I said "ponds" - not "barrages".
Consider such in (just for England & Wales): Severn estuary, any large bay on Welsh Coast, Dee estuary, Mesey estuary, Morecombe Bay, Eden estuary, Humber, Wash, all inlets on Essex coast.... Also turbines canbe deep-submerged, below hull bottoms, where strong tidal flows occur - better in Scotland, but bottom of Channel would also be good. This is ecologically damaging in what way?
Also J_b @ 594 YES - even better. Much too sensible to be implemented
]]>As for linking up WA with the East Coast grid... well, if you offered to pay for the cable across the Nullabor, I'm sure the current Premier wouldn't object. Especially if you offer to put a statue of him at the border (WA Liberal premiers are currently very much enamoured of the notion of leaving permanent monuments to their existence. Gods alone know why... I mean, I doubt we're going to forget the current incumbent in a hurry).
[1] The minority of firms which do a lot of business with Sydney and Melbourne object rather loudly to the prospect of having to start their workday at 5am in order to catch the t'othersiders before they've had enough coffee to be fully awake; this results in periodic calls for Western Australia to adopt daylight savings and "trials" of same, which happen approximately once a decade... we're just about due for another one[2]. [2] The last one was back in 2009, following a three year "trial". They lost, again, because at least half the state is north of the Tropic of Capricorn, and therefore doesn't see any need to shift daylight around at all, and of the other half of the state, there's enough of us with such a thorough respect for the joys of the heat of a WA summer that we really don't see the need to be exposing ourselves to more of it, thanks very much.
]]>This is really, really difficult. The most effective known approach involves tin-based paints -- "Tributyltin" -- which have been globally banned because they were so thoroughly slaughtering the planktonic larvae of all manner of sea life. There's a push to ban copper-based anti-fouling now because while copper has been in use for centuries, the volume of shipping has reached a point where all that soluble copper is having very worrying consequences. Microstructure approaches (emulating shark skin) are promising but nothing like commercial. Titanium isn't proof against fouling any more than aluminium is.
Any place you're talking about "ponds" you're messing about with mudflats; those mudflats are ecologically productive and you're talking about greatly diminishing the productivity. This is bad for everything that's eating that productivity now. (Fish, birds, etc.) Plus water and gravity is a very low density power source; 34.2 MJ in a litre of gasoline, isn't it? That's thereabouts the potential energy of seven hundred tonnes of water across a five metre fall. You have to pour a whole lot of concrete to get a return you could vastly improve on by applying the same resources to wind turbines, at a much, much lower ecological cost.
]]>Ooops. Sorry, I work in multiple timezones so even though I'm in Sdyney my "day" starts in NZ time and runs though to the funny zones in western Europe (Europe also has a nominal "european time (except where it's different)".
The cost of an HVDC link across Australia seems really high, until you start pricing nuclear generators. A few tens of billions for a high level waste dump is just the start. And given the astonishing cockup that the Liberals have made of the NBN ($40B tending to $60B but then "rescued" by the Liberals and now on course for 1/4 the performance for $90B)... can you imagine what a $200B crash program to build nukes within 20 years would look like?
One huge benefit of renewables is that you can roll them out in little pieces and still get the benefit. Right down to a couple of kilowatts of PV on a rooftop.
But you can also do big stuff - it's quite possible to buy a GW molten salt plant in WA and build a 3000km HVDC link to Sydney from there. BIG ENGINEERING. With statue "Opened by HRH the Premier of WA in the year of our Lord 2020". Whatever you want, statues are cheap compared to the benefit of linking the solar peak to the demand peak.
]]>The limiting factor for marine vessels of all kinds is hull speed. This is an outcome of the wave-making resistance of the hull, which is determined in part by its prismatic co-efficient but mostly (and pretty directly, almost crudely) by its length. The power needed to propel a hull increases asymptotically with speed until the vessel climbs onto its own bow wave, which is why a planing craft must be light and/or needs considerable power for its size. It's also why pure displacement ships trend larger - the longer the bathtub, the faster it can go, and why there's a special mention for multi-hulls where the individual hulls are long and thin.
There's no particular reason why you couldn't do this with a windmill powered vessel, it's just that the details may not stack up favorably - ungainly masthead turbines, hydrostatic and hydrodynamic stability, ocean waves all contributing their own challenges. And then the question would be whether it were more efficient or easier to handle than some other method for powering a ship (such as sails), although incremental improvements in materials and general arrangement seems to lead to significant change to those factors over time.
]]>And it you are still talking about TbT, you are seriously out-of-date.
]]>I don't know the answer, and I suspect any 'answer' is highly specific to each group, and will take a long time to resolve. It is time worth taking (and money well spent).
]]>Anyway, there's an answer to fouling: have the turbines hoik themselves out of the water every so often for an automatic scrub. Or a jetwash, which would probably be easier.
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