As is the case with wind power, I think the question of how predicatable and variable the power is will play a big part in how useful this is.

I would guess the power curve would fluctuate twice daily with the tides, with 2 periods of maximum and minimum amounts. If it is dependable and predictable it could be used to eliminate some of the power requirements coming from combustion.

Well, tides flow in and out, and I'm not sure when there is the most water in motion, but I'd think that there'd be four peaks, two per tide cycle.

As far as timing goes, if such a system were to supply the bulk of an area's power needs, they'd simply need to build a small power lake system (if the elevation is available) to smooth out the power delivery.

The environmentalist in me wants to ask, "What impact will this have on the seafloor?" Even so, I'd rather be pulling power from the sea then burning gunk that's been dug up or pumped out of the ground.

Unencumbered as I am by the facts, I am free to say I was thinking you'd have a peak at the midpoint between high and low tide, and vice versa, so 2 peaks a day.

As for smoothing out the flow, if you make it too small it won't move the turbine, so I don't know if average flow all day would do much.

I'm thinking this cool idea is going to fail the practicalityometer.

I would be very interested in seeing any projects which are underway in the water turbine power generation trials which my be underway. Are there any sources of information that I can use to see where all this activity is going on.

Bruno DiTosto
Wayne, N.J.

I would be very interested in seeing any projects which are underway in the water turbine power generation trials which my be underway. Are there any sources of information that I can use to see where all this activity is going on.

Bruno DiTosto
Wayne, N.J.

The Tide is very predictable as it depends on the orbit of the moon and earth relative to the sun. This predictability makes it possible to schedule existing plant more easily than with wind. The TidEl system also has a novel connection scheme which does not restrict the level of renewable power that can exsist on a grid, current wind technology has a percieved limit of ~20% making TidEl ideal to link to weaker grid systems.

The TidEL system is not an innovation but rather a redesign of an out of date patent by Philippe Vauthier who was the first to propose the floating design.... otherwise known as the Underwater Electric Kite. TidEL's design appeared publically soon after the original patent expired. Credit should be given to the first innovator.

well, a company has just today put a standing, non-chain secured underwater turbine in Strangford Lough, Northern Ireland, and the impact assessments will begin in earnest tomoro, obviously with the fish and marine mammals being forefront in determining how it will affect the environment it's been put into.

Just how much damage it does will be wieghed against the probability of long term benefits and how many more turbines could be accomodated in the same place. Most biologically minded folks over here are thinking its going to kill a lot of animals, and i think the damage done there will not be worth the power output

Was just thinking that they may need to apply some kind of diverter attached beyond the blades and designed to block larger fish and animals from actually contacting them..maybe a double cone of wire mesh...just a thought

There seem to be a lot of subjective statements being made! Here are some real facts:

- Ocean currents exist that flow constantly at sppeds in excess of 5knots (greater than 2.5 m/s). Due the incresed density of water this would provide the same energy as a 350 km/hr wind, per square meter of turbine frontal area, at a totally reliable rate.

- Tides times are known and therefore energy production can be planned and managed, unlike wind.

-The rotational speeds of underwater turbines are much slower than that of wind turbines, due to the increased density of the fluid and the fact that tip speeds in excess of 8 m/s will experience cavaitation. As such it is very unlikely that any significant damage could be caused to marine life.

- Generating energy from tidal and ocean currents is entirely practical and plausible but suffers from the kind of unfounded conjecture posted above.

- The quicker we get on with developing and more importantly applying this technology, the sooner we end our damaging dependency on fossil fuels.

I am intreseted to know more details on the installation in Strangford Lough, Northern Ireland.

I believe that it would be quite feasable to sling a turbine deep in an ocean current, thus eliminating the peak-valley cycle. It could be placed beneath the storm surge level. Anchoring it to the sea floor shouldn't be such a prohivitive problem, and it could be suspended by inflatable bladders, allowing for raising and lowering, for maintenance purposes.