with the agency Fugro, says that if a monopile will get caught in glauconite, a bigger (and certain costlier) hammer might be wanted. She really helpful builders predict and plan for this threat earlier than set up, because it may price them thousands and thousands extra to deal with the pile refusal with both a much bigger hammer or elimination of the pile.
Present predictions present that in some circumstances, accessible hammers might not be sufficiently sturdy to drive the piles to their goal depths, resulting from glauconite layers, amongst different elements within the soil, Peralta mentioned.
Fugro is engaged on an answer that might contain drilling the glauconite clog out of the hole monopile. After drilling, driving would recommence. In easier phrases: “drive-drill-drive.”
Don DeGroot, a professor of civil engineering at UMass Amherst and researcher on the builders’ challenge, mentioned he’s assured the {industry} will determine this problem with time.
“The geoscientists have executed quite a lot of work on [glauconite], however I feel it’s truthful to say not quite a lot of engineering analysis has been executed on it,” he mentioned. “It’s good to have the wind {industry} kickstart this attention-grabbing path.”
Builders and engineers use fashions to foretell how soil will behave throughout development, he defined, which in flip informs challenge design. Fashions for sands and clays are well-established, however a complete mannequin for glauconite must be developed (one thing the NGI challenge is working towards now).
Pending extra funding, the NGI challenge plans to begin one other section of analysis.
“It’s all a query of threat and cash, however there’s quite a lot of good folks within the offshore wind {industry}, and so they have a ton of expertise in Europe,” DeGroot mentioned. “I’m very assured that is all going to be taken care of, and will probably be appeared again upon as a very attention-grabbing alternative to use engineering analysis to a sensible challenge.”
