[Graeme]

Key facts and developments in marine energy

$this->bbcode_second_pass_quote('', 'M')arine energy, consisting of wave and tidal power, is the great untapped resource of renewable energy. While few of the technologies are up and working, many companies say they will be producing electricity from water in coming years, prompting interest from power firms and investors.

Waves and changing tides can produce more energy per acre than wind. Water is always moving whereas gusts only keep wind turbines producing around 30 percent of their maximum capacity.


Up to 20 percent of current UK electricity demand could be met by wave and tidal energy in future, according to the Marine Energy Challenge, a research document commissioned by the Carbon Trust. It is a government-backed agency which has already invested in the wave power technology of Pelamis, one firm considering an IPO.

[WildRose]

I've been following the Pelamis wave converter for a couple of years now, after first having learned about it when my son did a science fair project about wave energy.

The site below has some more information about Pelamis and how it works:

http://www.oceanpd.com/default.html

Wave energy has a decent chance in Portugal because of its geography and also because the prime minister sees its potential. Apparently, he has set a target of 45% renewable energy (between wind and wave) by 2020 in Portugal.

These Pelamis units are large, about 150 m long, and when arranged in a 1 sq km farm, are expected to power 20,000 homes.
If all goes ahead as planned, a target of powering 350,000 homes is set.

Wave power is just starting to take off, with a few different companies planning trial runs of their respective technologies. Of course, it's expensive at the beginning. It'll be interesting to see if it can displace much of the conventional power generation in areas with the appropriate geography.

[inculcated]

And what of the impacts? Have we sussed out the possible changes in ecosystem that placing such devices on a scale that could dent our energy addiciton might incur?

[thor]

In Holland they are introducing salinity generated power:

http://www.createacceptance.net/fileadm ... ASE_27.pdf

Using special membranes one is able to exploit the potential that occurs where river water meets sea water. A 200 MW electrical power plant is already planned.

$this->bbcode_second_pass_quote('', 'W')hen sweet and salt water join, the concentration will
diffuse until the salinity is equal in the total fluid (fundamental law). When a selective membrane
is placed between sweet and salt water, the diffusion can be controlled and potential energy
gained. There are two ways to get energy out of water via membranes: Pressure Retarded
Osmosis (PRO) and Reversed Electro Dialysis (RED). It is the second principle, RED, that has
gained renewed attention in The Netherlands for the last five years and has received the label
Blue Energy.

[Graeme]

Pelamis Wave Power: In the Sweet Spot of the Curl for Renewable Energy

$this->bbcode_second_pass_quote('', 'T')he Pelamis Wave Power located in Edinburgh, Scotland and recipient of the British Best Renewable Energy Company of 2007 is turning the energy of the ocean waves into renewable power sources. The company began in 1998 by founding developer Dr. Richard Yemm. The goal was to develop and make available in a commercial setting the Pelamis wave energy converter.

The term Pelamis assigned by the developers and branded by the company operates like the swimming sea snake it was named after. The Pelamis Wave Energy Converters in use produce are rated at 750 Kw. The Pelamis Wage Energy Converters are arrayed in wave farms similar to the concept developed in wind farm arrangements.

The first wave farm will be launched on a large scale in Portugal. There has been continued testing and refinement of the technology. The UK, France, New Zealand, Spain, Scotland, South Pacific, USA and South Africa are keenly involved in promoting the Pelamis Wave Energy Converter technology. Internal political forces aside and geo-political considerations at the forefront it appears Scotland is in the sweet spot of the curl of the wave.

[No-Oil]

Tidal current power generation is the ONLY reliable sustainable means to generate power from the seas at this time. The Tide NEVER stops everywhere at the same time, so places like the UK are endowed with a tremendous amount of energy potential that is guaranteed everyday & its output is wholly predictable unlike any other means. It's even better than hydro, as it will NOT suffer droughts ! It will work 24/7 night & day. wind or no wind, sun or no sun, waves or no waves. I hope you get the idea, all other means are a waste of TIME & ENERGY if we want RELIABLE power generation !!!!!

Wave power like wind suffers badly from having no guaranteed output, the sea is often flat when the wind stops blowing ! Wave suffers further in that the energy required to create the structures to survive in the marine environment is enormous when compared to its output & measured against that of wind. All turbine systems could be much better if we would spend 50-100% more per unit, to ensure that it is built to the highest efficiency & reliability levels, how many wind turbines do you see parked in wind farms due to system failures ??? Many because they are built CHEAP to reap government grants or meet targets for installed capacity, there are no targets for operational efficiency or UP TIME ! Hence the power companies put up CHEAP turbines with big potential output numbers to meet the targets, not to PRODUCE energy !!!!!

So the get rich brigade want the Government to support a Severn Barrage that whilst it could produce 5% of the UK's electrical energy requirements today & thus more of the futures (when the kack hits the fan, we WILL use less) It will suffer from TWO stoppages a day in electrical production & will require the demolition & transportation of a small Welsh mountain to build the barrage. Where as a distributed in-current turbine field would not suffer any stoppages in production & would cost substantially less to build, but more to maintain over time due to its distributed nature. The UK Government is barking up the wrong tree IMO, but hey what do I know.

Renewables at the moment are all about MAKING MONEY, not about GENERATING ENERGY which is what we need !!!!!