> Unlike the Atlantic Ocean, where offshore wind farms can be bolted into the seabed in relatively shallow water, the West Coast's continental shelf plunges quickly and steeply.
Those "floating" wind turbines are still bolted to the seabed (so they don't float away) and are interconnected with wires. They showed how they work via infographics on their website that was on the HN frontpage recently. So the OP's comment about the sloping sea shelf is still relevant.
Not as much as before, because the cost of cable to hold down the turbine is the only thing that gets more expensive with deeper water (the part connecting the floater to the "bolt"). These cables are relatively cheap.
The other option's jackets or monopiles (95% of the market) require almost a 500 kg of steel extra per meter (very rough guideline). This means that at depths more than 25meter the monopile/jacket is more expensive than the wind turbine on top. With the hywind style floaters, this is not the case.
Yeah, I remembered it as 4 turbines, but it looks like it's 5. So as I said, it's a test farm. But yes, it's real, production-size turbines, not small scale models. I should have clarified that, sorry.
I don't think anyone is going to build a major farm until this one has been running for a couple of years. And they've figured out how to cut costs. Happy to be proven wrong, of course. :)
Statoil isn't the only company working on floating foundations, by the way, although I think they are by far farthest along when it comes to actually putting a big one into production.
For instance, the former CTO of Siemens Wind Power is working on a design. He's going for standard components and as cheap as possible. I wouldn't be surprised to see that in a test production in a couple of years.
edit: Full mea culpa. Parent is right.
Keeping this post intact since it still contains green-relevant information and some historical information that may be of interest. Big ups to Scotland for pushing this forward. The Northerners[0] are doing some clever things too like running their own municipal fiber after having their pleas being ignored for ages.
The Danes have been at it for almost the better part of a decade[1]. IIRC, their national transport is 100% green 24/7 and has been for a few years now. They've hit events where 100% of their entire country grid was wind-powered, and are so good at it China[2] brought in Danish consultants for assistance. Here's a real time chart of their energy infrastructure (including exports to Sweden/Norway/Germany)[3].
As a MA native, I remember people on the Cape would joke about the "bridge tax" (i.e., anything coming into the Cape is ~25% more). I know until recently[4] their internet connectivity was horrenduous. Energy there is fairly intermittent as well. Hopefully, they'll pick up a few Siemens units (you can pick up retired Siemens Vestas units on ebay for < 100k that are rated in the 10s of MW!) and deploy a unit or two[6], if only as a PR stunt to make themselves look 'progressive'. A win/win if they can increase employment and bring jobs to the locals in addition to that energy.
[4] Thier municipality started to offer gigabit through a peering with the Boston/North Shore providers to position their community as a "business friendly, gigabit ready" region in order to attract more businesses, rather than relying on the traditional tourist-town economy. They brought in some contractors to lay cable from Boston (or likely just North of Boston[5]) which is active now with tons of businesses using it, though I'm not entirely sure if the general populace has FttH.
[5] IIRC Andover or Quincy or somewheres around there (http://nationwidecolocation.com/massachusetts_colocation.htm) was one of the major peering points where a significant amount of NE traffic ran through. Traditionally it has great connectivity first due to all of the DARPA peering that occured around universities (MIT still has the 18.x.x.x class A perma-leased from ARIN). This continued through the late 90s/2000s with Verizon using those DC's as their major peer-points (which is incidentally why FiOS was rolled out so early in the Boston suburbs).
[6] You'd have to deploy them strategically in a region that isn't going to interfere with the yuppies boating experience as they go to the Vineyaahhhd on the 4th. NE has the same NIMBY problem that SF has in that regard.
I'm not quite sure about the national transportation being 100% green, or at least I misunderstood what you are saying.
As a Dane I can promise you that our governmental public transport is not 100% green, our main long-distance trains (IC3) currently operate on diesel. Neither is the private transport 100% green, since people can buy traditional combustion engine based cars.
Indeed, only about a quarter of the Danish rail network is electrified -- quite poor when compared to the neighbours. There's a plan to electrify all the main lines by 2025, according to Wikipedia [1]. I'll be pleased when there's no longer an awful smog on the underground platforms at Nørreport.
Not sure if you know, but MA has been trying to build a wind farm off the cape for a decade or more. It's now under contract, but they get sued at every stage, so it's not clear when it will deliver the first watt. Literally everyone is teaming up against wind power off Cape Cod.
Offshore you can install bigger turbines, because sea transportation of turbine components is not size-limited like rail/road transport. Taller turbines help to reach wind resources that are stronger and steadier. Also, even at the same height, offshore wind resources are often better than they are a few km inland. Finally, offshore wind can supply power to densely populated coastal areas when there isn't room to build turbines on land.
The disadvantages are higher construction and maintenance costs; waves and salt water are much more challenging to materials than the ordinary conditions onshore turbine towers experience.
The turbines are anchored to the sea bed. The wind has a boundary condition against the ground. If the ground is the sea, then the sea current wrt to the sea bed adds to the wind speed wrt to the sea bed.
Therefore, the turbines have zero wind speed only if the wind is blowing exactly against the sea current. Which is hard and rare.
Because the land boundary condition is different, the further away offshore you are, the better the effect is. Also, you might as well pick spots with known stable sea currents.