Kylerhea tidal power plan

[Kelpie]

http://news.bbc.co.uk/1/hi/scotland/highlands_and_islands/10153669.stm

Does anybody know if this will affect navigability? I would hope not since the MOD use this passage...

 

[Quandary]

Something that will almost certainly will affect yacht navigation is the offshore wind farm that SSE has just announced off Macrahanish. Having covered most of the Kintyre hills with turbines they have now decided to go offshore. Definitely this years favoured green option. The initial announcement is (deliberately) sketchy, but says it is 3km. offshore, roughly square with an area of 70 sq.km. The water here is less than 25m. deep for a few miles offshore so obviously easier to build. If it is as described it will straddle the usual route from Mull of Kintyre Light to Gigalum used by boats from the Clyde and Ireland heading for Gigha. I used to do this half a dozen times per year and I suppose a 10km. or so diversion is no big deal, we are 'leisure' boaters after all, but it is directly off the longest sand beach and dune system in Argyll.
Note that this farm is additional to the one announced earlier off the west coast of Islay.
I think the tidal power systems are preferable, they can be located to avoid interference with passage as at Strangford Narrows or deep enough to sail over, they are relatively unobtrusive and they do produce power every day. The Scottish Government ambition to 'lead the world' in renewable energy is going to mean a lot more of these changes and I suspect that in 20 years the attraction of our wild coastline will be greatly diminshed so we are lucky to be the generation which had the opportunity to enjoy it at its best.

 

[armchairsailor]

The MOD are an official consultee for all Environmental Impact Assessments, which this development would be subject to. I'm sure that if they had a problem with it, it would have been considered a show-stopper. Similarly, if there were serious issues regarding transport connections, that would have been flagged up.

FWIW, wind farms located in a "deliberately" sketchy manner are probably like that because the developers aren't fully decided as to the most favourable location - a lot of to-ing and fro-ing goes on during the years before a WF design is finalised and is lodged with the relevant planning authorities. The whole business last year with the Crown Estate hiving off these areas of the sea bed is that they have a broad idea as to the most favourable zones, and they're working with developers who have bid for the various sectors on offer to take it forward, in a similar manner to the way the North Sea was divvied up into tranches for the oil. A huge amount of the area within these zones will end up being discounted on various grounds before anything's ever built.

 

[Searush]

From what I can see of the ones off the N Wales coast, they are broadly laid out in rows so it should be quite easy to plot a track thro the middle of a flock without hitting one. The blades are also deliberately quite high above HWS so the risks of passing thro should be prety low unless one stays below with your head in a bucket while on autohelm.

Quite what the wind currents in a flock of windmills is like I have no idea & as I no longer commute between the Rivers Dee & Conway I am unlikely to go that far out of my way to find out.

 

[NormanS]

Kylerea would seem an excellent site for power generation from the tide. There is a huge body of water on the move at up to 8 knots. I would be very surprised if anyone would propose a tidal generator at Kylerea which would affect through navigation. It's not just the MOD that use it. It's quite busy with all sorts of traffic. Worth checking on, though.

Tidal generation is the way to go. At least it is totally predictable, unlike wind power.

 

[Kelpie]

I agree that the tidal stream through channels like Kylerhea is an excellent potential source of power. But, like you say, the passage is busy- I saw plenty fishfarm well boats and general cargo boats when I went that way. I just find it hard to imagine how such a narrow channel (550m wide) can accomodate both shipping and tidal pwoer generators.

 

[armchairsailor]

How wide's the entrance at Lough Neagh? That has a tidal turbine, and there's also the experimental station in Orkney, which must take up more room (dunno whether it's a relatively unused area though). Given that they will take up less space than a small navigational hazard, eg, wreck, surely it won't make a huge amount of difference in the grand scheme of things, will it?

 

[dt4134]

How wide's the entrance at Lough Neagh?

Lough Neagh is non-tidal.

There's a tidal turbine at the entrance to Strangford Lough. It is an obstruction but is easily avoided. I understand that it rarely works, so as a tidal turbine it is pretty ineffective.

 

[DavidMcMullan]

Note on JCP's comment. I read the following recently that stated that the turbine was restricted in its running hours by its licence. Hoping to run 24/7 this year.

 

[armchairsailor]

There's a tidal turbine at the entrance to Strangford Lough.

My mistake...

 

[DaveS]

To answer the original question, I think this bit of the linked article might give a clue:

The device sits on the seabed, fully submerged and would not be visible on the surface of the sea.

I entirely agree about the predictability benefits of tidal generation. A good geographical distribution of generators would even out much of the diurnal cycle, too. Just a pity that not much can be done about the springs / neaps cycle... (See a sometimes heated discussion on Bluemoment a year or so back.)

 

[largerobert]

All

My name is Bob Smith and I am the CEO at Pulse Tidal - the developers of the tidal power project in Kyle Rhea.

It is great to see this debate on the forum and I hope I can offer you some interesting comments.

As mentioned, the device is fully submerged in operation - we have adopted this approach in response to concerns voiced by many that they do not want to be able to see the machine from the beach. Provided we are sufficiently submerged, this should also ensure that the machine doesn't pose an obstacle to shipping.

We are engaged as I write in a navigational risk assessment, which looks at all the traffic in the area and determines how to ensure that we do not create a hazard. The MCA, RNLI, RYA, and local shipping operators are all consultees to this process, but I wonder if you would give me a bit of direct feedback?

A number of people have suggested that if we keep the machine at least 3m away from the surface then it will pose no hazard to recreational sail-craft. Do you agree with this?

Thanks for your feedback, do visit our website for more info : www.pulsetidal.com

Bob

 

[webcraft]

A number of people have suggested that if we keep the machine at least 3m away from the surface then it will pose no hazard to recreational sail-craft. Do you agree with this?

Bob

Hi Bob,

I would say three metres at LAT (lowest astronomical tide) rather than chart datum, plus a little bit for luck perhaps. If there isn't enough depth for this then you will have to consider staggering the devices and buoying a safe channel.

An interesting looking device - and I am sure we would all rather see (or not see!) more of these instead of the current proliferation of windfarms. Have you looked at Cuan Sound (between the islands of Seil and Luing) as a possible location for one or more of these devices?


- W

 

[Quandary]

Hi Bob,


An interesting looking device - and I am sure we would all rather see (or not see!) more of these instead of the current proliferation of windfarms. Have you looked at Cuan Sound (between the islands of Seil and Luing) as a possible location for one or more of these devices?


- W

You don't need to encourage them, at least not until we know more about them; they will continue to breed if left alone, just like the b***y beavers.

 

[dt4134]

All

A number of people have suggested that if we keep the machine at least 3m away from the surface then it will pose no hazard to recreational sail-craft. Do you agree with this?

There are very few yachts with a draught of three metres or more. You'll also want to look at fishing vessels. Bear in mind that many of those are probably tough enough to destroy one of your generators without suffering more than the odd scratch.

I think Webcraft mean to say that LAT & CD were usually the same thing, but that is the lowest height a tide can fall to under astronomical effects. I presume that as a specialist in tidal power you're well aware of the concepts. Anyway, I'm assuming that you mean three metres below that level.

I'd also wonder whether three metres is deep enough to avoid effects at the surface in strong tidal flows. Not just creating waves, but also looking like submerged rocks to a passing navigator.

I presume you've also considered the effect of a large swell on your generators.

I'm intrigued by the horizontal oscillating blades. Are they efficient enough for widespread deployment? I ask that because as a general rule of thumb yachts sail in shallow water to avoid tides, and off the top of my head I'm guessing there aren't a huge amount areas with strong flows in shallow water.

It seems to me that the most successful tidal generators will be those that can efficiently generate usable quantities of power from flows of one or two knots, that way they can be widely distributed in the English Channel, Irish Sea, North Sea etc rather than been focused in a few small areas of strong flow.

 

[Kelpie]

A number of people have suggested that if we keep the machine at least 3m away from the surface then it will pose no hazard to recreational sail-craft. Do you agree with this?

Thanks for your post. I would think that there are much deeper draft vessels to worry about- I believe the well boats are around 5m draft? I don't know what size of ship the Navy sends through there. Also it would be good to know whether the devices have the same effect upon the water as most obstructions do (overfalls/turbulence etc) as this would increase the required clearance.

 

[largerobert]

Thanks for your advice. This is really useful insight.

On the point about overfalls & turbulence etc. The device does create a blockage of sorts, but it is not as dramatic as a submerged rock or similar. The machine we have operating in the Humber creates very little surface disturbance, even when it comes very close. The hydrodynamic models suggest there will be similarly small effects on the Kyle Rhea machine, but this will, of course, be one of the big areas of focus during our testing.

You are right that the big opportunity in tidal is to exploit the lower flow areas. In the short-term though, the machines are too expensive to generate commercial power in less than 2m/s, so we'll focus on the higher flow sites to get started. However, over time, the machine costs will fall quickly, and that will open up opportunities in the other areas.

Shallow water is a small, but quite significant sub-set of the high flow sites, and we are starting there because it is the cheapest place to operate. The machine works very happily in deeper water, where we will go later, and in fact can be made much larger in deeper locations - again helping keep the cost down.

Bob