Who's new
Who's online
There are currently 0 users and 9 guests online.
Recent user registrations
Registered Users
Windmills
Sat, 05/17/2008 - 23:18 — thebastidge
Obivously wind power has its advantages and disadvantages. It's one of the least predictable forms of power generation, and does require some up-front capital cost, but it's efficient over the long term as at least a supplemental system. And I think vertical may be the way to go:
- Takes up less (vital) deck space
- Places the mechanical parts needing the most service easier to reach
- Places the heavier parts and therefore center of gravity lower.
- Allows the top to be used for secondary purposes: radar mast? Antenna?
- Apparently more effiicient
- Quieter
- Safer for birds and aviation
Wind power vs station
You're almost certainy going
You're almost certainy going to need to moor somewhere most of the time anyway:
Times when you mnight want to up-anchor:
Methods of movement:
In any of these cases of movement, any superstructure that has wind resistance will make your movement somewhat less efficient. The sail are of your superstructure is probably far more than that of your windmill, but every little bit counts and wind direction, current, and your desired direction of travel may well not match up very well. This is another reason why you probably won't want to move very often, and it will not be as simple as simply pulling up your anchor.
How much of a hurry are you in? If you're in a big hurry, drifting ain't the way to go anyway.
offshore wind generation
Multiple windmills...
... are not so practical. Rule of thumb I read for downwind windmill placement is 6 times the radius of the windmill. I've tried to find it again, but I've read many things on wind power over the last couple years, and the field is so "Rah Rah" full of cheerleading that it is often difficult to find really practical online guidance among the chatter and noise.
I would agree. . .
that for a commercial utility farm, mutiple generators on a single platform would not be the best way to go, if the objective is to maximize output per capital cost. That work is ongoing and it looks like individual floats (and it looks like suction pile anchored TLP are winning that). But this is different. There is already an existing platform assumed. In the instance of a five pontoon semisub or TLP, a tall one in the middle (1-2 MW) and five smaller ones on each corner (.5-.75MW), 4 of them would have clear air at any one time. True for optimum output more spacing would be advantageous. But since wind is free, optimum performance is not really necessary I think. The two or three downwind ones would not have clear air but would still be producing quite well.
MUFOW (Multiple Unit Floating Offshore Windfarms) is doable, it's just that this is not what utility level economics seem to be dictating. Here's a good wind energy info sheet- here and here
The EPRI has some good info too- here wind and wave
stead is slow
to make windmills completely useless stead would need to move at the speed of the wind. which will not happen because big structure like stead makes large drag. sure wind pushes stead a little, but stead is very heavy and its wind profile guite small because of spar compared to its weight. in fact to make wind more effective mover, I think we should consider using sails or kites as moving method. offcourse it cannot be only method and them would need to be connected low on the structure, so that they would not tilt stead.
On mill desing i comp thebastidge. vertical mill are better on such close quarters space as stead. there is a design of vertical mills, that are basicly noiseless. http://www.quietrevolution.co.uk/ .just have to look for model that is rugged enough to stand storm winds.
storm winds
Storm winds are an issue for any windmill design. It would be worthwhile looking into all methods of storm prep for windmills, but any Seastead would have to have some system for predicting weather and prepping for it. There'd be a LOT of "battening down the hatches" on ay se-borne platform that can't outrace the storm. Evacuation wouldn't be the answer like it often is for oil and other function-specific platforms like radar and navigational stations.
On further reflection...
... even a spar design is almost certain to have an elevator. The FLIP is over 100 meters long, and even if a portion of that is inacccessible ballast and flooded compartment, even 70 meters of vertical stair climb will give most athletes pause, not to mention people who are in average physical condition and must haul themselves AND equipment up and down that distance EVERY DAY.
http://www.turby.nl/99-downlo
http://www.turby.nl/99-downloads/Turby-EN-Application-V3.0.pdf
Another advantage to windmills
It's typically necessary for a windmill to be placed as high as possible because of obstructions nearby. On the open ocean, the only obstruction is the seastead itself, and as long as your windmill is the highest structure (excepting radio/radar mast) you will have unobstructed access. Horizontally-oriented windmills need considerable spacing between them- I read once that the minimum downwind distance should be six times the span of the airfoil. I am trying to find a good reference on that again. It's unlikely that any small seastead would be able to host more than one windmill.
This re-inforces to me that Seasteds will have to be designed with a "range" in mind. Anothe rindication that a seastead probably cannot be practically and economically designed to be all things to all people.
Go fly a kite...or float a buoy.
I wonder if it might be a good idea to use independent structures for power generation. It would mean a windmill (or two) could break in a storm without taking down the whole enterprise, and would reduce interference between moving parts and the things that need to be done on the upper deck. One possibility would resemble the retrofitted oil platforms they talked about in Wired a while back. I wouldn't bet the farm on this, but it might be worthwhile to look into the alternative of a tethered flying turbine of some sort. Several designs are currently in the works: hopefully, at least one has some merit. At small enough scales, though, the integral vertical trubine & radar mast sounds really elegant, especially since most vertical turbines have a constant rotation speed anyhow. -Joel
Constant rotation speed
I'm not sure that vertical turbines have a constant speed, but the superstructure on which they rotate needs some sort of stationary axis and perhap even bracing outside the turbine blades, that could be used to mount the radar/radio mast.
Mooring
There is a huge continental shelf land grab going on. Many countries are trying to stake out as much continental shelf as possible. I think Russia is is on record of making a grab for pretty much all of the Arctic continental shelf. I think this trend will continue.
Mooring over a continental shelf is relatively tried and true technology. Mooring over the deep ocean is quite difficult and expensive.
Where am I heading with all of this. Well basing a seastead over a continental shelf may be viewed as parking in country's back yard. I don't want to talk about all of the boring maritime law here, since it will probably be changing. The bottom line is that deep ocean (non-continental shelf) seastead parking may become a requirement. Deep sea mooring such a seastead is not likely to be economical anytime soon.
Thus, seastead wind power extraction may need to be done without the benefit of mooring. Since extracting energy from wind will put a force on the seastead, some of the extracted energy will need to be budgeted for station keeping. I'm pretty sure that we will get a net positive energy flow, even with the station keeping component, but it needs to be part of the whole system design.
Claiming isn't necessarily
Claiming isn't necessarily owning. A lot of things depend on how muc effort they relaly put behind it and how much they are willing to look bad to enforce it. Also, how long you can squat before they force the issue.
Maybe we're talking apples and oranges here
What depths do you mean when you say continential shelf?
What depths do you mean when you say deep ocean?
I'm not an engineer, but I'd bet a case of Corona that a DP spar will not be able to stationkeep with onboard wind power. My sense is that the physics prevent it. It may be possible during opposing wind and current, but the power requirements for DP for that much windage in a 30 or 40 knot blow (not uncommon) and a few knots of wind driven or other current will be huge. DP has to be sized for maximum conditions. The spar will have too deep a draft to seek shelter. In light of the new methods of mooring (suction piles and suction embedded anchors) you might want to look at your cost figures again using up to date methodology. Certainly 10,000 to 20,000 ft depths are expensive,maybe prohibitively but 1000 to 3000 ft (OTEC depths) are not so much anymore.
I guess a pertinent question here is (if international waters are a requirement for the first offshore seastead) what are the range of depths of international waters. I don't know. In some places it sounds like it could be 11,375' which is certainly deep, probably too deep. If that's the objective, something more ship shaped might be in order. What about seamounts and shallower noncontiguous depths? Are there substantial areas of those?
But if you are flying a flag of convienence, and providing an economic benefit (like renewable energy that also generates carbon trade credits or OOA protein, or jobs) there are probably dozens of small island nations and islands that would offer red carpets for the seastead in their waters. If the situation becomes untenable, pick up your moorings and go elsewhere. Suction piles are real cheap (just pipe with a padeye) and can be cut and abandoned with a small shape charge that rides the chain or wire down and detonates at the bottom. Really a one hour $500 job and off you go.
On another note, I'd like to suggest a "businesses" or business focused forum. Revenue will be a primary concern won't it? I would think it needs to be a part of the strategic planning and design work.
Wind vs current
For something as deep as a spar, water current wins every time. The total area presented to the current is many times the area presented to wind, even with the most efficient wind turbine and sail arrangement I can think of. Water also has more mass than air by a considerable amount. I just don't see any way that wind power alone achieves station-keeping for a mass of hundreds, to thousands of tons. The only reason sailing shipscan use wind to go against current is their hydrodynamic shape and relatively low drag, smaller 'wetted' surface (draft).
compared speeds
"The only reason sailing shipscan use wind to go against current is their hydrodynamic shape and relatively low drag, smaller 'wetted' surface (draft)"
compared speeds
"...and that the wind blows orders of magnitude faster ;)"
business forum
Check in Community/General Chat/Industry
From what i understand,
From what i understand, claims made on the EEZ are intended for, and understood as only applying to natural resources.
I think, if we keep our hands off any natural resources, we could typically reside in waters claimed as an EEZ. I dont think nations would be particularly eager to defy our independence if we do reside there. There wouldnt be much to gain, and they would have to get away with setting that precedent in front of the entire international community, which i figure wouldnt be too enthausiastic about such a unilateral expansion of the scope of existing treaties.
That depends
It's all in how you define it and what you can make stick.