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Urban wind power | 21 comments (21 topical, editorial)
Re: bad math, and important data missing... (4.00 / 1) (#6)
by ADMIN (info74 at otherpower.com) on Thu Dec 15th, 2005 at 11:51:34 PM MST
(User Info)

There's some very important info missing from WindSave's documentation -- wind speed vs. power output, power output per month in kW/hrs, and average wind speed. All they say is that it can give "Savings up to 1/3 of the average annual UK electricity bill as the Windsave system will reduce the amount of electricity drawn through the existing utility meter." Folks, this is very basic stuff you NEED to know before buying a wind turbine -- even if they only give you a couple points on the curve. Take the average UK electrcical usage of 323 kW/hrs per month. 1/3 of that is 107 kW/hr/month. Do the math, or compare with other brands of turbine currently available -- You'll need a very high average wind speed (13 mph or more) to make 107 kW/hrs per month with a prop that's under 6 feet in diameter. And there's another really bad omission -- no mention of performance on low towers in urban areas. Their front page photo shows a turbine mounted LOWER than a house! You're not going to get 13 mph average on a low tower -- and all they show pictures of are low towers. Their turbine might make 100 kW/hrs per month on a 100 foot tower, I can believe that. But a 13 mph average windspeed on the towers shown will in reality be about 8 mph* -- I'm plugging in the alpha value for the coefficent of surface friction in a typical city. At 8 mph average-- oops, that's more like 30 kW/hrs per month, not 100.
(* sources of average wind speed derating for surface friction -- Blecker, Park, Sagrillo, Rohatgi & Nelson -- look 'em up!)

As for WindStor -- an example of a company (McKenzie Bay) that has no product to sell yet, asking for investors. All of the 'photos' on their website are 'simulations' of what it might look like if their product were installed. They DO have a test turbine -- but it's a much smaller version of what they propose to build. You can find it with some hard googling, it's at a university. They also give no information about possible power output at different wind speeds. How could any investor possibly drop a big load of cash on a wind turbine with no performance vs. wind speed data, and no data from any existing installation?

Sorry for the rant, folks, and no offense the posters on this thread. But I don't like bad wind math.

ADMIN



Re: bad math, and important data missing... (4.00 / 1) (#7)
by CG on Fri Dec 16th, 2005 at 03:27:40 AM MST
(User Info)

Yes, it is the claims of Windsave for their product which concerns me. Over a year ago this company was being discussed on the internet about their over optimism of the output of this turbine, and by the replies to this posting they will not have to worry too much about gullible customers. I am surprised that more users did not challenge these output figures, perhaps it's been a slow night on the board. I am also concerned about fixing the mast to the house, an 8 inch cavity brick wall just doesn't seem strong enough, and any structural damage will force your insurance up.

But it's not just the figures that sets me against this product. I live in a small village but we are all on the grid. I could put one of these turbines up and it would bother nobody too much because we have plenty of space. But in general I think most of the villagers a quite anti wind. It's because we are surrounded by open farmland, just the place for a 2 MW utility size wind turbine, and so we all become nimbys.

Most city dwellers probable pay lip service to wind energy, but what would happen if these little devils started popping up in their environment. I have a feeling that as soon as their neighbourhood became festooned with small wind turbines they would become also nimbys. For every happy Windsave customer, and they would probably be happy because the maths of this type of thing is very hard to monitor, there would be perhaps three unhappy neighbours, due to the sight and perhaps sound of these machines. And when somebody is agains one type of wind turbine they are generally against all types, and these people are voters; I don't want to turn too many people against wind energy. Here in the UK there is a rising tide of anti wind people/voters, that's why we have to site turbine in the sea, I don't want this to increase more than it has to.

There are probably two main reasons for wanting to generate your own energy if you are grid tied. One is a hedge against rising grid energy prices, and the other is concern over CO2 emmissions and global warming. But you could use other means of generating electricity. PV would be nice but it's a bit expensive. Thermal solar is cheaper, and although it doesn't generate electricity it does save it. You could buy a Whispergen CHP boiler (well done the Kiwis)which is just coming into use. None of these things should upset the neighbours. There are problably more ways that I haven't thought of.

But if you insist on using wind there is another way to go about it. Size important in wind power, so what's to stop people banding togther to buy large wind turbines and site them on more appropriate sites. I beleive this is done quite a lot in Denmark, it has been done here in the UK by people in a village using a second hand turbine. If it's global warming you are worried about it doesn't have to even be in your own country, you could site it in the most productive place in the world as long as countries co - operated with each other.

I don't want to get tied up with Windstor, I think it's a case of que sera, sera with that one. But I do think that these wind turbines will be sited on industrial estates and not housing estates, and that they come with storage, so their case is not quite the same as Windsave.

[ Parent ]



Re: bad math, and important data missing... (4.00 / 1) (#8)
by CG on Fri Dec 16th, 2005 at 04:29:25 AM MST
(User Info)

I managed to get another hour on this library computer so I took another look at Windsave's site as I have only kept half an eye on this company.

Take a look at the last FAQ on the technical page. What happens to the electricity generated while the house demand it low. Now remember this is not net metering, to have that in the UK you must have two meters, (it just needs a change in the law but Tony Blair doesn't have time for this simple law change he's too busy trying to get us to like nuclear). Anyway, it seems that this electricity is called spillage and it will go to the utility you are with, isn't that nice for them, free electricity to sell to someone else - no wonder it's a utility that is backing Windsave. I hope it will be different for US buyers of this product. Do you know your energy peaks and troughs in house usage. As I have already said the maths of this thing are hard to work out.

The bloke behind Windsave is a smart cookie who has already made a million with another idea, so read the small print, don't let your green energy heart rule your head.

[ Parent ]



Re: bad math, and important data missing... (4.00 / 1) (#9)
by finnsawyer on Fri Dec 16th, 2005 at 09:36:26 AM MST
(User Info)

To answer your last question: By getting some unit of government to kick in a pile of the taxpayer's money.  Hang onto your wallets folks!

As far as hanging the thing on a house, we all know how good an idea that is.  And I bet the insurance companies will like that as much as they like indoor wood fired furnaces.  My neighbor's outdoor wood furnace caused a fire that burned up a storage building and a tractor last winter.
GeoM
[ Parent ]



Re: bad math, and important data missing... (3.00 / 0) (#21)
by fungus (info@reenergy.co.uk) on Sat Jun 10th, 2006 at 02:36:55 PM MST
(User Info) http://www.reenergy.co.uk/

I'd just like to point out that it is 1kw at 12 M/S not mph. Thats more like 30mph.

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk
[ Parent ]


Urban wind power | 21 comments (21 topical, 0 editorial)

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