This topic contains 28 replies, has 12 voices, and was last updated by Anonymous 6 years, 7 months ago.
May 17, 2008 at 11:18 pm #482
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:
May 18, 2008 at 12:31 am #2047
- 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
- Safer for birds and aviation
May 18, 2008 at 8:28 am #2054
- Wind power vs station keeping: Are you not forced to anchor (rather than using dynamic positioning) when using windmills (unless of course you are happy drifting along with the wind)? Considering that the power you get out of the turbine will always be less than the added wind area on the platform pushing it about.
You’re almost certainy going to need to moor somewhere most of the time anyway:
- Station keeping using some kind of powered solution is wasteful. Engines are for planned movement.
- Not every place is the ocean is equally useful to you. Some places have worse weather, some are watery desert, some have shoals and hazards, and you DO NOT want to antagonize other nations or your own flag nation by drifting into commercial shipping
Times when you mnight want to up-anchor:
- Seasonal migration for weather or fishing
- When told to move along (not so politely)
Methods of movement:
- PLANNED current drift. This means know what the prevailing currents are, tracking your course, and paying attention to where you go, but mostly acheiving your goals through steering and timing, rather than brute force engines.
- Integral engines
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.
- If your are planning to drift, and using a windmill, the wind/current combination will either work together or not. If they work together, it makes you travel more efficient, power generation less so. If they work seperately, it makes your poweer generation more efficient, and lowers your speed.
How much of a hurry are you in? If you’re in a big hurry, drifting ain’t the way to go anyway.May 18, 2008 at 2:17 pm #2062
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.May 19, 2008 at 12:21 pm #2083
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.
May 19, 2008 at 1:24 pm #2084May 19, 2008 at 1:43 pm #2085
- A vertical design with external bracing (see the picture accompanying the first article I cited) might actually be shuttered in a storm, allowing less delicate parts requiring little precision machining to take the brunt of the wind and object damager.
- A large-enough seastead (not a spar design) might have a central lagoon (perhaps just a couple to a few meters in diameter) where towers for windmills, radar/radio masts, or other tall, fragile, freestanding structures could be lowered during a storm. (Hopefully any such structure would be multi-function rather than one for each).
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.
- On land, wind power is perhaps the least reliable (depending on location) and most expensive of electrical generation. However, fewer options exist on the open ocean, so regardless of expense, it may be worth while as the only alternative, and it quite conceivably may actually be cheaper than diesel power generation.
- It is also possible that due to “sail area” effects, it’s only practical on larger seasteads, or that the size of of the windmil (and therefore its generation capacity) and the size of the seastead have a direct relationship.
- Some areas of the ocean probably are less likely to benefit consistently from wind power (doldrums)
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.May 26, 2008 at 4:51 am #2403
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. -JoelMay 26, 2008 at 8:57 am #2417
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.May 26, 2008 at 4:33 pm #2446
… 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.
May 28, 2008 at 5:05 pm #2590
- A radar/radio mast could probably be extended from the same shaft using dual-purpose equipment from the elevator and stored away again when high winds hit. Likewise for a portion of the windmill structure, bring it in closer and down to be protected.
May 28, 2008 at 9:25 pm #2619
- I recently attended a DaVinci Institute “Night with a futurist” presentation by Walt Musial of the NREL.
- If you’ve been following offshore wind, you’ve probably seen how the NIMB (not in my backyard) monster has become a major obstacle. The solution is simply to move it a bit farther offshore to reduce the visual profile. This puts the wind farm into slightly deeper water (50 to 150 ft depths) where bottom mounted platforms are too expensive. So the trend is quickly moving to floating platforms. Musial’s department has been developing the computer modeling software for designing these wind gens. (it’s a bit different than fixed). One company has already deployed a prototype.
- A real measure of if a technology is ready for prime time is investment. Offshore wind is there.
- So by the time a seastead platform is ready, this technology will be mature and there’s no economic sense in reinventing the wheel.
- The seastead will probably be big and stable enough though to not even require the new turbines and blades developed for platforms that sway. It can probably use standard offshore 3-5MW units.
- thebastidge is dead right on the mooring. Moving something large would be a major endeavor involving a number of large tugboats. Drifting is not an option. There would be a specific destination and you can’t rely on drifting to hit it so you need towboats anyway. DP is expensive, anchors are cheap.
- Sail area is not a issue. The platforms for 3-5MW units under development are a fraction the size of any habitable seastead.
- Wind power is mature industry. The vertical rotor (Savonius, Darrieus) designs have been tried and discarded. Power is a function of area exposed to the wind (swept area). Putting off-the-shelf horizontial axis generators around the perimeter would be the most efficient layout.
- Modern wind gen designs rotate or feather the blades depending on the wind speed. After a unit’s maximum wind velocity rating is reached, the blades feather and it stops.
- Offshore the wind blows almost all the time. Storage is much less of a problem than near shore or onshore. between concentrated solar, wind, maybe some underwater current generation (all mature technologies), only a limited amnount of storage would be necessary.
- I think such a platform could easily be a net energy exporter. There are many small island nations and islands that high oil prices are driving deeper into poverty. (100% of their power is from oil-fired generators). These are excellent markets for power. Under the framework of a Kyoto protocol CDM project, in addition to the power sold, carbon offsets (CER’s) would be generated. Offsets are about to go through the roof as soon as the US gets into it legislatively (probably this year). Being connected to a few islands’ grids might eliminate storage altogether.
… 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.
May 30, 2008 at 6:25 am #2682
- Anyway, it’s unlikely to be worthwhile to put more than one mill per platform.
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.May 30, 2008 at 10:05 pm #2747
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.May 30, 2008 at 10:15 pm #2751
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.
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