Tide power

[lyledunn]

I live reasonably close to Strangford Lough in the north of Ireland. It has a narrow mouth and funnels millions of gallons of tidal water at speeds up to 14Km/hr. It has always impressed me as an ideal location for an underwater, environmentally benign turbine plant. You cannot fail to be impressed by the power of the water that ebbs and flows here in the tidal cycle. The experience of power is especially enhanced when you are aboard a 200HP fishing boat that barely makes way! However, they are doing some experimental work with the bedrock to ensure that the turbine can be anchored securely. Apparently the turbine is to be fitted with huge blades much like a wind turbine. This surprised me somewhat since I perceived water turbines to be more of a funnel device. Are blades the usual method?
Disappointingly, the turbine is to power only the equivalent of 600 houses.


Regards,

Lyledunn

 

[BJC]

There planning to do the same thing in New York

http://www.waterconserve.info/articles/reader.asp?linkid=34336

It seems pretty impractical to me. The power is there but maintaining anything underwater is not easy. There is also the fishing boats you were talking about, wait till one of then drops their anchor on a "windmill" and gets wound underwater.
It would be smarter to put the thing on the underside or a barge with a mechanism to raise it up. You would also have the top side of the barge to mount a wind turbine.

 

[jraef]

There was some talk about doing the same thing under the Golden Gate Bridge in San Francisco.

http://sfenvironment.cust.digitalims.net/articles_pr/2003/article/050003.htm

"Venditori de oleum-vipera non vigere excordis populi"

 

[tinfoil]

On the Bay of Fundy in Nova Scotia (where the tides exceed 15m!), they dammed up a small inlet, and used a huge turbine to generate from the 'headpond' once the tide has run out enough to create a head.

see

http://collections.ic.gc.ca/western/tidal.html

 

[SierraJ]

I am not an expert but I beleive it should be reasonalble to say that the use of "blades" is the natural solution, since you are trying to harvest water "flow", and the more blade area you provide the more energy you can harvest. This is different than harvesting the energy from a water "head", were you can concentrate all of the water flow in a very small area.

In the case you are talking about, you may have large water currents but if you install a small turbine (with a large torque required to move it) most of the water will flow past the turbine and not thru the turbine to make any productive work. This will be the inverse in the case of a very large blade.

 

[MikeHalloran]

Water turbines, the kind that live in powerdams, do indeed have house- sized funnels on the upstream side.

The funnels concentrate and accelerate the water flow to truck- sized cylinders in which rotate car-sized blades.

An open- water turbine of similar power would have to be quite a bit larger.




Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA

 

[RobWard]

Are these metric or imperial houses trucks and cars?
Sorry, back to the topic...

Will the turbines be bi-directional?

"I love deadlines. I love the whooshing noise they make as they go past." Douglas Adams

 

[Skogsgurra]

There is one plant in north-east France that uses tidal water. It has horisontally mounted Kaplan turbines in funnels and with control vanes (both turbine wings and vanes are adjustable). I think that it is producing about 200 MW maximum. The dam crosses the Rance estuary and it is a rather large installation. Has been running as long as I can remember - probably since the sixties (ninteenhundredsixties).

 

[dpc]

http://eecs.oregonstate.edu/news/story/759

 

[Bung]

Interesting one at Port Kembla, in Australia see

http://www.energetech.com.au/

and select the Port Kembla project. It uses waves to force air in a suck-and-blow action through a turbine. Not very big, more a "proof of concept" thing, I think.


Bung
Life is non-linear...

 

[Skogsgurra]

Correction: It is north-west France. Of course.

 

[seanmcc]

Lyledunn,
Yoy may find the website for a company called MCT who are building these types of tubines useful. It shows how they operate and how they can be raised for maintenance etc. The web site is

http://www.marineturbines.com.

They may be the company installing in your area as they are based in Bristol.

Sean