Southerly: New Zealand's Wave Energy Technology programme
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There are any number of small turbines on the market for power, the problem is it costs more then mains electricity. So unless its going to cost you a lot to run wires to where you need the power its cheaper to use mains.
Direct use of wind for pumping is viable, or you can get solar powered pumps.
On the bird chopping, that appears to only be a problem if you site it in the migratory path of the birds - as they did with a wind farm in the US. Your car or house will kill more birds then a turbine.
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Solar powered pumps... brilliant. And more likely to succeed in my case than a windmill.
Ta.
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You can't tilt at the solar-powered pumps though, when the pig gets into your poke, quixotely speaking.
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Juha Saarinen wrote:
I haven't been following the issue beyond feeling annoyed that electricity prices are rising fast and regularly. Good to hear that it's all under control then.
I wouldn't exactly describe it as under control. But we've certainly got the potential to have a very rosy energy future.
BTW, there's a *very* interesting story about electricity prices in New Zealand. I've found a couple of people who tell me horror stories of what happens (behind the scenes) off-the-record, but no-one (so far) who'll go on the record to tell me something that I can publish.
Mark Thomas wrote:
if you had wind turbines out in the sea, you could use the turbine base as the monolith, and have swingarms and floats poking out each side. so for every turbine you'd have four wave generators. and you'd save money on power cables. brilliant. i don't know why no-one's thought of this before!
It *is* a good idea -- and, in fact, such systems have actually been built (but I can't find a link off-hand). From memory, there were some design flaws in the big-ish system that was attempted, which meant that it ended in tears.
Some people are very keen on combined wind, wave, and tidal machines. The advantage being, as you say, that you don't have to duplicate mounting/transmission costs.
Alas, you couldn't use this approach on the IRL 'wave wobbler' system, because the 'monolith' bit is also floating in the sea (slack-moored).
Andrew Llewellyn wrote:
How feasible are small turbines, either wind or water driven?... Enough to feed back to the grid?
I've never installed micro-wind/hydro myself, but from engineering research/reports that I've read, water driven turbines are *very* feasible. Even quite a small flow can produce significant quantities of cheap electricity (as long as you've got a decent head). Small remote area (rural, etc.) wind turbines are also worthwhile -- I seem to remember that you're better off with wind if you need to install more than three power poles to connect you to the grid (but don't quote me on that).
But I have actually done the numbers on rooftop wind turbines for city-dwellers in Christchurch, and they don't stack up. At best, the payback period is on the scale of the expected life of the turbine. Of course, it's possible that other NZ cities might have a better wind resource -- but I note that a number of British owners of roof-top wind turbines have been disappointed, see:
http://www.reuk.co.uk/Consumers-Disappointed-With-Micro-Turbines.htm
http://www.scoraigwind.com/citywinds/index.htmIn the case of an urban roof-top wind turbine you would feed back electricity into the grid, but not to make money! You'd just use the grid as a battery bank, i.e. you'd dump surplus energy there when you had an over-supply, and take it back when you had a shortage. For a 'small' wind turbine and even a fairly energy-efficient household, you'd almost certainly still be running in deficit to the electricity company.
Juha Saarinen wrote:
What's the longest you can run an underseas power cable... here's an Aussie [wind turbine] mentioned that costs A$10,000 and spins at 100 rpm
Putting on my HTS hat: you could, in principle, run a High Temperature Superconducting (HTS) cable between NZ and Australia, which would efficiently transfer large amounts of electricity. But the cost would be absolutely staggering -- think of $100 per kWh (or more)...
Solwind (in New Zealand) also make an inexpensive vertical axis wind turbine...
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(as long as you've got a decent head)
Passing up the chance for a wisecrack... what does that mean?
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A head on the turbine perhaps?
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Andrew Llewellyn wrote:
RE: "as long as you've got a decent head"
Passing up the chance for a wisecrack... what does that mean?
Very noble to pass up that opportunity, Andrew...
'Head' just means "the pressure that results from a given height of water". In this case it refers to the height at which your water is sourced. For example, if your pipe inlet is on a hill 100 metres above your turbine (100 m of head) then a mere ten litres per minute of flow would give you about 2.75 kWh per day (allowing for a total turbine-generator efficiency of around 70 per cent).
If your pipe inlet is only 30 cm above your turbine (30 cm of head) then you get bugger all.
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Chinese wind turbines are now so cheap ($800 to $1k) that they are becoming viable. The Australian ones (that I've seen) all cost a LOT more- which adds financial vulnerability whenever the winds get very strong (and they do in Canterbury!). You can get (I'm told) a new blade for the chinese turbines for $100.
I'm looking into this very seriously at present. There IS a considerable set-up cost. As well as towers, you have to run 12v copper (or 24 v- better for us I think) from the turbine to the batteries- and this is expensive, if, like us, you don't want a whirring whirling whizzing vibrating machine right on top of the house.
On the other hand, as mentioned in another thread: we pay approx 10 x (per unit- we use about 7 kva a day/ 50 a week, which would make us low users anyway) what you pay the power comapies. Wind might reduce this a bit. Cleverer use of batteries etc also might help. But we may soon have the opportunity to get mains power (with approx 3 poles) and will probably jump at it. It'll cost `$10- $12k- and we'd save that in about 4 years, depending on how we change our use. -
On home wind turbines...
Wind turbines are much better off with "clean" air. So if you see people with home wind turbines out in the country, they tend to put them on bastard big poles. Basically, trees, houses, various other things, induce a high degree of turbulence. This make the turbine less efficient, and also causes a higher degree of wear. The height of a sensible tower in a built-up area is thus very likely to annoy your neighbours.
I know a couple of people with small scale hydro and it seems to work pretty well.
The biggest issue with going off-grid is the cost. The deep-cycle batteries are expensive (c. $600), and you need a few. They need replacing after a while, and if you try to use fewer you drain them lower reducing their life. You also need to spend a lot more on appliances (extra-energy efficient fridges etc.), educate your guests (e.g., a guest's hair-dryer causing too much load). You also need to arrange water-heating alternatives. Solar obviously, but probably an efficient wood-burner with wetback for back-up. Ditto cooking. You're likely to have to go gas.
One intermediate option is I believe some lines companies can install a current-restricted line for cheaper, negating issues about batteries, but you're still probably going to have to find hot-water solutions.
Friends seriously considered going off grid, with a house a reasonable distance from the road, but concluded that by the time all costs had been included, plus the environmental impact of battery production etc., that it just didn't stack up. -
oh yeah. Most common effect of dirty air is blade damage, and if you don't get to the blade damage in time, the vibration can root the turbine.
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Public Address reader Jon Knox has just directed me to this clip of a gigantic wave-powered musical instrument in Zadar, Croatia.
So cool!
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if you had wind turbines out in the sea, you could use the turbine base as the monolith
Am I right in thinking that NZ's coastline doesn't really lend itself to offshore windfarms? I'm trying to remember where I read that...
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http://www.windenergy.org.nz/documents/2005/050825-NZWEA-FactSheet5Siting.pdf
The other major reason is related to the geomorphology of our continental shelf which tends to be steeply sloping and narrow as a consequence of which the water gets very deep very
quickly. This means that the number of potential sites, for offshore wind farms, is actually quite limited despite the fact that we have one of the longest coastlines, relative to our land area, of any country in the world. -
...the number of potential sites, for offshore wind farms, is actually quite limited...
that's a shame. with all the RMA palaver over the makara wind farm, it would be nice to have a wind farm out of sight, just over the horizon from the shore. NIMBY etc
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it would be nice to have a wind farm out of sight, just over the horizon from the shore
Interesting that you assume that a wind farm out of sight would not have any problems with the RMA or other pieces of legislation. There would be issues over rights to the seabed, fishing, access etc.
And there is always the BANANA brigade too.We'll leave aside the issues of the cost of marine structures and cable runs longer the the HVDC link...
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it would be nice to have a wind farm out of sight, just over the horizon from the shore.
They'd have to be really far out, especially if they're trying the size of wind turbine Meridian have in mind for the Rock and Pillars. At 150m tall, that's quite something. By way of analogy, I think we were seeing icebergs 40km off the cost (although that was from a high point, but I don't think the icebergs were 150m tall)
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