Whales and Offshore Windmills

[FWT]

Remember the brief conversation buried in another thread on dead whales washing ashore in NJ, and the theory that the project to build offshore windmills was the root cause?

Well, just maybe that trend is ending.

Ignore any brief mentions on political slant. Not the point. It contains interesting info on the technical challenges in the mechanical gear.

https://www.zerohedge.com/weather/wi...-major-project

[Shrew]

This is pretty heavily skewed propaganda.

[KnotYet]

FWT, funny you caution 'brief mention' of political slant. You were joking, right?

You're not wrong about technical challenges, though. Like all innovative devices,
wind turbines aren't immune from the development curve. New and better designs
will continue to appear. Now, if there was just some way to get rid of the subsidies
for the oil industry!

https://www.imf.org/en/Topics/climat...ergy-subsidies

[psneeld]

Aside from tech issues that face the turbines even when ashore....

Building and maintaining them in the offshore environment is mindboggling. Sure it can be done but it is hugely expensive.

My old assistance tower boss got out of the little leagues and started betting on wind farms 2 decades ago...none have been built yet in his area and not sure any projects are even in the early stages other than leases and a few approvals. But it must not be dead yet as he just bought a 200 and some foot vessel for wind farm construction/maintenance.

He has told me or I have read some of his writings about much information that is incorrect on both sides of the fence on this topic...wouldn't discount general info, but specifics I am skeptical over.

[Larry M]

Technically the article is a joke.

…But long blades spinning rapidly can have the tips break the sound barrier,…

[KnotYet]

Originally Posted by Larry M

Technically the article is a joke.

…But long blades spinning rapidly can have the tips break the sound barrier,…

The sound barrier is a problem for any airfoil not intended to exceed it.
A wind turbine would have to experience multiple failures for rpm to get so high.
The blades' angle of attack are always being adjusted to adapt to the wind speed.
The blades also lose efficiency if the rpm exceeds design limits well before the
sound barrier at the tips.

[psneeld]

Pretty sure many windmills now turn very slow no matter the wind speed and there is variable gearing that generates more power as wind speeds go up.

[Shrew]

Originally Posted by psneeld

Pretty sure many windmills now turn very slow no matter the wind speed and there is variable gearing that generates more power as wind speeds go up.

Yes, if anyone has seen a wind turbine move, they would easily see that the bird would need to be blind to fly into it. The article is laced with the verbiage of those with multi-million dollar waterfront homes and fossil fuel lobbyists.

[FWT]

Certainly folks can just put aside the politics, which isn't the point.

Some folks here know a lot more about the engineering challenges than I do, and I'd love to understand how real they are.

But I'm not surprised to hear of the problems. A community college I know used to have a windmill on the edge of the campus. It wasn't functioning more than it worked. After maybe 5 years they got rid of it. That was on land. Easier to service.

If the barriers are real, at least today, there is one less thing for us and whales to run into on the water.

[sunchaser]

ESI energy has been fined about $8 million for hundreds of eagle kills at their wind farms located in 7 different Western states. Expert testimony said that as wind farms increase in numbers bird kills will continue until eagle populations in impacted areas are driven to near extinction.

This is not a new issue with bird kills globally rising due to burgeoning wind farms. Unintended consequences is the term used at various state agencies with the increased use of wind farms.

Globally power generation is largely a government or state owned endeavor with legal action for bird kills largely muted. In the US private and public companies are open for legal action with cease and desist orders or large fines emanating. Unfortunately, once again follow the money.

[SteveK]

But scientists say there’s no evidence to support a connection between the two.
From Maine to Florida, 178 whales have died, and scientists have examined about half of the incidents. Of those, about 40% were because whales were struck by ships or got tangled in ropes or nets in the water.
Ørsted’s New Jersey head of government affairs, Maddy Urbish, said the vessels the company had contracted to do its survey work haven’t “experienced any marine mammal strikes during offshore survey activity in the U.S.

Above from CNN link HERE

Some tidbits can be extracted. 40% of 50% of 178 were struck by ships or tangled in nets. So of 178, so 35.6 strikes confirmed and double that for the ones that were not tested.
if you read the whole article you will know that experts are sure the windmills and the work to install them played zero, nada, no part in any death of a whale. Then there were scientists who also agreed, and as we all know science does not care what you think.

[twistedtree]

Wow, what spew. This "news" outlet is a Bulgarian company called ABC Media Limited" to make it sound legitimate, when its just one disgraced former hedge fund guy. And the site espouses anonymous authorship. Nice way to spew garbage while dodging any credibility checks. I don't know why people bother reading this trash.

[Comodave]

Because if it is on the internet it must be true…

[KnotYet]

Originally Posted by Shrew

Yes, if anyone has seen a wind turbine move, they would easily see that the bird would need to be blind to fly into it. The article is laced with the verbiage of those with multi-million dollar waterfront homes and fossil fuel lobbyists.

Bear with me, math is following...
The current 'large' offshore wind turbines are the 6MW size which
have a rotor diameter of 492 ft. The tips cover 1545 ft per revolution.

At sea level in normal conditions the speed of sound is 1125 ft/sec.

The 6MW turbine turning 15 rpm (.25 rps) will have a tip speed of 386.25 ft/sec.
The same turbine turning 30 rpm (.50 rps) will have a tip speed of 772.5 ft/sec.
The same turbine turning 45 rpm (.75 rps) will have a tip speed of 1158.75 ft/sec,
and thus the blade tips will now be breaking the sound barrier.

At the rpm of a record player (of your youth).

Even at the sluggish 15 rpm, the tips of the 6MW turbine are going over 263 mph.

[twistedtree]

Originally Posted by KnotYet

Bear with me, math is following...
The current 'large' offshore wind turbines are the 6mW size which
have a rotor diameter of 492 ft. The tips cover 1545 ft per revolution.

At sea level in normal conditions the speed of sound is 1125 ft/sec.

The 6mW turbine turning 15 rpm (.25 rps) will have a tip speed of 386.25 ft/sec.
The same turbine turning 30 rpm (.50 rps) will have a tip speed of 772.5 ft/sec.
The same turbine turning 45 rpm (.75 rps) will have a tip speed of 1158.75 ft/sec,
and thus the blade tips will now be breaking the sound barrier.

At the rpm of a record player (of your youth).

Even at the sluggish 15 rpm, the tips of the 6mW turbine are going over 263 mph.

How fast do those turbines turn? I thought the big ones (they are all big now) were synchronous.

[sunchaser]

KY
Your speed calculation appears spot on. Early blades are now being replaced due to dust and debris wear affecting blade efficiency. Lots of data and information is being analyzed as time reveals necessary design and operational changes.

Unfortunately winged creatures cannot outrun or always avoid these fast moving turbine blades. There are ongoing studies to assess what impacts, if any, on marine mammals' sonar systems offshore wind farms low level harmonics may create.

I've taken TT's advice and not delved into the thumbnail that started this thread. So long as whales can't fly they should be safe from above water stuff though.

[Mischief Managed]

The author of that article cracked me up. I'd discuss it, but I'd be breaking the first rule of fight club.

[KnotYet]

Originally Posted by twistedtree

How fast do those turbines turn? I thought the big ones (they are all big now) were synchronous.

I have no inside knowledge beyond what I read but I think they are kept to 30 rpm or so.
Also pretty sure the rpm vary with wind speed so non synchronous AFAIK.

[psneeld]

Not in the business, so one article may or may not be accurate...but if this one is.... 150mph is a long ways from the speed of sound.

https://www.semprius.com/how-fast-do...0150%20mph.%20

Conclusion
Don’t be fooled by the seemingly slow rotation of a wind turbine. Those blades pack a punch! Rotating objects reach higher speeds at their edges, and so the blades of a wind turbine may reach speeds of over 100 miles per hour at the tip, with the largest blades breaking 150 miles per hour on especially windy days. Longer blades have higher tip speeds, as the larger diameter gives the blade more room to reach higher speeds. Engineers actually design the turbines to rotate at a given speed depending on the wind velocity. This is called the tip speed ratio. This affects the turbine’s power generation, as well as several other factors. The blades are made of specialized materials, and are crafted to be aerodynamically efficient so they can more easily cut through the air.

[Benthic2]

I suspect that vertical axis wind turbines will become more popular to deal with high speed wind conditions and bird deaths. They are not as efficient as the traditional horizontal axis designs but when you factor in reduced design, construction and maintenance costs I think they will be comparable.