First large-scale deep-sea floating offshore wind farm

This was my first thought after looking at their site. Amazing job by the UX guys.

And it works without enabling JavaScript!

A lot of startups are trying to cover for the fact that they don't have anything ready to offer and haven't previously accomplished anything.

It is also important to mention that this project happened because of the falling oil price, and Statoil needing to find alternative stuff to do. Not diversify their sources of income, but literally give their enployees something to do. A lot of highly educated people lost their jobs in Norway during the last few years, and a windpower project would be one way to get public funding and avoid firing too many employees (this is of political interest, Statoil don't need half of their eployees). I am not saying the project would never have happened, but it probably happened now and not in ten years because of this. Bottom line: this is busywork imposed on a huge, slow, old fashioned oil company which will never be able to compete comercially.

> so it's priorities

"its priorities"

It requires interesting control systems to keep stable and performing optimally. You can read about some of the challenges here (has some great figures) ...

http://www.sciencedirect.com/science/article/pii/S0167610515...

It appears the tethers are for positional stability, and the keel or whatever you want to call the underwater portion of the structure provides rotational stability, but I'm sure there is much more to it than that.

I have absolutely no clue as to how they yaw the thing. A 1° yaw error with the wind is like 2-3% efficiency penalty, and a penalty on durability.

Without some kind of active balance, it'll still tip to some degree. I wonder if there's much to be gained by tilting the 'keel' forwards to keep the mast vertical?

> I'm curious if they generate enough energy that they could do autonomous station keeping with thrusters in the base.

I cannot help but think during conditions where station keeping is really needed that the wind power would be at its highest, so it should be enough given the design of what is where.

re maintenance:

Knowing nothing about anything, my first thought was the RP FLIP.

https://en.wikipedia.org/wiki/RP_FLIP

>autonomous station keeping with thrusters in the base.

This adds far more complexity and risk than you might expect. Redundancy, reliability, etc. all are vitally important.

If one of several thrusters fails, and the environmental conditions are too great for the remaining thrusters to match, what happens?

How do you maintain the thrusters? You could have station-keeping with tugs during maintenance, but often maintenance of azimuthing thrusters requires a drydock.

Hypothetically speaking, if all the turbines were somewhat easily mobile, their position could be optimized for the given wind conditions. That could be pretty interesting! Today however that's science fiction.

Furthermore, there's always going to be a subsea tether for power. That's unavoidable.

In any case, moorings of various types are dumb, well-understood, and very effective.

And use all of the masts as an ELF antenna array. That will give those racks something to think about: subsurface phased-array radar for submarine spotting, earthquake and atmospheric study, etc.

The wind sector has decades (well, roughly two decades I would say) of experience in being permanently undercut by cheaper wind. Moderate shifts in the playing field won't take them by surprise.

In both cases the operator will try to negotiate a strike price rather than selling every watthour on the spot market.

UK wind strike prices are now below the strike price negotiated for Hinckley Point C.

Seems like the foundation that published that study is anti wind and might not be the most reputable source [1].

[1] http://www.ewea.org/blog/2012/12/study-on-turbine-lifespan-j...

Statoil has done offshore drilling since the 70s, the people who work there probably know more than anyone else in the world about designing and operating very large machinery at sea. You can read more on their web pages or search the web for statoil to find examples of what i mean.

Some thoughts:

Yes, the marine environment is harsh. Corrosion is an issue. Maintenance is challenging. But these are not new problems: these are solvable (and solved) engineering challenges. The O&G industry has considerable overlap with offshore wind; foundation design, transportation and installation, etc., all well-understood and in practice for literally decades.

I haven't read the report you cited, but it is already 5 years old (much has changed in the past decade). The wind farm performance degredation they speak of in Denmark and the UK might have a lot to do with outdated technology of these older turbines. The first offshore farm in Denmark was built in 1991. Technologies since even 2010 have greatly improved.

Statoil has been operating an 85 meter rotor pilot since 2009, so they have a lot of understanding about how to deal with such potential problems.

I know deterioration of the solar panels is a concern for land-based installations. I imagine that could be accelerated by sea salt, waves, and storms.

I'm also curious how cloudy/foggy ocean sites are compared to ideal desert-based land sites like Nevada. That also might be a factor.

The sun isn't so good around Norway.

I think wind makes more sense at sea than solar. It can operate 24x7 if things stay breezey. In these chosen locations, that is indeed most of the time, and what sets them apart from most land-based locations.

Going to the expense of making a large offshore solar farm which is useless for half the day doesn't seem like as good an investment, even if all the other technical and weather issues were OK.

Land in sparsely populated sunny places is cheap and the panels are easier to access and easier to connect to the grid when they're on land.

there is no shortage of space on roofs for solar panels. Wind turbines need a special place, far from houses, and have an acceptance by the population problem.

It's not clear. Even a mild wind storm creates myst.

And then you have to protect your project from salt water and the waves.

The waves are especially tough, because rogue waves can create pressures of 100 tons per square meter.

https://en.wikipedia.org/wiki/Rogue_wave

The sun does not shine 24 hours per day on a given piece of earth.

Panels are nice and quiet, we have plenty of roofs, and don't kill birds or bats. Wind Farms are a bit noisy, kill birds and bats, and have one heck of a bad failure condition if you've ever had the misfortune to be near one when things go bad. Also, the wind farms that don't float seem to make much better fishing spots, so bonus.

Also, the conditions at sea make me think that wind farms would have a bit of advantage. It would seem that during conditions that require the greatest energy to stabilize that wind has more power than solar.

There's still quite a lot of space for solar panels on land.

Among the benefits of offshoring wind turbines is generally higher and more consistent wind speeds offshore, less nuisance due to noise, and the ability to construct larger, more effective turbines than is possible on land.

For solar, there's not necessarily more or better sunshine offshore. There's no reason an offshore solar panel would be fundamentally different from an onshore one. And due to the much harsher environment, much of the difference between the two would relate to corrosion protection and reliability (adding to its cost).

For offshore solar you'd have the complexity and cost of offshore installation and maintenance, without the clear benefit of better sun offshore. That's a hard pill to swallow when there's so much potential to have solar panels on land.

No, it is a project by Statoil, one of the biggest oil companies in the world.