A good artiucle on sea turbines on the BBC:

http://www.bbc.co.uk/news/science-environment-18100191

Actually I think that's a bit far fetched since the vast majority of movement / motion in the sea / oceans are near the surface of the water not at the bottom where wave motion is hardly noticed or felt.

There was talk many years ago about the possibility of placing banks of turbines near the surface and using wave / tidal motion to generate electricity. I'm talking 20+ years ago so perhaps nothing's really new...just rediscovered.

It's not that far fetched to be honest Art, these technologies rely on tidal energy rather than wave action:

This article came out around the same time as my first post:

http://www.bbc.co.uk/news/uk-scotland-18096372

And the Wiki entry on Tidal Stream Generators

http://en.wikipedia.org/wiki/Tidal_stream_generator

Thanks for the clarification, DD. Yes, there is a distinct difference between Wave motion and Tidal energy. Good articles as well!

They also have one of these Tidal Stream Generators operating in Strangford Lough in Northern Ireland (UK), been going for a couple of years now I believe and has proven to be pretty reliable so far.

Of course there is a very powerful tidal race through the Lough so it's ideal conditions foir one of these.

Well I can't say much about the tidal energy systems over here but I do know we have our share of Wind Farms.
They don't do much for the landscape but the do produce a great deal of electricity.

They Wind Farms are usually found out west (Texas, California, Washington...etc.).
https://en.wikipedia.org/wiki/Wind_power_in_the_United_States

https://en.wikipedia.org/w/index.php?title=File:Wind_Turbines_in_Washington_State_IMG_7956WMC.tif&page=1

Not sure how far they're with this one.

The Severn river has one of the highest tidal ranges of any river in the world. (2nd I think to one in west Canada)
There are plans to build this though.

I'm a little sceptical on wind turbines, I've yet to find out at what point they go past the point where they have produced enough "green" energy to offset the carbon that went into their production, instalment and maintainence.

Bearing in mid that in the UK they are planning to instal large offshore wind farms no-one ever seems to make any reference to this when talking about find farms green credentials.

Quote from: Snowcrash on July 24, 2012, 18:37:11 PM
Not sure how far they're with this one.

The Severn river has one of the highest tidal ranges of any river in the world. (2nd I think to one in west Canada)
There are plans to build this though.

I have a feeling that I read that this had been binned snowy, mainly due to the enviromental impact to some of the most important wetland habitats in the UK.

Quote from: DD1975 on July 24, 2012, 18:40:36 PM
I'm a little sceptical on wind turbines, I've yet to find out at what point they go past the point where they have produced enough "green" energy to offset the carbon that went into their production, instalment and maintainence.

Bearing in mid that in the UK they are planning to instal large offshore wind farms no-one ever seems to make any reference to this when talking about find farms green credentials.

I would think when the cost of the electricity they produce has paid for their construction, delivery and installation. Maintenance is an expense but very nominal and usually scheduled a few times a year, perhaps quarterly. Similar to a lot of solar installed applications by homeowners, the initial cost of materials and installation is recovered in a few years of having "free electricity" or electricity for those demanding appliances like hot water heaters, clothes dryers, ovens, toasters, etc. Usually anything other than light bulbs that produce heat.

At what point do these alternate sources or power pay for themselves or how long does it take? I'd say it depends on the individual system, it's usage, consumer demand over time.

Kind of like a new toll bridge. After say 10 - 15 years it's paid for but maintenance is an ongoing operation...bolt tightening, replacement, scraping / cleaning / painting...etc. Paid for and then some but still collecting tolls to keep it going.

Catch 22....

What i was getting at here was not so much cost but more that construction of the turbines require fossil fueled machinery, not to mention that the materiels themselves may well contain elements that produce carbon when they make them.

Then because the places that they are sited tend to be remote, they require fossil fueled vehicles to transport them from where they are made to the site of operation.

And of course fossil fueled vehicles bring the engineers to the site to provide the maintainence, as you say several times a year, so when exactly do they become "green"............

Quote from: DD1975 on July 24, 2012, 18:43:10 PM

Quote from: Snowcrash on July 24, 2012, 18:37:11 PM
Not sure how far they're with this one.

The Severn river has one of the highest tidal ranges of any river in the world. (2nd I think to one in west Canada)
There are plans to build this though.

I have a feeling that I read that this had been binned snowy, mainly due to the enviromental impact to some of the most important wetland habitats in the UK.

Part right, the last government binned the scheme, the new government is reconsidereing the idea:

http://www.walesonline.co.uk/news/wales-news/2012/05/19/prime-minister-agrees-to-meet-severn-barrage-consortium-91466-30999967/

DD, While I can appreciate your "Green" ideals, the fact is that Carbon, the basic unit for organic molecules and even our body contains over 18 percent of carbon.

If you look around, practically everything you see...your bicycle, skateboard, kitchen cabinets, silverware, eyeglasses, computers, cars...everything is from the earth (and one day it and you will go back into it). No matter what the item, it took resources and energy to construct. No matter how GREEN someone thinks something we now have actually is, someone, somewhere likely used some derivative of fossil or carbon based fuel in order to produce it.

Maybe if we can get the Amish to build everything for us...

Sorry Art I probably didn't make myself very clear there, I'm not a green idealist.

I'm very much a sceptic frankly, hence my points above while green capaigners shout from the roof tops about so called green energy they do rather miss out things like production, instalations and mantainence of the units when talking about green energy production.

I'm all for a mix of energy production, anything that spreads production to differing sources can only be good in the long run.